Beer & Johnston — Stress and Strain—Axial Loading: Problem 2.106

2.106 Rod $ABC$ consists of two cylindrical portions $AB$ and $BC$; it is made of a mild steel that is assumed to be elastoplastic with $E = 200 \text{ GPa}$ and $\sigma_Y = 250 \text{ MPa}$. A force $P$ is applied to the rod until its end $A$ has moved down by an amount $\delta_m = 5 \text{ mm}$. Determine the maximum value of the force $P$ and the permanent set of the rod after the force has been removed.