A rotating shaft is made of 42 mm OD and 4-mm thick AISI 1018 cold-drawn steel tubing. It has has a 6-mm-diameter hole drilled transversely through it. Your colleague did some research to find out the corrected fatigue strength for this specific part to be 165 MPa. The Sut value is 440 MPa. He also found that the fatigue stress concentration factors: kf = kfm = 2.2 and kfs = kfsm = 1.7
Estimate the factor of safety guarding against fatigue failure for the following loading conditions:
(a) The shaft is subjected to a completely reversed torque of 120 N • m in phase with a completely reversed bending moment of 150 N • m.