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# sm11 47

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PROBLEM (11.47) Rework Prob. 11.45 for tube with fixed-pinned ends and a factor of
safety of n s = 1.5.
SOLUTION
Refer to Solution of Prob. 11.45. We now have
Le = 0.7 L = 0.7(2.5) = 1.75 m (See Fig. 11.3c)
Le 1.75 &times;103
=
= 75.92
r
23.05
Le
= 37.94
2r
(a) Equation (1) becomes
⎡
⎛
σ max = (9.794) ⎢1 + (2.141) sec ⎜ 37.96
⎜
⎢⎣
⎝
10 &times; 103
(1021)(210 &times; 103 )
⎞⎤
⎟ ⎥ = 31.5 MPa
⎟⎥
⎠⎦
⎡
⎛
⎞⎤
Py
⎢
1
(2.141)
sec
37.96
+
⎜
⎟⎥
3 ⎟
⎜
1021(10−16 ) ⎢
(1021)(210
10
)
&times;
⎝
⎠ ⎥⎦
⎣
Solving numerically, Py = 68.1 kN . Equation (11.22) results in
Py
250(106 ) =
Pall =
Py
ns
=
68.1
= 45.4 kN
1.5
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