고체역학 (Beer) — Torsion: Problem 3.102

3.102 An 18-mm-diameter solid circular shaft is made of a material that is assumed to be elastoplastic with \(\tau_Y = 145 \text{ MPa}\) and \(G = 77.2 \text{ GPa}\). For a 1.2-m length of the shaft, determine the maximum shearing stress and the angle of twist caused by a 200-N·m torque.