(Solved): The section of shaf shown in the figure is to be designed to approximate relative sizes of d=0.75D ...

The section of shaf shown in the figure is to be designed to approximate relative sizes of $$d=0.75D$$ and $$r=D/20$$ with diameter $$d$$ conforming to that of standard rolling-bearing bore sizes. The shaf is to be made of SAE 2340 steel, heat-treated to obtain minimum strengths in the shoulder area of $$175\mathrm{kpsi}$$ ultimate tensile strength and $$160\mathrm{kpsi}$$ yield strength with a Brinell hardness not less than 370 . At the shoulder the shaf is subjected to a completely reversed bending moment of $$600\mathrm{lbf}$$ - in, accompanied by a steady torsion of $$400\mathrm{lbf}$$ - in. Use a design factor of 2.5 and sine the shan for an infinite life using the DE-ASME Elliptic criterion. Section of a shaf containing a grinding-reliel groove. Ualess otherwise specified, the dianeter at the root of the prowe $$d,?d?2r$$, and though the section of diameber $$d$$ is around, the root of the groove is still a machined sarface.