고체역학 (Gere) — Torsion: Problem 3.3-1

3.3-1 A solid steel bar of circular cross section has diameter \(d = 63\text{ mm}\), \(L = 1.5\text{ m}\), and shear modulus of elasticity \(G = 80\text{ GPa}\). The bar is subjected to torques \(T = 1.4\text{ kN}\cdot\text{m}\) at the ends. Calculate the angle of twist between the ends. What is the maximum shear stress and the shear stress at a distance \(r_A = 25\text{ mm}\) measured from the center of the bar?