a) The shaft shown in the figure is machined from AISI 1040 CD steel. The shaft rotates at 1600rpm and is supported in rolling bearings at A and B. The

applied forces are F, = 1200 lbf and F,= 2400 lbf. Determine the minimum fatigue factor of safety based on achieving infinite life. If infinite life is not predicted, estimate the number of cycles to failure. From Fig. A-15-9 with,r/d = 0.0625/1.625 0.04, D/d 1.875/1.625 1.15, K, =1.95 b) Solve the above problem except include a steady torque of 2200 lbf in being transmitted through the shaft between the points of application of the forces. Use the Goodman criterion. From the problem above we find the completely reversed stress at the critical shoulder fillet to be o = 32.8kpsi, producing o, = 32.8 kpsi and on = 0 kpsi