MCEH420 Mechanical Design
Dr. MUTASEM SHEHADEH
American University of Beirut
Normal Stress
Axial
Pure Bending
Stress distribution due to bending
Shear Stress
Direct Shear
Transverse Shear
VQ It Q Ay
VQ It Q Ay
max max
3V 2A 4V 3A
Rectangular cross secti
Screws, Fasteners, and the design of nonpermanent joints
MECH 420
Nonpermanent Fasteners
Slide 1
Terminology
Pitch: distance between adjacent threads. Major diameter (d): the largest diameter of the screw thread. Minor diameter (dr , d1): the smallest di
Welding, bonding, and the design of permanent joints
MECH 420
Permanent Fasteners
Slide 1
Introduction
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MECH 420
Permanent Fasteners
Slide 2
History
file:/localhost/Users/D/Desktop/Welding.html
Iron pillar of De
Chapter 6
6-1 MSS: DE: 1 - 3 = S y /n n= Sy n= Sy 1 - 3
1/2
2 2 = A - AB + B
1/2
2 2 2 = x - x y + y + 3x y
(a) MSS:
1 = 12, 2 = 6, 3 = 0 kpsi 50 n= = 4.17 Ans. 12 = (122 - 6(12) + 62 ) 1/2 = 10.39 kpsi, 12 2
2
DE:
n=
50 = 4.81 10.39
Ans.
12 (b) A , B = 2
Project Fall 08-09 MECH 420 Machine Design
Follower motion
Figure1. Cam testing machine WARNING: Any two projects remotely similar in ANY way will get zero for both projects. You have been warned. Description: The machine in the drawing is a cam testing m
Chapter 18
Comment: This chapter, when taught immediately after Chapter 7, has the advantage of immediately applying the fatigue information acquired in Chapter 7. We have often done it ourselves. However, the disadvantage is that many of the items attach
Chapter 5 Failure from Static loading
MECH 420
Failure from static loading
Slide 1
Static Strength
Ideally, before designing a part, many strength tests should be performed on test specimens of the same material as the design part & under the same loadin
Static Failure Theories
Stress and Strain
1-Why do materials fail?
Given:
Stress-strain data for simple uniaxial tension
Find:
When failure occurs for general state of stress
Stress and Strain
2- What kind of stresses cause the material to fail?
Depends
Ductile Material Failure
1-Distortion Energy Theory (DE): von Mises
Yielding occurs when the distortion strain energy per unit volume reaches the strain energy per unit volume for yield in simple tension
( 1 2 ) ( 2 3 ) ( 3 1 ) 2
2 2 2
1/ 2
2 2 ( x y )
PROBLEM 1.1 FIND: Explain the hierarchy of standards. Explain the term standard. Cite example. SOLUTION
The term standard refers to an object or instrument, a method or a procedure that provides a value of an acceptable accuracy for comparison. A primary
Learn by writing methods are valuable for developing understanding of a new concept. Questions 5.1 5.4 provide some topics for Learn to Write exercises.
PROBLEM 5.1 SOLUTION
Systematic error is a constant error that shifts all measured values of a variabl
PROBLEM 6.1 KNOWN:
A current loop having N = 20 A = 1 in2 = 0.000645 m2 I = 0.02 A B = 0.4 Wb/m2 Torque on the current loop, T . The magnetic field is oriented at an angle of 90o to the current flow direction.
FIND:
ASSUMPTIONS: SOLUTION:
From (6.3)
T NIA
PROBLEM 7.1
KNOWN: FIND: SOLUTION The signal is converted to a discrete time series for using N = 8 and sample time increments of 0.125, 0.30, and 0.75 s and plotted below. The time increments of 0.125 and 0.30 s produce discrete series with a period of 1
PROBLEM 1.5 FIND: How does resolution affect accuracy? SOLUTION
The resolution of a scale is defined by the least significant increment or division on the output display. Resolution affects a user's ability to resolve the output display of an instrument o
PROBLEM 4.2 KNOWN: N > 10 000; x = 204 units ; Sx= 18 units FIND: x' - z1 x x' + z1 at P = 90% ASSUMPTIONS Measurand follows a normal density function
Data set sufficiently large such that x x and Sx
SOLUTION
Using the definition z1 = (x1 - x')/ we find
PROBLEM 5.5
KNOWN: Micrometer Resolution: 0.001 inch (0.025 mm)
FIND: ud at 95% confidence ASSUMPTIONS: Instrument error is negligible compared with error due to resolution. SOLUTION The interpolation error due to instrument resolution of an analog instru
Self-locking
Screw-based Jack
Mechanical Engineering Department
Mechanical Design I MECH 420
Dr. Elie Shammas & Dr. Mutassem Shehadeh
Group Members:
Omar El Alami 201400788
Mohamad Ezzedine 201402274
Amane Abdel Samad 201402205
Michel Abi Saber 201401539