(20%) A shaft, made of AISI 1050 CD steel, is loaded in bending and torsion such that Ma = 610 lbf · in, Ta= 375 lbf · in, Mm =

469 lbf · in, and Tm = 287 lbf · in. The shaft has a fully corrected endurance limit of Se = 30 kpsi and at the critical stress location, Kf= 2.3 and K= 1.9. Estimate the true fracture strength as being 50 k psi greater than the ultimate strength. The design factor is 2.5. Determine the minimum acceptable diameter of the shaft using the DE-Goodman criterion.