A 1-in-diameter solid round bar is made of AISI 1040 CD steel (sy= 71 kpsi, su = 85 kpsi ). It is

operating at a temperature of 300°F, and is subjected to a purely reversing torque of 2000 lbf.in.

Estimate the number of cycles to failure if the expected reliability is 99%. Redo the solution for a

reversing torque of 8500 lbf.in.

Note: The Von Mises stress for pure torsion would be o' = √37²