Numerically predicted J-integral as a measure of crack driving force for steels 1.7147 and 1.4762

Fracture behavior of two types of steel (1.4762 and 1.7147) is compared based on their
numerically obtained J-integral values. The J-integral are chosen to quantify the crack
driving force using the finite element (FE) stress analysis applied to single-edge notched
bend (SENB) and compact tensile (CT) type fracture specimens. The resulting J-values are
plotted for growing crack length (a – crack length extension) at different a/W ratios (a/W
– relative crack length; 0.25, 0.5, 0.75). Slightly higher resulting values of the J-integral for
1.4762 than 1.7147 can be noticed. Also, higher a/W ratios correspond to lower J-integral
values of the materials and vice versa. J-integral values obtained by using the FE model of
the CT specimen give somewhat conservative results when compared with those obtained
by the FE model of the SENB specimen.