고체역학 (Gere) — Torsion: Problem R-3.8

R-3.8 A stepped steel shaft (\(G = 75 \text{ GPa}\)) with diameters \(d_1 = 36 \text{ mm}\) and \(d_2 = 32 \text{ mm}\) is twisted by torques \(T\) at each end. Segment lengths are \(L_1 = 0.9 \text{ m}\) and \(L_2 = 0.75 \text{ m}\). If the allowable shear stress is \(28 \text{ MPa}\) and maximum allowable twist is \(1.8^\circ\), the maximum permissible torque is approximately: (A) \(142 \text{ N}\cdot\text{m}\) (B) \(180 \text{ N}\cdot\text{m}\) (C) \(185 \text{ N}\cdot\text{m}\) (D) \(257 \text{ N}\cdot\text{m}\)