Material is the same as for Problem 1. Let the loading be as follows:σav = 29,000 psi, σr...

Material is the same as for Problem 1. Let the loading be as follows:

σav = 29,000 psi, σr = 16,216 psi, for 0.45 of the time  

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σav = 35,000 psi, σr = 14,830 psi, for 0.30 of the time

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σav = 42,000 psi, σr, = 14,147 psi, for 0.25 of the time

Find the expected number of reversals N to failure.

Problem 1

A steel has a tensile strength of 90,000 psi and an endurance limit of 33,000 psi for a machined surface.

(a) For loading in the finite life range, find the value of constants A and B.

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(b) For σavg = 30,000 psi, σr = 16,565 psi, and K = 1.4 find the value of σR, the equivalent completely reversing stress.

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(c) Calculate the expected number of reversals to failure for the stresses of part (b).