2. A SENB 25 mm wide and 10 mm thick contains a through-thickness crack of length 4.5 mm. The span between the end supports S = 135 mm. Assuming plane strain condition, determine the critical load P at failure if the material has a Jc = 500 kJ/m. Given: =450 MPa, &* == E ,a=1.2, n= n = 10.0, E = 200 GPa, v = 0.3