Effect of specimen geometry on the essential work of plane stress ductile fracture

Abstract

The effect of specimen geometry on the specific essential work of fracture for a low work hardening aluminium sheet metal alloy (AA2S) are investigated. Four different test geometries, viz. the deeply double edge notched PENT), centre-notched (DCNT), single edge notched (DSEN) and modified double edge notched (MDENT) tension specimens, are used to evaluate the essential works of fracture in the crack tip process zone for both crack initiation and propagation. It is shown that the specific essential work at fracture initiation ( w i ), which can be identified with J i , is independent of test peice geometries. Owing to specific problems associated with the DCNT and DSEN specimens during fracture propagation only the DENT and MDENT specimens are successful in yielding specific essential work measurements which are constant and which can be identified with J p for propagation. The experimental results given in this paper confirm that the specific essential work of plane stress ductile fracture is a fundamental material property being independent of specimen geometry.