sm9 88

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PROBLEM (9.88) For the shaft of the system shown in Fig. P9.88, determine the diameter d,
applying the maximum principal stress theory of failure.
Given: all
σ
= 20 ksi.
SOLUTION
From statics: 1.6
yy
AB kips==
The critical section is between C and D. Thus
22 2 2
28.8 4.8 29.197 .
z
M
T kip in+= + = ⋅
Apply Eq. (9.32):
3
33
16 10 (28.8 29.197) 2.45 .
(20 10 )
din
π
×
=+=
×
Use a
12
2.in− diameter shaft.
x
y
A
C
B
x
M
z
z
3 ft
T
x
(d)
(
a
)
4.8 kips
⋅
in.
Ay
1.6 kips
1.5 ft By
1.6 kips
Figure S9.88
(
b
)
2.4x12=28.8 kip
⋅
in.
1.5 ft
4.8 kips⋅in.
D
4.8 kipin.