1
Name of Student ______________________
ME 452: Machine Design II
Spring Semester 2012
Homework Set 4
Attempt by Wednesday, February 8th
Solve the following problems from Chapter 6, Shigley’s Mechanical Engineering Design,
Ninth Edition, R.G. Budynas and J.K. Nisbett.
1.
Problem 615 page 349.
2.
Problem 616 page 349.
3.
Problem 617 page 349.
4.
Problem 620 page 350.
Notes and Reminders
Submit the progress report for Project 1 before noon, Room ME 3003, Friday, February
10th.
The report should include such items as:
(i)
A brief paragraph describing your approach to determine the acceleration of the piston
from a kinematic analysis of the single cylinder diesel engine. Include a copy of your
computer program, and tables of your kinematic results (the data should be printed at least
every 10 degrees of the crank position
2
θ
.)
(ii)
A brief paragraph describing your approach to determine the reaction forces acting on the
crankshaft as a function of the crank position
2
θ
. Use the NewtonEuler approach.
a.
Draw complete free body diagrams of each link of the engine.
b.
List all the unknown variables (forces, moments, etc.). Compare your results including the
weight of the piston and then neglecting the weight of the piston. Include a copy of your
computer program, and tables of your dynamic force results (the data should be printed at
least every 10 degrees of the crank position
2
θ
.
(iii)
A brief paragraph describing your approach to generate the shear force diagrams, bending
moment diagrams, and torque diagrams for five pieces of the crankshaft.
a.
Draw the shear force diagrams, bending moment diagrams, and torque diagrams for each of
the pieces of the crankshaft.
b.
Describe your approach to determine the critical planes of the crankshaft.
(iv)
Prepare a progress report summarizing the results of Steps (i) – (iii). Include a brief
paragraph describing the problem. Show all of your work, and include a copy of your
computer program, and plots, clearly showing your important results. Discuss the practical
significance of your results.
Class Test 1 is in lecture on Friday, February 10th. The test is open book and closed notes and
will focus on the material taken from the class lectures and Homework Sets 1, 2, 3, and 4.
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Solution to Homework Set 4.
Problem 615.
From Table A20 for AISI 1095 HR steel, see page 1040, the ultimate tensile
strength and the yield strength of the solid steel round bar, respectively, are
120
ut
S
=
kpsi
and
66
y
S
=
kpsi
(1)
Using Eq. (68), see page 282, the uncorrected endurance strength of the solid steel round bar is
0.5
0.5 120
60
eu
t
SS
′
==
×
=
kpsi
(2)
From Table 62, see page 288, the constants are
an
2.70 kpsi
0 2
d.
6
5
ab
−
(3)
From Eq. (619), see page 287, the surface factor is
0.265
2.70 120
0.76
b
au
t
ka
S
−
==×
=
(4)
From Eq. (624), see page 289, the equivalent diameter is
0.370
0.370 1.8
0.666
e
dd
=
=×
=
in
(5)
Therefore, from Eq. (620), see page 288, the size factor is
0.107
0.107
0.879
0.879 0.666
0.92
be
kd
−−
×
=
(6)
From Eq. (626), see page 290, the loading factor is
1
c
k
=
(7)
Using Eq. (618), see page 287, the corrected endurance strength of the solid steel round bar is
0.76 0.92 1 60
42.0
ea
c
Sk
k
k
S
=′
=
×
×
×
=
kpsi
(8)
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 Spring '09
 Machine Design, Kc, Eqs.

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