Plastic J-integral calculations using the load separation method for the double edge notch tension specimen

Abstract

The load separation method was used to determine the plastic work factor ( η pl) for the double edge notch tension (DENT) geometry for power-law hardening materials. The resulting expression for η pl compares favorably to the results of Rice, Paris, and Merkle. The results were also compared to η pl calculated from the plastic J results in EPRI Handbook NP-1931 and substantial differences were noted. A dependence on gage length was identified in the load separation results which indicate a gage length to half-width ratio of at least 3 is required to ensure that all of the plastic displacement is fully sensed and that η pl is independent of gage length. Additionally, a coupling term between crack size and material hardening exponent was identified in the geometric load separation function G.