고체역학 (Gere) — Axially Loaded Members: Problem 2.5-18

2.5-18 A steel wire \(AB\) is stretched between rigid supports (see figure). The initial prestress in the wire is 42 MPa when the temperature is 20°C. (a) What is the stress \(\sigma\) in the wire when the temperature drops to 0°C? (b) At what temperature \(T\) will the stress in the wire become zero? (Assume \(\alpha = 14 \times 10^{-6}/^\circ\text{C}\) and \(E = 200 \text{ GPa}\).)