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PROBLEM (9.1) A cylinder with external diameter D and internal diameter d is subjected to an
axial compressive load P and a torque T (Fig. P9.1). Calculate the maximum principal stress and the
maximum shearing stress. Show the results on a properly oriented element.
Given: D = 6 in., d = 4 in., P = 20 π kips, T = 15 π kip ⋅ in.
SOLUTION
State of stress on an element at the cylinder’s surface is
σx =
σx =
Tc
τ xy =
J
P
A
τ =−
−20π ×103
= −4 ksi
π (32 − 22 )
15π × 103 (3)
π
2
= −1.385 ksi
(3 − 2 )
4
4
Equation (9.1):
4
4
2
2
σ 1 = 0.433 ksi
σ 2 = −4.433 ksi
τ max = 2.433 ksi
Equation (9.3):
2(−1.385)
tan 2θ p =
,
2θ p = 34.7o
−4
Equation (4.4a) gives
1
1
σ x ' = (−4) + (−4) cos 34.7o − 1.385sin 34.7o
2
2
= −4.433 ksi
Thus
θ p " = 17.35o
σ 1,2 = − ± (− ) 2 + (−1.385) 2 = −2.433
2.433 ksi
4.433 ksi
17.35o
x
0.433 ksi
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