고체역학 (Beer) — Torsion: Problem 3.137

3.137 A 4-m-long steel member has a W310 × 60 cross section. Knowing that \(G = 77.2 \text{ GPa}\) and that the allowable shearing stress is \(40 \text{ MPa}\), determine (a) the largest torque \(T\) that can be applied, (b) the corresponding angle of twist. Refer to Appendix E for the dimensions of the cross section and neglect the effect of stress concentrations. (Hint: Consider the web and flanges separately and obtain a relation between the torques exerted on the web and a flange, respectively, by expressing that the resulting angles of twist are equal.)