Example: A mild steel shaft of 50 mm diameter is subjected to a bending moment of 2000 N-m and a torque T. If the yield point of the steel in tension is 200 MPa, find the maximum value of this torque without causing yielding of the shaft according to 1. the maximum principal stress. 2. The maximum shear stress. 3. the maximum distortion strain energy theory of yielding. 54 = = 200 MPa M=2000