Plastic J-integral calculations using the load separation method for the center cracked tension specimen

The load separation method was used to determine the plastic work factor (ηpl) for the center crack tension geometry for power law hardening materials with Ramberg–Osgood hardening exponents n ranging from 2 to 20 and crack sizes a/W ranging from 0.4 to 0.8. The resulting expression for ηpl compares favorably to the analytical work of Rice, Paris, and Merkle and to Sharobeam and Landes. The results were also compared to ηpl calculated from the plastic J results in EPRI Handbook NP-1931. Unlike the EPRI results, ηpl from the load separation method are not a function of crack size.