A structural component in the shape of a flat plate 29.6 mm thick is to be fabricated from a metal alloy for which the yield strength and plane strain fracture toughness values are 535 MPa and 38.5 MPa-m1/2, respectively. For this particular geometry, the value of Y is 1.5. Assuming a design stress of 0.5 times the yield strength, calculate the critical length of a surface flaw. mm