Using annealed Type 304 stainless steel plate specimens containing ellipsoidal, rectangular, or triangular-shaped surface flaws, critical values of J are calculated for three separate situations: (1) the assumption that the specimen consists of a single-edge notch (SEN) and two unflawed specimens, (2) the prediction of an equivalent-length through-thickness defect for the surface flaw, and (3) the use of an equation developed by Paris. It was concluded that J_init (Charpy specimen) and J_Ic cannot be used to successfully predict structural integrity using any of the three approaches for the 6.4-mm-thick (0.25-in.) annealed Type 304 stainless steel.

Since it was not possible to develop a comparison between the absolute values of J_init (from the surface-flawed specimen) and J_Ic, an attempt was made to evaluate a possible relative agreement. Values of J_init and J_pen from only those specimens containing rectangular-shaped defects were used to calculate ΔJ/Δα. The average values agree reasonably well with those obtained in the open literature.