고체역학 (Beer) — Pure Bending: Problem 4.24

4.24 A 60-N·m couple is applied to the steel bar shown. (a) Assuming that the couple is applied about the z axis as shown, determine the maximum stress and the radius of curvature of the bar. (b) Solve part a, assuming that the couple is applied about the y axis. Use E = 200 GPa.