A wide sheet of steel contains a semi-circular edge notch (K, = 3.0) with a radius of 0.5 in. Determine the transition crack length, 1,, for this geometry using both the Dowling (Eq. (4.27)] and Smith-Miller (Eq. (4.28)] approximations. Estimate the crack propagation life, No, of the plate at a zero-to-maximum (R = 0) nominal stress loading of 0 to 40 ksi. Use Eq. (4.30) for this calculation. Compare the predicted lives found using the two estimates for transition crack length. How do these values compare to a life estimate using the approximation that the initial craci length is equal to the depth of the notch? For all calculations use a value of 1.58 in. for the final crack length, ag. The crack growth properties of the steel are
C = 2.96 x 10⁻⁹ m = 2.385