| Practice Problem 9-3 |
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Given: A certain steel (shear yield stress, SY = 35 ksi) pressure vessel opperates at a pressure of 80 psi. The radius and thickness of the pressure vessel are 45" and 0.10", respectively. Req'd: Based on the maximum shear stress theory (Tresca) what is the factor of safety for the pressure vessel? |
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Solution: Based on the data the hoop and longitudinal stresses are: sH = pR/t = 36 ksi and sL = pR/2t = 18 ksi The maximum and minimum principal stresses are then: sI = sH =36 ksi and sIII = Out-of-Plane stress = 0 ksi The maximum shear stress is then: tmax = (36 MPa -0)/2 = 18 ksi Therefore, the factor of safety is: FS = ty/tmax = (35 ksi)/(18 ksi) = 1.94 |
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