고체역학 (Gere) — Torsion: Problem R-3.11

R-3.11 Torques \( T = 5.7 \, \text{kN}\cdot\text{m} \) are applied to a hollow aluminum shaft (\( G = 27 \, \text{GPa} \) and \( d_1 = 52 \, \text{mm} \)). The allowable shear stress is \( 45 \, \text{MPa} \) and the allowable normal strain is \( 8.0 \times 10^{-4} \). The required outside diameter \( d_2 \) of the shaft is approximately: (A) 38 mm (B) 56 mm (C) 87 mm (D) 91 mm