고체역학 (Gere) — Stresses in Beams (Advanced Topics): Problem 6.10-11

6.10-11 A hollow box beam with height \(h = 300 \text{ mm}\), width \(b = 100 \text{ mm}\), and constant wall thickness \(t = 15 \text{ mm}\) is shown in the figure. The beam is constructed of steel with yield stress \(\sigma_Y = 210 \text{ MPa}\). Determine the yield moment \(M_Y\), plastic moment \(M_P\), and shape factor \(f\).