sm9 29

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PROBLEM (9.29) A steel shaft. d = 2 in. in diameter and rotating at n = 2400 rpm is acted upon by
a bending moment of M = 5 kip-in. Calculate the torque and the horsepower that can also be applied
simultaneously to the shaft.
Given: all
τ
= 9 ksi, all
σ
= 14 ksi
SOLUTION
3
33
32 32(5 10 ) 6.37
(2)
xMc M ksi
Id
σππ
×
== = =
(637, τ )
τ
(
ksi
)
σ
(ksi)
O
1
σ
R
3.185
Tc
J
τ =
9
6.37 ksi
C
For Mohr's circle:
ksi42.8185.39 22 =−=
τ
ksiksi 14185.129185.3
1
<
=+=
σ
O.K.
Thus,
333
8.42 10 ( )(1) 13.23 .
22
Jc
Tk
c
ττπ π ×
== = = ⋅
ipin
Formula (5.26)
3
13.23 10 (2400) 504
63,000 63,000
TN
Ph
×
== =
p
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