A plastic-lined steel pipe has the cross-sectional shape shown in the figure. The steel pipe has outer diameter d3= 100 mm and inner diameter d2= 94 mm. The plastic liner has inner diameter d1= 82 mm. The modulus of elasticity of the steel is 75 times the modulus of the plastic.
Determine the allowable bending moment Mallow if the allowable stress in the steel is 35 MPa and in the plastic is 600 kPa.
