Beer & Johnston — Stress and Strain—Axial Loading: Problem 2.57

2.57 An aluminum rod (\(E_a = 70 \text{ GPa}\), \(\alpha_a = 23.6 \times 10^{-6}/^\circ\text{C}\)) and a steel link (\(E_s = 200 \text{ GPa}\), \(\alpha_s = 11.7 \times 10^{-6}/^\circ\text{C}\)) have the dimensions shown at a temperature of \(20^\circ\text{C}\). The steel link is heated until the aluminum rod can be fitted freely into the link. The temperature of the whole assembly is then raised to \(150^\circ\text{C}\). Determine the final normal stress in (a) the rod, (b) the link.