A comparison of critical stress intensity parameter with other nonlinear toughness parameters

In structural steels, the two nonlinear toughness parameters, i.e. Rice's J-integral and Liebowitz's G have been evaluated over a wide range of yield strength varying from 235 to 1035 MPa. The K toughness parameter has also been obtained by applying an iterative plasticity correction. The three toughness parameters have been compared and the thickness regime, over which a valid K_Ic can be obtained, has been identified.