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ADM701_CourseNotes - MSC.ADAMS MSC.ADAMS Basic Full...

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Unformatted text preview: MSC.ADAMS MSC.ADAMS Basic Full Simulation Package Training Guide Release 2003 Version 1.0 Visit us at: www.mscsoftware.com The information in this document is furnished for informational use only, may be revised from time to time, and should not be construed as a commitment by MSC.Software Corporation. MSC.Software Corporation assumes no responsibility or liability for any errors or inaccuracies that may appear in this document. Copyright Information This document contains proprietary and copyrighted information. MSC.Software Corporation permits licensees of MSC.ADAMS™ software products to print out or copy this document or portions thereof solely for internal use in connection with the licensed software. No part of this document may be copied for any other purpose or distributed or translated into any other language without the prior written permission of MSC.Software Corporation. Copyright © 2003 MSC.Software Corporation. All rights reserved. Printed in the United States of America. Trademarks ADAMS, EASY5, MSC, MSC., MSC.ADAMS, MSC.EASY5, and all product names in the MSC.ADAMS Product Line are trademarks or registered trademarks of MSC.Software Corporation and/or its subsidiaries. NASTRAN is a registered trademark of the National Aeronautics Space Administration. MSC.Nastran is an enhanced proprietary version developed and maintained by MSC.Software Corporation. All other trademarks are the property of their respective owners. Government Use Use, duplication, or disclosure by the U.S. Government is subject to restrictions as set forth in FAR 12.212 (Commercial Computer Software) and DFARS 227.7202 (Commercial Computer Software and Commercial Computer Software Documentation), as applicable. 2 Copyright &217(176 &RQWHQWV 3 :HOFRPH WR 06&$'$06 %DVLF 7UDLQLQJ 9 A Brief History of MSC.ADAMS 10 About MSC.Software 11 Content of Course 12 Getting Help 13 6WDPSLQJ 0HFKDQLVP 17 Virtual Prototyping Process 18 Workshop 1—Stamping Mechanism 19 $'$069LHZ ,QWHUIDFH 2YHUYLHZ 27 Model Hierarchy 28 Renaming Objects 29 ADAMS/View Interface 30 Simple Simulations 31 Saving Your Work 32 Workshop 2—ADAMS/View Interface Overview 34 $'$063RVW3URFHVVRU ,QWHUIDFH 2YHUYLHZ 45 PostProcessing Interface Overview 46 Animating 47 Plotting 48 Reporting 49 Workshop 3—ADAMS/PostProcessor Overview 50 )DOOLQJ 6WRQH 61 Coordinate Systems 62 Part Coordinate System 63 Coordinate System Marker 64 Differences Between Parts and Geometry 65 Parts, Geometry, and Markers 66 Types of Parts in ADAMS/View 67 Part Mass and Inertia 68 Measures 69 Workshop 4—Falling Stone 70 3 &RQWHQWV 3URMHFWLOH 0RWLRQ 79 Part Initial Conditions 80 Initial Velocities 81 Point Trace 82 Workshop 5—Projectile Motion 83 2QH '2) 3HQGXOXP 93 Constraints 94 Use of Markers in Constraints 95 Degrees of Freedom (DOF) 96 Joint Initial Conditions (ICs) 97 Merging Geometry 98 Angle Measures 99 Workshop 6—One DOF Pendulum 100 ,QFOLQHG 3ODQH 115 Euler Angles (Rotation Sequence) 116 Precise Positioning: Rotate 117 Modeling Friction 118 Measures in LCS 121 Workshop 7—Inclined Plane 122 /LIW 0HFKDQLVP , 137 Building Geometry 138 Construction Geometry Properties 140 Solid Geometry 142 Precise Positioning: Move 143 Workshop 8—Lift Mechanism I 144 /LIW 0HFKDQLVP ,, 153 Applying Motion 154 Joint Motion 155 Functions in MSC.ADAMS 156 Workshop 9—Lift Mechanism II 157 /LIW 0HFKDQLVP ,,, 163 Types of Joint Primitives 164 Perpendicular Joint Primitive 165 Workshop 10—Lift Mechanism III 167 4 Contents &RQWHQWV 6XVSHQVLRQ 6\VWHP , 171 Applying Point Motions 172 System-Level Design 173 Workshop 11—Suspension System I 174 6XVSHQVLRQ 6\VWHP ,, 181 Taking Measurements 182 Displacement Functions 183 Importing CAD-Based Geometry 184 Workshop 12—Suspension System II 185 6XVSHQVLRQ6WHHULQJ 6\VWHP 193 Add-On Constraints 194 Couplers 195 Assembling Subsystem Models 196 Workshop 13—Suspension-Steering System 197 6SULQJ 'DPSHU 205 Assemble Simulation 206 Simulation Hierarchy 207 Types of Simulations 208 Forces in MSC.ADAMS 210 Spring Dampers in MSC.ADAMS 211 Magnitude of Spring Dampers 212 Workshop 14—Spring Damper 213 1RQOLQHDU 6SULQJ 219 Single-Component Forces: Action-Reaction 220 Spline Functions 221 AKISPL Function 222 Workshop 15—Nonlinear Spring 223 6XVSHQVLRQ6WHHULQJ 6\VWHP ,, 229 Bushings 230 Workshop 16—Suspension-Steering System II 231 +DWFKEDFN , 237 Impact Functions 238 Velocity Functions 240 Workshop 17—Hatchback I 241 Contents 5 &RQWHQWV +DWFKEDFN ,, 249 STEP Function 250 Scripted Simulations 251 ADAMS/Solver Commands 252 Workshop 18—Hatchback II 253 +DWFKEDFN ,,, 261 ADAMS/Solver Overview 262 Solver Compatibility 263 Files in ADAMS/Solver 264 Example of an ADAMS/Solver Dataset (.adm) File 265 Stand-Alone ADAMS/Solver 266 Example: 2D Pendulum 267 Formulation of the Equations of Motion 268 Phases of Solution 269 Debug/Eprint (dynamics) 274 Workshop 19—Hatchback III 276 +DWFKEDFN ,9 285 Sensors 286 Design Variables 287 Workshop 20—Hatchback IV 288 &DP5RFNHU9DOYH 297 Splines from Traces 298 Curve Constraints 299 Automated Contact Forces 300 Flexible Parts—ADAMS/AutoFlex 302 Workshop 21—Cam-Rocker-Valve 303 7DUJHW 3UDFWLFH 317 Multi-Component Forces 318 Design Studies 320 Workshop 22—Target Practice 323 5HFRPPHQGHG 3UDFWLFHV 335 General Approach to Modeling 336 Modeling Practices: Parts 337 Modeling Practices: Constraints 338 Modeling Practices: Compliant Connections 339 Modeling Practices: Run-time Functions 340 Debugging Tips 342 6 Contents &RQWHQWV 6ZLWFK 0HFKDQLVP :RUNVKRS 347 7DEOHV 371 Constraints Tables (Incomplete) 372 Forces Tables (Incomplete) 373 Constraint Tables (Completed) 374 Forces Tables (Completed) 376 $QVZHU .H\ 377 ,QGH[  Contents 7 &RQWHQWV 8 Contents :(/&20( 72 06&$'$06 %$6,& 75$,1,1* MSC.ADAMS Full Simulation Package is a powerful modeling and simulating environment that lets you build, simulate, refine, and ultimately optimize any mechanical system, from automobiles and trains to VCRs and backhoes. The MSC.ADAMS Basic Full Simulation Package training guide teaches you how to build, simulate, and refine a mechanical system using MSC.Software’s MSC.ADAMS Full Simulation Package. 7KLV VHFWLRQ LQFOXGHV ■ A Brief History of MSC.ADAMS, 10 ■ About MSC.Software, 11 ■ Content of Course, 12 ■ Getting Help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·V $'$069LHZ ZDV UHOHDVHG ZKLFK DOORZHG XVHUV WR EXLOG VLPXODWH DQG H[DPLQH UHVXOWV LQ D VLQJOH HQYLURQPHQW 7RGD\ LQGXVWU\VSHFLILF SURGXFWV DUH EHLQJ SURGXFHG VXFK DV $'$06&DU $'$065DLO DQG $'$06(QJLQH 10 Welcome to MSC.ADAMS Basic Training $ERXW 06&6RIWZDUH )LQG D OLVW RI 06&6RIWZDUH SURGXFWV DW ■ http://www.mscsoftware.com/products/products.cfm )LQG D OLVW RI 06&$'$06 SURGXFWV DW ■ http://www.mscsoftware.com/products/products_detail.cfm?PI=413 )LQG DGGLWLRQDO WUDLQLQJ DW ■ http://www.engineering-e.com/training/ ■ Or your local support center 5XQ WKURXJK YHULILFDWLRQ SUREOHPV DW ■ http://support.adams.com/kb/faq.asp?ID=kb9587.dasp Welcome to MSC.ADAMS Basic Training 11 &RQWHQW RI &RXUVH $IWHU WDNLQJ WKLV FRXUVH \RX ZLOO EH DEOH WR ■ Build ADAMS/View models of moderate complexity. ■ Understand MSC.ADAMS product nomenclature and terminology. ■ Understand basic modeling principles and extend your proficiency by creating progressively more complex models. ■ Use the crawl-walk-run approach to virtual prototyping. ■ Debug your models for the most common modeling challenges (for example, redundant constraints, zero masses, and so on). ■ Use and be informed about all methods of MSC.ADAMS product support. ■ Use the product documentation optimally. 2UJDQL]DWLRQ RI JXLGH This guide is organized into modules that get progressively more complex. Each module focuses on solving an engineering-based problem and covers mechanical system simulation (MSS) concepts that will help you use MSC.ADAMS most optimally. The earlier workshops provide you with more step-by-step procedures and guidance, while the later ones provide you with less. Each module is divided into the following sections: 1 2 Concepts 3 Workshop 4 Optional tasks 5 12 Problem statement Module review Welcome to MSC.ADAMS Basic Training *HWWLQJ +HOS 2QOLQH KHOS To access the online help, do either of the following: ■ From the Help menu, select ADAMS/View Help to display the home page for the ADAMS/View online help. ■ While working in any ADAMS/View dialog box, press F1 to display online help specific to that dialog box. Once the online help is displayed, you can browse through the table of contents or the index, or search for any terms. Table of contents for selected tab Welcome to MSC.ADAMS Basic Training Show the students how they can search the guide to find text much as they would search through an index. Give outline of class – module with workshop at end Cover the “Organization of guide” section in detail, and reinforce this layout as you go over each module. 13 *HWWLQJ +HOS 3HUVRQDOL]HG QHZV DQG LQIRUPDWLRQ To receive more consistent, targeted news and information, go to: http://my.adams.com/cgi-bin/myadams.cgi, a Web personalization site for MSC.ADAMS users. Some of the news channels this site provides are: ■ Case studies - Practical application stories ■ Company news - MSC.Software’s corporate and financial information ■ Events - Seminars, user conferences, and trade shows ■ Product alerts - Known problems, workarounds, and Service Packs 7HFKQLFDO VXSSRUW To find your support center, go to http://www.mscsoftware.com/support/contacts/index.cfm To read the Service Level Agreement, go to http://www.mscsoftware.com/support/ prod_support/adams/ADM_02ZZZLT_T_SERL_HJ_R6.pdf NQRZOHGJH EDVH Go to http://support.adams.com/kb For a quick tour, go to http://www.adams.com/news/newsletter/vol3/kbtour.htm &RQVXOWLQJ VHUYLFHV http://www.mscsoftware.com/services/esg/ 14 Welcome to MSC.ADAMS Basic Training MSC.Software Technical Support: Discuss what is available through your local office or headquarters, if appropriate. Demonstrate the Customer Support Web site (knowledge base, ASK list and registration process, and so on). Demonstrate how to log CRs. *HWWLQJ +HOS $6N 06&$'$06 VROXWLRQV DQG NQRZOHGJH FRPPXQLW\ ■ To join the community of MSC.ADAMS users, go to http://ask.adams.com Welcome to MSC.ADAMS Basic Training Explain the ASK MSC.ADAMS tool and guide the students to register during class. 15 *HWWLQJ +HOS 16 Welcome to MSC.ADAMS Basic Training  67$03,1* 0(&+$1,60 Understand the virtual prototyping process by improving the design of the stamping mechanism shown next: Control link Stamp Inking pad Parcels Conveyor 7KLV PRGXOH LQFOXGHV ■ Virtual Prototyping Process, 18 ■ Workshop 1—Stamping Mechanism, 19 ◆ Module review, 25 17 In each module, review the problem statement and explain that you will use the concepts described below to solve it. Return to the problem statement after each concept to make the connection. 9LUWXDO 3URWRW\SLQJ 3URFHVV DESIGN PROBLEM %XLOG D PRGHO RI \RXU GHVLJQ XVLQJ %RGLHV ◆ -RLQWV )RUFHV ◆ 0RWLRQ JHQHUDWRUV ◆ Cut time and costs ◆ ◆ Build &RQWDFWV 7HVW \RXU GHVLJQ XVLQJ ◆ Test 0HDVXUHV ◆ $QLPDWLRQV ◆ 6LPXODWLRQV ◆ 3ORWV 9DOLGDWH \RXU PRGHO E\ ◆ ,PSRUWLQJ WHVW GDWD ◆ 6XSHULPSRVLQJ WHVW GDWD 5HYLHZ \RXU PRGHO E\ DGGLQJ ◆ Increase quality Review )ULFWLRQ ◆ )RUFLQJ IXQFWLRQV ◆ )OH[LEOH SDUWV ◆ &RQWURO V\VWHPV ,WHUDWH \RXU GHVLJQ WKURXJK YDULDWLRQV XVLQJ ◆ 3DUDPHWULFV ◆ 'HVLJQ YDULDEOHV ,PSURYH \RXU GHVLJQ XVLQJ Increase efficiency ◆ Improve '2(V ◆ 2SWLPL]DWLRQ $XWRPDWH \RXU GHVLJQ SURFHVV XVLQJ ◆ &XVWRP PHQXV ◆ &XVWRP GLDORJ ER[HV ◆ 0DFURV IMPROVED PRODUCT 18 Stamping Mechanism This course does not cover all the steps in the virtual prototyping process. It covers all steps up through Iterate. It does not cover Optimize or Automate. Through the course, seek opportunities to use the visual effect of the white board. Map out the process shown here one phase at a time, to emphasize it. Capture the students’ attention by using all the available tools (white board sketches, guide text, demos using ADAMS/View, KBA, online docs, and so on). :RUNVKRS ³6WDPSLQJ 0HFKDQLVP 3UREOHP VWDWHPHQW Understand the virtual prototyping process by improving the design of the stamping mechanism shown next: Control link Stamp Inking pad Parcels Conveyor 0RGHO GHVFULSWLRQ ■ This model represents a mechanism for stamping parcels that are moving along a conveyor belt. ■ During the work cycle, the stamp does not contact the parcels that it is supposed to label. ■ To fix this design flaw, modify the length of the control link. Stamping Mechanism 19 Review the problem statement. Objective of the exercise is to demonstrate the typical MSC.ADAMS process. We have built a model, parameterized it, and automated it. Students must use this customized version of MSC.ADAMS to make changes to the model, iterate, and optimize it. There is a file named aview.cmd in that directory that tells ADAMS/View what to do to build the model and put all the automation in place. Before starting, ask if there are any questions. :RUNVKRS ³6WDPSLQJ 0HFKDQLVP 6WDUW WKH ZRUNVKRS Your first step will be to start ADAMS/View from the directory exercise_dir/mod_01_stamper. When you start ADAMS/View from that directory, it automatically builds the model stamp and a fully customized version of ADAMS/View. We provide separate instructions for starting ADAMS/View in UNIX and Windows. Follow the set of instructions below depending on the platform you are using. ,I \RX DUH XVLQJ :LQGRZV WR VWDUW $'$069LHZ 1 From the Start menu, point to Programs, point to MSC.Software, point to MSC.ADAMS 2003, point to AView, and then select ADAMS - View. ADAMS/View starts and the Welcome dialog box appears. 2 From the Welcome dialog box, select Import a file. 3 Click the file folder. The Select Directory dialog box appears. 4 Find and select the directory mod_01_stamper (exercise_dir/mod_01_stamper). 5 Select OK. The File Import dialog box appears. 6 Set File Type to ADAMS/View command file (*.cmd). 7 Right-click the File to read text box, and then select Browse. The Select File dialog box appears. 8 Select the file, aview.cmd, and then select Open. 9 Select OK. ADAMS/View imports the commands to build: ■ Model named stamp. ■ Fully customized version of ADAMS/View. After importing the commands, an Information window appears. 10 Read the information describing the model, and then, in the upper right corner, select Close. 20 Stamping Mechanism You may want to make a rough sketch of the model on the white board and identify the variable that we’ll change (length of control arm) and the criteria we’re using to gauge our success--the penetration of the stamping face on the parcels. :RUNVKRS ³6WDPSLQJ 0HFKDQLVP ,I \RX DUH XVLQJ 81,; WR VWDUW $'$069LHZ 1 At the command prompt, enter the command to start the MSC.ADAMS Toolbar, and then press Enter. The standard command that MSC.Software provides is adamsx, where x is the version number, for example adams03, which represents MSC.ADAMS 2003. 2 From the MSC.ADAMS toolbar, right-click the ADAMS/View tool 3 Select Change Settings for A/View. . The Change Settings for A/View dialog box appears. 4 Select Working directory. 5 Right-click the Working directory text box, and then select Select a Directory. The Select a Directory dialog box appears. 6 Select the directory mod_01_stamper (exercise_dir/mod_01_stamper). 7 Select OK. 8 From the Change Settings for A/View dialog box, select OK. 9 From the MSC.ADAMS toolbar, select the ADAMS/View tool. ADAMS/View starts and automatically imports the commands to build: ■ Model named stamp. ■ Fully customized version of ADAMS/View. After importing the commands, an Information window appears. 10 Read the information describing the model, and then, in the upper right corner, select Close. Stamping Mechanism 21 :RUNVKRS ³6WDPSLQJ 0HFKDQLVP &KDQJH WKH PRGHO In this section, you see how you can change the length of the control link (control_link). 7R FKDQJH WKH PRGHO 1 From the Stamper menu, select Setting Up Model. The Stamper_Setup dialog box appears. 2 Use the arrow buttons to modify the length of the control_link. ■ The buttons shift the location of the top of the control_link upward and downward 3 mm at a time. ■ The parts connected to the control_link are parameterized in such a way as to move the appropriate amount automatically whenever you adjust the length of control_link. 3 Watch the model change as you press these buttons. 4 To reset your model to the original configuration, select Reset. Leave the Stamper_Setup dialog box open and continue with the next step. 6LPXODWH WKH PRGHO Now, you’ll simulate the model to see how it behaves. 7R VLPXODWH WKH PRGHO 1 From the Stamper menu, select Simulate. The Stamper_Simulate dialog box appears. 2 To simulate the current design variation, ensure that Single is selected. 3 To solve the equations of motion for the current design, select Apply. Note: You selected to display the model at every output step. If you were to change Model Update from At Every Output Step to Never, the model would not update on the screen but would solve faster. When a single simulation is completed, ADAMS/View tells you what the penetration was during the simulation. A positive number indicates penetration. 4 5 22 To continue, select OK. Leave the Stamper_Simulate dialog box open and continue with the next step. Stamping Mechanism :RUNVKRS ³6WDPSLQJ 0HFKDQLVP ,QYHVWLJDWH UHVXOWV Now you’ll look at the results of the simulation as an animation and a plot. 7R LQYHVWLJDWH UHVXOWV 1 From the Stamper menu, select Investigate Results. The Stamper_Investigate dialog box appears. 2 To see the motion resulting from your last simulation, select Animate Results. If necessary, use the stop sign in the lower right corner of the window to stop an animation before it has completed. 3 To plot the vertical travel of the stamper with respect to the parcel tops versus time, as calculated from your last simulation, select Measure Stamp Height Above Parcels. A stripchart appears, which shows a plot the height of the stamp above the parcels. 4 To save an existing curve so that the next simulation curve will not overwrite the existing curve, but will be superimposed on the saved curve, select Save Curve. 0DQXDOO\ ILQG WKH FRUUHFW KHLJKW Now change the model again to find the correct height at which the stamp makes minimal contact with the parcels. 7R ILQG WKH FRUUHFW KHLJKW ■ Repeat the steps on the previous page until you can identify the control_link length at which the stamp makes contact with the parcels, using 3 mm increments. Use this value to answer Question 1 in Module review, on page 25. If stamp_height > 0, stamper does not make contact with parcels. If stamp_height < 0, stamper makes contact with parcels. Stamping Mechanism 23 :RUNVKRS ³6WDPSLQJ 0HFKDQLVP 3HUIRUP D GHVLJQ VWXG\ Now you’ll perform a design study. The design study automatically analyzes the model using the specified upper and lower limits for control_link length, and the specified number of runs. Default values are given, but you can modify them if desired. 7R SHUIRUP D GHVLJQ VWXG\ 1 On the Stamper_Simulate dialog box, select Design Study. 2 To speed up the simulation, set Model Update to Never. 3 Select Apply to submit the design study. The design study automatically analyzes the model and a stripchart and Information window appears when the study is complete. 4 From the Information window, identify the range of the control_link length values within which the stamp makes contact with the parcels. Use this range to answer Question 2 in Module review, on page 25. 5 Close the Information window. 3HUIRUP DQ RSWLPL]DWLRQ VWXG\ Now, you’ll perform an optimization study. During an optimization study, ADAMS/View systematically varies the control_link length and runs a number of simulations until the specified penetration is achieved to within a set tolerance. 7R SHUIRUP DQ RSWLPL]DWLRQ VWXG\ 1 On the Stamper_Simulate dialog box, select Optimization. 2 Set the Desired Penetration to 4 mm. Note: ADAMS/View wraps the 4 mm in parentheses () to denote an expression. If you did not enter units, ADAMS/View uses the default units set for the model. 3 Set Model Update to Never. 4 Select Apply to submit the optimization study. The Information window appears, displaying the control_link length for a maximum penetration of 4.00. 5 24 From the displayed value of the control link length, note the maximum penetration. Use this value to answer Question 3 in Module review, on page 25. Stamping Mechanism :RUNVKRS ³6WDPSLQJ 0HFKDQLVP 6 Select OK. The value on the Stamper_Setup dialog box also updates to the optimized value. 7 Exit ADAMS/View: ■ From the File menu, select Exit. ■ From the dialog box that appears, select Exit, don’t Save. 0RGXOH UHYLHZ 1 Using 3 mm increments, at what control link length do you first notice penetration? 2 From the design study, what control link length results in penetration? How does this compare with your previous results? 3 If you specify a maximum desired penetration of 4 mm, what is the optimal length of the control link? How close is the maximum actual penetration from the maximum desired penetration? 4 How many moveable parts does the model consist of? 5 How many joints does the model consist of? 6 What would happen if you deleted the conveyor belt? Stamping Mechanism 25 (Did anyone notice what happened if you went past 270 mm in length?) Emphasize that the results reflect a 3 mm incremental setting. The workshop should have demonstrated that this is a loose setting. This could have been set up with a much smaller increment setting. It is up to the engineer to set tolerances such as this. The last three questions provide a translation to model hierarchy, which is the first concept of the next module. Leave the mechanism open to use to demonstrate early concepts of next module. :RUNVKRS ³6WDPSLQJ 0HFKDQLVP 26 Stamping Mechanism  $'$069,(: ,17(5)$&( 29(59,(: Use the ADAMS/View graphical-user interface (GUI) to manipulate, simulate, review, and refine the model shown next: Rocker Rod Guide (ground) Cam Valve For more information, see the ADAMS/View online help. 7KLV PRGXOH LQFOXGHV ■ Model Hierarchy, 28 ■ Renaming Objects, 29 ■ ADAMS/View Interface, 30 ■ Simple Simulations, 31 ■ Saving Your Work, 32 ■ Workshop 2—ADAMS/View Interface Overview, 34 ◆ Module review, 43 27 ■ Review the problem statement. ■ Explain that the objective of this module is to become familiar with the graphical-user interface (GUI) of ADAMS/View. ■ Ask them to explore and experiment, and to focus on understanding how the software is set up. Notes: ■ Focus only on the GUI. ■ Do not get into detailed explanation of functionality. ■ This module has the potential to take too much time if you start to answer all of the students’ questions. ■ Tell them that you will answer their questions later when the content is covered. ■ Do not jump ahead. 0RGHO +LHUDUFK\ $'$069LHZ PRGHOLQJ KLHUDUFK\ ■ ADAMS/View names objects based on this model hierarchy. For example, ADAMS/ View names geometry as .model_name.part_name.geometry_name. ■ To change the parent for an object, rename the object. Model Simulations More Objects Measures Constraints Parts Forces Analyses Markers Results Sets Components Construction Points Geometry Are not saved in model command files (.cmd) See also: Assembling Subsystem Models, on page 196 28 ADAMS/View Interface Overview Draw figure on board. Demonstrate: In the stamping mechanism, display the names of parts to illustrate the model hierarchy. Right-click the parcels part. Show how it is made up of several geometries. While right-clicking, reiterate that in ADAMS/View, clicking the left-clicking selects objects while right-clicking displays a menu. 5HQDPLQJ 2EMHFWV $'$069LHZ QDPLQJ FRQYHQWLRQV .mod Simulations More Objects .mod.meas_1 .mod.joint_1 .mod.part_1 .mod.spring_1 .mod.run_1 .mod.part_1.mar_1 .mod.part_1.point_1 .mod.part_1.box_1 .mod.run_1.joint_1 .mod.run_1.joint_1.fx Are not saved in model command files (.cmd) 5HQDPLQJ REMHFWV FODULILHV PRGHO WRSRORJ\ DV IROORZV Renamed Not renamed ADAMS/View Interface Overview Zoom in on bottom half of the page and stress the importance of renaming parts, joints, and so on. Stress that giving descriptive names to objects makes debugging much easier. 29 $'$069LHZ ,QWHUIDFH $'$069LHZ PDLQ ZLQGRZ Main Toolbox Model name Menus Working grid Tool Arrow denotes tool stack Toolbox container View triad 30 Status bar ADAMS/View Interface Overview 6LPSOH 6LPXODWLRQV 6LPXODWLRQ YHUVXV DQLPDWLRQ ■ Simulations are solutions to equations of motion describing a mechanical system. ■ Animations display a graphical playback of previously completed simulations. Simulation tool Animation tool Simulation time interval End time: absolute point in time to stop simulation Duration: relative amount of time to simulate over ADAMS/View Interface Overview Simulation output Step size: amount of time between steps Steps: total number of steps in a specified amount of time 31 Explain that the simulation time interval option of Forever is available from the Simulate menu, not from the toolbox. Create a simple pendulum and demonstrate all the items called out in the figure above. Demonstrate the Main Toolbox: Tool stacks - Accessed by right-clicking a tool. Container - Appears in the bottom half of the toolbox when a tool is selected. Demonstrate the Status bar: Ask them to look at the Status bar for directions from MSC.ADAMS. Explain that the view triad provides a visual reference; it is not an object and cannot be selected. Simulate the pendulum and then animate it for a graphical playback. Explain how the time interval and the output options work. 6DYLQJ <RXU :RUN 0RVW FRPPRQ IRUPDWV LQ ZKLFK \RX FDQ VDYH $'$069LHZ PRGHOV ■ ADAMS/View database files (.bin) ◆ ◆ Are typically very large. ◆ ■ Include the entire modeling session including models, simulation results, plots, and so on. Are platform independent in MSC.ADAMS, as of version 11.0, but all other versions are platform dependent. ADAMS/View command files (.cmd) ◆ ◆ Are relatively small, editable text files. ◆ 32 Include only model elements and their attributes. Are platform independent. ADAMS/View Interface Overview Demonstrate Export Versus Save Database: Use the pendulum you created earlier. Once both .cmd and .bin files are created, illustrate the difference in the size of the two files. Open the .cmd file in a text editor to show how simple it is but do not get into details about the commands. 6DYLQJ <RXU :RUN 2WKHU IRUPDWV LQ ZKLFK \RX FDQ LPSRUW DQG H[SRUW GDWD ■ ADAMS/Solver input files (.adm) ■ Geometry files (STEP, IGES, DXF, DWG, Wavefront, Stereolithography) ■ Test and spreadsheet data files ■ Simulation results files (.msg, .req, .out, .gra, .res). ADAMS/View Interface Overview The other formats will be discussed in greater detail later in the course. 33 :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 3UREOHP VWDWHPHQW Use ADAMS/View to manipulate, simulate, review, and refine the following model: rocker rod ground_engineblock cam valve 0RGHO GHVFULSWLRQ ■ The model represents a valvetrain mechanism. ■ The cam is being rotated at a given velocity. ■ The rod (follower) moves translationally based on its constraint to the cam. ■ The rocker pivots about a pin attached to the engine block. ■ The spring is always in compression to try and keep the rod in contact with the cam. ■ The valve moves vertically as the rocker rotates. ■ When the valve moves, it lets small amounts of air into the chamber below it (not modeled here). 34 ADAMS/View Interface Overview Illustrate the problem statement. Identify the stiffness variable and the valve displacement measure. :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 7LSV EHIRUH \RX VWDUW While working on this exercise, notice: ■ The use of the right mouse button. ■ The function of single-clicks and double-clicks. ■ The messages on the Status bar. ■ The animation options. 6WDUW WKH ZRUNVKRS Start ADAMS/View from the directory exercise_dir/mod_02_aview_interface and import the model command file valve.cmd. It contains commands to build a model named valve. 7R VWDUW $'$069LHZ LQ :LQGRZV ■ On the Start menu, point to Programs, point to MSC.Software, point to MSC.ADAMS 2003, point to AView, and then select ADAMS - View. 7R VWDUW $'$069LHZ LQ 81,; ■ From the MSC.ADAMS Toolbar, select the ADAMS/View tool . 7R ORDG WKH ZRUNVKRS ILOHV 1 From the Welcome dialog box, select Import a file. 2 Click the file folder. The Find Directory dialog box appears. 3 Find and select the directory mod_02_aview_interface (exercise_dir/ mod_02_aview_interface). 4 Select OK. The File Import dialog box appears. 5 Set File Type to ADAMS/View command file (*.cmd). 6 Right-click the File to read text box, and then select Browse. The Select File dialog box appears. ADAMS/View Interface Overview 35 :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 7 Find and select the file, valve.cmd and then select Open. 8 Select OK. 9LHZ WKH PRGHO Now you’ll learn how you can view models from different angles using the keyboard shortcuts for zooming, translating, and rotating. 7R YLHZ WKH PRGHO IURP GLIIHUHQW DQJOHV 1 To view a list of keyboard shortcuts, move the cursor away from the model, and then right-click in the ADAMS/View window. A menu appears, listing the keyboard shortcuts. To close the menu, left-click away from the menu. 2 In the space below, write the shortcut keys for performing the following view operations. Rotate: Translate: Zoom in and out: Zoom into a specific area: Fit: Front view: 3 Press the key representing the desired view operation, and follow the instructions in the Status bar. 36 Rotate: r Translate: t Zoom in and out: z Zoom into a specific area (window): w Fit: f (lower case) Front View: F (upper case) ADAMS/View Interface Overview :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 5HQDPH SDUWV Now you’ll rename the parts to match the names given in the figure in the problem statement on page 34. As you go through these instructions, notice that right-clicking always gives you a list of choices, while left-clicking selects an object. 7R UHQDPH SDUWV 1 Move the cursor over a part and right-click. (For example, move the cursor over the rocker part.) 2 Point to Part:PART_<x>, and then select Rename. The Rename Object dialog box appears. 3 In the New Name text box, enter .valve.<part name>, and then select OK. (For example, for the rocker, you would enter: .valve.rocker.) See the problem statement on page 34 for a listing of part names. 4 Continue renaming parts. ,QVSHFW WKH PRGHO Now inspect the model to determine the number and type of constraints in the model and check if the model verified correctly. Use the values to answer Question 1 in Module review, on page 43. 7R GHWHUPLQH WKH QXPEHU DQG W\SH RI FRQVWUDLQWV 1 Right-click the Information tool stack the Model topology by constraints tool. on the right side of the Status bar, and then select Model topology by constraints tool ADAMS/View Interface Overview 37 :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ The Information window appears as shown next: 2 3 38 Note the number and type of constraints and use them to answer Question 1 in Module review, on page 43. Select Close. ADAMS/View Interface Overview :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 7R FKHFN LI WKH PRGHO YHULILHG VXFFHVVIXOO\ 1 Right-click the Information tool stack again, and then select the Verify tool. Verify tool The Information window appears as shown next: Note that the text Model verified successfully appears in the Information window. 2 Select Close. ADAMS/View Interface Overview 39 :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 6LPXODWH WKH PRGHO In this section, you’ll run a simulation for 2 seconds with 100 steps, and save the simulation results. 7R UXQ D VLPXODWLRQ 1 From the Main Toolbox, select the Simulation tool . Simulation tool 2 In the container that appears in the lower portion of the Main Toolbox: ■ Select Default. ■ Select End Time, and in the text box, below End Time, enter 2.0. ■ In the text box below Steps, enter 100. 3 Select the Play tool . 4 When the simulation is complete, select the Reset tool . 7R VDYH WKH VLPXODWLRQ UHVXOWV 1 From the Simulate menu, select Interactive Controls. The Simulation Control dialog box appears. 2 To save the last simulation results to the database under a new name, select the Save Simulation tool . The Save Run Results dialog box appears. 3 4 Select OK. 5 40 In the Name text box, enter a name for the simulation results, such as first_results. Close the Simulation Control dialog box. ADAMS/View Interface Overview :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ $QLPDWH WKH UHVXOWV In this section, you’ll review the results of the simulation as an animation, which is a graphical playback of a simulation. You’ll use the built-in ADAMS/View tools to run the animation. Optionally, you could use the ADAMS/PostProcessor tools to run animations. $QLPDWH WKH PRGHO ZLWK LFRQV WXUQHG RII GHIDXOW  1 From the Main Toolbox, select the Animation tool . 2 Select the Play tool. 3 When the animation is complete, select the Reset tool. $QLPDWH WKH PRGHO ZLWK LFRQV WXUQHG RQ 1 From the Review menu, select Animation Controls. The Animation Controls dialog box appears. 2 At the bottom of the Animation Controls dialog box, select Icons. 3 Select the Play tool. 4 When the animation is complete, select the Reset tool. 5 Close the Animation Controls dialog box. ADAMS/View Interface Overview 41 :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 6DYH \RXU ZRUN Now you’ll save your work so the saved file contains only the model information. 7R VDYH \RXU ZRUN 1 From the File menu, select Export. 2 Set File Type to ADAMS/View command file. 3 In the File Name text box, enter valve1. 4 In the Model Name text box, enter valve. 5 Select OK. 6 If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 7 From the File menu, select Exit. 8 From the dialog box that appears, select Exit, don’t Save. 2SWLRQDO WDVNV +DYH IXQ ZLWK WKH PRGHO This exercise introduces you to the ADAMS/View interface. Manipulate the model and experiment with it as much as you want. 42 ADAMS/View Interface Overview :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 0RGXOH UHYLHZ 1 How many constraints are there in this system? What type of constraints are they? 2 Is it possible to have more than one model in a database? 3 Is geometry a direct child of a model? If not, what is geometry a child of? 4 If you are in the middle of an operation and you are not sure what input ADAMS/View wants next, where should you look? 5 If you are working with our technical support staff and you want them to look at one of your files, what file format would you send them, a .cmd or .bin? Why? ADAMS/View Interface Overview 43 :RUNVKRS ³$'$069LHZ ,QWHUIDFH 2YHUYLHZ 44 ADAMS/View Interface Overview  $'$063267352&(6625 ,17(5)$&( 29(59,(: Use the ADAMS/PostProcessor interface to simulate, review, and refine the model shown next: Rocker Rod Guide (ground) Cam Valve For more information, see the ADAMS/PostProcessor online help. 7KLV PRGXOH LQFOXGHV ■ PostProcessing Interface Overview, 46 ■ Animating, 47 ■ Plotting, 48 ■ Reporting, 49 ■ Workshop 3—ADAMS/PostProcessor Overview, 50 ◆ Module review, 60 45 ■ Review the problem statement. ■ Explain that the objective of this module is to become familiar with the graphical-user interface of ADAMS/PPT. ■ Ask students to explore and experiment, and to focus on understanding how the software is set up. Notes: ■ Focus only on the interface. ■ Do not get into detailed explanation of functionality. ■ This module has the potential to take too much time if you start to answer all of the students’ questions. ■ Tell them that you will answer their questions later when the content is covered. ■ Do not jump ahead. 3RVW3URFHVVLQJ ,QWHUIDFH 2YHUYLHZ $'$063RVW3URFHVVRU KDV WKUHH PRGHV ■ Animation ■ Plotting ■ Report ([DPSOH The tools in the Main toolbar change if you switch between the modes, as shown on the next few pages. 46 ADAMS/PostProcessor Interface Overview $QLPDWLQJ Treeview Main toolbar Viewport Mode type Property editor Dashboard For more information, see the Animate tab in the ADAMS/PostProcessor online help. ADAMS/PostProcessor Interface Overview 47 Use the pendulum example from Module 2 to demo PPT features. Simulate with the Save files option on. You will use the output to demo the new Report option. Demo the Animation option after a simulation of the pendulum. There’s now support for MPG format in the Record tab, making movie creation on UNIX possible. 3ORWWLQJ Treeview Main toolbar Viewport Mode type Property editor Dashboard For more information, see the Plot tab in the ADAMS/PostProcessor online help. 48 Demo creating a plot. ADAMS/PostProcessor Interface Overview 5HSRUWLQJ Treeview Main toolbar Viewport Mode type For more information, see the Report tab in the ADAMS/PostProcessor online help. ADAMS/PostProcessor Interface Overview Demo loading a report. Load the file ADAMS.res. 49 :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 3UREOHP VWDWHPHQW Use ADAMS/PostProcessor to manipulate, review, and refine the results of the valvetrain model you simulated in the previous module. Rocker Rod Guide (ground) Valve Cam 0RGHO GHVFULSWLRQ ■ The model represents a valvetrain mechanism. ■ The cam is being rotated at a given velocity. ■ The rod (follower) moves translationally based on its constraint to the cam. ■ The rocker pivots about a pin attached to the engine block. ■ The spring is always in compression to try and keep the rod in contact with the cam. ■ The valve moves vertically as the rocker rotates. ■ When the valve moves, it lets small amounts of air into the chamber below it (not modeled here). 50 ADAMS/PostProcessor Interface Overview Review the model description. Draw the model and identify the variables, K of spring and displacement of the valve. :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 6WDUW WKH ZRUNVKRS Start ADAMS/View from the directory exercise_dir/mod_03_ppt_interface and import the model command file valve1.cmd. This is the command file you created in the previous workshop. The command file contains commands to build a model named valve. 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View. 2 From the Welcome dialog box, select Import a file. 3 Click the file folder. The Find Directory dialog box appears. 4 Find and select the directory mod_03_ppt_interface (exercise_dir/mod_03_ppt_interface). 5 Select OK. The File Import dialog box appears. 6 Set File Type to ADAMS/View command file (*.cmd). 7 Right-click the File to read text box, and then select Browse. The Select File dialog box appears. 8 Find and select the file, valve1.cmd, which you created in the previous workshop, and then select Open. Note that the model file is not in the current working directory. It is in the directory exercise_dir/mod_02_aview_interface. If you need a fresh copy of the model, import the command file valve1_completed.cmd from the directory exercise_dir/mod_02_aview_interface/completed. 9 Select OK. ADAMS/PostProcessor Interface Overview 51 :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 6LPXODWH WKH PRGHO Run a simulation for 2 seconds with 100 steps, and then save the simulation results. 7R UXQ D VLPXODWLRQ 1 From the Main Toolbox, select the Simulation tool. Tip: If you closed the Main Toolbox, you can display it again by clicking the Main Toolbox tool 2 on the Status bar. From the container in the Main Toolbox: ■ Select Default. ■ Select End Time, and in the text box, below End Time, enter 2.0. ■ In the Steps text box, enter 100. 3 Select the Play tool. 4 When the simulation is complete, select the Reset tool. 5 Save the simulation results, with the name second_results, just as you did on page 40 of Workshop 2—ADAMS/View Interface Overview. 3ORW WKH UHVXOWV Now you’ll plot the results using ADAMS/PostProcessor. You will plot: ■ ■ 52 Displacement of the valve versus time. ADAMS/View tracks this data through a measure called valve_displacement. Force in the spring versus time. ADAMS/View tracks this data through a measure called force_in_spring. ADAMS/PostProcessor Interface Overview :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 7R SORW WKH UHVXOWV 1 From the Main Toolbox, select the ADAMS/PostProcessor tool or press F8. ADAMS/PostProcessor tool ADAMS/PostProcessor starts. 2 At the bottom of the window in the dashboard, from the Simulation list, select the name of the results set you saved in the previous section. 3 Set Source to Measures. 4 From the Measure list, select Valve_Displacement. 5 In the right corner of the dashboard, select Add Curves. 6 From the toolbar, select the Create a New Page tool . The following figure shows the Create a New Page tool and other page tools. Create a New Page Delete a Page Previous Page Next Page In the treeview, shown on the left side of the ADAMS/PostProcessor window, you now have two pages. 7 From the Measure list, select Force_in_Spring. 8 Select Add Curves. 9 To return to ADAMS/View, in the upper right corner of the main toolbar, select the ADAMS/View tool or press F8. Note: If you resized the ADAMS/PostProcessor window, the ADAMS/View tool is no longer visible. To display the tool, stretch the window. ADAMS/PostProcessor Interface Overview 53 :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 0DQLSXODWH PRGHO FKDUDFWHULVWLFV You’ll first find the spring stiffness coefficient, and then you’ll modify the spring stiffness to 200 lbf/foot. 7R ILQG WKH VSULQJ VWLIIQHVV FRHIILFLHQW 1 Zoom in on the spring by typing a lowercase w, and then drawing a window around the spring. 2 Right-click the spring, point to Spring:SPRING_1, and then select Info. The Information window appears. 3 Note the value of the stiffness coefficient. 4 Use the value to answer Question 2 in Module review, on page 60. 5 Select Close. 7R PRGLI\ WKH VSULQJ VWLIIQHVV WR  OEIIRRW 1 Right-click the spring, point to Spring:SPRING_1, and then select Modify. The Modify a Spring-Damper Force dialog box appears. 2 In the Stiffness Coefficient text box, enter 200 (lbf/foot). Note: In the value you entered, the parentheses () are necessary because you enter compound fractional units. 3 Select OK. 4 Fit the model on the screen by typing a lowercase f. 6LPXODWH WKH PRGHO Run a simulation for 2 seconds with 100 steps, and then save the simulation results (as third_results), just as you did in Simulate the model, on page 52. 54 ADAMS/PostProcessor Interface Overview :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 2YHUOD\ SORWV RI IRUFH LQ VSULQJ IRU ERWK VLPXODWLRQV Now you are going to overlay the results of both of your simulations to see the differences between the spring forces. 7R RYHUOD\ SORWV 1 From the Main Toolbox, select the ADAMS/PostProcessor tool . 2 From the Simulation list, select the new simulation in your session. 3 Set Source to Measures. 4 From the Measure list, select Force_in_Spring. 5 Below the heading Independent Axis:, ensure that Time is selected. 6 Select Add Curves. Notice the dashboard settings in the next figure. ADAMS/PostProcessor Interface Overview 55 :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ *HW SORW VWDWLVWLFV Now you’ll use the online help to find out how to get plot statistics and then find the plot statistics for the force_in_spring value. 7R XVH WKH RQOLQH KHOS WR KHOS \RX JHW SORW VWDWLVWLFV 1 From ADAMS/PostProcessor’s Help menu, select ADAMS/PostProcessor Help. 2 From the Plot tab, select the topic Displaying Plot Statistics. 3 Use the Plot Statistics toolbar to find the maximum Force_in_Spring value in the second simulation. 4 Once you find the Force_in_Spring value, use it to answer Question 3 in Module review, on page 60. 0RGLI\ WKH SORW JUDSKLFV Now you’ll modify the graphics of the plot to make the information in it more readable. 7R JLYH WKH SORW D WLWOH 1 In the treeview, expand page_2 by clicking the + sign. 2 Expand plot_2. 3 Select title. 4 In the property editor below the treeview, clear the current title valve, and then enter the new title Spring Force vs. Time. 5 Select Enter. 7R ODEHO WKH YHUWLFDO D[LV DV 6SULQJ )RUFH OEI  1 2 In the property editor, select Labels. 3 56 In the treeview, select vaxis. Change the label to Spring Force (lbf). ADAMS/PostProcessor Interface Overview :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 7R PRGLI\ WKH OHJHQG WH[W DQG LWV SODFHPHQW 1 In the treeview, select curve_1. 2 In the property editor below, change the Legend text box to k=100(lbf/foot). 3 Change the legend for curve_2 to k=200. 4 In the treeview, select legend_object. 5 In the property editor, set Placement to Top Right. $GG DQ DQLPDWLRQ ADAMS/PostProcessor lets you display animations and plots at the same time. In this section, you’ll add an animation next to your plot. You can also run the animation and watch the results appear in the plot. 7R DGG DQ DQLPDWLRQ QH[W WR \RXU SORW 1 In the treeview, select page_2. 2 Split the screen by right-clicking on the Page Layout tool stack in the main toolbar, and selecting the Split Screen tool. Split Screen 3 Set the new viewport to Animation by right-clicking in the viewport and choosing Load Animation from the pop-up menu. ADAMS/PostProcessor Interface Overview 57 :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 4 From the Database Navigator, select one of the simulation results that you want to animate. 5 Select OK. 9LHZLQJ UHVXOWV 7R YLHZ DQ DQLPDWLRQ RI WKH UHVXOWV ■ Adjust your view of the model on your screen using the tools in the main toolbar. The figure below highlights some of the tools that are available. Try experimenting with the rotate, zoom, and translate tools. Center Dynamic Translate Dynamic Rotate Select 58 View Zoom View Fit Front View ADAMS/PostProcessor Interface Overview :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 7R SOD\ DQ DQLPDWLRQ RI WKH UHVXOWV ■ Play an animation of your model using the tools that are located above the viewport and in the dashboard. Experiment with the play and pause tools. Pause Animation Play Animation Play Animation Backward Reset Animation Record Animation 0RGLI\LQJ WKH JUDSKLFV RI \RXU DQLPDWLRQ 7R PRGLI\ WKH JUDSKLFV VHWWLQJV RI \RXU DQLPDWLRQ 1 From the dashboard, select the View tab. 2 Experiment with the available options. 7R FKDQJH WKH FRORU RI WKH FDP 1 From the treeview, expand the model by clicking on the + sign. 2 Select cam. 3 In the property editor, set Color to Coral. 7R HQODUJH WKH JUDSKLFV WKDW LOOXVWUDWH IRUFH 1 From the Edit menu, select Preferences. The PPT Preferences dialog box appears. 2 In the Force Scale text box, enter a value that is greater than 50, and then select Save. Note: Make sure that you save your changes in this dialog box before you close it. If you do not save your changes, they will not be made. 3 Select Close. ADAMS/PostProcessor Interface Overview 59 :RUNVKRS ³$'$063RVW3URFHVVRU 2YHUYLHZ 7R FKDQJH WKH YLHZ IURP VKDGHG WR ZLUHIUDPH ■ On the main toolbar, select the Wireframe/shaded tool . You can now animate the model and view the position and direction of the reaction force. 6DYH \RXU $'$063RVW3URFHVVRU VHVVLRQ 7R VDYH \RXU VHVVLRQ 1 Return to ADAMS/View. 2 Save your work and then exit ADAMS/View. 0RGXOH UHYLHZ 1 2 What was the damping coefficient of the spring when you first opened the model? 3 60 What is the mass of the valve? What is this mass currently based on? What was the maximum spring force when the spring coefficient was 200 lbf/foot? ADAMS/PostProcessor Interface Overview  )$//,1* 6721( Find the displacement, velocity, and acceleration of a stone after one second, when the stone, with zero initial velocity, falls under the influence of gravity. mm g = 9810 -------s2 7KLV PRGXOH LQFOXGHV ■ Coordinate Systems, 62 ■ Part Coordinate System, 63 ■ Coordinate System Marker, 64 ■ Differences Between Parts and Geometry, 65 ■ Parts, Geometry, and Markers, 66 ■ Types of Parts in ADAMS/View, 67 ■ Part Mass and Inertia, 68 ■ Measures, 69 ■ Workshop 4—Falling Stone, 70 ◆ Module review, 77 61 ■ Review the problem statement. ■ Then, review the concepts while relating them to the problem statement. ■ For example, review the problem statement, click on the link Part Coordinate Systems. Review the concept page, then use the link at the bottom of the page, Falling Stone, to come back to this page. Repeat this with each concept. ■ Keep returning to the title page as you go through the module. Continue this throughout the course. &RRUGLQDWH 6\VWHPV 'HILQLWLRQ RI D FRRUGLQDWH V\VWHP &6 ■ A coordinate system is essentially a measuring stick to define kinematic and dynamic quantities. Point P ˆ yG R ˆ ˆ ˆ R = Rx x + Ry y + Rz z Point O ˆ xG ˆ zG 7\SHV RI FRRUGLQDWH V\VWHPV ■ Global coordinate system (GCS): ◆ ◆ ■ Rigidly attaches to the ground part. Defines the absolute point (0,0,0) of your model and provides a set of axes that is referenced when creating local coordinate systems. Local coordinate systems (LCS): ◆ Part coordinate systems (PCS) ◆ Markers 62 Specify that we will be dealing with Cartesian coordinates all week. Falling Stone 3DUW &RRUGLQDWH 6\VWHP 'HILQLWLRQ RI SDUW FRRUGLQDWH V\VWHPV 3&6 ■ They are created automatically for every part. ■ Only one exists per part. ■ Location and orientation is specified by providing its location and orientation with respect to the GCS. Part coordinate system Part 1 at location (10, 5.5, 0) ˆ y P1 ˆ x P1 ˆ z P1 5.5 ˆ yG ˆ zG ■ ˆ xG 10 Global coordinate system Ground body at location (0, 0, 0) When created, each part’s PCS has the same location and orientation as the GCS. Falling Stone 63 Create a sphere with the cm off of the origin, and then display information on one of its markers (cm or anchor marker) to show that it has its own PCS. This PCS is not visible, but by default it is at the global origin. Move the sphere by moving its anchor marker, to demonstrate how the PCS changes locations and is no longer at the global origin. Optional: Demonstrate turning display of PCS markers (Edit - Appearance - (filter to all) icons - part_axis; select OK) &RRUGLQDWH 6\VWHP 0DUNHU 'HILQLWLRQ RI D PDUNHU ■ It attaches to a part and moves with the part. ■ Several can exist per part. ■ Its location and orientation can be specified by providing its location and orientation with respect to GCS or PCS. Marker 1 on Part 1 at location (- 5, -1, 0) ˆ yG -1 ˆ z M1 ˆ zG ■ ˆ y P1 ˆ y M1 -5 ˆ x M1 ˆ z P1 Part coordinate system Part 1 at location (10, 5.5, 0) ˆ x P1 ˆ xG Ground body at location (0, 0, 0) It is used wherever a unique location needs to be defined. For example: ◆ ◆ ■ The location of a part’s center of mass. The reference point for defining where graphical entities are anchored. It is used wherever a unique direction needs to be defined. For example: ◆ ◆ Directions for constraints. ◆ ■ The axes about which part mass moments of inertia are specified. Directions for force application. By default, in ADAMS/View, all marker locations and orientations are expressed in GCS. 64 Falling Stone Simulate the falling of this sphere then start ADAMS/PostProcessor. On the same plot put Results SetÆ PART_2_XFORM, Component Y and Object Æ PART_2, Characteristic CM_Position, Component Y. Note the .res plot is with respect to LCS, while the .obj plot is with respect to GCS. If the sphere were created with the cm at the origin, these two measures would be the same. Explain that markers are local coordinate systems located relative to GCS and PCS. 'LIIHUHQFHV %HWZHHQ 3DUWV DQG *HRPHWU\ 3DUWV Define bodies (rigid or flexible) that can move relative to other bodies and have the following properties: ■ Mass ■ Inertia ■ Initial location and orientation (PCS) ■ Initial velocities *HRPHWU\ ■ Is used to add graphics to enhance the visualization of a part using properties such as: ◆ ◆ Radius ◆ ■ Length Width Is not necessary for most simulations. Note: Simulations that involve contacts do require the part geometry to define when the contact force will turn on or off. We will discuss contact forces in Hatchback IV, on page 285. .model_1.UCA (Part) .model_1.UCA.cyl_1 (Geometry) .model_1.UCA.sphere_1 (Geometry) Falling Stone All of the parts that are used in this course will be rigid bodies. 65 3DUWV *HRPHWU\ DQG 0DUNHUV 'HSHQGHQFLHV LQ 06&$'$06 To understand the relationship between parts, geometry, and markers in ADAMS/View, it is necessary to understand the dependencies shown next: Model .mod Part .mod.pend Geometry Marker Marker Marker Geometry .mod.pend.sph .mod.pend.mar_1 .mod.pend.cm .mod.pend.mar_2 .mod.pend.cyl pend mar_2 cyl cm sph mar_1 66 Falling Stone 7\SHV RI 3DUWV LQ $'$069LHZ 5LJLG ERGLHV ■ Are movable parts. ■ Possess mass and inertia properties. ■ Cannot deform. )OH[LEOH ERGLHV ■ Are movable parts. ■ Possess mass and inertia properties. ■ Can bend when forces are applied to them. *URXQG SDUW ■ Must exist in every model and is automatically created when a model is created in ADAMS/View. ■ Defines the GCS and the global origin and, therefore, remains stationary at all times. ■ Acts as the inertial reference frame for calculating velocities and acceleration. Falling Stone Demonstrate: Right-click any part, and then select Modify. Review the Part Modify dialog box in detail. Demonstrate: Use the Verify tool to find the DOF of the model. You will cover DOF in detail when you cover constraints. 67 3DUW 0DVV DQG ,QHUWLD 0DVV DQG LQHUWLD SURSHUWLHV ■ ADAMS/View automatically calculates mass and inertial properties only for threedimensional rigid bodies. ■ ADAMS/View calculates the total mass and inertia of a part based on the part’s density and the volume of its geometry. ■ You can change these properties manually. ■ ADAMS/View assigns mass and inertial properties to a marker that represents the part’s center of mass (cm) and principal axes. ■ You can change the position and orientation of the part’s cm marker. Part 1 Part 1 cm marker cm marker (shifts as new geometry is added to the part) ■ The orientation of the cm marker also defines the orientation of inertial properties Ixx, Iyy, Izz. 68 Mention the use of the Table Editor to change mass properties of multiple parts. Falling Stone 0HDVXUHV 0HDVXUHV LQ 06&$'$06 ■ Represent data that you would like to quantify during a simulation, such as: ◆ ◆ Forces in a joint ◆ Angle between two bodies ◆ ■ Displacement, velocity, or acceleration of a point on a part Other data resulting from a user-defined function Capture values of measured data at different points in time over the course of the simulation. 'HILQLWLRQ RI REMHFW PHDVXUHV Measure pre-defined measurable characteristics of parts, forces, and constraints in a model. 3DUW PHDVXUH FKDUDFWHULVWLFV ■ CM position ■ CM velocity ■ ■ 6SULQJ PHDVXUH FKDUDFWHULVWLFV ■ Deformation -RLQW PHDVXUH FKDUDFWHULVWLFV ■ Relative velocity ■ Force Kinetic energy ■ Torque Others ■ Others ■ Force Falling Stone Demonstrate: Right-click any model element (part, joint) in a model, and then select Measure. Review the basics of the Measure dialog box. Review the problem statement. Quiz them on what steps they would take to solve the problem. Ask if there are any questions before starting. Remind them to change directories. 69 :RUNVKRS ³)DOOLQJ 6WRQH 3UREOHP VWDWHPHQW Find the displacement, velocity, and acceleration of a stone after one second, when the stone with zero initial velocity, falls under the influence of gravity. mm g = 9810 -------s2 6WDUW WKH ZRUNVKRS First, start ADAMS/View and create a model in the directory exercise_dir/ mod_04_falling_stone. Executing ADAMS/View in that directory ensures that all saved data gets stored there. 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View. 2 In the Welcome dialog box: ■ ■ Name the model projectile. ■ Verify that Gravity is set to Earth Normal (-Global Y). ■ 70 Set the directory to exercise_dir/mod_04_falling_stone. ■ 3 Under the heading, How would you like to proceed, select Create a new model. Verify that Units are set to MMKS - mm, Kg, N, s, deg. Select OK. Falling Stone :RUNVKRS ³)DOOLQJ 6WRQH %XLOG WKH VWRQH Use the Sphere tool to create a stone part with a 50 mm radius and its center at the global origin. You’ll also rename the part and set its mass to 1 kg. 7R EXLOG WKH VWRQH 1 To view the coordinates as you create the sphere so you know its size, from the View menu, select Coordinate Window. 2 From the Main Toolbox, right-click the Rigid Body tool stack, and then select the Sphere tool . Rigid Body tool stack 3 Follow the Status bar instructions and pick the center of the sphere at the global origin, then drag the cursor until you create a sphere with a 50 mm radius. 7R UHQDPH WKH VWRQH 1 Right-click the sphere, point to Part:PART_2, and then select Rename. 2 In the New Name text box, enter .projectile.Stone, and then select OK. 7R VHW WKH PDVV WR  NJ 1 Right-click the sphere, point to Part:Stone, and then select Modify. 2 In the Define Mass by text box, select User Input. 3 If an alert box opens, select Close. 4 In the Mass text box, enter 1.0. 5 Select OK. Falling Stone 71 Introduce the closed-form solution in this module. You do not need to cover closed-form solutions in subsequent modules. Students can review them if they like. Demonstration: Start a new session and demonstrate the Welcome dialog box. Choose Create a new model to show initial environment parameters. Once the new model opens, demonstrate the use of the Settings menu (Coordinate system, Units, and Gravity dialog boxes). :RUNVKRS ³)DOOLQJ 6WRQH &UHDWH PHDVXUHV IRU WKH IDOOLQJ VWRQH To calculate the vertical displacement, velocity, and acceleration of the stone’s cm marker in ˆ the y g ,direction, you’ll create three object (part) measures. You’ll set Y as the component to measure. ˆ 7R FDOFXODWH WKH GLVSODFHPHQW RI WKH VWRQH LQ WKH y g GLUHFWLRQ 1 Right-click the stone, point to Part:Stone, and then select Measure. 2 In the Measure Name text box, enter displacement. 3 Set Characteristic to CM position. 4 Set Component to Y. 5 Set From/At to .projectile.Stone.cm. 6 Select Create strip chart. 7 Select OK. A measure stripchart appears. It is empty because you need to run a simulation before ADAMS/View has the necessary information for the stripchart. ˆ 7R FDOFXODWH WKH YHORFLW\ RI WKH VWRQH LQ WKH y g GLUHFWLRQ 1 2 In the Measure Name text box, enter velocity. 3 Set Characteristic to CM velocity. 4 Set Component to Y. 5 Set From/At to .projectile.Stone.cm. 6 Select Create strip chart. 7 72 Right-click the stone, and select Measure. Select OK. Falling Stone :RUNVKRS ³)DOOLQJ 6WRQH ˆ 7R FDOFXODWH WKH DFFHOHUDWLRQ RI WKH VWRQH LQ WKH y g GLUHFWLRQ ■ Follow the instructions above but set Measure Name to acceleration, and Characteristic to CM acceleration. 9HULI\ WKH PRGHO Now you’ll verify the model. When you verify the model, ADAMS/View checks for error conditions such as misaligned joints, unconstrained parts, or massless parts in dynamic systems and alerts you to other possible problems in the model. 7R YHULI\ WKH PRGHO 1 In the right corner of the Status bar, right-click the Information tool stack select the Verify tool . 2 In the Information window, check that the model has verified successfully. 3 , and then Close the Information window. 6HW XS DQG UXQ D VLPXODWLRQ Now you’ll zoom out the display so that the falling stone is clearly visible while it simulates. You’ll then simulate it for 1 second with 50 steps. 7R ]RRP RXW 1 Select the Select tool 2 Select the Zoom tool , and then click and drag the mouse to zoom out until the entire working grid is visible. 3 Select the Translate tool Falling Stone to display the view control options in the toolbox. , and then drag the working grid to the top of the screen. 73 :RUNVKRS ³)DOOLQJ 6WRQH 7R UXQ D VLPXODWLRQ IRU  VHFRQG ZLWK  VWHSV 1 In the Main Toolbox, select the Simulation tool . 2 In the End Time text box, enter 1.0 and in the Steps text box, enter 50. 3 Select the Play tool. As the stone falls, ADAMS/View plots the corresponding data on the displacement, velocity, and acceleration graphs. 4 When the simulation ends, reset the model to the input, or design configuration by selecting the Reset tool. 5 Animate the simulation to replay the simulation without simulating again. )LQG WKH YDOXHV RI GLVSODFHPHQW YHORFLW\ DQG DFFHOHUDWLRQ Now you’ll use ADAMS/PostProcessor to find the stone’s displacement, velocity, and acceleration after 1 second. 7R UXQ $'$063RVW3URFHVVRU ■ Right-click the blank area inside the stripchart .projectile.displacement, point to Plot:scht1, and then select Transfer to Full Plot. ADAMS/PostProcessor replaces the ADAMS/View window. 7R ILQG WKH YDOXH RI WKH VWRQH·V GLVSODFHPHQW 1 2 Because you want to know the final conditions after 1 second, move the cursor over the end point of the plot. 3 In the area below the menu bar, the value of X is displayed as 1. Note the value of Y; this is your answer. 4 Compare this value of Y to the results given in the closed-form solution on page 78. 5 74 In ADAMS/PostProcessor, from the main toolbar, select the Plot Tracking tool . Use the value to answer Question 1 in Module review, on page 77. Falling Stone :RUNVKRS ³)DOOLQJ 6WRQH 7R ILQG WKH YDOXH RI WKH VWRQH·V YHORFLW\ DIWHU  VHFRQG 1 Select Surf. This lets you view a selected measure without using the Add Curves button. 2 Set Source to Measures. 3 From the Measure list, select velocity. 4 Because you want to know the final conditions after 1 second, move the cursor over the end point of the plot. 5 In the area below the menu bar, the value of X appears. It is 1. Note the value of Y; this is your answer. 6 Compare this value of Y to the results given in the Closed-form solution, on page 78. 7 Use the value to answer Question 2 in Module review, on page 77. 7R ILQG WKH YDOXH RI VWRQH·V DFFHOHUDWLRQ DIWHU  VHFRQG 1 Set Source to Measures. 1 From the Measure list, select acceleration. 2 To display the acceleration plot, select Surf. 3 Because you want to know the final conditions after 1 second, move the cursor over the end point of the plot. 4 In the area below the menu bar, the value of X will be displayed as 1. Note the value of Y; this is your answer. 5 Compare this value of Y to the results given in the Closed-form solution, on page 78. 6 Use the value to answer Question 3 in Module review, on page 77. 7 To return to ADAM/View and close all three plots, select the ADAMS/View tool. Falling Stone 75 :RUNVKRS ³)DOOLQJ 6WRQH 6DYH \RXU ZRUN Now save your work such that the file contains only the model information. You will use this model in the next module. Tip: Save the model as a command file. 7R VDYH \RXU ZRUN 1 From the File menu, select Export, and then select OK. 2 If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 3 Exit ADAMS/View. 2SWLRQDO WDVNV Save your work before performing these tasks. Do not save your work after performing these tasks because you will use this model in the next module. If you must save the model after performing these tasks, give the model a different name. 7R LQVSHFW WKH EHKDYLRU RI WKH VWRQH DIWHU FKDQJLQJ LWV PDVV 1 Change the mass of the stone to 2 kg. 2 Simulate the model. 3 Compare the results of this simulation with the results of the simulation where the mass of the stone was 1 kg. 4 Does changing the mass affect the displacement, velocity, or acceleration? 5 Measure the kinetic energy of the stone. Do these results make sense? K.E. = (1/2)m*v2 6 Exit ADAMS/View. 76 KE solution is in units of N*mm. In ADAMS/Solver, a conversion from mm to m occurs. Falling Stone :RUNVKRS ³)DOOLQJ 6WRQH 0RGXOH UHYLHZ 1 What is the displacement of the stone after one second? 2 What is the velocity of the stone after one second? 3 What is the acceleration of the stone after one second? 4 What are the most basic building blocks in MSC.ADAMS, which are used in parts, constraints, forces, and measures? 5 Why is the ground part automatically created? 6 Can ADAMS/View automatically calculate mass properties for two-dimensional geometry? Falling Stone 77 :RUNVKRS ³)DOOLQJ 6WRQH 06&$'$06 UHVXOWV ■ Displacement after 1 sec = -4903.3 mm ■ Velocity after 1 sec = -9806.6 mm/sec ■ Acceleration after 1 sec = -9806.6 mm/sec2 &ORVHGIRUP VROXWLRQ $QDO\WLFDO VROXWLRQ s = ½ (at2) = 4903.325 mm v = at = 9806.65 mm/sec a= g = 9806.65 mm/sec2 KE = (1/2)*1kg ** 9806.65mm/sec)2 = 4.8085e7(kg*mm2/s2) conversion to N: 1 N = 1 (kg*m/s2) KE = 4.80852e7[(kg*mm/s2)(1m/100mm)]*mm = 48085.2 N*mm :KHUH s = Distance (mm) a = Acceleration (mm/sec2) t = Time (sec) v = Velocity (mm/sec) m = mass (kg) 78 Falling Stone  352-(&7,/( 027,21 Compute the range, R, when a stone is launched as a projectile with an initial speed of 6 m/s at an angle of 60o, as shown next. 6 m/s θ = 60o A B R 7KLV PRGXOH LQFOXGHV ■ Part Initial Conditions, 80 ■ Initial Velocities, 81 ■ Point Trace, 82 ■ Workshop 5—Projectile Motion, 83 ◆ Module review, 90 79 ■ Review the problem statement. ■ At regular intervals, ask if there are any questions. 3DUW ,QLWLDO &RQGLWLRQV ,QLWLDO ORFDWLRQ DQG RULHQWDWLRQ ■ The design configuration of all the parts (their part coordinate systems) in a model defines their initial locations and orientations. ■ You can fix a part’s location and orientation so it can be used during the assemble simulation procedure (covered later). 80 Projectile Motion Create two links. Deactivate gravity. Demonstrate fixing one link’s initial position and orientation. ,QLWLDO 9HORFLWLHV ,QLWLDO YHORFLWLHV In MSC.ADAMS, a part initially moves (at t = 0) as follows: No Yes Is an initial velocity specified? Yes Are there motions/constraints acting on the part? Are there constraints acting on the part? No Yes No MSC.ADAMS uses a default of zero MSC.ADAMS uses the initial velocity specified MSC.ADAMS calculates initial velocity; it may or may not be zero MSC.ADAMS uses initial velocity due to the motions/constraints Projectile Motion Consider illustrating the above flowchart on board. Demonstration: Create a block and constrain it to ground with a translational joint. Right-click the part and set its initial velocity. Simulate the model so you can watch it move. Right-click the joint and set its initial velocity opposite that of the parts. Simulate again to show precedence of the joint IC. 81 3RLQW 7UDFH 'HILQLWLRQ RI D SRLQW WUDFH ■ Tracks the location of a marker during an animation. ■ Can be used to visualize the clearance between two bodies during a simulation. ([DPSOH RI D SRLQW WUDFH ■ Trajectory of a ball. Boom! 82 Demonstrate: Review Æ Animation Controls Æ Trace Marker Projectile Motion :RUNVKRS ³3URMHFWLOH 0RWLRQ 3UREOHP VWDWHPHQW Compute the range, R, when a stone is launched as a projectile with an initial speed of 6 m/s at an angle of 60o, as shown next. 6 m/s A θ = 60o B R 0RGHO GHVFULSWLRQ In this workshop, you use the model you built in Workshop 4—Falling Stone, on page 70. Projectile Motion Illustrate the problem statement. Ask the students to give steps to complete workshop. Ask for questions. 83 :RUNVKRS ³3URMHFWLOH 0RWLRQ 6WDUW WKH ZRUNVKRS To start the workshop, import the model that you created in the previous module. 7R VWDUW WKH ZRUNVKRS 1 In the Welcome dialog box, under the heading, How would you like to proceed, select Import a file. 2 Set the directory to exercise_dir/mod_05_projectile. Executing ADAMS/View in this directory ensures that all saved data gets stored here. 3 Select OK. 4 Find and select the model file, projectile.cmd, which you completed in the previous workshop. Note that the model file is not in the current working directory. It is in the directory exercise_dir/mod_04_falling_stone. If you need a fresh copy of the model, import the command file stone_completed.cmd from the directory exercise_dir/mod_04_falling_stone/stone_completed. 5 Select OK. %XLOG WKH SODQH In this section, you’ll build a plane using the Box tool dimensions: ■ Length: 3500 mm ■ Height: 100 mm ■ . The plane will have the following On ground Before building the plane, you’ll set up the display by resetting the working grid to 4000 mm x 3000 mm with spacing of 50 mm, and zooming out. 84 Projectile Motion :RUNVKRS ³3URMHFWLOH 0RWLRQ 7R VHW WKH GLVSOD\ 1 From the Settings menu, select Working Grid. 2 In the Size: X text box, enter 4000. 3 In the Size: Y text box, enter 3000. 4 In the Spacing text boxes, enter 50, and then select OK. 5 Zoom out by typing a lowercase z, and then clicking and dragging the mouse to zoom out and view the entire working grid. 7R EXLOG WKH SODQH 1 Turn on the coordinate window (from the View menu, select Coordinate Window). 2 From the Main Toolbox, right-click the Rigid Body tool stack, and then select the Box tool . 3 In the toolbox container: ■ ■ Select Length, and then in the Length text box, enter 3500 mm. ■ 4 Select On Ground. Select the Height and Depth options, and then in the Height and Depth text boxes, enter 100 mm. Use the mouse to select the corner of the box at 0, -150, 0. The stone should appear to be balanced at the upper left corner of the plane in a front view. Projectile Motion 85 :RUNVKRS ³3URMHFWLOH 0RWLRQ 6HW LQLWLDO FRQGLWLRQV Now set initial velocity conditions for the stone as follows: ■ V x = 6000*cos(60o) = 3000 mm/sec ■ V y = 6000*sin(60o) = 5196 mm/sec o o 7R VHW LQLWLDO FRQGLWLRQV 1 Reset the Main Toolbox by selecting the Select tool . 2 Right-click the stone, point to Part:Stone, and then select Modify. 3 Set Category to Velocity Initial Conditions. 4 Under Translational velocity along, select X axis, and in the X axis text box, enter (6*cos(60d)(m/sec)) or (3000(mm/sec)). 5 Under Translational velocity along, select Y axis, and in the Y axis text box, enter (6*sin(60d)(m/sec)) or (5196(mm/sec)). 6 Select OK. &UHDWH PHDVXUHV IRU SURMHFWLOH PRWLRQ ˆ Next, create an object (part) measure to calculate the horizontal displacement, xg , of the stone’s center of mass (cm) marker when it is projected. 7R FUHDWH D PHDVXUH 1 2 In the Measure Name text box, enter R_displacement. 3 Set Characteristic to CM position. 4 Set Component to X. 5 Set From/At to .projectile.Stone.cm. 6 Select Create strip chart. 7 86 Right-click the stone, point to Part:Stone, and then select Measure. Select OK. Projectile Motion :RUNVKRS ³3URMHFWLOH 0RWLRQ 5XQ D VLPXODWLRQ Run a simulation for 1.5 seconds, using a sampling rate of .02 seconds. 7R UXQ D VLPXODWLRQ 1 From the Main Toolbox, select the Simulation tool. 2 In the End Time text box, enter 1.5. 3 In the Step Size text box enter 0.02. 4 Select the Play tool. ADAMS/View runs the simulation and plots the corresponding data in a stripchart. 5 When the simulation ends, select the Reset tool. )LQG WKH UDQJH 5 Using animation tools, determine the time at which the stone encounters the plane. Use the time value to answer Question 1 in Module review, on page 90. 7R ILQG WKH UDQJH 1 From the Main Toolbox, select the Animation tool 2 Select the Play tool. 3 When the stone makes contact with the plane, select the Stop tool 4 Use the Step Forward and Step Backward stone makes contact with the plane. 5 Note the time at which the stone makes contact with the plane in the plot. (The time is displayed in the upper-left corner of the ADAMS/View window.) 6 Select the Select tool Projectile Motion . . tools to obtain the exact point at which the . 87 :RUNVKRS ³3URMHFWLOH 0RWLRQ &UHDWH D SRLQW WUDFH Create a point trace to view the trajectory of the projectile during an animation. 7R FUHDWH D SRLQW WUDFH 1 From the Review menu, select Animation Controls. The Animation Controls dialog box appears. The remaining steps used to create the point trace will be done in this dialog box. 2 Select Icons. 3 Set No Trace to Trace Marker. 4 Right-click the empty text box that appears, select Marker, and then select Browse. 5 From the Database Navigator, select Stone.cm. 6 Note that the marker name is entered into the text box, and then select the Play tool. 7 Close the Animation Controls dialog box. )LQG KRUL]RQWDO GLVSODFHPHQW In ADAMS/PostProcessor, use the Plot Tracking tool to return the horizontal displacement corresponding to the time step determined earlier. Use the value to answer Question 2 in Module review, on page 90. 7R ILQG WKH KRUL]RQWDO GLVSODFHPHQW 1 Right-click a blank area inside the R_displacement stripchart, point to Plot: scht1, and then select Transfer to Full Plot. ADAMS/PostProcessor replaces ADAMS/View. 2 3 Because you want to know the displacement when the stone makes contact with the plane, move the cursor over the plot until the value of X is equal to the time at which contact was made. 4 Note the value of displacement, Y. This is your answer for Question 2 in Module review, on page 90. 5 Compare this value of Y to the results given in the closed-form solution on page 91. 6 88 Select the Plot Tracking tool . Return to ADAMS/View. Projectile Motion :RUNVKRS ³3URMHFWLOH 0RWLRQ 6DYH \RXU ZRUN Save your work such that the file contains not only the model information, but also the results and plots. 7R VDYH \RXU ZRUN 1 From the File menu, select Save Database As. 2 In the File Name text box, enter projectile, and then select OK. ADAMS/View creates a binary file that contains not only the model information but also the results and plots. 3 If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 4 Exit ADAMS/View. 2SWLRQDO WDVNV Save your work before performing these tasks. Do not save your work after performing these tasks. If you must save the model after performing these tasks, give the model a different name. 7R IROORZ WKH VWRQH GXULQJ DQ DQLPDWLRQ 1 Zoom in on the stone. 2 From the Review menu, select Animation Controls. Now change the reference frame while animating. 3 On the Animation Controls dialog box, change Fixed Base to Base Part. Select the part to which you want to fix the camera. 4 Go to the ADAMS/View online help and look up the Animation Controls dialog box to read about the other functionality available. Projectile Motion 89 :RUNVKRS ³3URMHFWLOH 0RWLRQ 0RGXOH UHYLHZ 1 2 What is the range, R, as defined in the problem statement? 3 If a part’s initial velocity conflicts with a system constraint, which will take precedence during a simulation? 4 90 At what time does the stone encounter the plane? What modifications would be necessary to convert the stone into a pendulum? Projectile Motion :RUNVKRS ³3URMHFWLOH 0RWLRQ 06&$'$06 UHVXOWV R = 3180 mm (Can vary slightly depending on several factors, most likely the sampling rate.) &ORVHGIRUP VROXWLRQ $QDO\WLFDO VROXWLRQ The analytical solution for R, the range covered by the projectile, is as follows: xo = 0 xf = R yo = 0 yf = 0 V x = 6000 × cos 60° = 3000 mm/sec o V y = 6000 × sin 60 ° = 5196 mm/sec o 1 2 y f = y o + V y t – -- gt o 2 0 = 0 + 5196t – 0.5 × 9806 × t 0 = 2 ( 5196 – 4905t )t t = 1.06 sec xf = xo + Vx t o R = 0 + 3000 × 1.06 R = 3180 mm Projectile Motion 91 :RUNVKRS ³3URMHFWLOH 0RWLRQ 92 Projectile Motion  21( '2) 3(1'8/80 Find the initial force supported by a pin at A for a bar that swings in a vertical plane, given the initial angular displacement ( θ 0 ) and initial angular velocity · ( θ 0 ). Also, find the pendulum frequency. A θ L= 4 50 m 2 kgs m B θ 0 = 30° · θ 0 = 300°/sec 7KLV PRGXOH LQFOXGHV ■ Constraints, 94 ■ Use of Markers in Constraints, 95 ■ Degrees of Freedom (DOF), 96 ■ Joint Initial Conditions (ICs), 97 ■ Merging Geometry, 98 ■ Angle Measures, 99 ■ Workshop 6—One DOF Pendulum, 100 ◆ Module review, 112 93 ■ Review the problem statement. ■ Return to the problem statement after each concept to make the connection. &RQVWUDLQWV 'HILQLWLRQ RI D FRQVWUDLQW ■ Restricts relative movement between parts. ■ Represents idealized connections. ■ Removes rotational and/or translational DOF from a system. ([DPSOH Wall Wall Door Door 7UDQVODWLRQDO FRQVWUDLQWV RI WKH KLQJH Zw XD – XW = 0 ZD Yw YD – YW = 0 YD Xw XD ZD – ZW = 0 5RWDWLRQDO FRQVWUDLQWV RI WKH KLQJH Φ D – Φ W = 0 (about x-axis) θ D – θ W = 0 (about y-axis) Therefore, φ D and φ W are free 94 One DOF Pendulum Explain how ADAMS/View took the four inputs (two bodies, one location, and one vector) and created a constraint. Highlight the markers that ADAMS/View creates when you add constraints. Explain that these two markers control the location and orientation of the pin joint. Explain that the two special markers that MSC.ADAMS created are called I and J. Demonstrate: Build a pendulum in ADAMS/View. Explain the importance of 2 Bodies - 1 Location. Explain difference between Normal to Grid and Pick Feature. 8VH RI 0DUNHUV LQ &RQVWUDLQWV &RQVWUDLQW HTXDWLRQV LQ 06&$'$06 ■ Constraints are represented as algebraic equations in ADAMS/Solver. ■ These equations describe the relationship between two markers. ■ Joint parameters, referred to as I and J markers, define the location, orientation, and the connecting parts: ◆ First marker, I, is fixed to the first part. ◆ Second marker, J, is fixed to the second part. $QDWRP\ RI D FRQVWUDLQW LQ 06&$'$06 Model (.model) Part Constraint Part (.model.door) (.model.hinge) (.model.wall) I marker J marker (.model.door.hinge_I_mar) (.model.wall.hinge_J_mar) One DOF Pendulum 95 Demonstrate: Display information on joint to demonstrate how to find out which two markers are used in a joint. Highlight each marker individually and emphasize their alignment. Also note that blue axis (z-axis of application) is indicator of the allowable DOF. 'HJUHHV RI )UHHGRP '2) &RQVWUDLQWV DQG '2) ■ Each DOF in mechanical system simulation (MSS) corresponds to at least one equation of motion. ■ A freely floating rigid body in three-dimensional space is said to have six DOF. ■ A constraint removes one or more DOF from a system, depending on its type. ˆ y Rigid body ˆ z ˆ x 'HWHUPLQLQJ WKH QXPEHU RI V\VWHP '2) ■ ADAMS/View provides an estimated number of system DOF by using the Gruebler’s Count: System DOF = ( number of movable parts ⋅ 6 DOF/ part ) – ∑ [ # Constraints ⋅ # DOF (Constraint) ] i = type ■ ADAMS/View also provides the actual number of system DOF, as it checks to see if: ◆ Appropriate parts are connected by each constraint. ◆ Correct directions are specified for each constraint. ◆ Correct type of DOF (translational versus rotational) are removed by each constraint. ◆ There are any redundant constraints in the system. See also: DOF removed by a revolute joint, on page 372 96 One DOF Pendulum Demonstrate: Use the Verify tool to display the model DOF and Gruebler’s Count. Illustrate four-bar link mechanism; solve the system using the Gruebler Count equation to show result of -2 DOF. The KBA at http:// support.adams.com/kb/faq.asp?ID=8711 illustrates such a mechanism. Actual count is 1 DOF. Gruebler Count indicates overconstraints. Optional demonstration: Create four-bar link (complete with rotational constraints) and verify. Use the link at the bottom of the slide to display the Constraints table. Quiz the students and ask them to enter the appropriate information about the revolute joint in the Constraints table in their guides. -RLQW ,QLWLDO &RQGLWLRQV ,&V &KDUDFWHULVWLFV RI MRLQW LQLWLDO FRQGLWLRQV ■ You can specify displacement and velocity initial conditions for revolute, translational, and cylindrical joints. ■ ADAMS/View uses the specified initial conditions of the joint while performing a simulation, regardless of any other forces acting on the joint. ■ If you do not specify joint ICs, ADAMS/Solver calculates the conditions of the connecting parts while performing a simulation depending on the other forces acting on the joint. Question: What would happen if the joint initial conditions in a system were different from the part initial conditions? One DOF Pendulum 97 Demonstrate: Use the pendulum model. Explain a positive rotation with respect to a negative rotation—it is very important that they understand this relationship. Optional: Turn on the icon display during simulation (Settings - Solver - Display - toggle icon button) to show that the I marker moves with the action body. Answer: To illustrate the answer, set the part initial conditions to be different from the joint initial conditions. 0HUJLQJ *HRPHWU\ 0HWKRGV RI DWWDFKLQJ PXOWLSOH JHRPHWU\ WR D SDUW ■ Using fixed joint to constrain geometric objects. ■ Adding new geometry to an existing part. Note: ADAMS/Solver handles simulations better if you merge geometry on a rigid part as opposed to constraining multiple parts. Question: When you merge geometry is the overlapping volume accounted for? 98 One DOF Pendulum Illustrate/explain using image provided: Two parts with one fixed joint equals 18 equations of motion (6/part and 6/constraint) One part with two geometries equals six equations of motion. Answer to question: No, there will exist overlapping geometry if you use merge (Add to Part). Minimize overlap when possible. Yes, if you use Boolean operations (unite two bodies). Demonstrate merge versus Boolean. $QJOH 0HDVXUHV 'HILQLWLRQ RI DQJOH PHDVXUHV They are used to measure the included angle, θ: ■ Between two vectors ■ Defined by three markers ■ Defined throughout a simulation ˆ y3 Third point ˆ z3 ˆ y2 Second point ˆ x2 ˆ x3 θ ˆ y1 ˆ z2 ˆ z1 First point ˆ x1 Notes: ■ The units used for angle measures are in current ADAMS/View angle units (degrees or radians). ■ The sign convention (+/-) is defined such that the first nonzero value is positive. One DOF Pendulum 99 Demonstrate: Build an angle measure using the Build menu (Build Measure Angle New). Explain that for a pendulum you have to create a new marker on ground to use as a reference. Æ Æ Æ :RUNVKRS ³2QH '2) 3HQGXOXP 3UREOHP VWDWHPHQW Find the initial force supported by the pin at A for a bar that swings in a vertical plane, given · the initial angular displacement (θ 0 ) and initial angular velocity ( θ 0 ). Also, find the pendulum frequency. A θ L= 45 0m 2 kgs m θ 0 = 30° B · θ 0 = 300°/sec 6WDUW WKH ZRUNVKRS First, you’ll start ADAMS/View from the directory exercise_dir/mod_06_pendulum and then you’ll create a new model. Executing ADAMS/View in this directory ensures that all saved data gets stored here. 7R VWDUW $'$069LHZ DQG FUHDWH PRGHO ■ Start ADAMS/View: ◆ Set the directory to exercise_dir/mod_06_pendulum. ◆ Create a new model named pendulum, with Gravity set to Earth Normal (-Global Y), and Units set to MMKS - mm, Kg, N, s, deg. 100 One DOF Pendulum Review the problem statement. Quiz the students on how they would solve the problem in MSC.ADAMS. Before they start, ask for questions. l For small displacements, the following approximation could apply: T = 2π -- g Our model swings through a large angle, however. :RUNVKRS ³2QH '2) 3HQGXOXP %XLOG WKH SHQGXOXP OLQN Now, build the link section of the pendulum using the following parameters: ■ Width: 20 mm ■ Depth: 27.5mm ■ Endpoints: (0, 0, 0) and (450, 0, 0) 7R EXLOG WKH OLQN 1 Turn on the coordinate window. 2 From the Main Toolbox, right-click the Rigid Body tool stack, and then select the Link tool 3 . In the container: ■ ■ Select Length, and in the Length text box, enter 450 mm, and then press Enter. ■ Select Width, and in the Width text box, enter 20 mm, and then press Enter. ■ 4 Select New Part. Select Depth, and in the Depth text box, enter 27.5 mm, and then press Enter. Using the mouse, select 0, 0, 0 and 450,0,0 as the endpoint locations. Tip: Use the Location Event (right-click away from the model) to help select the endpoints. When you right-click, the Location Event appears in the lower left corner of the ADAMS/View window. Enter the coordinates for the link in the upper text box and then press Enter. One DOF Pendulum 101 :RUNVKRS ³2QH '2) 3HQGXOXP %XLOG WKH VSKHUH VHFWLRQ Next, build the sphere section of the pendulum using the following parameters: ■ Add to Part ■ Radius: 25 mm ■ Centerpoint: 450, 0, 0 7R EXLOG WKH VSKHUH VHFWLRQ 1 From the Main Toolbox, right-click the Rigid Body tool stack, and then select the Sphere tool 2 . In the container: ■ Select Add to part. ■ Select Radius, and in the Radius text box, enter 25 mm, and then press Enter. 3 Using the mouse, select PART_2, which is the link, as the part to add to. 4 Using the mouse, select 450,0,0 as the location. 5HQDPH WKH SHQGXOXP Now you’ll rename the pendulum from PART_2 to Pendulum. 7R UHQDPH WKH SHQGXOXP 1 Right-click the link, point to Part:PART_2, and then select Rename. The Rename Object dialog box appears. 2 102 In the New Name text box, enter .pendulum.pendulum, and then select OK. One DOF Pendulum :RUNVKRS ³2QH '2) 3HQGXOXP 6HW WKH PDVV RI WKH SHQGXOXP Now, set the mass of the pendulum to 2 kg, set all three inertias (Ixx, Iyy, Izz) to 0, and change the location of the center of mass. 7R VHW WKH PDVV RI WKH SHQGXOXP 1 Right-click the pendulum, point to Part: pendulum, and then select Modify. 2 Set Define Mass by to User Input. An alert box will appear. Close it. 3 In the Mass text box, enter 2.0. 4 In the Inertia text boxes (Ixx, Iyy, Izz), enter 0. 5 Right-click the Center of Mass Marker text box, point to pendulum.pendulum.cm, and then select Modify. 6 In the Location text box, enter 450, 0, 0. 7 Select OK in both dialog boxes. You will receive a warning in the Message Window concerning the change in position of your center of mass marker. 8 Select Clear to close the Message Window. Your model should look like this (with shading turned on): One DOF Pendulum 103 :RUNVKRS ³2QH '2) 3HQGXOXP %XLOG WKH SLYRW In this section, you’ll build the pivot by creating a revolute joint between ground and the pendulum at location A, as shown in the figure on the page 94, and rename it Pivot. 7R EXLOG WKH SLYRW 1 From the Main Toolbox, right-click the Joint tool stack, and then select the Revolute joint tool . Joint tool stack 2 In the container, select 2 Bod-1 loc and Normal to Grid. 3 Select the pendulum as the first body. 4 Select the ground as the second body. 5 Select 0, 0, 0 as the location. 7R UHQDPH WKH MRLQW 1 Right-click the revolute joint, point to Joint:JOINT_1, and then select Rename. 2 In the New Name text box, enter .pendulum.pivot, and then select OK. 104 One DOF Pendulum :RUNVKRS ³2QH '2) 3HQGXOXP &UHDWH PHDVXUHV Create two object (joint) measures to track the force supported by the pin, resolved in the x g ˆ ˆ and y g directions. 7R FUHDWH REMHFW PHDVXUHV 1 Right-click the pivot joint, point to Joint:pivot, and then select Measure. 2 In the dialog box: ■ In the Measure Name text box, enter pivot_force_x. ■ Set Characteristic to Force, and select X as the Component. ■ Be sure .pendulum.MARKER_4 and Create Strip Chart are selected. ■ Select Apply. A stripchart displays the force during simulation and animation. 3 In the dialog box: ■ In the Measure Name text box, enter pivot_force_y. ■ Set Characteristic to Force, select Y as the Component. ■ Be sure .pendulum.MARKER_4 and Create Strip Chart are selected. ■ Select OK. A stripchart displays the force during simulation and animation. One DOF Pendulum 105 :RUNVKRS ³2QH '2) 3HQGXOXP &UHDWH D UHIHUHQFH PDUNHU Create a marker on ground to use as a reference location for the angle measure you will create in the next section. Instead of right-clicking on the marker to change its name, you’ll use the Edit menu. 7R FUHDWH D UHIHUHQFH PDUNHU 1 On the Main Toolbox, right-click the Rigid Body tool stack, and then select the Marker tool . 2 In the container, be sure that Add to ground and Global XY are selected. 3 Using the mouse, select 450, 0, 0 as the location. 4 With the marker still selected, from the Edit menu, select Rename. 5 In the New Name text box, enter .pendulum.ground.angle_ref, and then select OK. &UHDWH DQJOH PHDVXUH Now, create the angle measure to track the angular displacement of the pendulum, θ. 7R FUHDWH DQ DQJOH PHDVXUH 1 From the Build menu, point to Measure, point to Angle, and then select New. 2 In the Measure Name text box, enter pend_angle. 3 Right-click the First Marker text box, point to Marker, and then select Pick. 4 On the screen, pick a marker that is on the pendulum and at its end (for example, select the cm marker). Tip: Right-click the end of the pendulum to select the cm marker. 5 Right-click the Middle Marker text box, point to Marker, and then select Pick. 6 Pick a marker that is at the pivot location. 7 Right-click the Last Marker text box, point to Marker, and then select Pick. 106 One DOF Pendulum :RUNVKRS ³2QH '2) 3HQGXOXP 8 Pick the marker that is on the ground and at the end of the pendulum (this is the marker that you created in the previous section, .pendulum.ground.angle_ref). Note: By aligning the marker .pendulum.ground.angle_ref with the cm marker, the initial value of the measure will be zero. 9 Select OK. 6SHFLI\ LQLWLDO FRQGLWLRQV In this section, you’ll specify the following joint initial conditions: ■ Displacement initial condition of θ 0 = 30o ■ Initial velocity condition of θ 0 = 300o/sec · 7R VSHFLI\ WKH LQLWLDO FRQGLWLRQV 1 Right-click the pivot joint, point to Joint:pivot, and then select Modify. 2 Select Initial Conditions. 3 In the Joint Initial Conditions dialog box: ■ ■ 4 Select Rot. Displ and, in the Rot Displ. text box, enter -30. Select Rot. Velo. and, in the Rot Velo. text box, enter -300. Select OK in both dialog boxes. One DOF Pendulum 107 :RUNVKRS ³2QH '2) 3HQGXOXP 9HULI\ \RXU PRGHO Before simulating your model, verify it. 7R YHULI\ \RXU PRGHO 1 Select the Verify tool (from the Status bar, right-click the Information tool stack ). The Information window appears as shown next: You also receive a warning that the initial conditions for the joint position does not match the design configuration. This is what we expect. 2 Close the Information window. 6LPXODWH \RXU PRGHO Run a simulation for 2 seconds. 7R VLPXODWH \RXU PRGHO ■ 108 Run a simulation for 2 seconds with 100 steps, just as you did in Simulate the model, on page 52. One DOF Pendulum :RUNVKRS ³2QH '2) 3HQGXOXP 'HWHUPLQH JOREDO FRPSRQHQWV Now, determine the global components (x, y) of the initial force supported by the pivot. Use the value to answer Question 1 in Module review, on page 112. 7R GHWHUPLQH JOREDO FRPSRQHQWV 1 Right-click the blank area inside the pend_angle stripchart, point to Plot: scht1, and then select Transfer to Full Plot. ADAMS/PostProcessor replaces ADAMS/View. 2 Select the Plot Tracking tool . 3 Move the cursor over the plot at t =0. 4 In the area below the main toolbar, note the value of Y. 5 In the dashboard, select Clear Plot. 6 Set Source to Measures. 7 From the Measure list, select pivot_force_x. 8 Select Surf. 9 Move the cursor over the plot at t =0. 10 In the area below the main toolbar, note the value of Y. 11 From the Measure list, select pivot_force_y. 12 Move the cursor over the plot at t =0. 13 In the area below the main toolbar, note the value of Y. One DOF Pendulum 109 :RUNVKRS ³2QH '2) 3HQGXOXP 'HWHUPLQH WKH IUHTXHQF\ RI WKH SHQGXOXP Estimate the frequency by determining the period (seconds) and then inverting that value to obtain Hertz. This is the answer to Question 2 in Module review, on page 112. 7R GHWHUPLQH IUHTXHQF\ 1 From the Measure list, select pend_angle. 2 Estimate the period of the curve. 3 Invert the period to find Hertz. 4 Return to ADAMS/View. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Use the Save As option to save your modeling session such that the saved file contains not only the model information, but also the results and plots. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 2 110 Exit ADAMS/View. One DOF Pendulum :RUNVKRS ³2QH '2) 3HQGXOXP 2SWLRQDO WDVNV Save your work before performing these tasks. Do not save your work after performing these tasks. If you must save the model after performing these tasks, give the model a different name. 7R ILQG WKH IUHTXHQF\ RI WKH SHQGXOXP DXWRPDWLFDOO\ E\ SHUIRUPLQJ D )DVW )RXULHU 7UDQVIRUPDWLRQ ))7 RQ WKH SORW RI WKHWD YHUVXV WLPH 1 Set up for the FFT by simulating the model based on current findings: ◆ ◆ 2 End time = 1.65 (approximate time of one period) Steps = 127 In ADAMS/PostProcessor, from the Plot menu, select FFT. The FFT dialog box appears. 3 When preparing for an FFT operation, we recommend that: ■ The number of points be an even power of two (for example, 128, 256, 512, and so on). By solving the equation and asking for 127 steps, you will get 128 data points; 127 + 1 for the initial conditions. ■ You set Window Type to Rectangle. ■ You select Detrend Input Data. You should get approximately the same frequency as you did by calculating it manually. The peak value of the resultant curve is the frequency. 4 To perform the FFT, select Apply. To learn more about these values, press F1. You should get the same frequency as you did by calculating it manually. The peak value of the resultant curve is at the natural frequency. 5 Return to ADAMS/View. 6 Exit ADAMS/View. One DOF Pendulum 111 :RUNVKRS ³2QH '2) 3HQGXOXP 0RGXOH UHYLHZ 1 What are the global components of the initial force supported by the pivot? 2 What is the frequency of the pendulum using the initial conditions in the problem statement? 3 If the initial velocity of a part can be set through a connecting joint and the part itself, which will ADAMS/View use if they are both set? 4 If a model (human_hip) had two parts (femur and hip_bone) constrained by a joint, I and J markers would be created by MSC.ADAMS. If one marker were named MAR_1, and the other MAR_2, what would the complete name of the I and J markers be? 5 Can the I and J markers for a joint belong to the same part? Why? 112 Question 4: Draw it out on the board in the hierarchy format. One DOF Pendulum :RUNVKRS ³2QH '2) 3HQGXOXP 06&$'$06 UHVXOWV ■ Horizontal force supported by the pivot at A = -An cos 30. ■ Vertical force supported by the pivot at A = An sin 30. &ORVHGIRUP VROXWLRQ At I A = I zz + mr An I A = 0 + mL θ0 pt. A 2 2 ω 0 = 300°/sec ω 0 = 5.24rad/sec m ω o, α mg The analytical solution for the force supported by the pivot at A when θ 0 = 30o and ω 0 = 300 degrees/sec: 2 ΣM A = I A α – mg ( L cos 30 ) = ( mL )α g cos 30 = Lα g α = – -- cos 30 L α = – 18.88 rad/sec ΣF t = mrα 2 mg cos 30 – A t = mLα A t = m ( g cos 30 – Lα ) A t = 0N ΣF n = mrω 2 A n – mg sin 30 = mLω 2 2 A n = m ( g sin 30 + Lω ) A n = 34.53N One DOF Pendulum 113 :RUNVKRS ³2QH '2) 3HQGXOXP 114 One DOF Pendulum  ,1&/,1(' 3/$1( Find the minimum inclination that will ensure that a crate slides off an inclined plane, using the properties shown next: g = 32.2 ft/sec 2 µ s = 0.3 µ d = 0.25 10 in Crate 4 in 2 in Mass = 100 lbs Ramp 46 in 8 in 7KLV PRGXOH LQFOXGHV ■ Euler Angles (Rotation Sequence), 116 ■ Precise Positioning: Rotate, 117 ■ Modeling Friction, 118 ■ Measures in LCS, 121 ■ Workshop 7—Inclined Plane, 122 ◆ Module review, 133 115 ■ Review the problem statement. ■ Ask the students to enter the appropriate information about translational joints into the Constraints table. ■ Demonstrate translational joints. (XOHU $QJOHV 5RWDWLRQ 6HTXHQFH 'HILQLWLRQ RI (XOHU DQJOHV ■ ADAMS/View uses three angles to perform three rotations about the axes of a coordinate system. ■ These rotations can be space-fixed or body-fixed and are represented as Body [3 1 3], Space [1 2 3], and so on, where: ◆ 1 = x axis ◆ 2 = y axis ◆ 3 = z axis For rotation about these axes, use the right-hand rule Default in MSC.ADAMS is Body [3 1 3]. ■ ([DPSOH RI ERG\ >  @ >° ° °@ Initial Orientation (Base CS) ˆ x - ˆ y′ ˆ z″ +90° about the z-axis + ˆ y″ ˆ z ˆ y ˆ x ˆ z′ ˆ z After 3rd Rotation (Positioned CS) ˆ x″ ˆ x′ ˆ y + After 2nd Rotation After 1st Rotation +180° about the z´´-axis - 90° about the x´-axis ([DPSOH RI VSDFH >  @ >° ° °@ Initial Orientation (Base CS) After 1st Rotation + ˆ z +90° about the base CS z-axis 116 ˆ z″ ˆ x′ ˆ y ˆ x - ˆ y′ After 3rd Rotation (Positioned CS) After 2nd Rotation ˆ y″ ˆ z′ - 90° about the base CS x-axis ˆ x ˆ x″ ˆ y + +180° about the base CS z-axis ˆ z Inclined Plane Give an overview of rotation sequences and explain that there are different types of rotation sequences. Do not review the slide in detail. Take questions individually. Mention other methods of determining orientation (Along axis, inplane). Demonstrate: You can use this demonstration or recreate first example above. Create two markers that are both initially aligned with global orientation (0,0,0). Assign one of the two markers the Body [313] orientation described above, as follows: Modify one of the marker’s orientation to be 90,0,0, and then compare the two. Then modify its orientation to be 90,-90,0, and then compare the two. Then modify it to have the third and final rotation, 90,-90,180. 3UHFLVH 3RVLWLRQLQJ 5RWDWH 7R URWDWH REMHFWV DERXW DQ D[LV LQ $'$069LHZ VSHFLI\ ■ The objects to rotate. ■ The axis about which the objects are rotated. ■ The angle through which the objects are rotated. 45o Note: Be careful with the sign of the angle. ADAMS/View uses the right-hand rule. You can rotate several objects at once about the same axis. Inclined Plane 117 Demonstrate: Rotate an object. Use the Position: Rotate objects... tool in the tool stack in lower left side of the Main Toolbox. Then, rotate multiple objects at once using the select list. Question: In the figure, what information would you give ADAMS/View to rotate the objects? Answer: You could rotate either body, but, in this case, rotate the link (the lower part). Create a marker on the link on the edge closest to the cylinder, and rotate the link about the axis of the marker that runs along the long edge of the link. -45o (note negative sign) 0RGHOLQJ )ULFWLRQ -RLQW IULFWLRQ FDQ EH DSSOLHG WR ■ Translational joints (Translational Joint, DOF Removed by, see page 374) ■ Revolute joints ■ Cylindrical joints ■ Hooke/Universal joints ■ Spherical joints )ULFWLRQ IRUFHV )I ■ Are independent of the contact area between two bodies. ■ Act in a direction opposite to that of the relative velocity between the two bodies. ■ Are proportional to the normal force (N) between the two bodies by a constant (µ). F = µN f 3KDVHV WKDW GHILQH IULFWLRQ IRUFHV ■ Stiction ■ Transition ■ Dynamic 118 Demonstrate: Add joint friction to any constraint. Point out that the images on the next page exaggerate the stiction phase to better illustrate it. Bending and torsional moments are beyond the scope of this course. Do not explain these. Demonstrate the Joint Friction dialog box using the online documentation. In the online documentation, use the global search tool to find Joints: adding Friction to, and explain: Stiction threshold velocity, max stiction displacement, and preloads Go back to the module cover page to review the problem statement again, then continue. Inclined Plane 0RGHOLQJ )ULFWLRQ ,GHDOL]HG FDVH µ ■ Stiction: V rel = 0 µs 0 < µ < µs ■ µd Transition: 0 < V rel = V 1 Dynamic: Stiction Vrel µd < µ < µ s ■ Transition Dynamic V1 -V1 V 1 < V rel −µd −µs µ = µd $'$066ROYHU FDVH ■ Stiction: V rel < ∆V s Transition: ∆V s < V rel < 1.5∆V s µd < µ < µs ■ Transition Dynamic Stiction µs µd 0 < µ < µs ■ µ Dynamic: µ = µd -1.5∆Vs−∆Vs ∆Vs 1.5∆V s < V rel Vrel 1.5∆Vs −µd −µs Inclined Plane Use the illustrations to identify stiction threshold velocity and relate it to the maximum stiction deformation. 119 0RGHOLQJ )ULFWLRQ (IIHFW RI PD[LPXP GHIRUPDWLRQ RQ IULFWLRQ µs µd µ Vrel −µd −µs ∆Xs ∆Xs ∆Xs ,QSXW IRUFHV WR IULFWLRQ ■ ■ 120 Always include preload and reaction force. Bending and torsional moment are possible (however, advanced uses of joint friction are beyond the scope of this course). Inclined Plane 0HDVXUHV LQ /&6 0HDVXUHV FDQ EH UHSUHVHQWHG LQ ■ Global coordinate system (GCS) (default) ■ A marker’s local coordinate system (LCS) ([DPSOH ■ When a ball falls due to gravity: Gravity ˆ y ˆ y1 G θ = 30° ˆ zG ˆ xG Global ■ ˆ z1 ˆ x1 MAR_1 ˆ ˆ ˆ Acceleration due to gravity in the GCS using x g ,y g ,z g symbols to represent the global x, y, and z components is: ˆ ˆ ˆ m g = ( 0x g – 9.81y g + 0z g ) --s2 ■ Acceleration due to gravity in MAR_1's coordinate system is: ˆ ˆ ˆ m g = ( 0x 1 – ( 9.81 sin 30 ° ) y 1 – ( 9.81 cos 30 ° ) z 1 ) ---s2 ˆ ˆ ˆ m g = ( 0x 1 + – 4.91y 1 1 –1 8.50 z 1 ) ---s2 Inclined Plane 121 Demonstrate: Use a model in which you can use a reference marker in the Modify Measurement dialog box. The reference marker could be any marker in the model. It could be attached to the object being measured. Question: Compare the acceleration of a ball in the y-direction of two different CS. Why are they different? Because: In the global case, all of the ball’s acceleration is in the y-direction, and the acceleration in the x- and z-directions is zero. In MARKER_1’s case, only a portion of the acceleration is in the y-direction, the remaining acceleration is in the z-direction, and the acceleration in the x-direction is zero. :RUNVKRS ³,QFOLQHG 3ODQH 3UREOHP VWDWHPHQW Find the minimum inclination that will ensure that a crate slides off an inclined plane, using the properties shown next: g = 386.4 in/sec2 (32.2 ft/sec2) µ s = 0.3 µ d = 0.25 10 in Crate 4 in 2 in Mass = 100 lbs Ramp 46 in 8 in 6WDUW WKH ZRUNVKRS First, you’ll start ADAMS/View from the directory exercise_dir/mod_07_inclined_plane and then create a new model. 7R VWDUW WKH ZRUNVKRS ■ Start ADAMS/View: ◆ Set the directory to exercise_dir/mod_07_inclined_plane. ◆ Create a new model named inclined_plane, with Gravity set to Earth Normal (-Global Y), and Units set to IPS - inch, lb, lbf, s, deg. 122 Inclined Plane Illustrate the problem statement and quiz students on what they think needs to be done to complete the workshop. Before they start, ask if there are any questions. :RUNVKRS ³,QFOLQHG 3ODQH $GMXVW WKH ZRUNLQJ JULG Now adjust the spacing and orientation of the working grid. 7R DGMXVW WKH VSDFLQJ DQG RULHQWDWLRQ RI WKH ZRUNLQJ JULG 1 From the Settings menu, select Working Grid. 2 Set Spacing to 1 in in the x and y direction. 3 Make sure that the working grid is oriented along the global XY direction (default setting when you open ADAMS/View). The Set Orientation pull-down menu allows you to choose Global XY, YZ, XZ, or custom orientation. 4 Select OK. %XLOG WKH SDUWV When creating parts, use an inclination angle of 0o. You will rotate the parts to the desired inclination angle later in the exercise. Be sure to set the ramp geometry to be on ground. 7R EXLOG WKH SDUWV 1 Build the ramp geometry using the following parameters: ◆ ◆ Length: 46 in ◆ Height: 2 in ◆ 2 On ground Depth: 8 in Build the crate geometry using the following parameters: ◆ ◆ Length: 10 in ◆ Height: 4 in ◆ 3 New part Depth: 8 in Position the crate near the end of the ramp, as shown next: Crate Ramp Inclined Plane 123 :RUNVKRS ³,QFOLQHG 3ODQH 7R PRGLI\ WKH SDUWV 1 Rename the crate and the ramp geometry as shown in the figure on page 122. Note: Make sure that you rename just the geometry and not the ground part. ■ ■ Enter Ramp. ■ Select OK. ■ 2 Right-click on the large box, point to Block: Box_1, and then select Rename. Repeat this step for PART_2, naming it Crate. Set the Mass of the crate to 100 lbm: ■ Right-click the crate, point to Part:crate, and then select Modify. ■ Set Define Mass by to User Input. ■ In the Mass text box, enter 100 lbm. ■ Select OK. 6HW WKH PRGHO·V LQFOLQDWLRQ DQJOH Now you are going to rotate the model 15o. Because the ramp is on ground and you cannot rotate ground, to rotate the ramp, you are going to change the orientation of the ramp’s corner marker to 15, 0, 0. The orientation of this marker sets the orientation for the ramp. You’ll use the Rotate tool to rotate the crate since it is not on ground. You’ll rotate the crate about the same axis that you rotated the ramp about. 124 Inclined Plane :RUNVKRS ³,QFOLQHG 3ODQH 7R URWDWH WKH UDPS WR θ R 1 Right-click the ramp’s corner marker, point to MARKER_1, and then select Modify. 2 In the Orientation text box, change 0,0,0 to 15,0,0. Figure 1. Model of Inclined Plane Ramp Crate Corner marker 7R URWDWH WKH FUDWH R 1 In the Main Toolbox, from the Move tool stack, select the Align & Rotate tool . Move tool stack 2 In the container, in the Angle text box, enter 15 as the increment by which to rotate the crate. Note: After you enter this value, if your cursor does not sweep the text box (that is, move from inside the text box to outside the text box), press Enter to ensure that the text box registered the value you entered. 3 Select the crate as the object to rotate. Inclined Plane 125 :RUNVKRS ³,QFOLQHG 3ODQH 4 Select the z-axis of MARKER_1 as the axis about which to rotate. Tip: To easily select the z-axis, it helps if you slightly rotate the view around the x-axis. Select the z-axis Completed rotation &RQVWUDLQ WKH PRGHO Now you’ll create a translational joint between the ramp and the crate. 7R FRQVWUDLQ WKH PRGHO ■ From the Main Toolbox, right-click the Joint tool stack, and then select the Translational Joint tool . ◆ ◆ Set the location of the translational joint at the crate geometry’s base marker, MARKER_2. ◆ 126 Use the options 2 Bodies - 1 Loc and Pick Feature. Set the vector so it points up the ramp: select the x-axis of MARKER_2. Inclined Plane :RUNVKRS ³,QFOLQHG 3ODQH 7DNH PHDVXUHPHQWV 7R FUHDWH D PHDVXUH ■ Create an object (part) measure for the crate’s acceleration along the ramp as you did in To create object measures:, on page 105: ◆ Characteristic: CM acceleration ◆ Component: X ◆ Represent coordinates in: MARKER_1 (for the location of the corner marker, see Figure 1 on page 125). 9HULI\ WKH PHFKDQLVP FUDZOZDONUXQ 7R YHULI\ WKH PHFKDQLVP 1 Simulate the model for 1 second and 50 steps. 2 Find the value of the crate’s (constant) acceleration. To verify this value, see Without friction in the Closed-form solution, on page 134. If the values do not match, check the units in the closed-form solution and in the model. Inclined Plane 127 Some students might get values greater than 0 for acceleration plots when the crate shouldn’t be moving. To solve this problem. Reduce the step size of the simulation for greater accuracy of calculations. :RUNVKRS ³,QFOLQHG 3ODQH 5HILQH WKH PRGHO In this section, you’ll add joint friction to the translational joint using the µs, µd values from the problem statement on page 122. You’ll then simulate the model to see if the crate slides off the ramp. Tip: Be sure that the only friction forces to consider are those resulting from reaction forces. 7R DGG IULFWLRQ DQG VLPXODWH 1 Display the joint’s modify dialog box (right-click the translational joint, point to Joint:JOINT_1, and then select Modify). 2 In the lower right corner of the Modify dialog box, select the Friction tool 3 Fill in the coefficients of friction provided on page 122. 4 Leave the remaining friction parameters at their default values. 5 In the Input Forces to Friction section, deactivate Bending Moment and Torsional Moment. 6 Simulate the model and note if the crate slides off the ramp. 7 Right-click on the curve in the stripchart, and then select Save Curve. 128 . Inclined Plane :RUNVKRS ³,QFOLQHG 3ODQH 5RWDWH WKH UDPS DQG FUDWH WR WKHWD R To rotate the ramp and crate, you’ll create a group consisting of the crate part, joints, and geometry making up the ramp. You’ll then select that group and rotate it. 7R FUHDWH D JURXS 1 From the Build menu, select Group. 2 Make a group, named rotated_objects, containing: ■ The crate part. ■ The joint. ■ All of the geometry (including markers) on the ramp, but not the ground part itself, because, remember, you cannot rotate ground. Tip: Right-click the Objects in Group text box, and browse for the objects you need. You can select multiple objects by holding down the Ctrl key. The next figure shows the objects you should select: Inclined Plane Do not include friction in the group. It is dependent on the joint and will automatically move with the joint. 129 :RUNVKRS ³,QFOLQHG 3ODQH 7R URWDWH WKH JURXS 1 In the Main Toolbox, from the Move tool stack, select the Precision Move tool 2 Set Relocate the to group. 3 In the text box to the right of Relocate the, enter the group name. 4 Set the menus in the second row to About the and marker. 5 . In the text box to the right of these menus, enter MARKER_1. The Precision Move tool rotates objects in increments about a specified axis of the marker you just selected. 6 In the text box, enter 5. 7 Select the Z-axis box. Note that you can select the axis box (either X, Y, or Z) to rotate a group to the desired orientation. The following shows the Precision Move dialog box after you’ve entered the values in steps 2 through 6. Because you’ve already rotated the ramp to 15 degrees, and now you want to rotate it to 20, enter 5 as the angle. 8 130 Do not select OK or Apply. Inclined Plane :RUNVKRS ³,QFOLQHG 3ODQH )LQG LQFOLQDWLRQ DQJOHV 7R ILQG WKH LQFOLQDWLRQ DQJOHV EHWZHHQ ZKLFK WKH FUDWH VWDUWV WR VOLGH Simulate the model and note if the crate slides off the ramp. For an end time of 0.5 seconds, verify that the crate acceleration versus time stripchart matches the adjoining figure. The initial spike is due to the acceleration (due to gravity) present at t=0. inches/sec2 1 sec 2 Through trial and error, find the approximate angle (within 0.5o) at which the crate starts to slide off the ramp. Use it to answer Question 1 in Module review, on page 133. 6DYH \RXU ZRUN Save your model and, unless you want to further explore the model as suggested in the next section, exit ADAMS/View. Inclined Plane 131 :RUNVKRS ³,QFOLQHG 3ODQH 2SWLRQDO WDVNV Save your work before performing these tasks. Do not save your work after performing these tasks. If you must save the model after performing these tasks, give the model a different name. 7R YLHZ DQ DQLPDWLRQ DQG LWV FRUUHVSRQGLQJ SORW VLPXOWDQHRXVO\ 1 Open ADAMS/PostProcessor. 2 Create two views by right-clicking the Window layout tool the 2 Views, side by side tool . 3 Select the left view. 4 Plot crate acceleration versus time. 5 Select the right view, and then change the Plotting menu to Animation. 6 Right-click the right view, and then select Load Animation. 7 Run the animation. 132 on the toolbar and selecting Inclined Plane :RUNVKRS ³,QFOLQHG 3ODQH 0RGXOH UHYLHZ 1 What is the approximate angle (within 0.5o) at which the crate starts to slide off the ramp? 2 How can you tell if you can automatically add friction to a joint type? 3 What are the I and J markers? 4 If a joint with friction enabled crosses its stiction threshold velocity ( ∆ V s ), how does the maximum stiction displacement ( ∆ X s ) affect the system? Inclined Plane 133 :RUNVKRS ³,QFOLQHG 3ODQH &ORVHGIRUP VROXWLRQ ˆ y m⋅g ˆ x θ Ff N :LWKRXW IULFWLRQ ΣF x = ma x : – mg ⋅ sin θ = ma x a x = – g sin θ For θ = 15° , a x = – 32.2 sin ( 15° ) a x = – 99.96 in/sec2 (-8.33 ft/sec2) :LWK IULFWLRQ ΣF y = 0 : – mg ⋅ cos θ + N = 0 N = mg ⋅ cos θ Maximum angle (θmax) at which the crate will not slide: ΣF x = 0 : F f – mg ⋅ sin θ max = 0 µ s ⋅ N – mg ⋅ sin θ max = 0 µ s ⋅ mg ⋅ cos θ max – mg ⋅ sin θ max = 0 µ s – tan θ max = 0 θ max = atan ( µ s ) = atan ( 0.30 ) = 16.7° 134 Inclined Plane :RUNVKRS ³,QFOLQHG 3ODQH Once the crate starts sliding, ΣF x = ma x : F f – mg ⋅ sin θ = ma x µ k ⋅ N – mg ⋅ sin θ = ma x µ k ⋅ mg ⋅ cos θ – mg ⋅ sin θ = ma x ax µ k ⋅ cos θ – sin θ = ---g a x = ( µ k cos θ – sin θ ) ⋅ g For θ = 20o, a x = ( 0.25 ⋅ cos 20° – sin 20° ) ⋅ 32.2 ft/sec 2 a x = – 40.3 in/sec2 (-3.45 ft/sec2) 06&$'$06 UHVXOWV ■ At angle θ = 15o, a = 6.63e – 5 ≈ 0 ■ At angle θ = 20o, the crate accelerates down the inclined plane at: a = -41.35 in/sec2 (-3.45 ft/sec2) ■ Based on the angular increments of 0.5o, (16.5o < θmax < 17.0o) Inclined Plane 135 :RUNVKRS ³,QFOLQHG 3ODQH 136 Inclined Plane  /,)7 0(&+$1,60 , Use ADAMS/View to create each moving part of the lift mechanism shown next: Bucket Boom Shoulder Base Mount 7KLV PRGXOH LQFOXGHV ■ Building Geometry, 138 ■ Construction Geometry Properties, 140 ■ Solid Geometry, 142 ■ Precise Positioning: Move, 143 ■ Workshop 8—Lift Mechanism I, 144 ◆ Module review, 151 137 ■ Review the problem statement. ■ The objective of this module is to learn how to create geometry in ADAMS/View. ■ After this module you will not spend much time working with geometry. ■ Asking the students to divide into groups to work through modules 8 through 10 might help them get through those modules faster and understand them better. %XLOGLQJ *HRPHWU\ 3URSHUWLHV RI JHRPHWU\ ■ It must belong to a part and moves with the part. ■ It is used to add graphics to enhance the visualization of a part. ■ It is not necessary for performing simulations. ■ Locations and orientations are defined indirectly by parts using anchor markers. Note: If you move an anchor marker, all associated geometry moves with it. Conversely, anchor markers move when you move the associated geometry. 138 Lift Mechanism I Demonstrate: Display a Part Modify dialog box and a Geometry Modify dialog box. Highlight that the part tracks information such as mass and inertia, while the geometry tracks shape using parameters such as radius and length. %XLOGLQJ *HRPHWU\ 7\SHV RI JHRPHWU\ LQ $'$069LHZ ■ Construction geometry ◆ ◆ ■ Includes objects that have no mass (spline, arc, and so on). Is used to define other geometry. Solid geometry ◆ Includes objects with mass (box, link, and so on). ◆ Can be based on construction geometry. ◆ Is used to automatically calculate mass properties for the parent part. Lift Mechanism I Demonstrate building various geometries to show the anchor markers. 139 &RQVWUXFWLRQ *HRPHWU\ 3URSHUWLHV 0DUNHU JHRPHWU\ Has: ˆ y ■ ˆ z Anchor marker, which is itself ■ Parent: part ■ ˆ x Orientation and location 3RLQW JHRPHWU\ Has: ■ ■ Parent: part ■ 140 No anchor marker Location Lift Mechanism I &RQVWUXFWLRQ *HRPHWU\ 3URSHUWLHV 3RO\OLQH JHRPHWU\ Has: ■ No anchor marker ■ Parent: part ■ One line or multiple lines ■ Open or closed ■ Length, vertex points, and angle $UF JHRPHWU\ Has: ■ Anchor marker ■ Parent: part ■ Start and end angle, radius 6SOLQH JHRPHWU\ Has: ■ ■ Parent: part ■ Lift Mechanism I Anchor marker Segment count, open/closed, points 141 6ROLG *HRPHWU\ %ORFN JHRPHWU\ Has: ■ Anchor marker, which is the corner marker ■ Parent: part ■ Length (x), height (y), depth (z) with respect to corner marker 7RUXV JHRPHWU\ Has: ■ Anchor marker, which is the center marker ■ Parent: part ■ Radius of ring (xy plane), radius of circular cross section ( to xy plane) ([WUXVLRQ JHRPHWU\ Has: ■ Anchor marker, which is the reference marker ■ Parent: part ■ Open/closed profile, depth, forward/ backwards &\OLQGHU JHRPHWU\ Has: ■ ■ Parent: part ■ 142 Anchor marker, which is the center marker (placed at first end) Length (z), radius Lift Mechanism I All geometry has anchor markers. In the case of the cylinder, the anchor marker is referred to as a center marker. A sphere also has a center marker. The anchor marker for a block is called a corner marker. Sometimes, you have to move parts around by moving the anchor marker. Demonstrate how a link and plate are different from other solid geometries. Demonstrate: Create a cylinder and then identify the anchor marker at one end of the cylinder that defines the cylinder’s location and orientation. Move the anchor marker to demonstrate that the cylinder moves with it. Rotate the marker and the cylinder also rotates. 3UHFLVH 3RVLWLRQLQJ 0RYH 7R PRYH REMHFWV LQ $'$069LHZ VSHFLI\ ■ The object being moved (or copied). ■ And: ◆ Either, a point on the object, and the location to which the selected point will be moved. ◆ Or, a vector and a distance along the vector. From point To point The moved object maintains its orientation. Lift Mechanism I 143 You can move geometry by moving anchor markers, but there is a tool that allows you to translate any object, not just geometry. This tool is called the Position: Move - Translate Objects tool, and it is available in the Main Toolbox. Three other tools that you can use to move geometry are: Location event (demonstrate this). Working Grid (demonstrate the setting for Location and Orientation). Precision Move (demonstrate this). :RUNVKRS ³/LIW 0HFKDQLVP , 3UREOHP VWDWHPHQW Use ADAMS/View to create each moving part of the lift mechanism shown next: Bucket Boom Shoulder Base Mount :RUNVKRS FKDOOHQJH If you’d like a challenge, build this model without going through the detailed steps presented on the following pages. Use the dimensions shown on page 146 to: ■ Create the base ■ Create the mount ■ Create the shoulder ■ Create the boom ■ Fillet the mount to round off the edges ■ Create the bucket ■ Chamfer the bottom edges of the bucket ■ Hollow out the bucket Otherwise, continue by following the detailed instructions. 144 Lift Mechanism I :RUNVKRS ³/LIW 0HFKDQLVP , %DFNJURXQG PHFKDQLVP LQIRUPDWLRQ ■ The following diagrams provide the dimensions for building the lift mechanism. ■ All units are in meters. 7LSV EHIRUH \RX VWDUW ■ Check the three-dimensional view of the model at regular intervals to verify that the parts are being placed in the right location. ■ Rename parts as soon as you build them. ■ You should save your model periodically throughout the modeling process. This becomes more important as you start to build complex models (recall the crawl-walkrun approach introduced in Workshop 5—Projectile Motion, on page 83). 6WDUW WKH ZRUNVKRS First, you’ll start ADAMS/View from the directory exercise_dir/mod_08_lift_mech_1 and create a new model. 7R VWDUW WKH ZRUNVKRS ■ Start ADAMS/View: ◆ Set the directory to exercise_dir/mod_08_lift_mech_1. ◆ Create a new model named lift_mech, with Gravity set to Earth Normal (-Global Y), and Units set to MKS - m, kg, N, s, deg. 6HW XS WKH ZRUNLQJ HQYLURQPHQW Now you’ll set up the MSC.ADAMS environment to make it easier to build the model. 7R VHW XS WKH ZRUNLQJ HQYLURQPHQW 1 Adjust the grid based on the measurements given in the images on page 145. The grid must be slightly larger than the maximum heigth and width of the model. (A 20 m x 20 m grid, with 1 m spacing in each direction should be good.) 2 Because the grid spacing is much greater than the default, you’ll have to zoom out to see the grid on your screen. Lift Mechanism I 145 Review the problem statement and quiz the students on what they think needs to be done to complete the workshop. Demonstrate the fillet, chamfer, and hollow tools. Before they start, ask for questions. :RUNVKRS ³/LIW 0HFKDQLVP , Top View of Lift Mechanism Base 1.5 0.25 Mount Shoulder 4.0 8.0 3.5 Boom Bucket 0.25 1.0 dia ˆ xG 2.0 dia ˆ zG Front View of Lift Mechanism 4.5 Bucket 0.25 0.5 13.0 1.5 Shoulder 0.25 Mount Base 4.0 ˆ y 8.5 (y dimension) Boom 1.5 1.5 3.0 1.5 10.0 12.0 18.75 (x dimension) G ˆ xG 146 Lift Mechanism I :RUNVKRS ³/LIW 0HFKDQLVP , %XLOG DOO SDUWV H[FHSW IRU WKH EXFNHW In this section, you’ll create all the parts except the bucket. For information on how to build the parts, refer to the diagrams in Background mechanism information, on page 145. 7R EXLOG WKH SDUWV 1 Build the base part. Tip: Note the orientation of the block with respect to the xy plane. 2 Be default, the screen icons are set for models in millimeters. Because your model is in meters, you should adjust the icon sizes so you can see the icons. To adjust the icons, from the Settings menu, select Icons, and then set New Size to 1. 3 Build the main feature of the mount part by creating a block. 4 Inspect your model. Note that the mount must be centered on the base. If necessary, use (also known as the Position: Movethe vector option of the Point-to-Point tool Translate tool) on the Move tool stack to slide the mount along the base, in the global z direction, by 2.25 m. 5 Before building the shoulder, set the working grid to cut through the center of the block representing the mount part: Settings Æ Working Grid Æ Set Location Æ Pick, and then select the cm marker of the block. 6 Change the spacing of the working grid to .5 m. If you do not change the spacing, you will notice that when you try to create the shoulder part, ADAMS/View snaps to the nearest grid point, thus building the shoulder in a position that is not parallel to the base part. 7 Use the Cylinder tool 8 Build the boom part. 9 Use the Location Event, as you did in Build the pendulum link, on page 101, to start the cylinder 2 meters over from the center-of-mass (cm) marker of the mount part. Lift Mechanism I to build the shoulder part. 147 :RUNVKRS ³/LIW 0HFKDQLVP , 10 Apply fillets to the mount part using the Fillet tool : ■ In both the Radius and End Radius text boxes, enter 1.5 m. ■ Left-click each edge, and then right-click to create. Refer to the next figure to see the edges you should select. Select the top edges x x The filleted mount part should look as shown next: 148 Lift Mechanism I :RUNVKRS ³/LIW 0HFKDQLVP , %XLOG WKH EXFNHW Now build the bucket. 7R EXLOG WKH EXFNHW 1 Build a block with the largest dimensions of the bucket: ■ 4.5 m ■ Height: 3.0 m ■ 2 Length: Depth: 4.0 m Chamfer the front and back, bottom corners of the block using the Chamfer tool : ■ In the Width text box, enter 1.5 m. ■ Left-click each edge, and then right-click to create. Refer to the next figure to see the edges you should select. x x Select the bottom edges Lift Mechanism I 149 :RUNVKRS ³/LIW 0HFKDQLVP , The chamfered bucket should look as shown next: 3 Hollow out the solid bucket using the Hollow tool ■ In the Thickness text box, enter 0.25 m. ■ : Pierce the top face of the bucket. The hollowed bucket should look as shown next: &KHFN PRGHO WRSRORJ\ E\ SDUWV 7R FKHFN PRGHO WRSRORJ\ ■ Check model topology by parts (from the Status bar, right-click the Information tool stack , and then select the Model topology by parts tool no floating parts that are not accounted for. ) to ensure that there are There should be six parts, including ground. 6DYH \RXU ZRUN Save your work such that the saved file contains only the model topology and not the results (File Æ Export). 150 Lift Mechanism I :RUNVKRS ³/LIW 0HFKDQLVP , 2SWLRQDO WDVNV 7R UHILQH WKH JHRPHWU\ RI WKH OLIW PHFKDQLVP 1 Using the Torus tool, add tires to the lift mechanism. 2 Using the Fillet tool, round the edges of the base. 0RGXOH UHYLHZ 1 What is the basic difference between construction geometry and solid geometry? 2 In this workshop were instructions for changing the position of parts. Name three of the four methods introduced. Lift Mechanism I 151 :RUNVKRS ³/LIW 0HFKDQLVP , 152 Lift Mechanism I  /,)7 0(&+$1,60 ,, Constrain the lift mechanism model by adding joints and motions as shown next: Boom with respect to shoulder Mount with respect to base Boom with respect to bucket Shoulder with respect to mount 7KLV PRGXOH LQFOXGHV ■ Fixed Joint, DOF Removed by, 374 ■ Applying Motion, 154 ■ Joint Motion, 155 ■ Functions in MSC.ADAMS, 156 ■ Workshop 9—Lift Mechanism II, 157 ◆ Module review, 162 153 ■ Review the problem statement. ■ In this module, you will not only constrain the mechanism but you will also actuate it. ■ The first concept in this module introduces the fixed joint. Use the Fixed Joints link on the slide, to display the Constraints table. Ask the students to add the information about the fixed joint to the Constraints table. ■ Asking the students to divide into groups to work through modules 8 through 10 might help them get through those modules faster and understand them better. $SSO\LQJ 0RWLRQ $'$069LHZ SURYLGHV WZR W\SHV RI PRWLRQV ■ Joint motion ■ Point motion -RLQW PRWLRQ ■ There are two types: ◆ Translational: applied to translational or cylindrical joints (removes 1 DOF). ◆ Rotational: applied to revolute or cylindrical joints (removes 1 DOF). ■ You define the joint to which motion is applied. ■ MSC.ADAMS automatically uses the joint’s I and J markers, bodies, and single DOF. ■ You define function for magnitude. Questions: How does a motion remove DOF? Does this mean that a motion is considered a constraint? 154 Lift Mechanism II Demonstrate: Build a pendulum and simulate it with gravity turned on. Verify that the model has one DOF. Then, add a rotational joint motion to the revolute joint to show how the motion moves the pendulum. Verify again that the model has zero DOF. ADAMS/Solver uses radians for angle values in function expressions. To define motions using degrees, add a “d” after the number and MSC.ADAMS recognizes the value as degrees. Answer: Yes, a motion is a constraining factor as it removes one DOF. Example: If you want 55o, enter 55d. ADAMS/Solver takes the value 55, multiplies it by pi/180, and converts it to radians before using it. -RLQW 0RWLRQ 0DUNHU XVDJH LQ MRLQW PRWLRQV ■ The I and J markers (and, therefore, the parts to which they belong) referenced in the joint move with respect to each other as follows: ˆ ˆ y i, y j ˆ yi ˆ yj ˆ ˆ z i, z j ˆ xi ˆ ˆ x i, x j θ ˆ xj ˆ ˆ z i, z j ■ The I and J markers overlap when motion θt = 0. ■ During simulation, the z-axes of both markers are aligned. ■ You can define motion magnitude as a: ◆ Displacement ◆ Velocity ◆ Acceleration function of time Lift Mechanism II 155 )XQFWLRQV LQ 06&$'$06 'HILQLWLRQ RI IXQFWLRQV LQ 06&$'$06 ■ You use functions to define magnitudes of input vectors used in: ◆ Motion drivers ◆ Applied forces ■ Functions can depend on time or other system states, such as displacement, velocity, and reaction forces. ■ Every function evaluates to a single value at each particular point in time. ■ Motion drivers can only be a function of time: M = f(time) ■ Functions defining motion driver magnitudes can be: ◆ Displacement (time) ◆ Velocity (time) ◆ Acceleration (time) Note: You can use the Function Builder to create and verify functions in ADAMS/View. To access the Function Builder, right-click any text box that expects a function. Display the Function Builder and press F1 to learn about creating functions. 156 Lift Mechanism II You use the Function Builder to create and verify functions in ADAMS/View. You access the Function Builder from any text box in which you can enter a function. Demonstrate: Display the Function Builder. Explain the verify feature, the menus, the assist button--and pressing F1 to get help on the Assist dialog box, and so on. For help with the Function Builder or with function syntax, press F1. Go to the Simple Harmonic Function (SHF). In this course, you work with run-time functions. Other types of functions listed, such as design-time functions, are beyond the scope of this course. :RUNVKRS ³/LIW 0HFKDQLVP ,, 3UREOHP VWDWHPHQW Constrain the lift mechanism model by adding joints and motions as shown next: Boom with respect to shoulder Mount with respect to base Boom with respect to bucket Shoulder with respect to mount :RUNVKRS FKDOOHQJH If you’d like a challenge, add the following joints and motions without going through the detailed steps presented on the following pages: ■ Rotational motion to the mount-to-base joint. D(t) = 360d*time ■ Rotational motion to the shoulder-to-mount joint. D(t) = STEP(time, 0, 0, 0.10, 30d) ■ Translational motion to the boom-to-shoulder joint. D(t) = STEP(time, 0.8, 0, 1, 5) ■ Rotational motion to the bucket-to-boom joint. D(t) = 45d*(1-cos(360d*time)) Otherwise, continue by following the detailed instructions. Lift Mechanism II 157 Review the problem statement and quiz the students on what they think needs to be done to complete the workshop. Before they start, ask for questions. :RUNVKRS ³/LIW 0HFKDQLVP ,, 0RGHO GHVFULSWLRQ In this workshop, you use the model you built in Workshop 8—Lift Mechanism I, on page 144. 7LSV EHIRUH \RX VWDUW ■ Use the figure on page 157 to find out what type of constraints you need. ■ Simulate the model at regular intervals to check the constraints. ■ Rename joints as soon as you create them. ■ Adjust icon sizes whenever necessary (see Set up the working environment, on page 145 of Workshop 8—Lift Mechanism I.) 6WDUW WKH ZRUNVKRS Note that the file for this exercise is not in the current working directory. 7R VWDUW WKH ZRUNVKRS ■ Start ADAMS/View: ◆ Set the directory to exercise_dir/mod_09_lift_mech_2. ◆ From the directory exercise_dir/mod_08_lift_mech_1, import the model that you created in the previous module. If you need a fresh copy of the model, import the command file lift_mech_I_completed.cmd from the directory exercise_dir/mod_08_lift_mech_1/ completed. 158 Lift Mechanism II :RUNVKRS ³/LIW 0HFKDQLVP ,, &RQVWUDLQ WKH SDUWV In this section, you’ll constrain the parts that you created in the previous workshop. The figure in the Problem statement, on page 157, shows how you should constrain the parts. 7R FRQVWUDLQ WKH SDUWV 1 Use the Fixed joint tool 2 to fix the base to ground. Constrain mount to base ( ): ■ ■ Place the joint at the mount’s cm marker. ■ 3 Use the options 2 Bodies - 1 Loc and Pick Feature. Select the + y-axis as the axis for the rotation. Constrain shoulder to mount ( ): ■ ■ 4 Use the option Normal To Grid. Right-click to select the cylinder’s anchor marker. Constrain the boom to the shoulder ( ): ■ ■ 5 Use the option Pick Feature. Select the x-axis as the axis for the translation. Constrain the bucket to the boom ( ): ■ Use the option Normal To Grid. ■ Select the end point of the cylinder. Lift Mechanism II 159 :RUNVKRS ³/LIW 0HFKDQLVP ,, 9HULI\ WKH PRGHO FUDZOZDONUXQ Before continuing, check your work by checking model topology and by performing a simulation. 7R YHULI\ \RXU PRGHO 1 Check model topology by constraints (from the Status bar, right-click the Information tool stack , and then select the Model topology by constraints tool parts are constrained as expected. 2 ) to ensure that all the Perform a simulation. Are the visual results of the simulation (the animation), what you expected? $GG MRLQW PRWLRQV WR \RXU PRGHO When adding motions, follow the instructions in the Status bar. The Status bar instructs you to select a legitimate joint for the particular type of motion (for example, a revolute joint for rotational motion). When your cursor hovers over a potential joint, its name appears in the working window. To select a joint, simply left-click the joint, once its name appears. Build the joint motions using the default expressions in the Main Toolbox container and then modify the expressions using the Rotational Joint Motion Modify dialog box (right-click the joint, point to the joint name, and then select Modify). 7R DGG MRLQW PRWLRQV 1 Use the Rotational Joint Motion tool to add a motion to the mount-to-base joint such that: D(t) = 360d*time 2 Add a motion to the shoulder-to-mount joint such that: D(t) = -STEP(time, 0, 0, 0.10, 30d) Note: By using Normal to Grid, the motion will be opposite the illustration in Problem statement, on page 157 (by the right-hand rule). When a motion is opposite of what you expect, add a negative sign in front of the expression, in the Modify Motion dialog box. We will discuss the specifics of the STEP function in the next module, Lift Mechanism III, on page 163. 160 Lift Mechanism II :RUNVKRS ³/LIW 0HFKDQLVP ,, 3 Add a translational motion to the boom-to-shoulder joint such that: D(t) = -STEP(time, 0.8, 0, 1, 5) 4 Add a motion to the bucket-to-boom joint such that: D(t) = 45d*(1-cos(360d*time)) 5XQ D VLPXODWLRQ 7R UXQ D VLPXODWLRQ Run a simulation such that the mount achieves one full rotation. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN ■ Save the model such that the saved file contains only the model topology and not the results (File Æ Export). 2SWLRQDO WDVNV If you did not already do so as explained in the Optional tasks, on page 151, for Lift Mechanism I: ■ Add tires to your model using the Torus tool. ■ Constrain the tires to the base using revolute joints. Lift Mechanism II 161 :RUNVKRS ³/LIW 0HFKDQLVP ,, 0RGXOH UHYLHZ 1 What are the markers that a joint refers to called? 2 When motion is applied to a joint, what dictates its direction (positive versus negative)? 3 Are motions considered a constraint? Why? 4 Is it possible to determine the torque required to achieve a prescribed motion imposed on a revolute joint? How? 162 Lift Mechanism II  /,)7 0(&+$1,60 ,,, Constrain the bucket such that the base of the bucket always maintains its horizontal orientation (therefore, keeping the bucket-passenger safe) as shown next: 7KLV PRGXOH LQFOXGHV ■ Types of Joint Primitives, 164 ■ Perpendicular Joint Primitive, 165 ■ Workshop 10—Lift Mechanism III, 167 ◆ Module review, 170 163 ■ Review the problem statement. ■ Asking the students to divide into groups to work through modules 8 through 10 might help them get through those modules faster and understand them better. 7\SHV RI -RLQW 3ULPLWLYHV Description: DOF removed: Inline - One point can only move along a straight line Illustration: Two translational First part Inplane - One point can only move in Second part One translational First part a particular plane Second part Orientation - One coordinate system cannot rotate with respect to another Three rotational Second part Perpendicular - One coordinate system can rotate about two axes First part One rotational First part Second part Parallel axis - One coordinate system can rotate about one axis Two rotational First part Second part See also: DOF removed by joint primitives, on page 372 164 Lift Mechanism III 3HUSHQGLFXODU -RLQW 3ULPLWLYH ([DPSOH XVLQJ LQOLQH DQG SDUDOOHO SULPLWLYHV trans in y rot about z ˆ y ˆ z ˆ x ([DPSOH RI , DQG - PDUNHUV LQ D SHUSHQGLFXODU MRLQW SULPLWLYH Bucket ˆ z3 ˆ z2 Bucket Bucket ˆ z1 I marker ˆ z 1, 2 ,3 J marker on ground Lift Mechanism III 165 Use the online help (F1) to assist with defining joint primitives. Do not review all the joint primitives in detail. Ask if the students can think of a situation where an idealized constraint won’t work (example: a link that rotates about the global z, but translates about the global y). In such a case, the only solution is a combination of joint primitives. Question: For this problem statement, which of these joint primitives best meets our needs? (It might help to ask them this: “To keep the bucket oriented such that a passenger would not fall out, how many and what types of degrees of freedom should we constrain?”) Answer: The perpendicular joint primitive. Help the students figure out why other joint primitives won’t work. The parallel joint primitive will work, but will overconstrain by 1 DOF. 3HUSHQGLFXODU -RLQW 3ULPLWLYH ■ I marker: ◆ ◆ ■ Parent part: Bucket Its xy-plane is coplanar to the ground plane. J marker: ◆ Parent part: ground ◆ Its z-axis is perpendicular to the z-axis of the I marker. ■ When constrained, the z-axes of the I and J markers are always perpendicular during simulation. ■ Use the construction method 2 Bodies - 2 Locations. Question: Would the lift mechanism behave any differently if the J marker’s parent part was Base? 166 Demonstrate: Add a perpendicular joint primitive to the lift mechanism, as shown here. Display just the I and J markers of the perpendicular joint. Illustrate how you might need to reorient one of the two markers to achieve the desired effect. Review the question at the bottom of the page. Lift Mechanism III :RUNVKRS ³/LIW 0HFKDQLVP ,,, 3UREOHP VWDWHPHQW Constrain the bucket such that the base of the bucket always maintains its horizontal orientation (thus keeping the bucket passenger safe) as shown next: 0RGHO GHVFULSWLRQ In this workshop, you use the model you saved in Workshop 9—Lift Mechanism II, on page 157. Lift Mechanism III 167 Because you have already shown them how to do the problem, there is probably no need to review the problem statement again. Before they start, ask for questions. :RUNVKRS ³/LIW 0HFKDQLVP ,,, 6WDUW WKH ZRUNVKRS Note that the file for this exercise is not in the current working directory. 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_10_lift_mech_3. 2 From the directory exercise_dir/mod_09_lift_mech_2, import the model that you created in the previous module. If you need a fresh copy of the model, import the command file lift_mech_II_completed.cmd from the directory exercise_dir/mod_09_lift_mech_2/ completed. &RQVWUDLQ WKH EXFNHW Now you will constrain the bucket to ground using the appropriate joint primitive. 7R FRQVWUDLQ WKH EXFNHW 1 Delete the motion on the bucket-to-boom joint. 2 Verify the model. The model should have only one degree of freedom. 3 From the Build menu, select Joints. 4 Select the appropriate joint primitive and use it to constrain the bucket: ■ ■ Select the bucket and then select the ground. ■ When selecting the markers, note that I marker can be any marker on the bucket part and the J marker can be any ground marker (note that there is one at the fixed joint location). ■ 168 Use the construction method 2 Bodies - 2 Locations and refer to Example of I and J markers in a perpendicular joint primitive, on page 165 for assistance. When selecting the direction, select the first direction as the x direction of the I marker, and the second direction as the y direction of the J marker. Lift Mechanism III :RUNVKRS ³/LIW 0HFKDQLVP ,,, 9HULI\LQJ WKH RULHQWDWLRQ Now you will verify the orientation of the I and J markers in the joint primitive. 7R YHULI\ WKH RULHQWDWLRQ 1 In the right corner of the Status bar, select the Information tool . 2 Note the names of the I and J marker and select Close. 3 Select the I marker (on the bucket) and check that the z-axis of the marker on the bucket is pointing in the (positive or negative) global x direction. 4 Select the J marker (at the fixed joint location) and check that the z-axis of the marker on ground is pointing in the (positive or negative) global y direction. 9HULI\ WKH PRGHO DQG WKHQ UXQ D VLPXODWLRQ In this section, you will perform a simulation with icons on. 7R YHULI\ WKH PRGHO DQG UXQ D VLPXODWLRQ 1 Verify the model. The model should have zero degrees of freedom. 2 From the Settings menu, point to Solver, and then select Display. 3 Set Icons to On. 4 Simulate the model. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save the model such that the saved file contains only the model topology and not the results (File Æ Export). 2 Unless you want to further experiment with the model, as instructed in the next section, exit ADAMS/View. Lift Mechanism III 169 :RUNVKRS ³/LIW 0HFKDQLVP ,,, 2SWLRQDO WDVNV 7R FRPSOHWH H[WUD WDVNV IURP SUHYLRXV PRGXOH If you did not already do so as mentioned in the Optional tasks, on page 151, for Lift Mechanism 1: ■ Add tires to your model using the Torus tool. ■ Constrain the tires to the base using revolute joints. 7R PDNH WKH EXFNHW WUDQVSDUHQW 1 From the View menu, select Render Mode, and then select Shaded. 2 Right-click the bucket, point to Part: bucket, and then select Appearance. 3 To set the transparency of the part, use the slider bar: 0%: fully visible, 100%: completely invisible. 7R FKHFN JUDSKLFDO WRSRORJ\ RI WKH PRGHO 1 From the Tools menu, select Database Navigator. 2 Set the menu at the top of the Database Navigator to Graphical Topology. 3 Browse to the bucket and notice how many constraints act on the bucket. 0RGXOH UHYLHZ 1 170 When you use the construction method of 2 Bodies - 2 Locations, how does the order in which you select parts affect the order in which you select the locations and orientations? Lift Mechanism III  6863(16,21 6<67(0 , Set up the suspension such that it moves 80 mm in jounce and rebound. strut_upper upper_arm body_ground strut_lower steering_rack tie_rod lower_arm spindle_wheel 7KLV PRGXOH LQFOXGHV ■ Applying Point Motions, 172 ■ Workshop 11—Suspension System I, 174 ◆ Module review, 180 171 ■ ■ ■ ■ The given model represents a quarter-car suspension with most of the required constraints already in place. Model has been built using construction points. Construction points (or hardpoints) are used to parameterize the model. The tie rod needs to be constrained. To constrain the tie rod, use spherical and hooke constraints. Demonstrate: ■ The spherical and hooke constraints haven’t been used before. Use the Spherical and Hooke Joints link to go to the Constraints table. ■ Ask the students to fill out the spherical and hooke fields in the Constraints table and demonstrate these joints. ■ Be prepared to discuss the differences between the hooke, universal, and constant velocity joints. ■ Open the model for this workshop. $SSO\LQJ 3RLQW 0RWLRQV 3RLQW PRWLRQV ■ There are two types: ◆ ◆ ■ Single-point motion (removes 1 DOF) General-point motion (removes 1 to 6 DOF) You define: ◆ I and J markers to which motion is applied (via two bodies, location and orientation). ◆ Constraint nature of the motion (between 1 and 6 DOF). ◆ Functions for magnitudes of motion. ˆ ˆ y i, y j ˆ yi ˆ yj ˆ ˆ z i, z j ˆ xi ˆ ˆ x i, x j θ ˆ xj ˆ ˆ z i, z j 172 Suspension System I You will use a point motion to drive the spindle and wheel up and down to test the model. Demonstrate: Illustrate the single point motion. Explain that the default direction for a translational point motion is along the z-axis of the J marker. 6\VWHP/HYHO 'HVLJQ 7KH FUDZOZDONUXQ DSSURDFK ■ Do not build the entire mechanism at once. ■ As you add a new component, make sure that it works correctly. ■ Check your model at regular intervals. $YRLG WKH QHHG IRU FRPSOH[ GHEXJJLQJ E\ IROORZLQJ WKH FUDZOZDONUXQ DSSURDFK ◆ Suspension System I 173 Stress the importance of the crawl-walk-run approach. Specify that MSC.Software Technical Support recommends users to follow this approach. When a user contacts Technical Support, they ask for two copies of the model, one copy of the model in working condition, and one copy of the model that does not work. Comparing the two models is essential for debugging. Following the crawl-walk-run approach makes it easy to provide Technical Support with essential information. :RUNVKRS ³6XVSHQVLRQ 6\VWHP , 3UREOHP VWDWHPHQW Inspect the toe angle that the wheel exhibits throughout its vertical travel of 80 mm in jounce and rebound. strut_upper upper_arm body_ground strut_lower tie_rod steering_rack lower_arm spindle_wheel 0RGHO GHVFULSWLRQ ■ The given model is a geometric representation of a short-long arm (SLA) suspension subsystem. ■ The steering_rack and body_ground are constrained as shown in the following figure: ◆ A translational joint connects the steering_rack to the body_ground. ◆ A fixed joint connects the body_ground to ground. steering_rack body_ground HP-12 tie_rod HP-13 Translational joint Fixed joint 174 Suspension System I You will use construction points in this workshop. Explain construction points, and how to use them. You will not create any, but you will reference existing construction points while building joints. Construction points are named HP1, HP2, and so on. HP stands for hardpoint. Demo the Table Editor and show the students how to access the hardpoint locations. :RUNVKRS ³6XVSHQVLRQ 6\VWHP , ■ The lower_arm and lower_strut are constrained as shown next: ◆ A spherical joint connects the lower_strut to the lower_control_arm. ◆ A revolute joint connects the lower_arm to the body_ground. lower_strut spindle_wheel tie_rod HP-5 HP-6 lower_arm HP-10 Spherical Spherical joint joint ■ HP-4 Revolute joint The upper_arm and upper_strut are constrained as shown next: ◆ A revolute joint connects the upper_arm to the body_ground. ◆ A hooke joint connects the upper_strut to the body_ground. HP-9 Hooke joint upper_arm HP-2 Revolute joint HP-13 Spherical joint HP-1 HP-11 Translational joint upper_strut Suspension System I 175 :RUNVKRS ³6XVSHQVLRQ 6\VWHP , 6WDUW WKH ZRUNVKRS 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_11_suspension_1. 2 Import the model command file suspension_parts_start.cmd. This file contains commands to build a model named suspension and the following parts with geometric representation: strut_upper upper_arm body_ground strut_lower tie_rod steering_rack lower_arm spindle_wheel 176 Suspension System I Illustrate jounce and rebound on the board, so the students know what result they should be looking for. :RUNVKRS ³6XVSHQVLRQ 6\VWHP , ,QVSHFW WKH PRGHO In this section, you’ll investigate the model to note its movement and topology, especially that of the part tie_rod. 7R LQVSHFW WKH PRGHO 1 Simulate the model, noting the movement of tie_rod. 2 From the Tools menu, select Database Navigator. 3 Set the pull-down menu at the top of the Database Navigator to Graphical Topology. 4 Double-click suspension, and then select tie_rod. &RQVWUDLQ WKH VXVSHQVLRQ VXEV\VWHP PRGHO Constrain the tie rod as shown next: HP13 steering_rack tie_rod body_ground Spherical joint HP7 HP8 Hooke joint When constraining the tie_rod, use the ADAMS/View hardpoints provided with the model. Suspension System I 177 :RUNVKRS ³6XVSHQVLRQ 6\VWHP , 7R FRQVWUDLQ WKH PRGHO 1 Create a spherical joint : ■ Select the 2 Bod-1 Loc option, Normal to Grid. ■ First body: Spindle_Wheel ■ Second body: tie_rod ■ Set the location to HP8. Note: HP8 belongs to ground. We are simply referencing its location for the creation of the new markers (I and J) that represent the joint. 2 Use the Hooke joint tool to create a hooke joint: ■ Select the 2 Bod-1 Loc option, Pick Feature. ■ First body: tie_rod ■ Second body: steering_rack ■ Set the location to HP7. ■ Set the first direction from vector HP7 to HP8. ■ Set the second direction from vector HP7 to HP13. Tip: When setting the direction, move your cursor in the direction of the ending vector (HP8 and HP13, respectively), until its name appears on the screen. When the name appears, left-click to select it. 3 Inspect the tie rod again, and notice the connection representations to the steering_rack and spindle_wheel. 4 Simulate the model. 178 Suspension System I :RUNVKRS ³6XVSHQVLRQ 6\VWHP , $SSO\ PRWLRQV 7R DSSO\ PRWLRQV 1 At the marker .Spindle_Wheel.Center, apply a point motion Spindle_Wheel.Center. , in the y direction of the Tip: Make sure Construction is set to 1 Location, Pick Feature. 2 Modify the motion to use the function, Displacement(time) = 80*sin(360d*time). 3 Modify the translational joint, rck_body_joint, between the steering_rack and the body_ground to be a fixed joint, so that the steering_rack is unable to translate during a simulation. rck_body_joint 9HULI\ DQG VLPXODWH WKH PRGHO Now, to see the model’s full range of motion, simulate it. 7R YHULI\ DQG VLPXODWH WKH PRGHO 1 Verify the model. 2 Run a one-second, 50-step simulation. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save your model as suspension_parts.cmd. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 2 Exit ADAMS/View. Suspension System I 179 :RUNVKRS ³6XVSHQVLRQ 6\VWHP , 2SWLRQDO WDVNV 7R PRGLI\ KDUGSRLQW ORFDWLRQV 1 From the Tools menu, select Table Editor. 2 From the options along the bottom of the Table Editor, select Points. 3 Change the Loc Y value of HP3 from 351.05 to 400. As you make this change, note how the upper arm’s connection to the spindle changes. 0RGXOH UHYLHZ 1 180 What is the difference between a point motion and a joint motion? Suspension System I  6863(16,21 6<67(0 ,, Inspect the toe angle that the wheel exhibits throughout its vertical travel of 80 mm in jounce and rebound. strut_upper upper_arm body_ground strut_lower tie_rod steering_rack lower_arm spindle_wheel 7KLV PRGXOH LQFOXGHV ■ Taking Measurements, 182 ■ Displacement Functions, 183 ■ Importing CAD-Based Geometry, 184 ■ Workshop 12—Suspension System II, 185 ◆ Module review, 192 181 7DNLQJ 0HDVXUHPHQWV 3RLQWWRSRLQW PHDVXUHV ■ Measure kinematic characteristics of one point relative to another point, such as the relative velocity or acceleration. ■ To define them, you specify: ◆ ◆ To-point marker location (I marker) ◆ From-point marker location (J marker, default is global origin) ◆ Represent coordinates in marker coordinate system (R marker, default is GCS) ◆ ■ Characteristic (displacement, velocity, or acceleration) Component to return (x, y, z, or magnitude) ADAMS/View uses displacement, velocity, or acceleration functions. )XQFWLRQ PHDVXUHV ■ Let you evaluate arbitrary, user-defined expressions of interest during solution runtime, such as: ◆ Flow rate ◆ Aerodynamic pressure ◆ Stress ■ ■ 182 You can create them in the Function Builder. Unlike other measures, function measures let you specify plotting attributes. Suspension System II In this module, you will use a point-to-point measure to create the wheel height measurement and a function measure to create the toe angle measure Demonstrate: Create a Point-to-Point measure. To Point and From Point boxes in the dialog box are of different colors, because you must fill in the white boxes, while the gray boxes are optional. In blank gray boxes, ADAMS/View uses defaults. Demonstrate: Create a function measure. Display the Function Builder instead of a dialog box when you create a function measure. Explain the plot attributes section and the function menus in the Function Builder. 'LVSODFHPHQW )XQFWLRQV 'LVSODFHPHQW IXQFWLRQV ■ For translational displacement, return scalar portions of vector components (measurements are taken to I from J, resolved in R’s CS), as shown below. ■ For rotational displacement, return angles associated with a particular rotation sequence. ([DPSOH ˆ y I ˆ y ˆ x DM(I,J) (+) DY(I,J,R) ˆ x J (-) DX(I,J,R) ˆ y ˆ x R Suspension System II 183 Explain that the displacement function is the same as a point-to-point measure, but because it is a function you can use it as part of another function. In this module, you use a displacement function to create the toe angle measure. ,PSRUWLQJ &$'%DVHG *HRPHWU\ &RQFHSWXDO 'HVLJQ 0HWKRG 'HVLJQ 9DOLGDWLRQ 0HWKRG CAD Assembly Dynamic Motion! Dynamic Motion! Import .res Import .res ■ ■ ■ ADAMS/Solver or ADAMS/View without Geometry ■ ■ ■ ■ Rigid Bodies Mass Properties Detailed Geometry Joints Springs Applied Forces Kinematic Motion ADAMS/View with Geometry Export .adm ■ ■ ■ ■ ■ ■ ■ Rigid Bodies Mass Properties Joints Springs Applied Forces Advanced Modeling Dynamic Motion .cmd + .adm + .shl, .slp ■ ■ ■ ■ ■ ■ ■ ■ 184 Rigid Bodies Mass Properties Detailed Geometry Joints Springs Applied Forces Advanced Modeling Dynamic Motion Suspension System II Explain how geometry is used in ADAMS/View when interfacing with CAD packages. Explain the two methods shown here. The only difference between the two methods is that CAD geometry is used in the design validation method but not in the conceptual design method. CAD geometry is only graphics; it does not affect the results of the simulation. :RUNVKRS ³6XVSHQVLRQ 6\VWHP ,, 3UREOHP VWDWHPHQW Inspect the toe angle that the wheel exhibits throughout its vertical travel of 80 mm in jounce and rebound. strut_upper upper_arm strut_lower tie_rod body_ground steering_rack lower_arm spindle_wheel 0RGHO GHVFULSWLRQ In this workshop, you use the model you built in Workshop 11—Suspension System I, on page 174. Suspension System II 185 Be sure to point out that the model does not contain the spindle geometry. They will add the geometry at the end of the workshop. :RUNVKRS ³6XVSHQVLRQ 6\VWHP ,, 6WDUW WKH ZRUNVKRS Note that the file for this workshop is not in the current working directory. 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_12_suspension_2. 2 From the directory exercise_dir/mod_11_suspension_1, import the model that you created in the previous workshop. If you need a fresh copy of the model, import the command file suspension_1_completed.cmd from the directory exercise_dir/mod_11_suspension_1/ completed. 3 Simulate the model to verify the motion. &UHDWH PHDVXUHV 7R FUHDWH PHDVXUHV 1 Create a point-to-point measure, named .suspension.Wheel_Height, for the relative wheel ˆ displacement in the yG direction: ■ To Point: ■ From Point: ground.WH_ref Spindle_Wheel.Center Tip: From the Build menu, point to Measure, point to Point-to-Point, and then select New. 2 Run a one-second, 50-step simulation. ADAMS/View displays the relative wheel displacement as shown next. 186 Suspension System II :RUNVKRS ³6XVSHQVLRQ 6\VWHP ,, 3 Using an ADAMS/Solver function measure, create a toe angle measure using the markers Spindle_Wheel.Center and Spindle_Wheel.TA_ref (see Figure 2 on page 188): ■ From the Build menu, point to Measure, point to Function, and then select New. ■ Fill in the Function Builder as shown next. To get help while working in the Function Builder, press F1 Use the Assist option to help you define the DZ and DX functions Before selecting OK, select Verify to check the syntax of your function Note: You must run a simulation after creating the function to view its plot. Suspension System II 187 :RUNVKRS ³6XVSHQVLRQ 6\VWHP ,, Figure 2. Markers for Toe Angle Measure φ, toe angle .Center .Center (provided with model) ∆Z .TA_ref ˆ zG ˆ xG (provided with model) ∆X .TA_ref φ, toe angle – 1 ∆Z φ = tan ------ ∆X ADAMS/View updates the measure stripchart. 4 In ADAMS/PostProcessor, plot toe angle versus wheel height. ■ ■ Select Wheel Height. ■ Select OK. ■ From the Measure list, select Toe_Angle. ■ 188 Set Independent Axis to Data. Select Add Curves. Suspension System II :RUNVKRS ³6XVSHQVLRQ 6\VWHP ,, ,PSRUW &$'EDVHG JHRPHWU\ Now, you’ll import more realistic, CAD-based spindle/wheel geometry, as shown next. knuckle wheel The two geometry files that make up the spindle/wheel are: ■ wheel.slp ■ knuckle.slp They are render files, which have an extension of .slp. They were created in Pro/ENGINEER. By default, when you import the files, ADAMS/View names the geometry based on the Pro/ENGINEER assembly from which they came and not based on their file names. In this case, the CAD geometry came from a model named suspensn. Therefore, ADAMS/View names the geometry suspensn and suspensn_2. When you export your model, ADAMS/View exports one .cmd file (suspension.cmd) and one .shl file for each CAD geometry (suspensn.shl and suspensn_2.shl). 7R LPSRUW WKH JHRPHWU\ 1 Import the geometry files located in exercise_dir/mod_12_suspension_2/ suspension_cad. Make sure you import one file, select Apply, and then import the other: ■ From the File menu, select Import. ■ Set File Type to Render. ■ Attach the geometry to the part named Spindle_Wheel. Suspension System II 189 :RUNVKRS ³6XVSHQVLRQ 6\VWHP ,, 2 Turn off the appearance of ADAMS/View spindle geometry so that only the CAD geometry is visible: ◆ ◆ Highlight the following items: ◆ Select OK. ◆ Change the Visibility setting to Off. ◆ 190 From the Edit menu, select Appearance. Select OK. Suspension System II :RUNVKRS ³6XVSHQVLRQ 6\VWHP ,, 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save your model as suspension_parts.cmd. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 2 Exit ADAMS/View. 2SWLRQDO WDVNV 5HSODFH RWKHU $'$069LHZ JHRPHWU\ ZLWK &$' JHRPHWU\ 1 From the directory exercise_dir/mod_12_suspension/suspension_cad/more_susp_cad, import the rest of the CAD-based suspension component geometry. Tips: Remember to associate each CAD geometry with the appropriate part in the ADAMS/View model. Not all the CAD geometry is associated with the Spindle_Wheel part. These geometry files are called render files, which have an extension of .slp. There is one file for each ADAMS/View part. 2 Turn off the appearance of ADAMS/View geometry so that only the CAD geometry is visible. Suspension System II 191 :RUNVKRS ³6XVSHQVLRQ 6\VWHP ,, 0RGXOH UHYLHZ 1 Is there any difference between a point-to-point measure and a function measure using a displacement function (for example, DX(I, J, R))? 2 Where does a CAD file fall in the model hierarchy? What is the CAD file a child of? 192 Suspension System II  6863(16,2167((5,1* 6<67(0 Assemble a suspension-steering system and inspect the toe angle that the wheel exhibits at steering wheel angles of 45o, 0o, and -45o. 7KLV PRGXOH LQFOXGHV ■ Add-On Constraints, 194 ■ Couplers, 195 ■ Assembling Subsystem Models, 196 ■ Workshop 13—Suspension-Steering System, 197 ◆ Module review, 204 193 $GG2Q &RQVWUDLQWV $GGRQ FRPSOH[ FRQVWUDLQWV ■ Set up relationships between existing constraints in a system. ■ Connect parts directly and indirectly. 7\SHV RI DGGRQ FRQVWUDLQWV 6FUHZ -RLQWV Axis of translation and rotation Pitch First Part Second Part xj &RXSOHUV φj Joint 2 Joint 1 *HDUV 194 Joint 1 Joint 2 Suspension-Steering System Tell the students that we will examine the coupler. The screw and the gear complex constraints are implemented the same way. &RXSOHUV 'HILQLWLRQ RI FRXSOHUV ■ Couplers connect multiple parts indirectly by coupling 2 joints. ■ Couplers can be defined: q2 Couplers remove 1 DOF. ■ Joint 6 ◆ By scales ◆ ■ By displacements ◆ Joint 4 User defined q1 Modeling of couplers requires two joints (applicable types are translation, revolute, and cylindrical) ([DPSOH RI D FRXSOHU As the steering shaft rotates the steering_rack translates For help on defining By Displacement and User Defined, press F1. Suspension-Steering System 195 $VVHPEOLQJ 6XEV\VWHP 0RGHOV :KHQ \RX DVVHPEOH PRGHOV ■ Any number of models can be assembled. ■ Assembling models will create a new model. ■ All assembled models (model1, model2) will continue to exist in the database along with the new model (model3). model_1 model_2 steering_rack steering_rack model_3 steering_rack 3DUWV LQ DVVHPEOHG PRGHOV ■ They maintain their global location and orientation, unless otherwise specified. ■ If parts have the same name in different merged models, ADAMS/View will either: ◆ Merge them into one part. ◆ Rename the parts. See also: Model Hierarchy, on page 28 196 Suspension-Steering System :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP 3UREOHP VWDWHPHQW Assemble a suspension-steering system and inspect the toe angle that the wheel exhibits at steering wheel angles of 45o, 0o, and -45o. 0RGHO GHVFULSWLRQ ■ You will use the following two models in this workshop: ◆ ◆ ■ A geometric representation of a short-long arm (SLA) suspension subsystem. A geometric representation of a rack-and-pinion steering system. The rack-and-pinion steering model is constrained as shown next: HP-17 Hooke joint HP-18 Revolute joint between steering-wheel-column and body_ground HP-16 HP-13 Translational joint between steering_rack and body_ground Hooke joint HP-15 Cylindrical joint between steering-shaft and body_ground Fixed joint between body_ground and ground Suspension-Steering System Quiz students about the steps required to complete the workshop. 197 :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP 6WDUW WKH ZRUNVKRS Note that the file for this workshop is not in the current working directory. 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_12__suspension_2. 2 From this directory, import the model that you created in the previous module. If you need a fresh copy of the model, change your working directory to exercise_dir/mod_12_suspension_2/completed, then import the command file suspension_2_completed.cmd. &KDQJH ZRUNLQJ GLUHFWRU\ Change the directory to exercise_dir/mod_13_susp_steer. Running ADAMS/View in this directory ensures that all saved data gets stored there. 7R FKDQJH WKH ZRUNLQJ GLUHFWRU\ 1 From the File menu, select Select Directory. 2 Change to exercise_dir/mod_13_susp_steer. 198 Suspension-Steering System :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP ,PSRUW WKH VWHHULQJ PRGHO Import the steering model, shown below. It is in the command file steering_parts_start.cmd. The file contains a model named rack_and_pinion_steering. steering_wheel_column intermittent_shaft steering_shaft body_ground steering_rack 7R LPSRUW WKH PRGHO ■ Import the ADAMS/View model command file steering_parts_start.cmd. Suspension-Steering System 199 :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP &RQVWUDLQ WKH VWHHULQJ PRGHO Now you’ll constrain the steering model. Each time you add a modeling element, you’ll simulate the model to verify its movement. 7R FRQVWUDLQ WKH VWHHULQJ PRGHO 1 Apply a rotational joint motion ( ) to the revolute joint, strwheel_body_rev, on the steering_wheel_column. strwheel_body_rev 2 Right-click the motion icon, point to Motion: MOTION_1, and then select Modify. 3 In the Function (time) text box, enter the following function: Displacement(time) = 45d*sin(360d*time) 4 Run a one-second, 50-step simulation. 5 Use the Coupler tool to couple the rotation (strshft_body_cyl) of the steering_shaft with the translation (rck_body_trans) of the steering_rack. 200 Suspension-Steering System The difference between merging two models and assembling models is found in the command line help. Type help ‡ model ‡ assemble to get a description of the merge and assemble differences. :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP 6 Right-click the coupler icon, point to Coupler: COUPLER_1, and then select Modify. coupler 7 Modify the coupler so that for every 7o of rotation the steering_rack travels 1 mm: 8 To verify that the steering_rack travels as expected, simulate the model. Suspension-Steering System 201 CR 42605 was created to remove “Driver Scale” and “Slave 1 Scale” display. It’s not clear what method is used to derive the scale magnitudes and this adds more confusion than value to users. :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP $VVHPEOH WKH VXVSHQVLRQ DQG VWHHULQJ PRGHOV 7R DVVHPEOH WKH PRGHOV 1 Assemble the rack_and_pinion_steering model with the suspension model: ■ From the Tools menu, select Command Navigator. ■ In the Command Navigator, double-click model, and then double-click assemble. ■ Name the model steering_suspension. ■ Right-click the Model Names text box, point to Guesses, and then select *. Selecting * prompts ADAMS/View to include in the text box every item that is displayed under the Guesses option. 2 To display the assembled model, from the View menu, select Model. 3 Double-click steering_suspension. 9HULI\ WKH PRGHO Verify the model to ensure it is not overconstrained. To ensure that the model is not overconstrained, look for duplicate joints as explained next. 7R YHULI\ WKH PRGHO 1 From the Tools menu, select Database Navigator. 2 Set the top pull-down menu in the Database Navigator to Graphical Topology. 3 Double-click the new model name, steering_suspension, and then select body_ground. 4 Delete the unwanted joints by right-clicking them and selecting Delete (make sure that Highlight is not selected): ■ Delete one of the fixed joints between body_ground and ground. ■ Delete the fixed joint between body_ground and steering_rack. Note: Leave both the rotational motion and the revolute joint between body_ground and steering_wheel_column because both are needed. 202 Suspension-Steering System :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP 5 To redisplay the measures you created in Create measures, on page 186, from the Build menu, point to Measure, and then select Display. 6 Select both measures, Wheel_Height and Toe_Angle. 5XQ DQG FRPSDUH D VHULHV RI VLPXODWLRQV In this section, you’ll run three simulations, each with different steering wheel angles. You’ll then compare the results of the simulations. 7R UXQ DQG FRPSDUH D VHULHV RI VLPXODWLRQV 1 Modify the motion you created in Step 3 on page 200 to be a constant 45o steering wheel angle (Displacement(time) = 45d). 2 Simulate the model. 3 Save the simulation results as right_turn. Save the results just as you did in To save the simulation results:, on page 40 of Workshop 2—ADAMS/View Interface Overview. 4 Run a simulation with a 0o steering wheel angle (Displacement(time) = 0d). 5 Save the simulation results as straight. 6 Run a simulation with a -45o steering wheel angle (Displacement(time) = -45d). 7 Save the simulation results as left_turn. 8 Launch ADAMS/PostProcessor. Suspension-Steering System 203 :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP 9 Plot toe_angle versus wheel height for all three simulations, on the same plot, just as you did on page 188. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save the database so you retain the analyses. 2 Exit ADAMS/View. 0RGXOH UHYLHZ 1 What information do you need to provide ADAMS/View to create a coupler? 2 What is the default name that ADAMS/View assigns to simulation results? 204 Suspension-Steering System  635,1* '$03(5 Create and investigate the linear spring-damper system shown in the following figure, using different types of simulations in ADAMS/View. M: 187.224 Kg K: 5.0 N/mm K C C: 0.05 N-sec/mm L L0: 400 mm F0: 0 M 7KLV PRGXOH LQFOXGHV ■ Assemble Simulation, 206 ■ Simulation Hierarchy, 207 ■ Types of Simulations, 208 ■ Forces in MSC.ADAMS, 210 ■ Spring Dampers in MSC.ADAMS, 211 ■ Workshop 14—Spring Damper, 213 ◆ Module review, 217 205 $VVHPEOH 6LPXODWLRQ 'HILQLWLRQ RI DVVHPEOH VLPXODWLRQ ■ Attempts to resolve any conflicts in the initial conditions specified for the entities in the model (for example, broken joints). ■ Is also known as an initial conditions simulation. ,QLWLDO ORFDWLRQ DQG RULHQWDWLRQ RI SDUWV ■ You specify the initial position and orientation for a part when you create it. ■ For a part to be held fixed during the assemble simulation, you can specify up to three ˆ ˆ ˆ positions ( x , y , z ) and up to three orientations (psi, theta, phi). G G G Note: Use initial positions sparingly. If you fix the initial positions of too many parts, the assemble simulation can fail. 206 Spring Damper Demonstrate: Use the example of a 2 bodies - 2 locations joint to demonstrate the assemble simulation and the initial location and orientation of parts. 6LPXODWLRQ +LHUDUFK\ Assemble Simulation Assemble Nonlinear Linear Motion Study Equilibrium Calculation(s) Default* Static* Nonlinear DOF = 0 Kinematic* DOF > 0 Eigensolution or State Matrices Dynamic* Linear * Automatically performs an assemble simulation Note: Often a linear simulation is used after a static equilibrium or dynamic simulation. While working in any ADAMS/View dialog box, press F1 to display online help specific to that dialog box. Spring Damper 207 The assemble simulation must precede all simulations. ADAMS/Solver performs the assemble simulation automatically for all simulations except linear. Mention that to run a linear simulation, they must have a license of ADAMS/Linear. For a linear simulation, you must indicate the operation point about which ADAMS/Solver should linearize. For example, to linearize about the equilibrium position of a model, perform a static equilibrium simulation immediately followed by a linear simulation. 7\SHV RI 6LPXODWLRQV 6WDWLF ■ System DOF > 0. ■ All system velocities and accelerations are set to zero. ■ Can fail if the static solution is a long way from the initial condition. '\QDPLF ■ System DOF > 0. ■ Driven by a set of external forces and excitations. ■ Nonlinear differential and algebraic equations (DAEs) are solved. NLQHPDWLF ■ System DOF = 0. ■ Driven by constraints (motions). ■ Only constraint (algebraic) equations are being solved. ■ Calculate (measure) reaction forces in constraints. 208 Compare the three simulations. Demonstrate a static simulation. Spring Damper 7\SHV RI 6LPXODWLRQV /LQHDU ■ ADAMS/Solver can linearize the system of nonlinear equations of motion about a particular operating point. ■ From the linear set of equations, you can ask for an eigen-simulation to obtain eigenvalues and eigenvectors for the linearized system to: ◆ Visualize the natural frequencies and mode shapes of your system. ◆ Compare with test data or results data from FEA. ([DPSOH RI OLQHDU VLPXODWLRQ ■ Must linearize about an operating point (often the equilibrium). ■ Extraction of natural frequency. ■ M Natural frequency = K Spring Damper Demonstrate: Perform an equilibrium simulation followed by a linear simulation. K ---- . M 209 )RUFHV LQ 06&$'$06 'HILQLWLRQ RI IRUFHV ■ Try to make parts move in certain ways. ■ Do not perfectly connect parts together the way constraints do. ■ Do not absolutely prescribe movement the way motion drivers do. ■ Neither add nor remove DOF from a system. &KDUDFWHULVWLFV RI IRUFHV The characteristic: Defines: Bodies Which parts are affected Points of application Where the parts are affected Vector components How many vector components there are Orientation How the force is oriented Magnitude If the force is pre-defined or user-defined 210 The given table applies to all forces in MSC.ADAMS. This table will be used whenever you discuss a new force element. Explain all five items in detail. Spring Damper 6SULQJ 'DPSHUV LQ 06&$'$06 'HILQLWLRQ RI VSULQJ GDPSHUV ■ They are pre-defined forces. ■ They represent compliance: ◆ ◆ Acting over a distance. ◆ I marker Between two bodies. Along or about one particular direction. B J marker (+) A &KDUDFWHULVWLFV RI VSULQJ GDPSHUV The characteristic: Defines: Bodies Two (A, B) Points of application Two (I and J marker) Vector components One Orientation (only for translational) Acts along the line of sight between the I and J markers: Positive force repels the two parts ■ Magnitude ■ Negative force attracts the two parts Pre-defined equation based on either: ■ Stiffness and damping coefficients (linear) ■ Splines based on test data (nonlinear) See also: Characteristics of a spring damper, on page 376 Spring Damper 211 Demonstrate: Create a spring by hanging a mass on a spring. Then, simulate the model and watch it oscillate. The markers you select as the end points of the spring determine the bodies to which the spring is attached and the location of the spring. Open the Modify Spring dialog box and explain all the text boxes. Press F1 to show they can always use the online help to learn about the text boxes. Explain “length at preload” and “free length” and explain the difference between the two. Use the link near the bottom of the slide to go to the forces table. Ask the students to fill in the appropriate information for a spring damper. 0DJQLWXGH RI 6SULQJ 'DPSHUV 0DJQLWXGH EDVHG RQ VWLIIQHVV DQG GDPSLQJ FRHIILFLHQWV ■ Linear spring-damping relationship can be written as: · ForceSPDP = − k(q - q0) − c q + F0 where: q - Distance between the two locations that define the spring damper · q - Relative speed of the locations along the line-of-sight between them k - Spring stiffness coefficient (always > 0) c - Viscous damping coefficient (always > 0) F0 - Reference force of the spring (preload) q0 - Reference length (at preload, always > 0) t■ Time In ADAMS/Solver, the user-defined equation is: - k*(DM(I, J) - q0) - c*VR(I, J) + F0 Linear Spring Linear Damper Fc Fk kq0+F0 Fk = −k(q-q0) + F0 Fc = −c(dq/dt) −c F0 -k r q0 ■ dq/dt free length Spring-damper forces become ill-defined if endpoints become coincident because of undefined direction. 212 Spring Damper The second equation on the page defines how ADAMS/Solver writes the spring-damper equation. You need this equation to replace the pre-defined spring damper with a user-defined single-component force in the next workshop. :RUNVKRS ³6SULQJ 'DPSHU 3UREOHP VWDWHPHQW Create and investigate the linear spring-damper system shown next, using different types of simulations in MSC.ADAMS. M:187.224 Kg K: 5.0 N/mm K C C: 0.05 N-sec/mm L L0: 400 mm F0: 0 M 6WDUW WKH ZRUNVKRS 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_14_spring_damper. 2 Create a new model named spring_mass. %XLOG DQG FRQVWUDLQ WKH PRGHO 7R EXLOG DQG FRQVWUDLQ WKH PRGHO 1 Build the block with the given mass. Tip: Right-click the part and select Modify. Set Define Mass By to User Input. 2 ˆ Constrain the block to move only in the y G direction. Tip: Add a translational joint. 3 To verify the expected behavior, simulate the model. Spring Damper 213 :RUNVKRS ³6SULQJ 'DPSHU $GG WKH SUHGHILQHG VSULQJ GDPSHU 7R DGG D SUHGHILQHG VSULQJ GDPSHU 1 Use the Translational spring damper tool to create the spring damper, aligned along the y direction, between the cm marker of the block and a point on ground 400 mm above it ˆG (make sure to use the K and C values from Problem statement, on page 213). 2 To ensure that the spring damper is aligned with the y G direction, move the working grid ˆ to the cm of the block prior to creating the spring (see Build all parts except for the bucket, on page 147). 3 To set the second location, use the Location Event (see Build the pendulum link, on page 101): ■ ■ Change from Rel. to Origin to Rel. to Grid. ■ Enter 0, 400, 0. ■ 4 Right-click anywhere on the ground to display the Location Event. Select Apply. To ensure that the spring damper has a free length (qo) of 400 mm with a preload of 0, from the Tools menu, select Measure Distance to measure the spring. )LQG WKH IRUFH LQ VSULQJ GDPSHU DW VWDWLF HTXLOLEULXP 7R ILQG WKH IRUFH DW VWDWLF HTXLOLEULXP 1 Use the Static Equilibrium tool to run a static equilibrium simulation. 2 Note the value of the force graphic. Tip: To display the force value, from the Settings menu, select Force Graphics. Select Display Numeric Values. 3 Zoom out until you can see the force value. The block’s mass is 187.224 kg. Therefore, to balance the force of gravity, the spring damper must generate: 187.224kg*9806.65mm/s2(=1836.04 N) 214 Review the problem statement. Quiz the students on what steps they would take to solve the problem. Before they start, ask if there are any questions. Spring Damper :RUNVKRS ³6SULQJ 'DPSHU 5XQ D VLPXODWLRQ DQG FUHDWH D PHDVXUH 7R FUHDWH D PHDVXUH DQG UXQ D VLPXODWLRQ 1 Create a point-to-point measure, named Spring_Length, to measure the spring’s length. Measure to the upper spring-damper attachment point from the block’s cm marker. The measured value at t=0 should be 400 mm. 2 To see the oscillation, run a 2-second, 50-step dynamic simulation. )LQG WKH QDWXUDO IUHTXHQF\ 7R ILQG WKH QDWXUDO IUHTXHQF\ 1 Run another static equilibrium simulation ( 2 Select Close but do not reset the model. 3 From the Simulate menu, select Interactive Controls. 4 Select the Compute Linear Modes tool 5 View the results. 6 Note the natural frequency, and compare this value with that given in Closed-form solution, on page 217. Spring Damper ). . 215 :RUNVKRS ³6SULQJ 'DPSHU 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save the model. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 2 Exit ADAMS/View. 2SWLRQDO WDVNV $GG D '2) WR WKH PRGHO 1 Modify the translational joint to be a cylindrical joint. 2 Linearize about the static equilibrium position. Do the resulting modes make sense? 3 Add a torsional spring damper that resists the rotation of the cylindrical joint. 4 Linearize about the static equilibrium position. Are the results different from those above (no torsional spring damper)? 5 Do not save your work. 06&$'$06 UHVXOWV ω n = 0.8222 Hz ω n = ( 0.8222 Hz ) ( 2 ⋅ π rad ) = 5.168 rad/sec 216 Spring Damper :RUNVKRS ³6SULQJ 'DPSHU 0RGXOH UHYLHZ 1 ˆ At design configuration, do the z directions of markers referenced in a revolute joint have to be aligned? Does this information get reported when verifying a model? &ORVHGIRUP VROXWLRQ &KHFNLQJ WKH QDWXUDO IUHTXHQF\ RI WKH V\VWHP At equilibrium: ·· · mx + cx + kx = 0 ·· c · k x + --- x + --- x = 0 m m Laplace Transform is: 2 2 c 2 k s + --- s + --- = 0 ⇔ s + 2 ζω n s + ω n = 0 m m Therefore: 2 k ω n = --m ωn = k --m k = 5 N/mm = 5000 N/m m = 187.224 kg ωn = 5000 ------------------ rad/sec 187.224 ω n = 5.168 rad/sec Spring Damper 217 :RUNVKRS ³6SULQJ 'DPSHU 218 Spring Damper  121/,1($5 635,1* Investigate the differences between a linear spring and a nonlinear spring using a spline function. M: 187.224 Kg K: 5.0 N/mm K C C: 0.05 N-sec/mm L L0: 400mm F0: 0 M 7KLV PRGXOH LQFOXGHV ■ Single-Component Forces: Action-Reaction, 220 ■ Spline Functions, 221 ■ AKISPL Function, 222 ■ Workshop 15—Nonlinear Spring, 223 ◆ Module review, 228 219 6LQJOH&RPSRQHQW )RUFHV $FWLRQ5HDFWLRQ &KDUDFWHULVWLFV RI DFWLRQUHDFWLRQ VLQJOHFRPSRQHQW IRUFHV 6IRUFHV I marker B ce Sfor J marker A (+) The characteristic: Defines: Bodies Two (A, B) Points of application Two (I and J markers) Vector components One Orientation Acts along the line of sight (between the I and J markers) ◆ Positive force repels the two parts ◆ Negative force attracts the two parts Magnitude User-defined See also: Characteristics of an action-reaction S-force, on page 321 Note: MSC.ADAMS applies action and reaction forces to the I and J markers that it automatically creates. 220 Nonlinear Spring Demonstrate: Replace the spring damper you created earlier with an action-reaction single-component force set to custom. Open the Modify dialog box and review it. Open the Function Builder from the Function text box and show how you can use the displacement and velocity functions available in the Function Builder to create a spring-damper force. Use the link on the slide to go to the Forces table and fill in the appropriate information on action-reaction singlecomponent forces. 6SOLQH )XQFWLRQV 7HVW GDWD WKDW FDQ EH LQFRUSRUDWHG LQWR D VLPXODWLRQ LQFOXGHV ■ Empirical data from suppliers or standard tables for: ◆ ◆ ■ Nonlinear compliances (force versus velocity). Curves for torque versus motor speed (torque versus angular velocity). Data taken from physical prototype simulations for: ◆ Accelerometer data (acceleration versus time). ◆ Tire lateral force as a function of normal force and slip angle. 7R LQFRUSRUDWH GDWD LQWR D VLPXODWLRQ ■ First, create a spline from either: ◆ Data points entered manually into the Spline Editor. ◆ Imported test data from a file. y (x3,y3) (xn,yn) (x2,y2) Independent Variable - x (x1,y1) ■ Then, reference the spline through a spline function used in a motion or force. Several interpolation methods are available (using the function type): ◆ Cubic-fitting method (CUBSPL) ◆ Akima-fitting method (AKISPL) ◆ B-spline method (CURVE) Nonlinear Spring 221 Demonstrate: Import data to create a spline (File Import). Use the Spline Editor (Build Data Element Spline Modify). Æ Æ Æ Æ AKISPL )XQFWLRQ 6\QWD[ IRU AKISPL IXQFWLRQ AKISPL (x, z, spline, iord) ■ x - Independent variable specifying the value along the x-axis. ■ z - Optionally, a second independent variable specifying the value along the z-axis of the surface being interpolated. ■ spline - Spline used to map the one-to-one correspondence of the dependent variables (y) against independent variable values (x or z). ■ iord - An integer variable that specifies the order of the interpolated point (usually 0, but can be 1 or 2). ([DPSOH RI DQ AKISPL IXQFWLRQ AKISPL (DM(I, J), 0, spline_1, 0) DM (I, J) x Force y 150 -1000 200 -200 250 -50 300 0 350 50 400 200 450 Force y 100 x 300 DM (I, J) Note: You can create the CUBSPL and CURVE functions exactly as you create the AKISPL function. 222 Nonlinear Spring Demonstrate: Use spline functions in the Function Builder. Press F1 to show them the online help for the Function Builder. :RUNVKRS ³1RQOLQHDU 6SULQJ 3UREOHP VWDWHPHQW Investigate the differences between a linear spring and a nonlinear spring using a spline function. M: 187.224 Kg K: 5.0 N/mm K C C: .05 N-sec/mm L L0: 400mm F0: 0 M 6WDUW WKH ZRUNVKRS Start by importing the model you created in the last workshop. Note that this file is not in the current working directory. 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_15_spring. 2 From the directory exercise_dir/mod_14_spring_damper, import the model that you created in the previous module. If you need a fresh copy of the model, import the command file spring_damper_completed.cmd from the directory exercise_dir/mod_14_spring_damper/completed. Nonlinear Spring Review the problem statement. 223 :RUNVKRS ³1RQOLQHDU 6SULQJ 5HSODFH WKH SUHGHILQHG VSULQJ GDPSHU Now you will replace the spring damper, that is already in the model, with a user-defined linear spring damper. 7R UHSODFH WKH VSULQJ GDPSHU 1 Delete the predefined spring damper. 2 Create a single-component, action-reaction force ( ■ Characteristic: K and C ■ K: 5.0 ■ 3 Run-time Direction: Two Bodies ■ C: ) 0.05 Right-click SFORCE_1 and select Info. Note that the syntax of the function matches that of a spring damper, introduced on page Magnitude based on stiffness and damping coefficients, on page 212. Note: You could have entered the linear spring-damper function manually in the Function Builder. 4 Right-click SFORCE_1 and select Measure. 5 Create a measure, named spring_force: ■ ■ 6 224 Characteristic: Force Component: Mag To see oscillations, run a 2-second, 50-step simulation. Nonlinear Spring :RUNVKRS ³1RQOLQHDU 6SULQJ 7 Plot spring_force versus Spring_Length. Note that the slope at the beginning of this plot is 5 (K). The time-dependency of damping (C=.05) results in a deviation from a slope of 5 (slope ~ stiffness +/- damping). 8 Save the simulation results ( ) as linear_force. &KDQJH WKH OLQHDU VSULQJ WR D QRQOLQHDU VSULQJ In this section, you change the spring damper you just created to a nonlinear spring. You’ll import spring stiffness data to define the spring properties. 7R FKDQJH WKH VSULQJ 1 To import the spring stiffness data, from the File menu, select Import. 2 Set the following parameters, and then select OK. ■ ■ Create Splines ■ File to Read: exercise_dir/mod_15_spring/spring_data.txt ■ Independent Column Index: 1 (Because the first column is the independent column.) ■ Units: Force ■ 3 File type: Test Data Model Name: .spring_mass To open SPLINE_1 in the Spline Editor, from the Build menu, point to Data Elements, point to Spline, and then select Modify. Nonlinear Spring 225 :RUNVKRS ³1RQOLQHDU 6SULQJ 4 View the plot to understand the relationship between the deformation (x-axis) and stiffness force (y-axis). Tip: In the upper right corner, set View As to Plot. 5 Right-click SFORCE_1 and select Modify to replace the force function describing the singlecomponent force with an Akima spline function, as shown next. The I and J markers in the DM function might be different in your model. 226 Nonlinear Spring :RUNVKRS ³1RQOLQHDU 6SULQJ &RPSDUH WKH OLQHDU DQG QRQOLQHDU IRUFHV 7R FRPSDUH WKH IRUFHV 1 Verify that the nonlinear spring is working properly by running a 2-second, 50-step dynamic simulation. 2 Save the simulation results as non_linear_force. 3 Overlay the two plots: ■ spring_force vs. Spring_Length for the linear_force simulation ■ spring_force vs. Spring_Length for the non_linear_force simulation Note that in the nonlinear case, the curve changes slope as Spring_Length increases. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save only the model. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 2 Exit ADAMS/View. Nonlinear Spring 227 :RUNVKRS ³1RQOLQHDU 6SULQJ 2SWLRQDO WDVNV 1 Create a spline in the Spline Editor to represent a nonlinear damping force versus velocity: From the Build menu, point to Data Element, point to Spline, and then select New. 2 Add the spline function representing a damping force to the single-component force function so you have a nonlinear spring-damper in between the mass and ground. Tip: You will need to change the Akima spline function so that the first independent variable tracks velocity (VM function). 0RGXOH UHYLHZ 1 What are the four inputs for a spline function? 2 If you are not sure what inputs are required for an ADAMS/Solver function, where in the online help would you look for assistance? 228 Nonlinear Spring  6863(16,2167((5,1* 6<67(0 ,, Investigate the effect on toe angle when you replace the idealized constraint between the lower control arm and ground with bushings, while the steering wheel is held at an angle of 0o. 7KLV PRGXOH LQFOXGHV ■ Bushings, 230 ■ Workshop 16—Suspension-Steering System II, 231 ◆ Module review, 236 229 %XVKLQJV 'HILQLWLRQ RI D EXVKLQJ ■ Pre-defined force. ■ Represents compliance: ◆ Between two bodies. ◆ Along or about three vectors. &KDUDFWHULVWLFV RI D EXVKLQJ Characteristic: Description: Bodies Two Points of application Two (action force at I marker and reaction force at J marker) Vector components Three translational and three rotational Orientations Based on the J marker Magnitudes (Fx, Fy, Fz + Tx, Ty, Tz) Pre-defined equation based on: K ■ Stiffness matrix, ■ Damping matrix, C See also: Forces Tables (Incomplete), on page 373 230 Demonstrate creating a bushing. Suspension-Steering System II :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP ,, 3UREOHP VWDWHPHQW Investigate the effect on toe angle when you replace the idealized constraint between the lower control arm and ground with bushings, while the steering wheel is held at an angle of 0o. 0RGHO GHVFULSWLRQ ■ The model is the short-long-arm front suspension model combined with a steering model that you created in the previous workshop. ■ A spring damper has been added to represent the force input of a coil-over shock. ■ Currently, a revolute joint connects the lower control arm to the frame of the vehicle. ■ You are going to replace the revolute joint with two bushings and investigate the differences. Suspension-Steering System II 231 :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP ,, 6WDUW WKH ZRUNVKRS 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_16_susp_steer_2. 2 Import the command file susp_steer_2_start.cmd. 5XQ D EDVHOLQH VLPXODWLRQ You’ll start by running a simulation with the model as it currently is to see how it performs with a revolute joint. 7R UXQ D EDVHOLQH VLPXODWLRQ 1 Verify that the steering wheel angle is a constant 0o (Displacement(time) = 0d). 2 Run a simulation for 1 second with 50 output steps. 3 Save the simulation results ( ) as with_joint. 'HDFWLYDWH WKH UHYROXWH MRLQW Now, instead of removing the revolute joint, you’ll just deactivate it so it is not used in simulations. 7R GHDFWLYDWH WKH UHYROXWH MRLQW 1 Right-click the lowerarm_grnd_rev revolute joint that currently exists between Lower_Arm and ground. 2 Select (De)activate. 3 Clear the selection of Object Active. 232 Suspension-Steering System II :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP ,, &UHDWH EXVKLQJV EHWZHHQ /RZHUB$UP DQG JURXQG You will need to create two bushings because there are two connection points between Lower_Arm and ground. 7R FUHDWH EXVKLQJV 1 2 From the Main Toolbox, point to the Create Forces tool stack, and select the Bushing tool. Create the rear bushing with the following properties, using the options 2 Bod - 1 Loc, Pick Feature: ■ First Part: Lower_Arm ■ Second Part: ground ■ Location: HP4 ■ Direction Vector (+z axis): Z-direction of marker .Lower_Arm.bushing_ref. Tip: To easily find the marker .Lower_Arm.bushing_ref, display the Database Navigator, locate the marker under Lower_Arm, and then select Highlight from the bottom of the Database Navigator. Back in your model, right-click at the marker location, and then select .Lower_Arm.bushing_ref.Z. 3 Modify the bushing to reflect the following properties: Kmatrix Cmatrix 2.9e7 0 0 0 0 0 0 2.9e7 0 0 0 0 0 0 1e8 0 0 0 0 0 0 1e6 0 0 0 0 0 0 1e6 0 0 0 0 0 0 0 Translational K Preloadmatrix 7.3e5 0 0 0 0 0 0 7.3e5 0 0 0 0 0 0 1.5e6 0 0 0 0 0 0 4e5 0 0 0 0 0 0 4e5 0 0 0 0 0 0 0 0 0 0 0 0 0 Translational C Rotational K Suspension-Steering System II Rotational C 233 :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP ,, 4 Create the forward bushing with the following properties: ■ ■ Second Part: ground ■ Location: HP5 ■ 5 First Part: Lower_arm Direction Vector (+z axis): Z-direction of marker .Lower_Arm.bushing_ref Modify the bushing to reflect the properties given in Step 3 on page 233. 5XQ D VLPXODWLRQ WR YLHZ WKH HIIHFW RI DGGLQJ WKH EXVKLQJ 7R UXQ D VLPXODWLRQ 1 Run a static simulation ( steps. ) followed by a dynamic simulation for 1 second with 50 output 2 Save the simulation results as with_bushings. 5HYLHZ WKH UHVXOWV 7R UHYLHZ WKH UHVXOWV 1 Launch ADAMS/PostProcessor. 2 Create a plot that contains the Toe_Angle measure using the simulation results with_joint and with_bushings as a function of time. 234 Suspension-Steering System II :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP ,, 3 Estimate the difference in the maximum toe angle between the two simulations and use it to answer Question 1 in Module review, on page 236. 2YHUOD\ DQLPDWLRQV 7R RYHUOD\ DQLPDWLRQV 1 Make sure that ADAMS/PostProcessor is in Animation mode. 2 From the dashboard, select the Overlay tab. 3 Select both with_joint and with_bushings analyses. 4 In the Offset text box, enter 0.0, 40.0, 0.0. 5 Select the Animation tab. 6 Set the Speed Control slider to approximately 50%. 7 Select Play. Note: To emphasize the difference, zoom in on the lower arm. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save your model. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 2 Exit ADAMS/View. 2SWLRQDO WDVNV 1 Replace the revolute joint between Upper_Arm and ground with two bushings. Use the same bushing properties given for the bushing between Lower_Arm and ground. 2 Run a static simulation followed by a dynamic simulation for 1 second with 50 output steps. 3 Save the simulation results as with_all_bushings. 4 Compare these toe_angle results with those from the previous two simulations. Suspension-Steering System II 235 :RUNVKRS ³6XVSHQVLRQ6WHHULQJ 6\VWHP ,, 0RGXOH UHYLHZ 1 What was the approximate difference in the maximum toe angle that was a result of removing the revolute joint and replacing it with bushings? 2 Why did you perform a static simulation before the dynamic simulation after you added the bushings? 3 Why did you not have to perform a static simulation before the dynamic simulation when the Lower_Arm was constrained with the revolute joint? 236 Suspension-Steering System II We will revisit removing the transient effects (performing static solution) in Cam-Rocker-Valve, on page 297.  +$7&+%$&N , Create the forces required to open the hatchback for the given Mazda MX-6 model. lid left_cylinder left_piston left_shortarm left_longarm ground 7KLV PRGXOH LQFOXGHV ■ Impact Functions, 238 ■ Velocity Functions, 240 ■ Workshop 17—Hatchback I, 241 ◆ Module review, 248 237 ,PSDFW )XQFWLRQV ,PSDFW IXQFWLRQV LQ 06&$'$06 ■ Are used with user-defined force elements to model contacts, impacts, collisions, and so on. ■ Mimic nonlinear spring and damping forces that turn on and off depending on the distance between two objects. ■ Just like a compression-only spring damper, MSC.ADAMS turns the force on when the distance between two objects, q, becomes less than the user-specified reference distance, q0: F IMPACT = Off , if q > q0 F IMPACT = On , if q < q0 $SSOLFDWLRQV RI RQHVLGHG LPSDFW IXQFWLRQV ,03$&7 $SSOLFDWLRQV RI WZRVLGHG LPSDFW IXQFWLRQV %,6723 238 Provide an overall idea of what the IMPACT and BISTOP functions are. Explained in detail on the next page. Hatchback I ,PSDFW )XQFWLRQV 6\QWD[ IRU ,03$&7 IXQFWLRQ · IMPACT(q, q , qo, k, e, cmax, d) ■ q - Actual distance between the two objects (defined with a displacement function) ■ · q - Time rate of change of the variable q ■ qo - Trigger distance used to determine when the contact force turns on and off; it should be specified as a real, constant value ■ k - Stiffness coefficient ■ e - Stiffness force exponent ■ c - Damping coefficient ■ d - Damping ramp-up distance ,Q 06&$'$06 WKH RQHVLGHG LPSDFW IRUFH LV FDOFXODWHG DV F = 0 if q > qo e · F = k ( q o – q ) – c max q *STEP(q, q o – d, 1, q o, 0) if q < qo Compression-only spring force from one-sided IMPACT function Compression-only damping force from one-sided IMPACT function Fk = f(q) e=1 C = f(q) e>1 d Cmax e<1 qo- 1 Hatchback I qo q qo - d qo q 239 See Demonstration on next page. Question: If added to the equation, should e>1 or e<1? Which is more realistic? Answer: e>1, and this is easier on Solver. It results in a nonlinear stiffness force. Write the equation for damping. Question: Why is the damping portion not C*qdot? Answer: The damping force would go from 0 to some value on contact. This would cause discontinuities. As the ball penetrated and slowed down, the damping force would decrease. This is unrealistic. Therefore, the damping coefficient is a function of q. C=Cmax*STEP(q,q1-d,1,q1,0), which results in the plot on the right side of the slide. This C function is then multiplied by qdot to provide a nonlinear damping force. 9HORFLW\ )XQFWLRQV 'HILQLWLRQ RI YHORFLW\ DQG DFFHOHUDWLRQ IXQFWLRQV ■ Returns scalar portions of velocity or acceleration vector components (translational or rotational). 6\QWD[ IRU YHORFLW\ IXQFWLRQV ■ VM(I,[J], [L]) ■ VR(I,[J], [L]) ■ VX, VY, VZ(I,[J],[R], [L]) Notes: ■ ■ If the markers are separating: VR > 0. ■ 240 Velocity function, VR, is used to define velocity along the line of sight, which is commonly used in spring dampers. If the markers are approaching: VR < 0. Hatchback I :RUNVKRS ³+DWFKEDFN , 3UREOHP VWDWHPHQW Create the forces required to open the hatchback for the given Mazda MX-6 model. lid left_cylinder left_piston left_shortarm left_longarm ground Hatchback I Review the problem statement. Quiz students about the steps needed to complete the workshop. 241 :RUNVKRS ³+DWFKEDFN , 0RGHO GHVFULSWLRQ ■ When compressed, the force in each gas shock is 550 Newtons. ■ The motion of the assembly is limited by stops in the gas shocks at full extension. ■ Parts are constrained as shown next: Location: Parts: Type: POINT_1 left_shortarm and ground Revolute POINT_4 left_longarm and ground Revolute POINT_2 left_shortarm and lid Spherical POINT_6 left_cylinder and lid Spherical POINT_8 right_cylinder and lid Spherical POINT_3 lid and left_longarm Hooke POINT_5 ground and left_piston Hooke POINT_7 ground and right_piston Hooke POINT_56 left_piston and left_cylinder Translational POINT_78 right_piston and right_cylinder Translational 6WDUW WKH ZRUNVKRS 7R VWDUW WKH ZRUNVKRS 1 Run ADAMS/View from the directory exercise_dir/mod_17_hatchback_1. 2 Import the model command file hatchback_start.cmd. 242 Hatchback I Tell students: The step where they have to create the single-component forces (SFORCE) causes the most confusion. To create an SFORCE, select two parts and two points on the respective parts in the same order. For example, if you first select the piston, and then select the cylinder, then you should select the pis_impact marker before the cyl_impact marker. If you select the markers in the wrong order and simulate the model, it runs fine until the IMPACT is triggered. When the IMPACT is triggered, instead of the two ends of the objects repelling each other, they attract each other. In this case, the SFORCE is incorrectly defined, and not the IMPACT function. Therefore, modify the SFORCE and change the order of the parts by switching the action and reaction bodies. :RUNVKRS ³+DWFKEDFN , 'HDFWLYDWH PRYDEOH SDUWV QRW XVHG IRU VLPXODWLRQ You must deactivate the parts on the right side of the model because they are not needed to constrain the model. The constraints from the left side of the model are sufficient to constrain this rigid-body model. 7R GHDFWLYDWH SDUWV 1 Deactivate right_shortarm. Tip: Right-click the part and select De(activate). Clear the selection of Object Active. 2 Deactivate right_longarm. &UHDWH IRUFHV WR UHSUHVHQW JDV VKRFNV ZLWK OLPLW VWRSV In this section, you will practice debugging your model. To ensure that your model is running correctly, run a simulation after you add each new force. 7R FUHDWH JDV VKRFNV 1 Create a marker ( ), named lpiston_ref, at POINT_5, located on left_piston: ■ ■ 2 Add to Part From the screen, select the left piston and then select POINT_5. Create a marker, named lcyl_ref at POINT_6, located on left_cylinder. You will use these markers to create the spring damper in the next step. 3 Create a spring damper between left_piston (first body) and left_cylinder (second body) using the markers lpiston_ref (first location) and lcyl_ref (second location), with the following parameters: ■ Stiffness: 0.21578 (N/mm) ■ Damping: 2.0 (N-sec/mm) 4 Modify the spring damper to add a preload of 550 N. 5 Create a marker, named rpiston_ref, at POINT_7, located on right_piston. 6 Create a marker, named rcyl_ref at POINT_8, located on right_cylinder. You will use these markers to create the spring damper in the next step. Hatchback I 243 :RUNVKRS ³+DWFKEDFN , 7 Create a spring damper between right_piston (first body) and right_cylinder (second body) using the markers rpiston_ref (first location) and rcyl_ref (second location): ■ 0.21578 (N/mm) ■ 8 Stiffness: Damping: 2.0 (N-sec/mm) Modify the spring damper to add a preload of 550 N. 7R FUHDWH OLPLW VWRSV 1 Create an SFORCE, on the left piston/cylinder, described by an impact function to stop the hatchback motion: ■ Use the two bodies method. ■ Use the existing markers, pis_impact (located on left_piston) and cyl_impact (located on left_cylinder), as shown next. pis_impact cyl_impact left_piston left_cylinder 25mm trigger distance Tip: Make sure that you select the parts and markers in the same order. If you select the piston to be the action body, and the cylinder to be the reaction body, you should use the same order when selecting the action point (pis_impact) and the reaction point (cyl_impact). 244 Hatchback I :RUNVKRS ³+DWFKEDFN , 2 Modify the SFORCE and use the Function Builder to create a one-sided impact function. The impact functions are located in the Contact category in the Function Builder. ■ The displacement parameter is equal to the magnitude of the distance between the markers, pis_impact and cyl_impact (use the DM function). ■ The velocity parameter is equal to the velocity along the line of sight between the markers, pis_impact and cyl_impact (use the VR function). Note: Do not enter units into the Function Builder. ■ 1e5 (N/mm) ■ Stiffness Force Exponent: 1.01 ■ Damping Coefficient: 100 (N-sec/mm) ■ Trigger for Displacement Variable: 25 mm ■ 3 Stiffness Coefficient: Damping Ramp-up Distance: 1e-3 mm While still in the Function Builder, verify the function to make sure that the syntax is correct. The function should look as shown next: Note: This syntax reflects the piston as the action part. If you chose the cylinder as the action part, the syntax should be opposite. Hatchback I 245 :RUNVKRS ³+DWFKEDFN , 4 Create another SFORCE, on the right piston/cylinder, described by an impact function, to stop the hatchback motion: ■ Use the two bodies method. ■ Use the existing markers, pis_impact (located on right_piston) and cyl_impact (located on right_cylinder). Tip: Make sure that you select the parts and markers in the same order. If you select the piston to be the action part, and the cylinder to be the reaction part, you should use the same order in the force definition. 5 Modify the SFORCE and use the Function Builder to create a one-sided impact function. The impact functions are located in the Contact category in the Function Builder. ■ ■ The velocity parameter is equal to the velocity along the line of sight between the markers, pis_impact and cyl_impact (use the VR function). ■ Stiffness Coefficient: 1e5 (N/mm) ■ Stiffness Force Exponent: 1.01 ■ Damping Coefficient: 100 (N-sec/mm) ■ Trigger for Displacement Variable: 25 mm ■ 246 The displacement parameter is equal to the magnitude of the distance between the markers, pis_impact and cyl_impact (use the DM function). Damping Ramp-up Distance: 1e-3 mm Hatchback I :RUNVKRS ³+DWFKEDFN , 6 While still in the Function Builder, verify the function to make sure that the syntax is correct. The function should look as shown next: Note: This syntax reflects the piston as the action part. If you chose the cylinder as the action part, the syntax should be opposite. 6HOHFWLQJ SDUDPHWHUV IRU D UHDOOLIH PRGHO For information on how to select parameters for a real-life model, see the following Knowledge Base articles: ■ Modeling Impact: http://support.adams.com/kb/faq.asp?ID=8230 ■ Suggestions for debugging your IMPACT function: http://support.adams.com/kb/faq.asp?ID=7301 ■ Example of using Hertzian Contact Theory to estimate contact stiffness: http://support.adams.com/kb/faq.asp?ID=8470 ■ Ballpark values for 3D automated contact between various materials: http://support.adams.com/kb/faq.asp?ID=9629 Hatchback I 247 :RUNVKRS ³+DWFKEDFN , 6LPXODWH WKH PRGHO Simulate the model to make sure that the hatchback opens and stops at a reasonable angle. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save your model. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 2 Exit ADAMS/View. 0RGXOH UHYLHZ 1 Are there any limitations to the trigger distance used in an IMPACT function? In other words, can you choose any value? 2 If you wanted to stop the hatchback from opening at a 45-degree angle, what steps would you take? 248 Hatchback I  +$7&+%$&N ,, Find the approximate maximum force at the winglet required to close the lid in three seconds, for the given Mazda MX-6 hatchback model. lid left_cylinder left_piston left_shortarm left_longarm ground 7KLV PRGXOH LQFOXGHV ■ STEP Function, 250 ■ Scripted Simulations, 251 ■ ADAMS/Solver Commands, 252 ■ Workshop 18—Hatchback II, 253 ◆ Module review, 260 249 67(3 )XQFWLRQ 'HILQLWLRQ RI D 67(3 IXQFWLRQ ■ In MSC.ADAMS, the STEP function approximates an ideal mathematical step function (but without the discontinuities). ■ Avoid discontinuous functions because they lead to solution convergence difficulties. ■ The STEP function steps quantities, such as motions or forces, up and down, or on and off. Note: A STEP function is used when a value needs to be changed from one constant to another. 6\QWD[ IRU 67(3 IXQFWLRQ STEP (q, q1, f1, q2, f2) where: q - Independent variable q1 - Initial value for q f1 - Initial value for f q2 - Final value for q f2 - Final value for f Note: q1 < q2 ([DPSOH STEP (time,1,5,3,10) Time 250 Hatchback II Draw the example given here on the board and highlight the relationship between q1 and f1 and between q2 and f2. 6FULSWHG 6LPXODWLRQV ,Q $'$069LHZ WKHUH DUH WZR ZD\V WR UXQ D VLPXODWLRQ ■ Scripted ■ Interactive 6LPXODWLRQ VFULSWV ■ Let you program the simulation before submitting the simulation. ■ Let you quickly repeat a simulation with the same set of parameters. ■ Let you perform more sophisticated simulations. ■ Are required for design studies, design of experiments, and optimization simulations. ■ Simulation scripts are children of a model, and are, therefore, saved in a command file. 7\SHV RI VFULSWHG VLPXODWLRQV LQ $'$069LHZ ■ Simple run ■ ADAMS/View commands ■ ADAMS/Solver commands Hatchback II 251 Demonstrate: Create a script (Simulate Simulation Script New). Use the Append ACF menu on the Create Simulation Script dialog box. Run a Scripted Simulation (Simulate Scripted Controls). Æ Æ Æ $'$066ROYHU &RPPDQGV 6FULSWHG VLPXODWLRQV EDVHG RQ $'$066ROYHU FRPPDQGV ■ ADAMS/Solver commands let you perform sophisticated simulations, such as: ◆ ◆ Using different output step sizes over different simulation intervals (versus specifying only one duration and output step size). ◆ ■ Changing model parameters during a simulation. Using different solution parameters (such as convergence tolerance) over different intervals. Example of a simulation script that changes model topology while you work on your model: simulate/dynamic, end=3.0, steps=30 deactivate/joint, id=3 simulate/dynamic, duration=2.0, steps=200 Before: 252 After: Hatchback II :RUNVKRS ³+DWFKEDFN ,, 3UREOHP VWDWHPHQW Find the approximate maximum force at the winglet required to close the lid in three seconds, for the given Mazda MX-6 hatchback model. lid left_cylinder left_piston left_shortarm left_longarm ground 0RGHO GHVFULSWLRQ In this workshop, you will use the model you built in Hatchback I, on page 237. 6WDUW WKH ZRUNVKRS 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_18_hatchback_2. 2 From the directory exercise_dir/mod_17_hatchback_1, import the model that you created in the previous module. If you need a copy of the model, import the command file hatchback_1_completed.cmd from the directory exercise_dir/mod_17_hatchback_1/completed. Hatchback II 253 :RUNVKRS ³+DWFKEDFN ,, 'HWHUPLQH VWHDG\VWDWH URWDWLRQ RI OHIWBVKRUWDUP 7R PHDVXUH WKH URWDWLRQ RI WKH OLG 1 Right-click l_shortarm_rev joint and create a measure, named shortarm_rotation, of the rotational displacement: ■ Characteristic: Ax/Ay/Az Projected Rotation ■ Component: Z ■ From/At: .ground.MAR_7 2 Run a 5-second, 50-step simulation. 3 In ADAMS/PostProcessor, plot the shortarm_rotation versus time. 4 From the shortarm_rotation plot, use the Plot Tracking tool angle of the left_shortarm. to determine the steady-state The steady-state angle is 96.0693 d. &ORVH WKH OLG Currently the lid opens because of the preload in the springs and stops opening because of the impact forces. To close the lid, you will rotate the left_shortarm part back to its original position, as shown next. To rotate the left_shortarm, apply a joint motion to the left_shortarm_rev joint, as explained next. lid closing lid lid closed closing motion on left_shortarm lid left_shortarm lid 254 Review problem statement. Quiz the students about the steps needed to complete this workshop. Hatchback II :RUNVKRS ³+DWFKEDFN ,, 7R FUHDWH D PRWLRQ WR FORVH WKH OLG 1 Create a joint motion on the joint l_shortarm_rev, named closing_motion. 2 Use a STEP function to modify the motion to drive the lid back to its closed position: ■ Start the STEP function at the steady-state rotation (determined in Step 4 on page 254) of the left_shortarm at 4 seconds. ■ End the STEP function at 0o rotation of the left_shortarm at 7 seconds. Rotational motion Steady state opening angle motion deactivated step Steady state time ■ The function should look as shown next: STEP(time, 4.0, 96.0693d, 7.0, 0.0d) 3HUIRUP D VFULSWHG VLPXODWLRQ In this section, you’ll create a simulation script containing ADAMS/Solver commands that deactivate the motion and run a simulation, then activate the motion and run a second simulation. 7R FUHDWH WKH VFULSW 1 From the Simulate menu, point to Simulation Script, and then select New. 2 Name the script, script_1. 3 Set Script Type to ADAMS/Solver Commands. Hatchback II 255 :RUNVKRS ³+DWFKEDFN ,, 4 Enter the following ADAMS/Solver commands: DEACTIVATE/MOTION, id=1 SIMULATE/DYNAMIC, END=4, STEPS=40 ACTIVATE/MOTION, id=1 SIMULATE/KINEMATIC, END=7, STEPS=30 5 Select OK. 7R SHUIRUP D VFULSWHG VLPXODWLRQ 1 From the Simulate menu, select Scripted Controls. 2 Enter the name of the script that you created, script_1. 3 Select the Play tool. 0HDVXUH WKH WRUTXH You now create a measure of the torque required to close the lid. You then deactivate this measure because it is dependent on the motion that is deactivated when the scripted simulation starts. 7R FUHDWH WKH PHDVXUH ■ Create a motion measure, named closing_torque_measure (right-click closing_motion, and then select Measure): ◆ Characteristic: Torque ◆ Component: Z 7R GHDFWLYDWH WKH PHDVXUH 1 By default, when you deactivate something using the Edit menu, ADAMS/View deactivates anything that is currently in your Select list. Therefore, first clear your Select list by selecting the Select tool, so you do not accidentally deactivate something else in your model. 2 From the Edit menu, select Deactivate. 256 Hatchback II :RUNVKRS ³+DWFKEDFN ,, 3 Use the Browse option to filter only on measures. 4 Select closing_torque_measure. 5 Select OK. Hatchback II 257 :RUNVKRS ³+DWFKEDFN ,, ,QVSHFW WKH PHDVXUH 7R LQVSHFW WKH WRUTXH PHDVXUH 1 In ADAMS/PostProcessor, plot torque in the motion versus time (the closing_torque_measure). Nmm Figure 3. Plot of Approximate Torque Required to Close the Lid sec 2 Edit the torque curve to find the approximate force required to lower the lid in three seconds. To find this force, use the Scale a Curve tool to divide the motion torque by a moment arm of 700 mm: ■ To display the Scale a Curve tool, from the View menu (inside ADAMS/PostProcessor), point to Toolbars, and then select Curve Edit Toolbars. A new toolbar appears. ■ ■ Set Scale to 1/700. ■ 258 Select the Scale a Curve tool . Follow the instructions in the Status bar to create the scaled curve. Hatchback II :RUNVKRS ³+DWFKEDFN ,, 3 To display only the force curve, delete the motion torque curve. N Figure 4. Plot of Approximate Force Required to Close the Lid sec 4 Note the approximate maximum force required to close the lid. Use the value to answer Question 1 in Module review, on page 260. 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save your model. 2 Exit ADAMS/View. Hatchback II 259 :RUNVKRS ³+DWFKEDFN ,, 0RGXOH UHYLHZ 1 What is the approximate maximum force required to close the lid? 2 Is it possible to modify a force from one constant value to another instantaneously, such as shutting off a motor’s torque? 3 Is it possible to use different output step sizes over different intervals by submitting an interactive simulation? 260 Hatchback II  +$7&+%$&N ,,, Use ADAMS/Solver to simulate the given Mazda MX-6 hatchback model. lid left_cylinder left_piston left_shortarm left_longarm ground 7KLV PRGXOH LQFOXGHV ■ ADAMS/Solver Overview, 262 ■ Files in ADAMS/Solver, 264 ■ Example of an ADAMS/Solver Dataset (.adm) File, 265 ■ Stand-Alone ADAMS/Solver, 266 ■ Example: 2D Pendulum, 267 ■ Formulation of the Equations of Motion, 268 ■ Phases of Solution, 269 ■ Debug/Eprint (dynamics), 274 ■ Workshop 19—Hatchback III, 276 ◆ Module review, 283 261 It is important to learn how to use standalone ADAMS/Solver because in some cases it is quicker to simulate models in standalone ADAMS/Solver with .adm files than it is to simulate in ADAMS/View. $'$066ROYHU 2YHUYLHZ ADAMS/View Integrated ADAMS/Solver Import Export Analysis files .out .gra Dataset .adm .req .res Output Input Input Interactive Solver commands ADAMS/Solver OR Input MSC.ADAMS Command file .acf Output Message file .msg 262 Identify each analysis file (.out, .gra, .req, .res, and .msg) and explain the differences. Hatchback III 6ROYHU &RPSDWLELOLW\ :LWK 06&$'$06  WKH QHZ $'$066ROYHU & YHUVLRQ KDV DGGHG VLJQLILFDQW IXQFWLRQDOLW\ :LWK WKHVH DGGLWLRQV $'$066ROYHU & QRZ VXSSRUWV VRPH HQWLWLHV WKDW DUH QRW VXSSRUWHG IRU $'$066ROYHU )2575$1  )RU WKLV UHDVRQ D VROYHUFRPSDWLELOLW\ FKHFN KDV EHHQ DGGHG :KHQ XVLQJ $'$069LHZ WKLV FKHFN LV FDOOHG DV HDFK REMHFW LV FUHDWHG The check is also called for: ■ Each object as it is created when a .cmd file is imported ■ The entire model when an .adm file is imported ■ The entire model before simulation Hatchback III 263 )LOHV LQ $'$066ROYHU $'$066ROYHU GDWDVHW ILOHV DGP ■ Statements define an element of a model such as a part, constraint, force, and so on. ■ Functions are numeric expressions that define the magnitude of an element such as a force or motion. For more information, see the ADAMS/Solver online help. $'$066ROYHU FRPPDQG ILOHV DFI Commands define an action that needs to be taken during a simulation. See also: ADAMS/Solver Commands, on page 252 264 Demonstrate: Start ADAMS/Solver and use it as you go over this slide. Hatchback III ([DPSOH RI DQ $'$066ROYHU 'DWDVHW DGP )LOH Pendulum !-------------------------------- SYSTEM UNITS -------------UNITS/FORCE = NEWTON, MASS = KILOGRAM, ,LENGTH = MILLIMETER, TIME = SECOND !------STATEMENTS FROM ORIGINAL DATASET ----! MATERIAL/1, NAME = steel, YOUNGS_MODULUS = 2.07E+005, , POISSONS_RATIO = 0.29 , DENSITY = 7.801E-006 ! PART/1, GROUND ! MARKER/1, PART = 1 ! MARKER/5, PART = 1, QP = 175, -225, 0 ! PART/2, MASS = 70.94, CM = 3, IP = 2.01E+006, 1.80E+005 , 2.01E+006, MATERIAL = steel ! MARKER/2, PART = 2, REULER = 37.87498365D, 90D, 0D ! MARKER/3, PART = 2, QP = 175, -225, 0, REULER = 37.87498365D, 0D, 0D ! MARKER/4, PART = 2 ! GRAPHICS/1, CYLINDER, CM = 2, LENGTH = 570.08, RADIUS = 71.26 ! JOINT/1, REVOLUTE, I = 4, J = 1 ! REQUEST/1, DISPLACEMENT, I = 3, J = 5, RM = 5 ACCGRAV/JGRAV = -9806.65 OUTPUT/REQSAVE, GRSAVE RESULTS/ ! MOTION/1, ROTATIONAL, JOINT = 1, FUNCTION = 30.0d * time Hatchback III 265 6WDQG$ORQH $'$066ROYHU 6LPXODWLRQV LQ VWDQGDORQH $'$066ROYHU ■ Interactive: ◆ ◆ ■ Not scripted: enter commands one by one. Scripted: use an ADAMS/Solver command file (.acf). Batch - Run multiple jobs in the background using an ADAMS/Solver command file (.acf). Note: ADAMS/Solver command files must start with the name of the model to be analyzed and must end with a STOP command. <RX FDQ UXQ VLPXODWLRQV H[WHUQDOO\ LQ $'$066ROYHU IURP ZLWKLQ $'$069LHZ 266 Hatchback III ([DPSOH ' 3HQGXOXP 06&$'$06 ,PSOHPHQWDWLRQ (XOHU/DJUDQJH (TXDWLRQV 'HVFULSWLRQ ■ A link of mass M, moments of inertia I, and length 2L is attached to ground using a revolute joint at the global origin O. The joint is oriented in such a way that motion is only allowed in the X-Y plane of the global coordinate system. ■ The coordinates of the center of mass of the link, with respect to the global origin, are represented by the states (x,y). ■ A coordinate system (Op-Xp-Yp) is attached at the center of mass of the link, such that Xp is along the length of the link. The angle between Xp and Xg is denoted by q. Force balance equations Momenta equations (only in θ) Kinematic differential equations Constraint equations Hatchback III 267 )RUPXODWLRQ RI WKH (TXDWLRQV RI 0RWLRQ 1RQOLQHDU V\VWHP  1LQH GLIIHUHQWLDO DQG DOJHEUDLF HTXDWLRQV '$(·V Equations of motion Unknowns Force balance Momenta Kinematics 268 Hatchback III 3KDVHV RI 6ROXWLRQ 7DVN Solve the differential and algebraic equation: 7ZR PDMRU FRPSRQHQWV 3UHGLFWRU DQG &RUUHFWRU 3KDVH  Predict an initial solution 3KDVH  Correct the prediction 3KDVH  Evaluate quality of solution (accept solution) 3KDVH  Prepare for next step Hatchback III Illustrate each step of the process on the board. Use image from page 272 to help. 269 3KDVHV RI 6ROXWLRQ 7DVN Solve the differential and algebraic equation: 3KDVH  Predict an initial solution Predict an initial value using an explicit method: ■ The predictor is simply looking at past values to guess the solution at the next time. The governing equations G are not satisfied. ■ This is simply a good starting point for the next phase. 3KDVH  Correct the prediction 3KDVH  Evaluate quality of solution (accept solution) 3KDVH  Prepare for next step 270 Hatchback III 3KDVHV RI 6ROXWLRQ 7DVN Solve the differential and algebraic equation: 3KDVH  Predict an initial solution 3KDVH  Correct the prediction Evaluate G. If G is near zero, corrector is finished. Go to phase 3. Use the Newton-Raphson method to correct the prediction. Solve for ∆y. Update y. Repeat iteration until ||∆y|| < corrector error tolerance Example: As a first guess, set q = 2 The exact answer is q = 1.0 3KDVH  Evaluate quality of solution (accept solution) 3KDVH  Prepare for next step Hatchback III 271 3KDVHV RI 6ROXWLRQ 7DVN Solve the differential and algebraic equation: 3KDVH  Predict an initial solution 3KDVH  Correct the prediction 3KDVH  Evaluate quality of solution (accept solution) Estimate local truncation error if estimated < (εL) Yes Æ Accept solution. Go to phase 4 No Æ Reject solution and repeat phase 1 and 2 with new step size Global Error (eG) The difference between the current solution and the true solution Local Truncation Error (eL) The error introduced in a single step 3KDVH  Prepare for next step 272 Hatchback III 3KDVHV RI 6ROXWLRQ 7DVN Solve the differential and algebraic equation: 3KDVH  Predict an initial solution 3KDVH  Correct the prediction 3KDVH  Evaluate quality of solution (accept solution) 3KDVH  Prepare for next step Update higher order derivatives used in prediction for the next step Determine step size and order for next step Go back to phase 1, and start new step Hatchback III 273 'HEXJ(SULQW G\QDPLFV (DFK *67,)) LQWHJUDWRU VWHS FRQVLVWV RI WZR SKDVHV 3KDVH  D IRUZDUG VWHS LQ WLPH WKH SUHGLFWRU IRU G\QDPLFV 1 The step number - A running count of the number of steps taken and can be used as a measure of how hard ADAMS/Solver is working. 2 The order of the predictor for dynamics - Corresponds to the order of the polynomial ADAMS/Solver uses to predict the solution at the end of the integration step. 3 The value of time at the beginning of the step. 4 The size of the step. 3KDVH  WKH VROXWLRQ RI WKH HTXDWLRQV RI PRWLRQ WKH FRUUHFWRU IRU G\QDPLFV  5 The cumulative number of iterations - A running count of the iterations needed to solve the equations of motion and can be used as a measure of how many computations ADAMS/Solver is performing. 6 The iteration number - One at the beginning of each step and increments by one until ADAMS/Solver converges to a solution or exceeds the maximum allowable number of iterations. 7 Absolute value of largest equation residual error - This number is an indicator of how far ADAMS/Solver is from a solution. This number should decrease after every iteration in healthy simulations. 8 Dataset element associated with #7 - The equation that has the largest equation residual error for the above dataset element. 9 Equation associated with #8. 10 Absolute value of largest change in a variable - The final iteration should not need to change variables very much. This number is an indicator of how far ADAMS/Solver needs to change variables to approach a solution. Ideally, this number should decrease after every iteration. 11 Dataset element associated with #5. 12 Variable with the largest change for #6. 13 Jacobian updates - If ADAMS/Solver has updated the Jacobian, YES appears under the Jacobian new? header. 274 Hatchback III Run the completed model from Workshop 18—Hatchback II, on page 253 with the EPRINT turned on. 'HEXJ(SULQW G\QDPLFV  3. Time at beginning of step 1. Running count of successful steps 2. Order of predicting polynomial 5. 4. 6. 7. Hatchback III 8. 9. 10. 11. 12. Corrector information 13. 275 :RUNVKRS ³+DWFKEDFN ,,, 3UREOHP VWDWHPHQW Use ADAMS/Solver to simulate the given Mazda MX-6 hatchback model. lid left_cylinder left_piston left_shortarm left_longarm ground 0RGHO GHVFULSWLRQ In this workshop, you use the model you saved in Workshop 18—Hatchback II, on page 253. 6WDUW WKH ZRUNVKRS 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_19_hatchback_3. 2 From the directory exercise_dir/mod_18_hatchback_2, import the model that you created in the previous module. If you need a fresh copy of the model, import the command file hatchback_2_completed.cmd from the directory exercise_dir/mod_18_hatchback_2/ completed. 276 Hatchback III :RUNVKRS ³+DWFKEDFN ,,, ([SRUW D GDWDVHW DGP ILOH 7R H[SRUW D GDWDVHW ILOH 1 From the File menu, select Export. 2 Enter the following, and then select OK: ■ File Type: ADAMS/Solver Data Set ■ File Name: hatchback.adm ADAMS/View exports this file to your current working directory, exercise_dir/ mod_19_hatchback_3. &UHDWH D FRPPDQG ILOH DFI 7R FUHDWH D FRPPDQG ILOH 1 Open a text editor (UNIX: vi or Jot; Windows: Notepad or Wordpad), and create an ADAMS/Solver command file (.acf) that contains the following commands: hatchback.adm (the .adm extension is optional) hatchback_test1 OUTPUT/NOSEPARATOR DEACTIVATE/MOTION, id=1 SIMULATE/DYNAMIC, END=4, STEPS=40 ACTIVATE/MOTION, id=1 SIMULATE/KINEMATIC, END=7, STEPS=30 STOP 2 Save the file as hatchback.acf in your current working directory, exercise_dir/ mod_19_hatchback_3. Hatchback III Review the problem statement and quiz the students on what steps they would take to solve it. Ask for questions before letting them start. You can simulate a model in ADAMS/Solver using two methods. In this workshop, you will simulate interactively in ADAMS/Solver with a scripted simulation. 277 :RUNVKRS ³+DWFKEDFN ,,, 3HUIRUP D VLPXODWLRQ LQ VWDQGDORQH $'$066ROYHU To perform a simulation in stand-alone ADAMS/Solver, you use the MSC.ADAMS Program Menu, a menu- and text-based interface that allows you to enter information on the command line. 7R SUHSDUH WR UXQ $'$066ROYHU 1 Depending on the platform you’re on, do the following: ■ Windows: From the Start menu, select Run and open a command window by typing in cmd. Change directories to your working directory, exercise_dir/mod_19_hatchback_3. Table 1. Common Windows Commands change directory change disks <drive_letter>: (for example, C:) list ■ cd <directory_name> dir UNIX: Open a UNIX shell and change directories to your working directory, exercise_dir/mod_19_hatchback_3. Table 2. Common UNIX Commands change directory list 278 ls list path 2 cd <directory_name> pwd Leave the window open because you will be running ADAMS/Solver from this window. Hatchback III :RUNVKRS ³+DWFKEDFN ,,, 7R SHUIRUP WKH VLPXODWLRQ 1 Perform a simulation in stand-alone ADAMS/Solver using the command file you just created, hatchback.acf. Type the following commands in the window you just prepared: ■ Windows: ◆ ◆ ru-s (runs ADAMS/Solver with standard MSC.ADAMS executable) ◆ ■ adamsxx (where xx is the version number; for example, adams03) (displays the MSC.ADAMS Program Menu) hatchback.acf (identifies the .acf ADAMS/Solver file and runs the simulation) UNIX: ◆ adamsxx -c (where xx is the version number; for example, adams12 -c) (displays the MSC.ADAMS Program Menu) ◆ ru-s (runs ADAMS/Solver with standard MSC.ADAMS executable) ◆ i (sets interactive mode) ◆ hatchback.acf (identifies the .acf ADAMS/Solver file and runs the simulation) ◆ exit (exits ADAMS/Solver) Note: As common practice, you should open the message file (.msg) and search for errors and warnings. Correct the model or the .acf file to eliminate the errors and warnings. 2 Leave the window open because you will be using it again soon. Hatchback III 279 :RUNVKRS ³+DWFKEDFN ,,, 0RGLI\ WKH GDWDVHW DGP ILOH Now change the spring stiffness in the .adm. 7R FKDQJH WKH VSULQJ VWLIIQHVV 1 In a text editor, open hatchback.adm. 2 Modify the value of spring stiffness (for both springs) to -0.30 N/mm. 3 Save the file as hatchback2.adm. 280 Hatchback III :RUNVKRS ³+DWFKEDFN ,,, 0RGLI\ WKH $'$066ROYHU FRPPDQG ILOH DFI Modify the .acf to run with hatchback2.adm. 7R PRGLI\ WKH DFI 1 In a text editor, open hatchback.acf. 2 Modify the first and second lines of the .acf file so they are: hatchback2 hatchback_test2 3 Save the file as hatchback2.acf. 3HUIRUP D VLPXODWLRQ LQ VWDQGDORQH $'$066ROYHU ■ Using the new command file, perform a stand-alone ADAMS/Solver simulation. &RPSDUH WKH UHVXOWV RI WKH WZR VLPXODWLRQV LQ $'$069LHZ Import both sets of results (hatchback_test1 and hatchback_test2) into ADAMS/View, and then compare them. 7R LPSRUW DQG FRPSDUH WKH UHVXOWV 1 In ADAMS/View, from the File menu, select Import. 2 To import the results for hatchback_test1, enter the following, and then select OK: ■ ■ File to Read: hatchback_test1.res ■ 3 File Type: Model Name: hatchback ADAMS/Solver Analysis (.req, .gra, .res) To import the results for hatchback_test2, repeat Step 2 above to import the results, hatchback_test2.res. 4 Display the Database Navigator. 5 Set the Filter type from Modeling to Analyses. 6 Double-click the hatchback model to make sure that the two analyses, hatchback_test1 and hatchback_test2, are children of the model. Hatchback III 281 :RUNVKRS ³+DWFKEDFN ,,, 7R LQVSHFW ERWK VLPXODWLRQV 1 Launch ADAMS/PostProcessor. 2 From the Simulation list, select the two analyses, hatchback_test1 and hatchback_test2. 3 From the Measure list, select closing_torque_measure, and then select Add Curves. 4 Select the Scale a Curve tool to individually scale both curves by the moment arm (1/700) (proceed just as you did in Inspect the measure, on page 258). 5 Delete the old curves. 6 Use the Subtract one curve from another tool to find the approximate difference between the maximum force values. Use this value to answer question Step 2 in Module review, on page 283. 7 Save your model. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 8 Exit ADAMS/View. 2SWLRQDO WDVNV 6LPXODWH WKH PRGHO LQ $'$066ROYHU 1 Simulate interactively but without a script (no .acf file). 2 From a DOS prompt, enter the following commands, where xx is the current version of MSC.ADAMS: ■ adamsxx ■ ru-standard ■ <CR> (Because you do not have an ADAMS/Solver command file (.acf), press the enter key). ADAMS/Solver starts. 282 Hatchback III :RUNVKRS ³+DWFKEDFN ,,, 3 In ADAMS/Solver, enter: ■ hatchback (the name of your MSC.ADAMS Dataset (.adm) file) ■ hatchback_test3 (the desired output file names .gra, .res, .out, and so on) ADAMS/Solver reads in the file and performs the assemble simulation. 4 At the MSC.ADAMS command prompt, enter commands one at a time in the same order in which they appear in the .acf file. 5 After entering all the commands, exit ADAMS/Solver and import your results into ADAMS/View so you can inspect them using animations and plotting. 0RGXOH UHYLHZ 1 What is the difference between a statement and a command? 2 What is the maximum force difference between the two tests (hatchback_test1 and hatchback_test2) you performed? Hatchback III 283 :RUNVKRS ³+DWFKEDFN ,,, 284 Hatchback III  +$7&+%$&N ,9 In Workshop 19—Hatchback III, on page 276, you determined the approximate force needed to close the lid. Now you are part of a group of design engineers for the Mazda MX-6 hatchback. Your goal is to make the model more realistic and ensure that it meets the following criteria: ■ Lid opens completely in less than 4 seconds. ■ Requires less than 210 N to close the lid. ■ Takes no more than 3.0 sec to close the lid. 7KLV PRGXOH LQFOXGHV ■ Sensors, 286 ■ Design Variables, 287 ■ Workshop 20—Hatchback IV, 288 ◆ Module review, 295 285 ■ Ask students to separate into groups when working through this workshop. 6HQVRUV 6HQVRUV ■ Monitor any quantity of interest in a model during a simulation, and take a specified action when the quantity reaches or exceeds a critical value. ■ Take one of the following actions: ◆ ◆ ■ Completely stop the simulation. If used with a script, sensors halt the current simulation and continue with the next command in the script. A sensor basically represents an If/Then statement: If quantity = value (+/- tolerance) Then take a specified action ([DPSOH RI XVLQJ VHQVRUV ZLWK VFULSWV ■ Monitor the reaction force in a constraint and deactivate the constraint when the force exceeds a specified value. ■ Monitor the distance between two objects and reduce the solution step size just before contact, to avoid convergence problems. 286 Demonstrate: Use a sensor to stop a simulation Hatchback IV 'HVLJQ 9DULDEOHV 'HVLJQ YDULDEOHV ■ Define independent parameters that can be tied to objects. ■ Organize the critical parameters of the design into a concise list of values that can be easily reviewed and modified. ([DPSOH Cylinder_length Cylinder_length Cylinder_length Cylinder_length Cylinder_length = 300 Cylinder_length Cylinder_length = 150 Cylinder_length You can create a design variable called cylinder_length to control the lengths of all three cylinders as shown next: Note: You can also use parametric analyses to automatically run a series of simulations that vary your design variables, which you will do in Workshop 22—Target Practice, on page 323. Hatchback IV Demonstrate: Create a design variable (Build 287 Æ Design Variable). :RUNVKRS ³+DWFKEDFN ,9 3UREOHP VWDWHPHQW In Workshop 19—Hatchback III, on page 276, you determined the approximate force needed to close the lid. Now you are part of a group of design engineers for the Mazda MX-6 hatchback. Your goal is to make the model more realistic and ensure that it meets the following criteria: ■ Lid opens completely in less than 4 seconds. ■ Requires less than 210 N to close the lid. ■ Takes no more than 3.0 sec to close the lid. 6WDUW WKH ZRUNVKRS In this workshop, you use the model you saved in Workshop 19—Hatchback III, on page 276. 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_20_hatchback_4. 2 From the directory exercise_dir/mod_19_hatchback_3/completed, import the command file named hatchback_3_completed.cmd. 0DNH PRGHO PRUH UHDOLVWLF In Workshop 19—Hatchback III, on page 276, you used a motion to close the lid. In this section, to make this model more realistic, you will deactivate that motion and replace it with a perpendicular force to close the lid. 7R GHDFWLYDWH WKH PRWLRQ ■ Deactivate the motion closing_motion located on the revolute joint l_shortarm_rev. 288 Quiz students about the steps needed to complete this workshop. Hatchback IV :RUNVKRS ³+DWFKEDFN ,9 7R FUHDWH DQ 6)25&( 1 Create an SFORCE ( ) located at the marker, sforce_ref, at the tip of the lid: ■ Run-time Direction: Body Moving ■ Action body: lid ■ Location: sforce_ref ■ Direction: y direction of sforce_ref 2 Rename the SFORCE to closing_force. 3 Modify the SFORCE function to be equal to the following STEP function: STEP(time, 4, 0, 4.2, -247). Note: 247 N is the approximate force needed to close the lid, as you calculated in Workshop 19—Hatchback III, on page 276. 4 Run a 7-second, 100-step simulation to verify that the force closes the lid. Because you’re not activating or deactivating any motions during the simulation, you can run a simple interactive simulation. Note: When using an SFORCE, there is no constraint stopping the rotation of the lid beyond the closed position. You will see that this approximate force is not large enough to close the lid. 5 Modify the STEP function that defines the SFORCE to have a maximum value of 300 N: STEP(time, 4, 0, 4.2, -300). Hatchback IV 289 :RUNVKRS ³+DWFKEDFN ,9 $GG D VHQVRU Add a sensor to stop the lid at the closed position. 7R DGG D VHQVRU 1 Create a sensor based on the measure, shortarm_rotation: ■ ■ 2 From the Simulate menu, point to Sensor, and then select New. Fill in the dialog box as follows: Run another simulation to verify that the sensor works as expected. Why does the sensor stop the simulation when the lid doesn’t appear to be fully closed? _______________________________________________________________________ _______________________________________________________________________ 3 290 Select Generate Additional Output Steps at Event and rerun simulation. Hatchback IV Be sure that the sensor is tracking the results as angular values. Answer: The simulation stops because the output step is large and the zero angle position (fully closed) occurs between output steps. The sensor is triggered at the last output step before the < zero criteria. :RUNVKRS ³+DWFKEDFN ,9 0RGLI\ VSULQJ SUHORDG DQG VWLIIQHVV Because the force required to close the lid is greater that the design criteria, you will modify the spring preload and stiffness for each spring. 7R PRGLI\ WKH SUHORDG 1 Modify the preload to be equal to 400 N. 2 Run a simulation. The sensor was triggered at time 3.5e-3, meaning that instead of having the hatchback open, it dropped past the closing position because the springs were not strong enough to open the lid. 3 Modify the preload again to be 470 N. 7R PRGLI\ WKH VWLIIQHVV 1 Modify the stiffness to be .10 N/mm. 2 Modify the STEP function to have a maximum value of 210 N: STEP(time, 4, 0, 4.2, -210). This maximum value of 210N is the maximum force that we can use to close the lid, as defined in our design criteria from the problem statement. 3 Run a simulation. While the springs now open the lid, the closing force is still too large. Hatchback IV 291 :RUNVKRS ³+DWFKEDFN ,9 &UHDWH GHVLJQ YDULDEOHV Creating design variables in your model will help to speed up the design iteration process. 7R FUHDWH GHVLJQ YDULDEOHV 1 From the Build menu, point to Design Variable, and then select New. 2 Create three design variables as follows: Name: Units: Standard Value: Value Range By: Min. Value Max. Value preload force 460 300 600 stiffness stiffness .21578 .1 .5 damping damping 2 .5 4 0RGLI\ WKH VSULQJV WR UHIHUHQFH GHVLJQ YDULDEOHV 7R PRGLI\ GHVLJQ YDULDEOHV 1 Modify the left spring as follows: Right-click, point to Parameterize, select Reference Design Variable, and then doubleclick the appropriate design variable. 2 292 Repeat Step 1 for the right spring. Hatchback IV :RUNVKRS ³+DWFKEDFN ,9 2SWLPL]H GHVLJQ Modify the SFORCE and the design variables to satisfy design criteria. To verify the parameters, simulate the model between the changes. 7R RSWLPL]H WKH GHVLJQ 1 Modify the SFORCE to be equal to the design criteria (maximum force of 210 N). 2 Modify the standard value of the design variables until the lid opens and closes as required (Build Æ Design Variables Æ Modify). Note: There could be many parameter combinations that would meet the design criteria. Try a few different values to get a feel for the sensitivity of each parameter. 3 Save the model and exit ADAMS/View. Hatchback IV Meet requirements, for example: preload = 480, stiffness = 0.1, damping = 0.67. 293 :RUNVKRS ³+DWFKEDFN ,9 2SWLRQDO WDVNV Run an optimization to find a set of values that meet the criteria of the problem statement. 7R UXQ DQ RSWLPL]DWLRQ 1 Import the custom macro /misc/optimization_optional_task.cmd. Note: This custom macro creates measurements, a design variable, a simulation script, and constraints needed to run this optimization. It also modifies your optimization settings and the values of your design variables to allow for the model to quickly optimize. 2 From the Simulate menu, select Design Evaluation. 3 Select Optimization. 4 Complete the dialog box as shown next: 294 Hatchback IV :RUNVKRS ³+DWFKEDFN ,9 5 Select Start. Note: Several sets of values will meet the design criteria. Further investigation is needed to determine the optimal design. 6 Select the tool Create tabular report of results . ADAMS/View automatically updates the standard values for each design variable to the values found during the optimization process. For this problem, the values that you receive from the optimization are very sensitive to the starting points of the design variables. If time permits, try to modify the starting values of the design variables and run the above optimization again. Did you find an optimal value? What went wrong? Hint: Did the lid even open? 0RGXOH UHYLHZ 1 Which parameters were most sensitive to meeting the design criteria? 2 How did the design variables help to speed the iteration process? Hatchback IV 295 :RUNVKRS ³+DWFKEDFN ,9 296 Hatchback IV  &$052&N(59$/9( Design a cam profile based on desired valve displacement, and ensure that there is no follower liftoff when the cam is rotated at 3000 rpm. Rocker Spring Rod Guide (ground) Cam Valve Valve displacement (mm) Time (sec) 7KLV PRGXOH LQFOXGHV ■ Splines from Traces, 298 ■ Curve Constraints, 299 ■ Automated Contact Forces, 300 ■ Flexible Parts—ADAMS/AutoFlex, 302 ■ Workshop 21—Cam-Rocker-Valve, 303 ◆ Module review, 315 297 6SOLQHV IURP 7UDFHV 'HILQLWLRQ RI VSOLQH IURP D WUDFH ■ A point trace tracks a location of a marker or circle over time with respect to another part. ■ ADAMS/View can create a two- or three-dimensional spline from a trace. ■ Creating a spline from a trace is used to back-calculate (reverse engineer) the shape of an existing part based on its motion (cam synthesis). Notes: ■ When you trace an object and create a spline from it, the point or circle should move in a smooth, even path. ■ If the path is closed, you should simulate for one cycle only. 298 Cam-Rocker-Valve Demonstrate: Open the model you will use in this module. Create a point trace on the model (Review Create Trace Spline). Æ &XUYH &RQVWUDLQWV 7\SHV RI FXUYH FRQVWUDLQWV LQ 06&$'$06 ■ Point-on-curve ■ Curve-on-curve &XUYHRQFXUYH FRQVWUDLQWV ■ Used where a curved edge on one part always follows a curved edge on a different part. ■ Remove two DOF. ■ Modeling of curve-on-curve constraints requires: ◆ ◆ ■ Two parts Two curves that will always remain in contact Typical applications include general cam-to-cam systems. Note: Curve-on-curve constraints do not allow lift off. See also: DOF removed by curve constraints, on page 372 Cam-Rocker-Valve Demonstrate: Create a curve-to-curve constraint and simulate the model noting the no-lift criteria. 299 $XWRPDWHG &RQWDFW )RUFHV &RQWDFW IRUFHV ■ Are special forces acting on parts that are activated when part geometries come in contact with each other. ■ Have values that are determined by a set of contact parameters identical to those in the IMPACT function. ■ Multiple contact forces can be combined to create more complex contacts. &RQWDFW SDLUV LQ 06&$'$06 solid-to-solid curve-to-curve sphere-to-plane curve-to-plane sphere-to-sphere point-to-curve point-to-plane 300 Demonstrate: Replace the curve-curve constraint from the last demonstration with a contact force. Notes: Review the button that switches the side of the curve that the force uses. Review the contact array and its fields. Cam-Rocker-Valve $XWRPDWHG &RQWDFW )RUFHV 7KLQJV WR QRWH ZKLOH FUHDWLQJ DXWRPDWHG FRQWDFW IRUFHV ■ Point-to-curve ■ Curve-to-curve ■ Sphere-to-plane ■ Curve-to-plane ■ Point-to-plane Cam-Rocker-Valve The xy planes of the two reference markers must be parallel. The z-axis of the reference marker of the plane (the plane’s normal vector) must point away from the plane and at the circle or sphere. 301 )OH[LEOH 3DUWV³$'$06$XWR)OH[ %HWWHU ORDGLQJ SUHGLFWLRQV IRU GXUDELOLW\ DQDO\VHV ■ The flexible component is the focus of your attention. ■ Basically asking the question: "What is the system doing to my flexible component?" ,PSURYHG V\VWHP SHUIRUPDQFH ■ The model fidelity is the focus of your attention. Component flexibility is just another parameter of the system design. ■ Basically asking the question: "What is the flexible component doing to my system?" $OORZV \RX WR FUHDWH IOH[LEOH ERGLHV LQ WKH 06&$'$06 HQYLURQPHQW $OORZV IRU HDV\ VXEVWLWXWLRQV RI IOH[LEOH ERGLHV IRU ULJLG ERGLHV LQ \RXU 06&$'$06 PRGHOV &DQ SHUIRUP TXLFN PRGLILFDWLRQV RQ WKH IOH[LEOH ERGLHV WR SHUIRUP PXOWLSOH LWHUDWLRQV RI WKH IOH[LEOH ERG\ PRGHO To run through a workshop, see the ADAMS/AutoFlex Training Guide. For more information, see the ADAMS/AutoFlex online help. 302 Cam-Rocker-Valve :RUNVKRS ³&DP5RFNHU9DOYH 3UREOHP VWDWHPHQW Design a cam profile based on desired valve displacement, and ensure that there is no follower liftoff when the cam is rotated at 3000 rpm. Rocker Spring Rod Guide (ground) Cam Valve Valve displacement (mm) Time (sec) 0RGHO GHVFULSWLRQ ■ The model represents a valvetrain mechanism. ■ The cam is being rotated at a velocity of 1 rotation per second. ■ The rocker pivots about a pin attached to the engine block (ground). ■ The valve displaces up and down as the rocker moves. ■ When the valve moves, it lets small amounts of air in the chamber below it (not modeled here). Note: At the location of the translational joint, between the valve and ground, the model includes a spherical dummy part. You will use this dummy part when you make the valve a flexible part. This dummy part will not affect the rigid body dynamics. Cam-Rocker-Valve Review the problem statement and quiz them on what steps they would take to solve it. Before they start, ask for questions. 303 :RUNVKRS ³&DP5RFNHU9DOYH 6WDUW WKH ZRUNVKRS 7R VWDUW WKH ZRUNVKRS 1 Open ADAMS/View from the directory exercise_dir/mod_21_camrocker. 2 From the directory exercise_dir/mod_21_camrocker, import the model command file valve_train_start.cmd. The file contains a model named valve_train. $SSO\ PRWLRQ 7R DSSO\ PRWLRQ 1 Use the Translational Joint Motion tool to add a motion to the joint, Valve_Ground_Jt, such that its displacement appears as shown next: Add two STEP functions. 13 0 0 -13 0.4 0.6 0.6 0.8 13 0 0.4 0.6 0.8 Tip: The functions should look as follows: STEP(time, .4, 0,.6,13)+ STEP(time,.6,0,.8,-13). 2 304 Run a 1-second, 100-step simulation to verify that the valve displaces as a result of the joint motion. Cam-Rocker-Valve :RUNVKRS ³&DP5RFNHU9DOYH &UHDWH D FDP SURILOH Use a point trace to create a cam profile. 7R XVH D SRLQW WUDFH 1 From the Review menu, select Create Trace Spline. 2 Select the marker on the rod (ref_marker) and then the part named cam. 3 Verify that you now have a spline representing the cam profile. ref_marker cam profile cam 4 Run a simulation to verify that the Rod appears to move along the surface of the Cam. Cam-Rocker-Valve 305 :RUNVKRS ³&DP5RFNHU9DOYH &RQVWUDLQ WKH URG WR WKH FDP 7R FRQVWUDLQ WKH URG 1 Delete the joint motion on the joint, Valve_Ground_Jt. 2 Use the Curve-Curve Constraint tool to create a curve-on-curve constraint between the circle on the Rod and the cam profile on the Cam. CIRCLE_1 GCURVE_176 3 306 Run a simulation to verify that the new constraint works. Cam-Rocker-Valve :RUNVKRS ³&DP5RFNHU9DOYH 0HDVXUH WKH IRUFH LQ WKH FXUYHRQFXUYH FRQVWUDLQW 7R PHDVXUH WKH IRUFH ■ Create a force measure for the curve-on-curve constraint (right-click the constraint and then select Measure). Measure the force along the z-axis of ref_marker, which belongs to the rod: ◆ Characteristic: Force ◆ Component: Z ◆ Represent coordinates in: ref_marker The curve-on-curve constraint applies a negative force that keeps the rod follower on the cam, avoiding any liftoff. 0DNH WKH FDPWRURG FRQWDFW PRUH UHDOLVWLF Now you’ll replace the curve-on-curve constraint with a curve-to-curve contact force. 7R UHSODFH WKH FXUYHRQFXUYH FRQVWUDLQW 1 Deactivate the curve-on-curve constraint you created in Step 2 on page 306. 2 From the Main Toolbox, right-click the Create Forces tool stack, and then select the Contact tool Cam-Rocker-Valve . 307 :RUNVKRS ³&DP5RFNHU9DOYH 3 Use the following contact parameters: ■ Contact Name: rod_cam_contact ■ Contact Type: Curve to Curve ■ I Curve: CIRCLE_1 and then press Enter ■ J Curve: GCURVE_176 and then press Enter Tip: Pressing Enter after entering the names of the I and J curves activates the Change Directions option. ■ ■ Normal Force: Impact ■ Stiffness (K): 1e6 (N/mm) ■ Force Exponent (e): 1.5 ■ Damping (C): 10 (N-sec/mm) ■ Penetration Depth (d): 1e-3 mm ■ Friction Force: Coulomb ■ Coulomb Friction: On ■ 308 Use the Change Direction tool to make sure that the normal arrows point outward from the curves, as shown next: Static Coefficient (µs): 0.08 Cam-Rocker-Valve :RUNVKRS ³&DP5RFNHU9DOYH ■ Dynamic Coefficient (µd): 0.05 ■ Stiction Transition Vel. (vs): 1 (mm/sec) ■ Friction Transition Vel. (vt): 2 (mm/sec) ■ Run a simulation to check if liftoff occurs. 3UHYHQW OLIWRII XVLQJ D VSULQJ GDPSHU 7R SUHYHQW OLIWRII 1 Add a marker on the valve at the location, Valve_Point: ■ Add to Part ■ From the screen, select valve and the location Valve_Point. Cam-Rocker-Valve 309 :RUNVKRS ³&DP5RFNHU9DOYH 2 Add a spring damper between the marker you just created and the point, Ground_Point (which is a point on ground, at the top of the guide) using the following parameters: ■ 20 (N/mm) ■ Damping (C): 0.002 (N-sec/mm) ■ 3 Stiffness (K): Preload: 100 N Find the static equilibrium of the model ( ). Do not reset the model before going on to the next step. Note: You perform the static equilibrium to eliminate the transient effect that results from the time-dependent damping characteristic of the spring damper. In addition, positioning the model in static equilibrium establishes initial contact between the roller and the cam. 4 310 Run a dynamic simulation to view the effects of the spring starting from static equilibrium. Cam-Rocker-Valve The following demo might be helpful for the students to understand why they perform an initial static analysis, and also the complexity of contacts in a model: - Set your model_display to At every Iteration. - Zoom in close to the cam. - Perform a static simulation then a dynamic simulation. :RUNVKRS ³&DP5RFNHU9DOYH 5 Modify the rotational motion on the cam to a speed of 3000 rpm. Enter the function as follows: -50*360d*time. 6 To view only one rotation of the cam, run a static equilibrium followed by a dynamic simulation for end=1/50 seconds, steps=100. An easy way to run this simulation sequence is to create a simulation script. 7 Measure the contact force (Build Æ Measure Æ Function Æ New). ■ Category: Force in Object Note: Make sure the function looks as shown next: 8 Rerun the simulation to populate the new measure stripchart. 9 Modify the spring-damper characteristics (stiffness, damping, and preload) to prevent liftoff based on the new rotational speed of the cam. Note: Experiment with different values until the no-lift criteria is met. 10 Save the model. Cam-Rocker-Valve There are many combinations of parameters that will prevent liftoff. One set that works is: K = 100N/mm; C = 2e-3; l0 = default length; F0 = 300N 311 :RUNVKRS ³&DP5RFNHU9DOYH &UHDWH DQG VXEVWLWXWH WKH IOH[LEOH SDUW You will define the mesh properties and then use the Automatic Replace Part option to substitute this flexible body automatically into your model. The Automatic Replace Part option does the following: ■ Finds attachments based on the location of joints and forces that are applied to the rigid body ■ Finds the closest four slave nodes of the temporary mesh to each attachment point and connects them through rigid bars ■ Creates the flexible body ■ Applies the joints and forces at the attachment points of the flexible body ■ Deactivates the rigid body 7R ORDG WKH $'$06$XWR)OH[ SOXJLQ 1 From the Tools menu, point to Plugin Manager. 2 To the right of autoflex, set Load to Yes. Select OK. 3 7R FUHDWH WKH PHVK 1 From the Build menu, point to Flexible Bodies, and then select ADAMS/AutoFlex. ■ Geometry ■ Part to be meshed: valve ■ FlexBody Name: flex_valve ■ Element Type: Solid Tetra ■ Element Specification: Size ■ Element Size: 10 mm ■ Number of Modes: 10 ■ 312 FlexBody Type: Element Order: Parabolic Cam-Rocker-Valve :RUNVKRS ³&DP5RFNHU9DOYH ■ Leave all other options at their default settings. ■ Select Mesh preview. 7R VXEVWLWXWH WKH IOH[LEOH ERG\ LQWR WKH PRGHO 1 At the bottom of the ADAMS/AutoFlex dialog box, select Replace Part. 2 Select OK. ADAMS/AutoFlex automatically substitutes the flexible part into your model to replace the rigid part. It also writes the MNF and AFI files to your current working directory. This step may take a couple of minutes to complete. 7R YHULI\ WKDW WKH ULJLG SDUW LV D IUHH ERG\ 1 Display the Database Navigator. 2 Set the pull-down menu at the top to Graphical Topology. 3 Double-click valve_train. 4 Select valve. 5 The valve should not be attached to any other part. If the valve is attached to any parts, take corrective measures. Cam-Rocker-Valve 313 This process will generate two new dummy parts in your model (ip_4788_1 and ip_4789_1). These parts were automatically created so that the spring and the fixed joint can be quickly attached to the new flexible part. :RUNVKRS ³&DP5RFNHU9DOYH 5XQ D VLPXODWLRQ 7R UXQ D VLPXODWLRQ 1 To view only one rotation of the cam, run a static equilibrium followed by a dynamic simulation for end=1/50 seconds, steps=100. 2 Use ADAMS/PostProcessor to investigate how the flexible body affects the model. Does liftoff occur in the model now? ________________ 6DYH \RXU ZRUN 7R VDYH \RXU ZRUN 1 Save the model. If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step. 2 Exit ADAMS/View. 2SWLRQDO WDVNV &KDQJH WKH VKDSH RI WKH IROORZHU 1 Delete the circle-to-curve contact force between the Rod circle and the Cam curve. 2 Add a spline to the Rod that is a shape other than a circle and use that as the follower. Change the grid spacing to 5mm in the x and y directions and draw the new follower geometry on the grid. 3 Recreate the contact force between the Rod and the Cam using the new spline as the follower. Use a curve-to-curve contact force. 314 Cam-Rocker-Valve :RUNVKRS ³&DP5RFNHU9DOYH 0RGXOH UHYLHZ 1 How many DOF are removed by adding a curve-on-curve constraint? 2 How many DOF are removed by a curve-to-curve force? Cam-Rocker-Valve 315 :RUNVKRS ³&DP5RFNHU9DOYH 316 Cam-Rocker-Valve  7$5*(7 35$&7,&( Complete the construction of a parametric gun and find the launch-spring stiffness that will allow the marbles to hit the target. 7KLV PRGXOH LQFOXGHV ■ Multi-Component Forces, 318 ■ Design Studies, 320 ■ Workshop 22—Target Practice, 323 ◆ Module review, 334 317 0XOWL&RPSRQHQW )RUFHV 7\SHV RI PXOWLFRPSRQHQW IRUFHV ■ Vector force (three translational components) ■ Vector torque (three rotational components) ■ General force vector (three translational, three rotational components) &KDUDFWHULVWLFV RI YHFWRU IRUFH The characteristic: Defines: Bodies Two Points of application Two (action force at I marker and reaction force at floating J marker) Vector components Three translational Orientations Based on reference marker (R marker) Magnitudes (Fx, Fy, Fz) User-defined Notes: ■ ■ 318 The floating J marker always maintains the same location as the I marker. The characteristics of other multi-component forces conceptually work the same way. Target Practice 0XOWL&RPSRQHQW )RUFHV ([DPSOH RI D IRUFH YHFWRU A vector force representing a contact between a ball and a cantilever: ■ I marker A J marker R marker B I marker belongs to part A J marker belongs to part B but floats its location with the I marker R marker belongs to part B ■ Because the J marker belongs to part B, the force acts on part B when the bodies collide. ■ Because the J marker moves with the I marker, part B knows where to apply the reaction force. Note: In the example, the J and R markers must belong to the same part. However, the R marker can belong to any part. See also: Characteristics of a multi-component force, on page 373 Target Practice 319 Question: Why is it easier to use a force vector than using single-component forces? Demonstrate to answer question: Use the link on this slide to go to the Forces table, and enter the appropriate information about the multi-component forces. Build the model shown in the example on this slide to demonstrate force vectors. Demonstrate solid-to-solid contacts using the model files in the contact_demo subdirectory under bfs_exercises. 'HVLJQ 6WXGLHV 7ULDO DQG HUURU PHWKRG PDQXDO LWHUDWLRQV Model ■ Parts ■ Joints ■ Forces Simulate View results Is the design optimal? Loop is repeated several times Manually change the variable Yes Completed No 'HVLJQ VWXG\ PHWKRG DXWRPDWHG LWHUDWLRQV Design Variable (V) Objective (O) Model Parts ■ Joints ■ Forces ■ Model gets updated Results automatically generated Simulate Variable changes automatically No Is this the final iteration? (i=n) Yes The loop goes through specified number of iterations (i=1,n) 320 Tabular report Plot O versus V (for each iteration) Target Practice Demonstrate: Set up and run a design study (Simulate Design Study). Demonstrate: Use the example on the next page to explain the importance of the floating J-marker and the reference marker. Æ 'HVLJQ 6WXGLHV 'HILQLWLRQ RI D GHVLJQ VWXG\ ■ Varies a single design variable (V) across a range of values. ■ Runs a simulation at each value. ■ Reports the performance measure for each simulation. )URP WKH UHVXOWV JHQHUDWHG \RX FDQ GHWHUPLQH ■ The best value for V among the values simulated. ■ The approximate design sensitivity of V (rate of change of performance measure with respect to V). Target Practice 321 'HVLJQ 6WXGLHV 6HQVLWLYLW\ 6 DW LWHUDWLRQ L 1 O i + 1 – O Oi – Oi – 1 S i = -- ----------------------i + ---------------------- 2 V i + 1 – V i V i – Vi – 1 ■ Looking at Trial 4 (i = 4): 1 ( – 0.62784 ) – 0.017103 ( – 0.017103 ) – 0.58166 S 4 = -- ---------------------------------------------------- + ------------------------------------------------------- 2 10.7 – 10.6 10.6 – 10.5 S4 = -6.0475 ■ S4 is the approximate slope at Trial 4 (tip_y_loc=10.6) in the plot. Design Study Summary Model Name : stamp Date Run : 15:48:55 23-Dec-98 Objectives O1) Minimum of stamp_height Units : inch Maximum Value: 1.48945 (trial 1) Minimum Value: -0.627838 (trial 5) Design Variables V1) tip_Y_loc Units : inch Trial stamp_height tip_Y_loc 1 2 3 4 5 1.4894 1.1281 0.58166 -0.017103 -0.62784 10.300 10.400 10.500 10.600 10.700 Sensitivity -3.6131 -4.5389 -5.7262 -6.0475 -6.1073 322 Don’t cover this slide in detail. It is for future reference. Target Practice :RUNVKRS ³7DUJHW 3UDFWLFH 3UREOHP VWDWHPHQW Complete the construction of a parametric gun and find the launch-spring stiffness that will allow the marbles to hit the target. 0RGHO GHVFULSWLRQ ■ Currently, the model has all the geometry, parts, and constraints it needs. ■ There is a single-component force representing the spring force between the hammer and the launch pad. ■ The single-component force is designed so that it changes characteristics depending on the type of simulation being run (static versus dynamic): ◆ ◆ If a static simulation is run, the spring has a free length of 40 mm. If a dynamic simulation is run, the spring has a free length of 100 mm. ■ Therefore, initially run a static simulation, so the marble falls on the hammer and compresses the spring a little. Then when you run a dynamic simulation, the spring thinks it is compressed a great deal, and shoots the marble. ■ The model is already parameterized with variables describing the elevation angle of the launch pad and the stiffness and damping of the spring. ■ You will only modify the stiffness of the spring. ■ Initially, the spring stiffness is 20 N/mm. Target Practice 323 Quiz the students about the steps needed to complete this workshop. The Stability parameter of the Solver Equilibrium settings has been increased to 3 to assist in stabilizing the iteration process. :RUNVKRS ³7DUJHW 3UDFWLFH 6WDUW WKH ZRUNVKRS Import the file to build the model target_practice. 7R VWDUW WKH ZRUNVKRS 1 Start ADAMS/View from the directory exercise_dir/mod_22_target_practice. 2 Import the model command file target_practice_start.cmd. &UHDWH D FRQWDFW EHWZHHQ WKH KDPPHU DQG WKH PDUEOH 7R FUHDWH D FRQWDFW 1 Run a simulation to see the forces that affect the model in its current configuration. 2 Create a marker on the hammer to represent the plane in the sphere-to-plane contact force that you will create next. Orient the z-axis of this marker so it points toward the center of mass of the ball. ■ ■ Orientation: Z-Axis (orient the z-axis along the x-axis of the cm marker of the marble) ■ 324 Add to Part: hammer In your model, right-click at the face of the hammer, and then select hammer.CYL10.E1 (center). Note that hammer.CYL10.E1 (center) is a place-holder that represents the geometry, and is only accessible when prompted for a location. Target Practice :RUNVKRS ³7DUJHW 3UDFWLFH 3 Orient the working grid along the XY-plane of the new marker, aligned with the face of the hammer (Settings Æ Working Grid) ■ Set Location: Pick (from your model, select the marker you just created, MARKER_46) ■ Set Orientation: X-Y-axes (first select the x- and then the y-axis of MARKER_46, as prompted in the Status bar) Target Practice 325 :RUNVKRS ³7DUJHW 3UDFWLFH 4 Adjust the view until the new working grid’s xy-plane encompasses the window, as shown next. Tip: Set the model to a Right view, then rotate the model down, and turn shading on. 5 Use the Plane tool to create a plane to be used in the contact definition: ■ ■ 6 Add to Part: hammer (right-click the sphere image and select hammer) Left-click on any grid point outside of the hammer face and drag across, covering the hammer face. Reset the working grid to the default position: ■ Set Location: ■ Set Orientation: Global XY Global Origin &KDQJH WKH $'$066ROYHU HTXLOLEULXP VHWWLQJV 7R FKDQJH WKH VHWWLQJV 1 From the Settings menu, point to Solver, and then select Equilibrium. 2 In the Error text box, enter 1.0E-002. 3 Select Close. 326 Target Practice :RUNVKRS ³7DUJHW 3UDFWLFH 4 Create a sphere-to-plane contact force ( marble and the hammer: ■ Contact type: Sphere-to-Plane ■ Sphere: ELL3 ■ Plane: PLANE_36 ■ Stiffness: 100 (N/mm) ■ Force Exponent: 1.01 ■ Damping: 1.0 (N-sec/mm) ■ Penetration Depth: ) that represents the contact between the 0.2 mm &UHDWH FRQWDFW EHWZHHQ WKH PDUEOH DQG WKH ODXQFK SDG 7R FUHDWH DQRWKHU FRQWDFW 1 Create a solid-to-solid contact force ( and the launch pad: ) that represents the contact between the marble ■ Contact type: Solid-to-Solid ■ First Solid: ELL3 ■ Second Solid: CSG_35 ■ Stiffness: 100 (N/mm) ■ Force Exponent: 1.01 ■ Damping: 1.0 (N-sec/mm) ■ Penetration Depth: 0.2 mm ■ Friction Force: Coulomb ■ Static Coefficient: 0.3 ■ Dynamic Coefficient: 0.1 ■ Stiction Transition Vel.: 50 ■ Friction Transition Vel.: 200 Target Practice 327 :RUNVKRS ³7DUJHW 3UDFWLFH 6LPXODWLQJ WKH PRGHO The marble is not initially in contact with the hammer; therefore, you must precede each dynamic simulation that you submit with a static equilibrium simulation. Launch pad Hammer Launch spring Marble 7R VLPXODWH WKH PRGHO 1 Using ADAMS/Solver commands, create a script that performs a static equilibrium simulation followed by a dynamic simulation: SIMULATE/STATIC SIMULATE/DYNAMIC, END=1.0, STEPS=100 The script will make running simulations easier and will be needed for the design study later. 2 Create a measure, named x_displacement, of the marble’s global x displacement (rightclick the marble and select Measure): ■ Characteristic: CM position ■ Component: X ■ From/At: ground 3 Run a simulation. 4 Save the simulation results ( 328 ) as no_aero. Target Practice :RUNVKRS ³7DUJHW 3UDFWLFH ,QFOXGH DHURG\QDPLF GUDJ IRUFH Use the following parameters to describe the global x and y components of the drag force: ■ Fx = -1/2*ρ*Vx*Vm*Cd*A ■ Fy = -1/2*ρ*Vy*Vm*Cd*A where: ◆ ρ = 1.3e-9 kg/mm3 = density of air ◆ Vx = global x component of the marble’s velocity ◆ Vy = global y component of the marble’s velocity ◆ Vm = magnitude of the marble’s velocity ◆ Cd = 0.45 = drag coefficient ◆ A = πr2 = two-dimensional area of the marble face 7R LQFOXGH DHURG\QDPLF IRUFH 1 Create a multi-component force ( ) at the marble center of mass, between the marble and ground, whose directions are aligned with the global coordinate system (Hint: Set Characteristic to Custom). 2 Select the Function Builder tool Target Practice to the right of X Force. 329 :RUNVKRS ³7DUJHW 3UDFWLFH 3 Enter the aerodynamic function as shown next: 4 Select Verify, and then select OK. 5 Select the Function Builder tool 6 Enter the function similar to the one above, changing only VX to VY, and then verify the function. 7 Run a simulation using the script you created in Step 1, on page 329. 8 Save the simulation results ( 330 to the right of Y Force. ) as with_aero. Target Practice :RUNVKRS ³7DUJHW 3UDFWLFH 9 Compare the x displacement of the marble for each set of simulation results (with and without aerodynamic forces). 7UDFN ZKHQ WKH VLPXODWLRQ LV FRPSOHWH 7R WUDFN 1 Create a measure, named y_displacement, that tracks the global y displacement of the center of the marble. ■ Characteristic: CM position ■ Component: Y ■ From/At: ground Target Practice 331 :RUNVKRS ³7DUJHW 3UDFWLFH 2 Create a sensor to determine when the ball passes the global xz plane. Have the sensor monitor the global y displacement measure created earlier, and when it is less than or equal to 0.0 mm, direct the sensor to: ■ ■ 332 Generate an additional output step. Terminate the current simulation step and stop the simulation script. Target Practice :RUNVKRS ³7DUJHW 3UDFWLFH 6HW XS D GHVLJQ VWXG\ 7R VHW XS D GHVLJQ VWXG\ 1 Create a point-to-point measure of the global x distance from the target center (.ground.target) to the marble center (.marble._cm) and name it target_error. 2 From the Settings menu, point to Solver, and then select Display. 3 Set Upgrade Graphics to Never. 4 Run a design study that gives the last value of target_error over six default levels of the existing design variable, launch_spr_stiffness. ■ From the Simulate menu, select Design Evaluation. ■ Fill in the dialog box as follows: Target Practice 333 :RUNVKRS ³7DUJHW 3UDFWLFH 5 Select Start. 6 Note the approximate value of stiffness at which the marble hits the target and use it to answer Question 2 in Module review, on page 334. 6DYH \RXU ZRUN ■ Save your model and then exit ADAMS/View. 2SWLRQDO WDVNV 1 Multiply the aerodynamic forces by STEP functions to eliminate any aerodynamic effects that might occur when the marble moves to the static position. Tip: The independent variable of the STEP function will be DM(.marble.cm, .TIP). 2 Tighten the minimum and maximum values of the design variable of the launch-pad stiffness and increase the number levels to 10 to achieve a more precise solution. 3 Run additional design studies for other design variables. 0RGXOH UHYLHZ 1 What defines the force directions (Fx, Fy and Fz) in a force vector? 2 What is the approximate value of stiffness at which the marble hits the target? 334 Target Practice  5(&200(1'(' 35$&7,&(6 What are the recommended practices in debugging a model? 7KLV PRGXOH LQFOXGHV ■ General Approach to Modeling, 336 ■ Modeling Practices: Parts, 337 ■ Modeling Practices: Constraints, 338 ■ Modeling Practices: Compliant Connections, 339 ■ Modeling Practices: Run-time Functions, 340 ■ Debugging Tips, 342 335 *HQHUDO $SSURDFK WR 0RGHOLQJ &UDZOZDONUXQ ■ ■ Use building blocks of concepts that have worked in the past. ■ Add enhancements to the model while testing periodically. ■ Build kinematic models before building dynamic models. ■ Use motions to check models before applying forces. ■ Use motions which start with zero velocity. ■ 336 Try to understand the mechanism from a physical standpoint. Verify enhancements to a complex model on a simpler model first. Recommended Practices 0RGHOLQJ 3UDFWLFHV 3DUWV *HRPHWU\ DVVRFLDWLYLW\ HUURUV Geometry may be added to the wrong part. 0DVV SURSHUWLHV ■ Using imported CAD-created geometry (IGES, STL, and so on) can yield inaccurate mass properties. ■ Ensure inertia matrix is realistic. ■ Use aggregate mass for a quick check of system mass and inertia. ■ Use the Table Editor to do a quick check and potentially fix individual part masses and inertia. ■ Small part mass and inertia lead to unrealistically high frequencies. ,QLWLDO YHORFLWLHV Check to see that part initial velocities are consistent (look in the .out file). 'XPP\ SDUWV ■ Whenever possible, avoid using them. ■ If absolutely needed, constrain all six DOF and assign a mass of 0.0 (not 1e-20). 'HVLJQ FRQILJXUDWLRQ ■ Build a model close to assembled position. ■ Build a model close to a stable equilibrium position, if possible. Recommended Practices 0RGHOLQJ 3UDFWLFHV &RQVWUDLQWV )L[HG MRLQWV ■ Not needed, since two or more parts can be combined or merged into a single part. ■ An extra part with a fixed joint adds unnecessary equations to your system. ■ When locking a part to ground, enormous torque may develop due to large moment arms. ■ If absolutely needed, then add fixed joints at the center-of-mass (cm) location of lightest part. ■ If locking a part to ground, consider assigning a very large mass/inertia to it so it can behave like ground. Note: Whenever possible, avoid using fixed joints. 8QLYHUVDO MRLQWV When a universal joint is at 90o, you get a singular matrix. 0RWLRQ ■ Motion elements should only be functions of time. Note: Avoid redundant constraints. 338 Recommended Practices 0RGHOLQJ 3UDFWLFHV &RPSOLDQW &RQQHFWLRQV 6SULQJ GDPSHUV ■ Ensure that the marker endpoints (DM(I,J)) are never superimposed. ■ Watch out for springs with very stiff spring constants. ■ Watch out for springs with no damping. %XVKLQJV Watch out for bushings with large rotations. Recommended Practices 0RGHOLQJ 3UDFWLFHV 5XQWLPH )XQFWLRQV )XQFWLRQ %XLOGHU ■ Assists in building functions. ■ Assists in function verification. ■ Has function plot capability. 9HORFLW\ Make sure velocities are correct in force expressions. For example, in the damping function: -c*VX(i, j, j, _), the fourth term is missing. 6SOLQHV ■ Approximate forces with smooth, continuous splines. ■ Extend the range of spline data beyond the range of need. ■ Cubic splines (CUBSPL) work better on motions than Akima. ■ Akima splines (AKISPL) work better on forces than Cubic. ■ The Akima interpolation method is faster and can be defined as a surface, but its derivatives are generally discontinuous. ,03$&7V%,6723V ■ Do not use 1.0 for exponent on IMPACT or BISTOP functions. ■ Models with IMPACTs/BISTOPs should have slight penetration in design position when doing statics. 0HDVXUHV ■ ■ Set up measures of components of your run-time functions. ■ 340 Set up measures of your run-time functions. Ensure that your function will not try to divide by zero. Recommended Practices 0RGHOLQJ 3UDFWLFHV 5XQWLPH )XQFWLRQV &RQWDFWV ■ Do not use 1.0 for exponent on IMPACT or BISTOP functions. ■ Models with contacts should have slight penetration in design position when doing statics. 7LUHV ■ Models with tires should have slight penetration in model position when doing statics. ■ If only rear tires penetrate, the static position could be a “handstand.” 8QLWV ■ Use consistent units throughout the model (time, mass, stiffness, damping, and so on). ■ Choose units (mass, force, time, and so on) that do not require using very large or very small numbers. ■ Be wary when your model contains numbers like 1e+23 or 1e-20. ■ Use appropriate units—when modeling large models such as an aircraft landing on a runway, length units of millimeters may not be appropriate. Conversely, when modeling small models such as a power window switch (made up of small moving parts), using length units of meters may not be appropriate. ■ Use reasonable time units—high frequencies may be better modeled with time units of milliseconds rather than seconds. *UDYLW\ ■ Check magnitude and direction. ■ Check for multiple gravity elements. Recommended Practices 'HEXJJLQJ 7LSV 0RGHO YHULI\ ■ Lists number of moving parts, number of each type of constraint. ■ Lists Gruebler’s count and actual DOF count. ■ Lists redundant constraints. ■ Reports misaligned forces/force elements, joints, and so on. ■ Helps identify and eliminate causes for input warning (don’t ignore). 0RGHO WRSRORJ\ ■ Text or graphical model topology. ■ Table Editor provides spreadsheet-like overview of model content. ,FRQ IHHGEDFN Broken icon in design configuration probably means incorrectly defined joint or force. 7DEOH (GLWRU Convenient way to inspect and modify models (particularly large ones). ,QWHUDFWLYH VLPXODWLRQ By default, is turned on. 342 Recommended Practices 'HEXJJLQJ 7LSV 0RGHO GLVSOD\ XSGDWH As ADAMS/Solver performs the simulation, you have the option to get immediate graphical feedback of the simulation at every: ■ Output step ■ Integration step ■ Iteration ,FRQV YLVLEOH GXULQJ VLPXODWLRQ This may help you monitor behavior of model components. 6XEURXWLQHV ■ Check for their existence. ■ While debugging a model, eliminate user subroutines so that they are not the source of the error. *UDYLW\ Turning gravity off can accentuate modeling errors and make debugging easier. Recommended Practices 'HEXJJLQJ 7LSV 6WDWLFV ■ When applicable, perform an initial static first. ■ If static solution fails: ◆ Turn on Model display update = at every iteration to provide additional insight. ◆ Identify and eliminate the undesired static configuration—there could be more than one static configuration and ADAMS/Solver could be finding the undesired one. ■ ■ Check the signs of applied forces. ■ Experiment with Alimit/Tlimit/Maxit/Stability. ■ Check if impacts are initially in contact; if not, they should be. ■ 344 Check to see if there are any floating parts. Running an initial dynamic simulation can help you determine why the model is not finding static equilibrium. Recommended Practices 'HEXJJLQJ 7LSV '\QDPLFV ■ If integrator fails to start-up: ◆ ◆ Look at accelerations to understand what is happening. ◆ Perform initial static analysis first. ◆ Try a quasi-static simulation. ◆ Try changing integrator parameter - HINIT. ◆ ■ Check sign and magnitude of forces. Try a different integrator. If integrator fails in the middle of a simulation: ◆ ◆ Decrease integrator parameter - HMAX. ◆ Do not let the integrator step over important events. ◆ Short duration events, such as an impulse can be captured by setting the maximum time step, HMAX, to a value less than the impulse width. ◆ Use HMAX so ADAMS/Solver acts as a fixed-step integrator ◆ Decrease error. ◆ ■ Look at animation and plots until failure, to understand simulation. Try a different integrator. If integrator takes very small steps: ◆ Look for sudden changes in force and motion input. ◆ Rescale model to get more uniform numbers. 9HORFLWLHV DW WLPH  Check initial velocities using the .out file. Recommended Practices 1RWHV 346 Recommended Practices  6:,7&+ 0(&+$1,60 :25N6+23 3UREOHP VWDWHPHQW Determine the minimum force necessary to toggle the switch mechanism to the forward and rearward directions. Switch Mechanism Base Actuator Left Follower Left Contact Right Follower Right Contact ˆ zG ˆ yG xG ˆ 347 6ZLWFK 0HFKDQLVP :RUNVKRS 0RGHO GHVFULSWLRQ The given switch model contains parts with shell geometry and mass properties: Part name: Geometry (shells): Mass (grams): base (ground) base_main_geo (ground) base_right_front_geo base_right_mid_geo base_right_rear_geo base_left_front_geo base_left_mid_geo base_left_rear_geo actuator 1.52 right_contact right_contact_geo 0.51 left_contact left_contact_geo 0.51 right_follower right_follower_geo 0.1076 left_follower 348 actuator_geo left_follower_geo 0.1076 Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS The switch model contains construction points for adding the necessary modeling elements to address the problem statement. They are: Point: Description: POINT_1 Actuator to base pivot location POINT_2 right_follower to actuator spring lower location POINT_3 left_follower to actuator spring lower location POINT_4 right_follower to actuator spring upper location POINT_5 left_follower to actuator spring upper location POINT_6 Contains z-coordinate of base contact plane with left_contact and right_contact at four corners POINT_7 left_contact to base idealized constraint location POINT_8 right_contact to base idealized constraint location POINT_9 Location of base front contact surface with actuator POINT_10 Location of base rear contact surface with actuator POINT_11 Location of actuator front contact point with base POINT_12 Location of actuator rear contact point with base POINT_13 Location of right_contact to base mid-contact point POINT_14 Location of left_contact to base mid-contact point POINT_15 Location of force application The switch model is mounted such that the model’s global negative x-axis defines forward and positive z-axis defines up (see Problem statement, on page 347). Switch Mechanism Workshop 349 6ZLWFK 0HFKDQLVP :RUNVKRS 6HFWLRQ , 7HVW WKH ULJKW KDOI ZLWK FRQVWUDLQWV RQO\ You can think of the switch mechanism as consisting of two halves. In this exercise, first constrain the right half of the mechanism and perform a kinematic simulation to visually verify correct motion. Then, add spring and contact forces to the right half to ensure that the mechanism actually toggles. Then, add more detail to the right half, introduce the left half, and then finally perform a system-level simulation. This section emphasizes the crawl-walk-run method. In this section, you will crawl. 7R LPSRUW WKH PRGHO 1 Start ADAMS/View from the directory exercise_dir/switch_workshop. 2 From the directory exercise_dir/switch_workshop, import the model command file switch_start_new.cmd. This file contains commands to build a model named switch. 7R VHW XS WKH PRGHOLQJ HQYLURQPHQW 1 Turn the working grid off. 2 To modify the preset views in ADAMS/View so that they are relevant to the global coordinate system, from the Tools menu, select Command Navigator. The Command Navigator appears. 3 In the Command Navigator, from the View menu, select Management, and then select Orient. See Model description, on page 348 for an explanation of how the global axes are defined. 4 Preset the front view. All other views will be defined based on this front view. Ensure that the preset views (front, top, and so on) are correctly defined based on the global coordinate system. 5 To set the transparency of the actuator part to 80%, right-click the actuator, and then select Appearance. 6 Turn off the visibility of the base part geometry, base_main_geo. 7 Deactivate the left_contact and left_follower parts. 8 Turn off the visibility of the left_contact and left_follower parts. 350 Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS 9 Set gravity in the global negative-z direction. The model view should look as follows: ˆ zG xG ˆ ˆ yG 7R DGG FRQVWUDLQWV 1 Constrain the actuator to the base at POINT_1 such that the only relative allowable degree of ˆ freedom is rotation about yG . Establish a reference marker with global orientation on the base (ground) part that makes picking of global direction vectors easy. Setting the color and size of the marker aids in referencing it later. POINT_1 ˆ zG ˆ yG xG ˆ Switch Mechanism Workshop 351 6ZLWFK 0HFKDQLVP :RUNVKRS 2 Constrain the right_follower to the actuator at POINT_2 such that the only relative allowable ˆ degree of freedom is translation along z G . POINT_2 3 Constrain the tip of the right_follower to the upper curve on the right_contact part. When creating the curve-to-curve constraint, select the red circle, right_follower.right_follower_circle_geo_2, at the tip of the right_follower part, parallel to the global-xz plane, and then select right_contact_right_control_upper_bspline. 352 Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS 4 Constrain the right_contact part to the base at POINT_8 such that the only relative allowable ˆ degree of freedom is translation along yG . POINT_8 This might not seem intuitive, but it ensures that there are no redundant constraints in the model. It is a good modeling practice to remove all redundant constraints in your system prior to performing a simulation. 5 Add displacement joint motion to the actuator-to-base revolute joint such that the actuator oscillates sinusoidally with an amplitude of 15.1 degrees and one cycle per second. Switch Mechanism Workshop 353 6ZLWFK 0HFKDQLVP :RUNVKRS 7HVW WKH PRGHO 1 Verify the model. Your system should have 0 degrees of freedom and no redundant constraints at this configuration. If it does not, inspect the model to determine the discrepancy. 2 Simulate the model kinematically to visually verify correct motion, using an end time of 1 second with 100 output steps. 3 Save your work. 6HFWLRQ ,, 7HVW WKH ULJKW KDOI ZLWK IURQW DQG UHDU FRQWDFWV Change the constraints on the right_contact part so that it can rotate and make contact with the right front and rear terminals on the base part (it will rock back and forth like a see-saw). Use the curve-to-curve constraint created earlier. In this section you will start to walk. 7R DGG GHWDLO WR WKH FRQQHFWLRQV EHWZHHQ WKH ULJKWBFRQWDFW DQG EDVH SDUWV 1 Remove the translational joint constraining the right_contact to the base at POINT_8. 2 Constrain the right_contact to the base at POINT_13 such that the only allowable degree of ˆ freedom is rotation about yG . POINT_13 354 Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS 3 Create a sphere-to-plane contact force between the front end of the right_contact part and the front right corner of the base part. Use right_contact.PLANE_72 and base_ELLIPSOID. Using the ellipsoid and plane geometries will improve run time when solving. The contact parameter should be: ■ Stiffness: 1e5 (milliNewton/mm) ■ Force exponent: 2.2 ■ Damping: 1e2 (milliNewton-sec/mm) ■ Penetration depth: 1e-3 mm ■ Static friction: off ■ Dynamic friction: off Switch Mechanism Workshop 355 6ZLWFK 0HFKDQLVP :RUNVKRS 4 Create a sphere-to-plane contact force between the rear end of the right_contact part and rear right corner of the base part. Use right_contact.PLANE_128 and base_ELLIPSOID_73. 7R DGG VSULQJ IRUFH WR WKH ULJKW KDOI 1 Create a spring between the right_follower at POINT_2 and actuator at POINT_4 using the following parameters: ■ Stiffness: 852 (milliNewton/mm) ■ Damping: 0.1 (milliNewton-sec/mm) ■ Free length: 9 mm POINT_4 POINT_2 You need markers to create the spring. First create markers for each endpoint belonging to the appropriate parts. 356 Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS 2 Override default spring geometry by using these custom parameters: ■ Coil count: 10 ■ Diameter of spring: 2.5 mm ■ Damper diameter at ij: 0, 0 ■ Tip length at ij: 0, 0 ■ Cup length at ij: 0, 0 With nothing selected, from the Edit menu, select Modify. Filter on geometry, then double-click SPRING_1, then select spring_graphic (not damper_graphic). To make it stand out, change the color to white. 7R WHVW WKH PRGHO ■ Verify the model. The system should now have one degree of freedom and one redundant constraint. At this time, does the redundant constraint affect what you are doing? Switch Mechanism Workshop 357 6ZLWFK 0HFKDQLVP :RUNVKRS 7R UHSODFH WKH ULJKWBIROORZHU WR ULJKWBFRQWDFW FXUYHWRFXUYH FRQVWUDLQW ZLWK D IRUFH 1 Remove the curve-to-curve constraint between the tip of the right_follower and the upper curve on the right_contact part. 2 Create a curve-to-curve contact force between the tip of the right_follower and the upper curve on the right_contact part. Use the same curves used in Step 3 on page 352 and the same contact parameters from Step 3 on page 355. Note: After you fill in the I and J Curve text boxes, press Enter, in each text box, to activate the I and J Direction(s) text boxes. 7R WHVW WKH PRGHO 1 Verify the model. Your system should have two degrees of freedom and no redundant constraints. 2 Simulate the model: ■ ■ 358 Turn on Debug/EPRINT so you can monitor the ADAMS/Solver performance. ■ 3 Set Update Graphics to Never. Perform a 1-second, 100-step dynamic simulation. Animate the results to visually verify the correct motion. Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS 7R FUHDWH VWRSV IRUFHV EHWZHHQ WKH DFWXDWRU DQG EDVH 1 Create a sphere-to-plane contact force between the rear end of the actuator and the base part. As the actuator rotates, its sphere strikes a surface parallel to the global-yz plane on the base. Use the following parameters: ■ Sphere: sphere on the actuator part at POINT_12 with a radius of 0.1 mm ■ Plane: parallel to global yz-plane at POINT_10 ■ Contact parameters: same as in Step 3 on page 355 POINT_10 POINT_12 First create a sphere on the actuator part at POINT_12, with a radius of 0.5mm. Use this sphere in the sphere-to-plane contact force. Switch Mechanism Workshop 359 6ZLWFK 0HFKDQLVP :RUNVKRS Then create a plane on the base part at POINT_10. Position the plane as shown next. Tip: Changing the position and orientation of the working grid may make this easier. Again, use the same contact parameters as used in Step 3 on page 355. 2 360 After you’ve created the contact, make the plane and ellipsoid transparent. Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS 3 Create a sphere-to-plane contact force between the front end of the actuator and the base part. Use the following parameters: ■ Sphere: sphere on the actuator part at POINT_11 with a radius of 0.1 mm ■ Plane: parallel to global yz-plane at POINT_9 ■ Contact parameters: same as in Step 3 on page 355 POINT_9 POINT_11 First create a sphere on the actuator part at POINT_11, with a radius of 0.5mm. Use this sphere in the sphere-to-plane contact force. Then, create a plane on the base part at POINT_9, parallel to the global yz-plane. You will need to rotate the plane 180o such that the z-axis of the geometry anchor markers points toward the actuator. 4 After you’ve created the contact, make the plane and ellipsoid transparent. 7R WHVW WKH PRGHO XVLQJ WKH DFWXDWRU PRWLRQ LQSXW 1 Verify the model. Your system should have two degrees of freedom and no redundant constraints. 2 Simulate the model to visually verify correct motion. Perform a 1-second, 100-step dynamic simulation. Plot the magnitude of the element force for the two contacts you just created. If these stop forces are not returning a nonzero value, inspect the model further. Switch Mechanism Workshop 361 6ZLWFK 0HFKDQLVP :RUNVKRS 3 362 In ADAMS/PostProcessor, plot the torque at the actuator’s revolute joint (due to the motion input) versus time. On the same page, animate the model. Can you explain the shape of the curve? Is this intuitive? Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS Switch Mechanism Workshop 363 6ZLWFK 0HFKDQLVP :RUNVKRS 7R FUHDWH IRUFH DSSOLFDWLRQ 1 Remove the motion applied to the revolute joint constraining the actuator to the base. 2 ˆ Apply a force to the actuator part at POINT_15 in the positive x G direction, moving with the body. Use the following function: f(t) = -100*time POINT_15 7R WHVW WKH PRGHO 1 Verify the model. Your system should have three degrees of freedom and no redundant constraints. 2 Create a function measure named contact_force, based on the force magnitude of the right front contact force between the right_contact part and the base part. 3 Create a sensor that triggers when the force magnitude of the right front contact force (measured in the above step) is greater than or equal to 1mN within a tolerance of 1e3 mN. When sensed, ADAMS/Solver should terminate the current simulation step and continue the simulation script. Use the Function Builder to assist in referencing the expression you are monitoring. In the Function Builder, get object data for measures, select Browse, and then select contact_force. Then insert the object name into the text box of the Function Builder. 364 Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS Remember, the force applied to the switch is a function of time. Before you run the simulation, you do not know how much force needs to be applied to toggle the switch; therefore, you do not know how long to simulate. For that reason, you create the sensor. You will purposely simulate for a larger amount of time than is needed, letting the sensor stop the simulation when the switch has been toggled. 4 Simulate the model to visually verify correct rearward toggle motion using a simulation script based on the following ADAMS/Solver commands: SIMULATE/DYNAMICS,END=10.0,DTOUT=0.1 DEACTIVATE/SENSOR,ID=<your right front sensor id #> SIMULATE/DYNAMICS,DURATION=0.5,DTOUT=0.1 By using this simulation script, the model will simulate until the switch is toggled (assuming it toggles before 10 seconds), at which time the sensor is deactivated and the model simulates an additional 0.5 seconds to review follow-on transient behavior. 5 Save your work. 6HFWLRQ ,,, 5HILQH WKH ULJKW KDOI RI WKH PHFKDQLVP Replace the pivoting constraint at POINT_13 (the lower_contact to base revolute joint) with a more realistic connection that accounts for dynamic phenomena like sliding and liftoff. 7R UHILQH ULJKWBFRQWDFW FRQQHFWLRQV 1 Remove the revolute joint constraining the right_contact to the base at POINT_13. POINT_13 Switch Mechanism Workshop 365 6ZLWFK 0HFKDQLVP :RUNVKRS 2 Constrain the right_contact to the base at POINT_8 such that the only allowable degrees of ˆ ˆ freedom are translation along z G and rotation about yG . POINT_8 This involves creating two joint primitives (inline and parallel). You must ensure that the J marker of each primitive belongs to the base part, and not to the right_contact part. This will absolutely affect the simulation. See the instructor if you do not fully understand this concept. 3 Create a point-to-curve contact force between the underside on the right_contact part and the mid-contact point, POINT_13, on the base. Use the same contact parameters as in Step 3 on page 355. However, set the stiffness to 1e8 N/mm. POINT_13 First create a marker on the base part at POINT_13. Use this marker as the point marker in the point-to-curve contact force. For the curve, use right_contact.right_contact_lower_bspline. 366 Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS 7R WHVW WKH PRGHO 1 Verify the model. Your system should have four degrees of freedom and no redundant constraints. 2 Simulate the model to visually verify correct rearward toggle motion using a simulation script based on the following ADAMS/Solver commands: SIMULATE/DYNAMICS, END=10, DTOUT=0.01 DEACTIVATE/SENSOR, ID=<your right front sensor id #> SIMULATE/DYNAMICS, DURATION=0.5, DTOUT=0.01 Note the force at which the switch toggles to the rearward direction when accounting for only the right_follower and right_contact parts and corresponding connections. 3 Save your work now. In Sections IV and V you will incorporate the left half of the switch and add friction. Switch Mechanism Workshop 367 6ZLWFK 0HFKDQLVP :RUNVKRS 6HFWLRQ ,9 $GG WKH OHIW KDOI Since the right half of the switch mechanism is working properly at this time, apply the same steps to the left half of the mechanism. If desired, you can use a different crawl-walk-run method to connect parts in the left half. Below is a copy of the key locations that will help you define the left half connections: Point: Description: POINT_1 Actuator to base pivot location POINT_2 right_follower to actuator spring lower location POINT_3 left_follower to actuator spring lower location POINT_4 right_follower to actuator spring upper location POINT_5 left_follower to actuator spring upper location POINT_6 Contains z-coordinate of base contact plane with left_contact and right_contact at four corners POINT_7 left_contact to base idealized constraint location POINT_8 right_contact to base idealized constraint location POINT_9 Location of base front contact surface with actuator POINT_10 Location of base rear contact surface with actuator POINT_11 Location of actuator front contact point with base POINT_12 Location of actuator rear contact point with base POINT_13 Location of right_contact to base mid-contact point POINT_14 Location of left_contact to base mid-contact point POINT_15 Location of force application 7R FRQQHFW WKH OHIWBIROORZHU DQG OHIWBFRQWDFW ■ 368 Reintroduce the left_follower and left_contact parts by reactivating them and ultimately connect these parts to the switch mechanism the same way that you did for the right_follower and right_contact parts. Switch Mechanism Workshop 6ZLWFK 0HFKDQLVP :RUNVKRS 7R WHVW WKH PRGHO 1 Verify the model. Your system should now have seven degrees of freedom and no redundant constraints. 2 In the Message Window, select Settings. 3 Change Display messages only at or above severity level from Warning to Error. This prevents the Message Window from opening each time you verify or simulate due to the difference in orientation of the markers and curves used to define the pt_cv contact. 4 Simulate the model to determine rearward toggle motion using a simulation script based on the following ADAMS/Solver commands: SIMULATE/DYNAMICS,END=10.0,DTOUT=0.1 DEACTIVATE/SENSOR,ID=<your right front sensor id #> SIMULATE/DYNAMICS,DURATION=0.5,DTOUT=0.01 5 Note the force at which the switch toggles to the rearward direction now, when accounting for both halves of the mechanism? 6 Simulate the model to determine rearward toggle motion, and then switch to forward toggle motion using a simulation script based on the following ADAMS/Solver commands: SIMULATE/DYNAMICS,END=10.0,DTOUT=0.1 DEACTIVATE/SENSOR,ID=<your left rear sensor id #> SFORCE/2, FUNCTION=100*TIME SIMULATE/DYNAMICS,DURATION=3.0,DTOUT=0.01 Notice how you are reversing the input force applied to the actuator part through an ADAMS/Solver command in the simulation script, as opposed to in the model’s design configuration. You can modify a force on-the-fly. 7 Note the force at which the switch toggles to the forward direction when accounting for both halves of the mechanism? 8 Save your work. Switch Mechanism Workshop 369 6ZLWFK 0HFKDQLVP :RUNVKRS 6HFWLRQ 9 5HILQH WKH VZLWFK You will now refine your model to account for friction. 7R DGG IULFWLRQ WR WKH FXUYHWRFXUYH FRQWDFW IRUFHV 1 Modify the curve-to-curve contact force between the tip of the right_follower and the upper curve on the right_contact part such that static and dynamic friction is accounted for. Use the following default parameters for contact friction: ■ 0.3 ■ Dynamic Friction Coefficient: .1 ■ Stiction Transition Vel.: 1 mm/sec ■ 2 Static Coefficient: Friction Transition Vel.: 10 mm/sec Modify the curve-to-curve contact force between the tip of the left_follower and the upper curve on the left_contact part such that static and dynamic friction is accounted for. Use the same contact array you used in the previous step. 7R WHVW WKH PRGHO 1 Verify the model. Your system should still have seven degrees of freedom and no redundant constraints. 2 Simulate the model to visually verify correct rearward toggle motion using a simulation script based on the following ADAMS/Solver commands: SIMULATE/DYNAMICS,END=10.0,DTOUT=0.1 DEACTIVATE/SENSOR,ID=<your right front sensor id #> SFORCE/(<original input sforce id #>), FUNCTION=100*TIME SIMULATE/DYNAMICS,DURATION=0.5,DTOUT=0.01 SIMULATE/DYNAMICS,DURATION=2.0,DTOUT=0.1 Note the force at which the switch toggles to the forward and rearward directions when accounting for friction in the contact between the follower parts and the contact parts. Were the effects of friction negligible in this mechanism? 3 370 Save your work. Switch Mechanism Workshop $ 7$%/(6 This appendix contains tables that describe the various elements in ADAMS/View. 7KLV DSSHQGL[ LQFOXGHV ■ Constraints Tables (Incomplete), 372 ■ Forces Tables (Incomplete), 373 ■ Constraint Tables (Completed), 374 ■ Forces Tables (Completed), 376 371 &RQVWUDLQWV 7DEOHV ,QFRPSOHWH Translation along X: Translation along Y: Translation along Z: Translation along X: Translation along Y: Translation along Z: Translation along X: Translation along Y: Translation along Z: Rotation about X: Rotation about Y: Rotation about Z: Total: Rotation about X: Rotation about Y: Rotation about Z: Total: Rotation about X: Rotation about Y: Rotation about Z: Total: Fixed Revolute Translational Cylindrical Universal/ hooke/ Constant velocity Spherical Planar Point-to-curve Curve-to-curve Orientation Inline Parallel axis Inplane Perpendicular 372 Tables )RUFHV 7DEOHV ,QFRPSOHWH Translational Spring-Damper: Torsional Spring-Damper: Bushing: Beam: Field: Number of Bodies Affected Points of Application Number of Components Direction/ Orientation Magnitude Multi-Component Forces Single-Component Forces Between 2 Bodies Translational: Between 2 Bodies Rotational: 1 Body Space Fixed: 1 Body Moving: Vector Force/ Torque: General Force: Number of Bodies Affected Points of Application Number of Components Direction/ Orientation Magnitude Tables 373 &RQVWUDLQW 7DEOHV &RPSOHWHG Translation along X: Translation along Y: Translation along Z: Rotation about X: Rotation about Y: Rotation about Z: Total: Fixed 6 Revolute 5 Translational 5 Cylindrical 4 Universal/ hooke/ Constant velocity 4 Spherical 3 Planar 3 Translation along X: Translation along Y: Translation along Z: Rotation about X: Rotation about Y: Rotation about Z: Total: Point-to-curve 2 Curve-to-curve 2 374 Tables &RQVWUDLQW 7DEOHV &RPSOHWHG  Translation along X: Translation along Y: Translation along Z: Rotation about X: Rotation about Y: Rotation about Z: Total: Orientation 3 Inline 2 Parallel axis 2 Inplane 1 Perpendicular 1 Tables 375 )RUFHV 7DEOHV &RPSOHWHG Spring-Damper Translational: Magnitude Beam: Field: 2 2 2 2 2 (I & J markers) 2 (I & J markers) 2 (I & J markers) 2 (I & J markers) 2 (I & J markers) 1 1 6 6 6 Line of sight between the (I & J markers) Z-axis of J marker J marker J marker J marker Number of Components Direction/ Orientation Bushing: 2 # Bodies Affected Points of Application Spring-Damper Torsional: Defined by parameters, such as stiffness, damping, cross-sectional area. Multi-Component Forces Single-Component Forces Between 2 Bodies Translational: Number of Bodies Affected Points of Application Number of Components Direction/ Orientation Magnitude Between 2 Bodies Rotational: 1 Body Space Fixed: 2 2 1 1 2 2 2 (I & J markers) 2 (I & J markers) 1 (I marker) 1 (I marker) 2 (I & J markers)* 2 (I & J markers) * 1 1 1 1 3 6 Line of sight between I and J markers A-axis of J-marker Z-axis of J-marker Z-axis of J marker R marker R marker 1 Body Moving: Vector Force/ Torque: General Force: Defined by whole functions of which the user must take ownership. * The J markers created for a vector force/torque and a general force are floating markers. 376 Tables % $16:(5 .(< 7KLV DSSHQGL[ LQFOXGHV ■ Answer Key for Workshop 1, 378 ■ Answer Key for Workshop 2, 378 ■ Answer Key for Workshop 3, 378 ■ Answer Key for Workshop 4, 379 ■ Answer Key for Workshop 5, 379 ■ Answer Key for Workshop 6, 379 ■ Answer Key for Workshop 7, 380 ■ Answer Key for Workshop 8, 380 ■ Answer Key for Workshop 9, 381 ■ Answer Key for Workshop 10, 381 ■ Answer Key for Workshop 11, 381 ■ Answer Key for Workshop 12, 381 ■ Answer Key for Workshop 13, 381 ■ Answer Key for Workshop 14, 382 ■ Answer Key for Workshop 15, 382 ■ Answer Key for Workshop 16, 382 ■ Answer Key for Workshop 17, 382 ■ Answer Key for Workshop 18, 383 ■ Answer Key for Workshop 19, 383 ■ Answer Key for Workshop 20, 383 ■ Answer Key for Workshop 21, 383 ■ Answer Key for Workshop 22, 383 377 $QVZHU .H\ $QVZHU .H\ IRU :RUNVKRS  Question 1, page 25: 269 mm Question 2, page 25: 269 mm. This is the same as the previous results. Question 3, page 25: 267.87 mm Question 4, page 25: Six: 5 make up the stamper mechanism, while 1 makes up the part parcels. Question 5, page 25: Eight: 7 are on the stamper mechanism, while 1 keeps the parcels moving translationally. Question 6, page 25: Nothing: the conveyor is simply a graphic attached to ground. It adds nothing to the model other than for animation purposes. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 43: There are nine constraints (two revolute, one translational, three inplane, one orientation, one motion, one curve_curve). Motions are considered constraints; these will be covered in detail later in the course. Question 2, page 43: Yes Question 3, page 43: No, geometry is a direct child of a part. Part geometry is a “grandchild” of a model. Question 4, page 43: Status bar Question 5, page 43: Our technical support staff prefers to receive .cmd files because they are smaller in size, and platform independent. Using .bin files is sometimes unavoidable, however. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 60: 1.635 pound mass based on geometry and density Question 2, page 60: 100 lbf/foot*second Question 3, page 60: Approximately 8.6 lbf 378 Answer Key $QVZHU .H\ $QVZHU .H\ IRU :RUNVKRS  Question 1, page 77: 4903 mm Question 2, page 77: 9807 mm/sec Question 3, page 77: 9807 mm/sec2 Question 4, page 77: Coordinate system markers Question 5, page 77: The ground part is automatically created - it must exist in every model. It serves as a reference frame for the model. Question 6, page 77: No, because MSC.ADAMS cannot calculate a volume for two- dimensional objects. You can, however, assign mass properties to a part that is made up of twodimensional geometry by changing Defined by to User Input. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 90: ~1.06 sec (can vary slightly depending on the sampling rate chosen). Question 2, page 90: ~3180 mm (can vary slightly depending on the sampling rate chosen). Question 3, page 90: The system constraint takes precedence. Question 4, page 90: You would have to constrain the stone to ground with a revolute (pin) joint. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 112: Fx = -29.9N, Fy = 17.24 N Question 2, page 112: Approximately 0.61 Hz Question 3, page 112: ADAMS/View will use the one specified by the connecting joint. This is because the initial conditions in the constraint always override the initial conditions of a part if these two differ. Question 4, page 112: The marker names would be .human_hip.femur.MAR_1 and .human_hip.hip_bone.MAR_2. Which one is I and which one is J depends on the order in which the parts were selected when creating the constraint. Question 5, page 112: No, a constraint constrains two different bodies to one another. Answer Key 379 $QVZHU .H\ $QVZHU .H\ IRU :RUNVKRS  Question 1, page 133: Between 16.5o and 17o (Exactly 16.7o). Question 2, page 133: You can tell because there is an icon ( ) for the joints to which you can add friction in an automated way. Question 3, page 133: I and J markers are automatically created when you add a joint, motion, or force to a system. MSC.ADAMS uses the I and J markers’ relative displacement, velocity, and so on to define equations that describe part movement. Question 4, page 133: Once the joint crosses the stiction threshold velocity, it exits the stiction phase and the maximum stiction displacement is ignored until the joint reenters the stiction phase (comes to rest). One of these two parameters is reached first, the other parameter is ignored until the joint enters the stiction phase again. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 151: Construction geometry is two-dimensional, and solid geometry is three- dimensional. Question 2, page 151: ■ ■ Location Event: Right-click away from the model when prompted for a position. ■ Working grid: Settings Æ Working Grid Æ Set Location. ■ 380 Position: Move-Translate . Precision Move: Edit Æ Move (or ) Answer Key $QVZHU .H\ $QVZHU .H\ IRU :RUNVKRS  Question 1, page 162: I and J markers. The I marker belongs to the first body you selected when the creating the joint. The J marker belongs to the second body you selected. Question 2, page 162: The orientation of the I and J markers. For example, if you added translational motion to a translational joint, the z-axis of the I and J markers would describe the axis of translation. The z-axis direction is positive. Question 3, page 162: Yes. Even though they do not restrict movement, they still prescribe movement, therefore, removing degrees of freedom. Question 4, page 162: Yes. You must measure the torque generated by the motion not the revolute joint. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 170: The order in which you chose the bodies (parts) should be the same as the order in which you chose the corresponding locations and orientations. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 180: A joint motion uses a joint to determine its direction and location. A point motion does not require a joint; it needs two bodies. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 192: No. The point-to-point measure is just a quicker and easier way to create a function measure of the displacement of one marker with respect to another. Question 2, page 192: A CAD file represents geometry in a model. Therefore, it is a child of a part. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 204: You need to provide the two (or three) joints, and either the scalar coefficients, displacements, or user-defined constraint equations. Question 2, page 204: Last_run Answer Key 381 $QVZHU .H\ $QVZHU .H\ IRU :RUNVKRS  Question 1, page 217: No, in the design configuration they do not have to be aligned. If they are not aligned, however, ADAMS/View warns you during a model verify or during the assemble simulation. Also, during the assemble simulation, MSC.ADAMS realigns the markers for you. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 228: ■ ■ ■ ■ First independent variable Second independent variable Spline name Derivative order Question 2, page 228: ADAMS/Solver -> Function Expressions (see the online help for reference) $QVZHU .H\ IRU :RUNVKRS  Question 1, page 236: ~1.46 degrees (.0255 radians) Question 2, page 236: To remove the initial transient effects in the dynamic system because of mismatches in the preloading of the bushings. Question 3, page 236: Because the model was kinematic, in this case (DOF=0), there is no initial transient response because you have specified the motion of the system for all points in time. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 248: Yes, it must be greater than zero (not negative and not zero). Question 2, page 248: Reposition the I and J markers of each single-component force such that the trigger distance is reached sooner and the full impact is felt earlier. Measuring the rotation of the I marker of joint l_shortarm_rev will determine the angle. 382 Answer Key $QVZHU .H\ $QVZHU .H\ IRU :RUNVKRS  Question 1, page 260: Approximately 247 N. Question 2, page 260: Yes: you could use a simulation script with ADAMS/Solver commands to simulate for a while, then DEACTIVATE or ACTIVATE the force, and simulate again. Question 3, page 260: Yes. For example, you could simulate the model with output step sizes of 0.01 seconds. When that simulation is complete, don’t reset the model. Start another simulation with a step size of 0.001. The results of that simulation will be seamless, but you will notice a change when the step size changes. The animation changes speeds. A common reason for doing this is if you want the simulation to use smaller step sizes or be more accurate before a contact. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 283: A statement describes an element in a model, such as a part or force. A command tells ADAMS/Solver what to do with the model, such as simulate it or deactivate it. Question 2, page 283: 7.57 N/mm. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 295: Preload must be above 460 N to open the lid. Higher damping values increase the amount of time needed to close the lid. Higher stiffness values increase the resistance in closing the lid. Question 2, page 295: It allowed for easy manipulation of the spring parameters. Changing the design variables changed the parameters for both springs at the same time. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 315: A curve-on-curve constraint removes two translational DOF. Question 2, page 315: A curve-to-curve contact force removes no DOF. $QVZHU .H\ IRU :RUNVKRS  Question 1, page 334: The reference marker (R marker) Question 2, page 334: Between 17 and 18 N/mm Answer Key 383 $QVZHU .H\ 384 Answer Key ,1'(; $% Acceleration calculating 73 finding value of 75 functions 240 Accessing online help 13 ADAMS/AutoFlex about 302 loading 312 working with 312 ADAMS/PostProcessor leaving 53 modes of 46 modifying animation graphics in 59 playing animations in 59 starting 53 using 53 viewing animations in 58 ADAMS/PostProcessor overview workshop module review 60 problem statement 50 ADAMS/PostProcessor tool, using 53 $% &' () *+ ,./ 01 23 45 67 89 := ADAMS/Solver command files 264 dataset files 264 history of 10 overview of 262 simulations in stand-alone, about 266 simulations in stand-alone, performing 278 ADAMS/View starting on UNIX 21 starting on Windows 20 385 ,QGH[ ADAMS/View interface overview workshop module review 43 optional tasks 42 problem statement 34 ADAMS/View tool, using to start on UNIX 21 Add-on constraints about 194 types of 194 AKISPL function creating 226 example of 222 syntax for 222 Align & Rotate tool, using to rotate objects 125 Angle measures about 99 creating 106 Animation adding to plot 57 compared to simulation 31 how to perform 41 modifying graphics in ADAMS/PostProcessor 59 playing in ADAMS/PostProcessor 59 viewing in ADAMS/PostProcessor 58 $% &' () *+ ,./ 01 23 45 67 89 := Animation tool, using 41 Arc geometry, about 141 ASK group, about 15 Assembling models about 196 how to 202 Assembly simulation, about 206 Binary files, saving as 89 386 Index ,QGH[ Block creating 85 geometry, about 142 Body 313, example of 116 Box tool, using 85 Bushing tool, using 233 Bushings characteristics of 230 creating 233 defined 230 recommended practices 339 &' CAD-based geometry importing, about 184 importing, how to 189 Cam profile, creating 305 Cam-rocker-valve workshop module review 315 optional tasks 314 problem statement 303 Chamfer tool, using 149 Change Direction tool, using 308 $% &' () *+ ,./ 01 23 45 67 89 := Command files about 32, 264 creating 277 modifying 281 Compute Linear Modes tool, using 215 Constraining a model, about 126 Index 387 ,QGH[ Constraints add-on (complex) 194 and DOF 96 couplers 195 curve-on-curve, creating 306 curve-on-curve, replacing 307 defined 94 determining number and type 37 diagrammed 95 DOF they remove 374 equations in MSC.ADAMS 95 example 94 types of 299 Contact forces about 300 creating solid-to-solid 327 creating sphere-to-plane 327 Contact pairs, types of 300 Contact tool, using 307 Coordinate systems defined 62 types of 62 Coupler creating 200 defined 195 example of 195 modifying 201 requirements for modeling 195 $% &' () *+ ,./ 01 23 45 67 89 := Coupler tool, using 200 Course, what you will achieve in 12 Crawl-walk-run approach, about 173 Create a New Page tool, using 53 Curve-Curve Constraint tool, using 306 388 Index ,QGH[ Curve-on-curve constraint creating 306 replacing 307 Cylinder creating 147 geometry, about 142 Cylinder tool, using 147 Cylindrical joints, DOF they remove 374 Database files, about 32 Dataset files about 264 example of 265 exporting 277 modifying 280 Debug, about 274 Dependencies, about 66 Design studies defined 321 performing 24 types of 320 Design variables about 287 creating 292 example 287 modifying 292 $% &' () *+ ,./ 01 23 45 67 89 := Displacement calculating 72 finding horizontal 88 finding value of 74 Displacement functions about 183 example 183 Index 389 ,QGH[ DOF constraints and DOF 96 determining number of 96 Dynamic simulation about 208 performing 227 Dynamics, debugging tips 345 () Eprint, about 274 Equations of motion, formulation in ADAMS 267 $% &' () *+ Euler angles, defined 116 ,- Extrusion geometry, about 142 ./ Falling stone workshop module review 77 optional tasks 76 problem statement 70 File formats, about 32 Fillet tool, using 148 Fixed joint tool, using 159 Fixed joints DOF they remove 374 recommended practices 338 01 23 45 67 89 := Flexible bodies creating 312 defined 67 390 Index ,QGH[ Forces characteristics of 210 compare linear and nonlinear 227 contact forces 300 definition 210 friction 118, 119 multi-component 318 single component, about 220 spring dampers 211 vector 318 Frequency determining 110 finding natural 215 Friction adding to joint 128 effect of deformation on 120 forces, about 118 input forces to 120 phases of 118 $% &' () *+ ,./ 01 23 Function Builder about 340 using 187 45 Functions acceleration 240 AKISPL 222 defined 156 displacement 183 IMPACT 238, 239 spline 221 STEP 250 velocity 240 89 Index 67 := 391 ,QGH[ *+ Geometry arc 141 block 142 cylinder 142 extrusion 142 importing CAD-based, about 184 importing CAD-based, how to 189 marker 140 merging 98 point 140 polyline 141 spline 141 torus 142 types of 139 Global components, determining 109 $% &' () *+ ,./ Graphical topology, checking 170 01 Gravity, recommended practices 341 23 Ground parts, about 67 45 Gruebler’s count 96 Hatchback I workshop module review 248 problem statement 241 Hatchback II workshop module review 260 problem statement 253 67 89 := Hatchback III workshop module review 283 optional tasks 282 problem statement 276 Hatchback IV workshop module review 295 optional tasks 294 problem statement 288 392 Index ,QGH[ Help, online 13 Hierarchy of simulation 207 Hollow tool, using 150 Hooke joint tool, using 178 Hooke joint, creating 178 $% ,- &' Icons animating with icons off 41 animating with icons on 41 () *+ IMPACT function ,- about 238 applications of one sided 238 applications of two sided 238 syntax 239 ./ 01 Importing CAD-based geometry, about 184 CAD-based geometry, how to 189 files 35 test data 221 23 Inclination angle finding 131 modifying 124 89 45 67 := Inclined plane workshop module review 133 optional tasks 132 problem statement 122 Inertia properties, about 68 Information tool stack, using 37 Information tool, using 169 Index 393 ,QGH[ Initial conditions about 80 joint initial conditions 97 locations and orientations 80, 206 setting for joints 107 setting for velocity 86 velocity 81 $% Inline joint primitives, about 164 &' Inplane joint primitives, about 164 () Joint friction, about 118 Joint motion about 154 creating 160 marker usage in 155 Joint primitives inline 164 inplane 164 orientation 164 parallel axis 164 perpendicular 164 perpendicular, usage of I and J markers 165 types of 164 Joint toolstack, using 104 Joints friction 118 initial conditions of 97 *+ ,./ 01 23 45 67 89 := ./ Kinematic simulation about 208 performing 354 Knowledge base, about 14 Lift mechanism I workshop module review 151 optional tasks 151 problem statement 144 394 Index ,QGH[ Lift mechanism II workshop module review 162 optional tasks 161 problem statement 157 Lift mechanism III workshop module review 170 optional tasks 170 problem statement 167 Linear simulation about 209 example 209 $% &' () *+ Link tool, using 101 ,- Links, creating 101 ./ Local coordinate system, about 62 Location Event, using 101 01 01 23 Main Toolbox tool, using 52 45 Marker tool, using 106 67 Markers defined 64 geometry, about 140 reference, creating 106 89 := Mass properties about 68 recommended practices 337 Mass, setting 71 Index 395 ,QGH[ Measures angle 99 angle, creating 106 creating 72, 86 creating function 187 creating point-to-point 186 defined 69 function 182 in LCS 121 object, creating 105 point-to-point 182 recommended practices 340 representation 121 $% Merging geometry, about 98 ,- Mesh, creating 312 ./ Model topology checking by constraints 160 checking by parts 150 01 Model topology by constraints tool, using 160 &' () *+ 23 45 Model topology by constraints tool, using to determine constraints 37 Model topology by parts tool, using 150 Models animating 41 assembling 196 clarifying topology 29 constraining 126 hierarchy of 28 simulating 40 verifying 39 67 89 := Modifying animation graphics 59 coupler 201 parts 124 plot graphics 56 plot legend 57 spring stiffness 54 396 Index ,QGH[ Motion applying 179 joint motion 154, 155 point motion 172 recommended practices 338 types 154 Move tool stack, using 130 Moving objects, about 143 $% &' () MSC.ADAMS about 10 history of 10 list of products 11 verification problems for 11 *+ MSC.ADAMS Full Simulation Package, about 9 ./ Multi-component forces characteristics of 376 creating 329 types of 318 01 Naming convention, about 29 News and information, obtaining personalized 14 Nonlinear spring workshop module review 228 optional tasks 228 problem statement 223 ,- 23 45 67 89 := 23 Object measures creating 72 defined 69 Objects creating a group of 129 rotating about an axis 117 Index 397 ,QGH[ One DOF pendulum workshop module review 112 optional tasks 111 problem statement 100 Online help, accessing 13 Optimization study, performing 24 $% Optimizing a design, about 293 &' Orientation joint primitives, about 164 () Orientation, verifying 169 Overlaying plots, how to 55 *+ Page layout tool stack, using 57 ,- Parallel axis joint primitives, about 164 ./ Part coordinate system, about 63 01 Parts building 71 defined 65 initial locations and orientations 80 initial velocity 81 renaming 37, 71 rotating 125 23 Perpendicular joint primitives about 164 usage of I and J markers 165 := 45 67 89 Planar joints, DOF they remove 374 Plane tool, using 326 Plane, creating 326 Play tool, using to play simulation 40 Plot graphics, modifying 56 Plot legend, modifying 57 Plot statistics, obtaining 56 398 Index ,QGH[ Plot Tracking tool, using 88 Plots creating 53 overlaying 55 Plotting option, about 48 Point geometry, about 140 Point motion about 172 applying 179 Point trace creating 88 defined 82 using 305 Point-to-Point tool, using 147 Polyline geometry, about 141 Precision Move tool, using 130 Projectile motion workshop module review 90 optional tasks 89 problem statement 83 45 $% &' () *+ ,./ 01 23 45 67 89 := Range, finding 87 Reference markers, creating 106 Renaming objects, about 29 Reset tool, using to reset model 40 Revolute joint tool, using 104 Revolute joints creating 104 deactivating 232 DOF they remove 374 Rigid bodies, defined 67 Index 399 ,QGH[ Rigid Body tool stack, using 106 Rotating group of objects 130 objects, about 117 parts, how to 125 Rotational Joint Motion tool, using 160 $% 67 &' Save simulation tool, using 40 () Saving command files 42 model information 42 simulation results 40 *+ Scripted simulations based on ADAMS/Solver commands 252 creating script for 255 in ADAMS/View 251 performing 256 Select tool, using 86 Sensitivity, at iteration 322 Sensors about 286 adding to model 290 example of using with scripts 286 ,./ 01 23 45 67 89 := SFORCE, see Single-component forces 220 400 Index ,QGH[ Simulation about scripts 251 compared to animation 31 comparing results 281 dynamic 208 hierarchy 207 how to perform 40 kinematic 208 linear 209 saving results of 40 static 208 submitting 31 types of 208, 251 $% Simulation tool, using to simulate model 40 ,- Single-component forces about 220 characteristics of 376 creating 289 ./ &' () *+ 01 Solution, phases of 269 23 Space 313, example of 116 45 Sphere tool, using 102 67 Sphere, creating 102 89 Spherical joints creating 178 DOF they remove 374 := Splines about 221 from point trace 298 geometry, about 141 recommended practices 340 Spring dampers characteristics of 211 creating 214 defined 211 find force in 214 recommended practices 339 replacing predefined 224 Index 401 ,QGH[ Spring stiffness coefficient, finding 54 modifying 54 Spring, changing linear to nonlinear 225 Spring-damper workshop optional tasks 216 problem statement 213 Stamping mechanism workshop module review 25 problem statement 19 Stand-alone ADAMS/Solver about simulations in 266 performing simulations in 278 Starting ADAMS/View on UNIX 21 on Windows 20 Static Equilibrium tool, using 214 Static equilibrium, running simulation 214 Static simulation about 208 performing 214 Statics, debugging tips 344 $% &' () *+ ,./ 01 23 45 67 89 := Step Backward tool, using 87 Step Forward tool, using 87 STEP function defined 250 example of 250 syntax for 250 Stop tool, using 87 402 Index ,QGH[ Suspension system I workshop module review 180 optional tasks 180 problem statement 174 Suspension system II workshop module review 192 optional tasks 191 problem statement 185 Suspension-steering system II workshop module review 236 optional tasks 235 problem statement 231 Suspension-steering system workshop module review 204 problem statement 197 Switch mechanism workshop, problem statement 347 Target practice workshop module review 334 optional tasks 334 problem statement 323 Technical support, about 14 Test data 221 Torus geometry, about 142 $% &' () *+ ,./ 01 23 45 67 89 := Training guide, organization of 12 Translating models, how to 73 Translational Joint Motion tool, using 304 Translational Joint tool, using 126 Translational joints creating 126 DOF they remove 374 Translational spring damper tool, using 214 Transparent, making a part 170 Index 403 ,QGH[ 89 Units, recommended practices 341 Universal joints, recommended practices 338 Vector force 318, 319 Velocity calculating 72 finding value of 75 functions 240 Verification problems, running through 11 Verify tool, using to verify model 39 Verifying models about 342 how to 39 Viewing models, how to 36 Virtual prototyping process, diagrammed 18 $% &' () *+ ,./ 01 23 := 45 Working grid adjusting 123 resetting to default position 326 set up to run through part center 147 setting display of 85 67 89 := Zooming, how to 73 404 Index ...
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