고체역학 (Gere) — Stresses in Beams (Basic Topics): Problem 5.5-2

5.5-2 A steel wire (\(E = 200 \text{ GPa}\)) of a diameter \(d = 1.25 \text{ mm}\) is bent around a pulley of a radius \(R_0 = 500 \text{ mm}\) (see figure). (a) What is the maximum stress \(\sigma_{\text{max}}\) in the wire? (b) By what percent does the stress increase or decrease if the radius of the pulley is increased by 25%? (c) By what percent does the stress increase or decrease if the diameter of the wire is increased by 25% while the pulley radius remains at \(R_0 = 500 \text{ mm}\)?