고체역학 (Beer) — Torsion: Problem 3.105

3.105 A solid circular rod is made of a material that is assumed to be elastoplastic. Denoting by \(T_Y\) and \(\phi_Y\), respectively, the torque and the angle of twist at the onset of yield, determine the angle of twist if the torque is increased to (a) \(T = 1.1 T_Y\), (b) \(T = 1.25 T_Y\), (c) \(T = 1.3 T_Y\).