고체역학 (Gere) — Stresses in Beams (Advanced Topics): Problem 6.10-15

6.10-15 The hollow box beam shown in the figure is subjected to a bending moment M of such magnitude that the flanges yield but the webs remain linearly elastic. (a) Calculate the magnitude of the moment M if the dimensions of the cross section are \(h = 350 \text{ mm}\), \(h_1 = 310 \text{ mm}\), \(b = 200 \text{ mm}\), and \(b_1 = 175 \text{ mm}\). Also, the yield stress is \(\sigma_Y = 220 \text{ MPa}\). (b) What percent of the moment M is produced by the elastic core?