A new ductile failure criterion with stress triaxiality and Lode dependence

Abstract

An accurate failure criterion is crucial for mechanical and structural design. In this paper, the effects of three stress invariants on material failure are studied based on microscopic mechanisms. A new ductile failure criterion that accounts for the influence of stress triaxiality and normalized third invariant of deviatoric stress tensor is proposed. The parameters in the new failure criterion are analyzed to determine their effects on the failure loci. The new proposed failure criterion is calibrated with a series of test results on 2024-T351 aluminum alloy, TRIP690 steel and additively manufactured Ti-6Al-4V. The results demonstrate that the new criterion can predict the failure loci of these materials with high accuracy. Comparisons with three criteria indicate that the new failure criterion has a broader application than Lou-Huh criterion and extended Mohr–Coulomb criterion for the above three materials.