고체역학 (Gere) — Stresses in Beams (Advanced Topics): Problem R-6.3

R-6.3 A steel pipe (\(d_3 = 104\text{ mm}\), \(d_2 = 96\text{ mm}\)) has a plastic liner with inner diameter \(d_1 = 82\text{ mm}\). The modulus of elasticity of the steel is 75 times that of the modulus of the plastic. Allowable stresses in steel and plastic are 40 MPa and 550 kPa, respectively. The allowable bending moment for the composite pipe is approximately: (A) 1100 N·m (B) 1230 N·m (C) 1370 N·m (D) 1460 N·m