고체역학 (Beer) — Stress and Strain—Axial Loading: Problem 2.102

2.102 The cylindrical rod AB has a length L = 6 ft and a 1.25-in. diameter; it is made of a mild steel that is assumed to be elastoplastic with \(E = 29 \times 10^6\) psi and \(\sigma_Y = 36\) ksi. A force P is applied to the bar until end A has moved down by an amount \(\delta_m\). Determine the maximum value of the force P and the permanent set of the bar after the force has been removed, knowing (a) \(\delta_m = 0.125\) in., (b) \(\delta_m = 0.250\) in.