sm12 4

________________________________________________________________________
PROBLEM (12.4) An aluminum bar AB is of yield strength 38 ksi and modulus of elasticity E =
10 x 106 psi (see Fig. P12.4). A strain energy of U =150 in.-lb must be stored in the bar when axial load
P is applied. Calculate diameter d so that the factor of safety with respect to yielding is ns = 4.
SOLUTION
4 4(150) 600 .
y
UU inl== = ⋅ b
232 3
06
(38 10 )
( ) 72.2 . .
22(1010)
y
y
Ui
E
σ
×
== = ⋅
×nlbin
L
or
0
()
yy
UUA=()
y
oy
U
AUL =
Substituting the given data
2
600
72.2(6 12) 4
d
A
π
==
×, 0.383 .din
=
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