Q1. Determine the plastic moment Mp of a beam with the cross section shown when the beam is bent about the horizontal axis. Assume the material is elastoplastic with a yield strength of 240 MPa. 100 mm T 20 mm 60 mm 20 mm 80 mm 20 mm Q2. The box beam is made of an elastic perfectly plastic material for which y= 250 MPa. Determine the residual stress in the top and bottom of the beam after the plastic moment Mp is applied and then released. 25 mm 150 mm 25 mm 25 mm 150 mm 25 mm