_______________________________________________________________________
PROBLEM (9.9) A turbine shaft of diameter d is under a thrust load P and a torque T (Fig. P9.9).
Calculate the largest permissible value of the load P if the allowable normal stress is not to exceed all
σ
.
Given: d = 60 mm, T = 2 kN m,
⋅all
σ
= 220 MPa
SOLUTION
Maximum normal stress
occurs at a point A.
d
C
A
z
We have
3
33
16 16(2 10 ) 47.16
(0.06)
T
M
Pa
d
τππ
×
== =
22
44
353.7
(0.06)
PP P
d
σππ
== = (P in MN)
Hence
22
1()
22 all
σσ
σ
τσ
=+ + =
22
220 176.8 (176.8 ) (47.16)PP=+ +
22
(220 176.8 ) 31,258 2,224PP−= +
or
22
48,400 77,792 31,258 31,258 2,224PP P−+ = +
Solving,
0.594 594
PMN==kN
y
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