Knowing that for the extruded beam shown in Figure 1, the allowable stress is 120 MPa in tension and 150 MPa in compression, determine the largest couple M that can be applied. PROBLEM 2 A copper strip (Ec =105 GPa) and an aluminium strip (Ea = 75 GPa) are bonded together to form the composite bar shown in Figure 2. Knowing that the bar is bent about a horizontal axis by a couple of moment 35 N·m, determine the maximum stress in (a) the aluminium strip, (b) the copper strip and (c) the radius of curvature caused by the couple