Ductile failure modelling in pre-cracked solids using coupled fracture locus theory

Abstract

Ductile fracture locus models are extensively used in applied mechanics to predict the initiation of failure thanks to the ease of numerical implementation and simple calibration from experiments. Here, an attempt is made to investigate its potential to model complicated failure modes in pre-cracked structures. A tensile test specimen with a side notch and a pre-crack is fabricated from an off-the-shelf engineering aluminium alloy. Mechanical testing revealed two dissimilar failure patterns whose ambiguity is elaborated in the numerical study. The coupled fracture locus theory combined with the local damage/element deletion approach is adopted as a local failure modelling method. The numerical results show failure process predictions that are in accordance with experimentally observed failure modes in terms of the failure paths and the global force-displacement response. Fundamentally different failure processes, i.e. the mechanisms of strain localisation and classical crack propagation, have been rather well captured. These results suggest high predictive capabilities of the method employed, which captures well the stress-state dependent damaging process governing the development of the failure mode.