ME 325
Mechanical Component Design "Machine Design"
Fasteners
Rafael Radkowski
[email protected]
Definitions and Standards
pitch: the distance between a
screw thread.
major diameter d: the maximal
di
HW3 Solution
1
Sut 230 kpsi, N 150 000 cycles
Fig. 6-18, point is off the graph, so estimate:
Eq. (6-8):
Eq. (6-14):
Eq. (6-15):
Eq. (6-13):
Sut > 200 kpsi, so
f = 0.77
Se Se 100 kpsi
( f Sut ) 2 0.77
A solid round bar, 25 mm in diameter, has a groove 2.5 mm deep with a 2.5 mm radius
machined into it. The bar is made of AISI 1018 CD steel and is subjected to a purely reversing
torque of 207 N m. Fo
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countershaft runs at 2,000 rev/min and the bearings are to have a life of 40 kh at a combined
reliability of 0.96. The belt te
$QVHULHVVLQJOHURZGHHSJURRYHEDOOEHDULQJZLWKD PP bore (see the following
tables for specifications) is loaded with a N1 axial load and a N1 radial load. The outer
ring rotates at 513 rev/min. Determine
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5 teeth/in
with DWRRWK pinion driving a WRRWKJHDU 7KHLQSXWLVKSPD[LPXPDW
1,800 rev/min. Find the magnitude of the forces acting on bear
M a = 66.5 Nm, T a = 49.7 Nm,
M m = 60.0 Nm, T m = 31.6 Nm. For the shaft, S u = 650 MPa and S y = 595 MPa, and a
fully corrected endurance limit of S e = 160 MPa is assumed. Let K f = 2.20 and K f s
$SDUDOOHOKHOLFDOJHDUVHWXVHVDWRRWKSLQLRQGULYLQJDWRRWKJHDU7KHSLQLRQKDVD
ULJKWKDQGKHOL[DQJOHRI , a normal pressure angle of 20 , and a normal diametral pitch of
5 teeth/in. Find:
(a ) The normal, transve
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pressure angle. The
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milled. If the face width is 2 in, estimate the bending stress.
S
A spur gearset has a module of 3 mm and a velocity ratio of 2.93. The pinion has 20 teeth. Find
the number of teeth on the driven gear, the pitch diameters, and the theoretical
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A steel spur pinion has a module of 1 mm and 16 teeth cut on the 20
IXOOGHSWKV\VWHPDQGLV
to carry 0.15 kW at 379 rev/min. Determine a suitable face width based on an allowable
bending stress of 142 MP
Shaft a in the figure rotates at 626 rev/min in the direction shown. Find the speed and
direction of rotation of shaft d .
Given:
N 2 = 20
N 3 = 40
N4 =8
N 5 = 17
N 6 = 20
N 7 = 60
n = 626 rev/min
Ste
For the bearing application specifications given in the table, determine the Basic Load Rating
for a ball bearing with which to enter a bearing catalog. Assume the rating life to be 10
revolutions, a
A part is loaded with a combination of bending, axial, and torsion such that the following
stresses are created at a particular location:
Bending:
Axial:
Torsion:
Completely reversed with a maximum st
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strength corresponding to a life cycle of 150 kcycles of stress reversal.
Step 1:
S ut = 250 kpsi, N = 150000 cycles
Step 2:
S e = 276 MPa, S y = 413 MPa, and
S ut = 551 MPa. The bar is subjected to a steady torsional stress of 99 MPa and an
alternating bending stress of 171 MPa. Find the factor of safety guarding against a
F = 1500( /4)22 = 4712 lbf. From Table A-20, Sy = 37.5 kpsi
Pcr = nd F = 2.5(4712) = 11 780 lbf
1.
(a) Assume Euler with C = 1
1/4
1/4
64 11790 502
64 Pcr l 2
d 3
3
6
1 30 10
CE
Use d = 1.25
s 1 and 2: For each of the plane stress states listed below, draw a Mohr's
Problem
circle diagram properly labeled, find the principal normal and shear stresses, and
determine the angle from the x axi
ME 325
Mechanical Component Design "Machine Design"
Gears - Safety Analysis
Rafael Radkowski
[email protected]
AGMA
The American Gear Manufacturer Association (AGMA) sanctioned a method to
determine
ME 325
Mechanical Component Design "Machine Design"
Shaft Components
Rafael Radkowski
[email protected]
Content
Shaft components
Keys
Retaining rings
ME 325 Course Notes
Spring 2016
Keys
Keys are use
ME 325
Mechanical Component Design "Machine Design"
Working with Fluctuating Stress
Rafael Radkowski
[email protected]
Content
Fluctuating Stress
Stess
Gerber and Goodman relations
Failure diagram
ME
ME 325
Mechanical Component Design "Machine Design"
Shaft Design Introduction
Rafael Radkowski
[email protected]
Content
Introduction
Shaft design.
Design for Stress
Go home messages:
ME 325 Course N
ME 325
Mechanical Component Design "Machine Design"
Brittle Failure Theory
Rafael Radkowski
[email protected]
Today
Overview - Failure Theories
Maximum Normal Stress Theory
Modified Mohr Failure Theo
Midterm exam:
Monday, February 29, 2016
You need:
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Calculator
Your notes
ME 325 Course Notes, Iowa State University
1
Spring 2016
ME 325
Mechanical Component Design "Machine Design"
In-Class Problem
Determine the approximate weight fractions of L and solid for an
overall composition C0 of 25 wt% B at T1.
C= 40 wt% B
CL= 15 wt% B
C C L
=
40 25
40 15
= 0.60 = 60% L
L
Temperature
WL
A part is loaded with a combination of bending, axial, and torsion such that the following
stresses are created at a particular location:
Bending:
Axial:
Torsion:
Completely reversed with a maximum st