Broad stress triaxiality ratio band fracture experiments in DP900 metal sheets and corresponding predictive capability of advanced phenomenological and micromechanical fully coupled damage models

Correct prediction of the fracture time and location and their evolution in metallic materials has always been a research hotspot in the field of metal forming. To this end, and in the context of metal forming process simulation, an advanced mathematical material model is crucial. In this paper, we investigate the accuracy of two fully-coupled damage models, one of which is phenomenologically-based and the other one micromechanically-based, in predicting the failure in DP900 steel plates subject to various loading paths. These are applied throughout tests, including tensile tests on unnotched and notched specimens with different notch radii as well as butterfly wing shear tests. Through the comparisons of the numerical and experimental results, in terms of force-displacement curves and fracture strains (or ductility) under wide range of strain paths, the accuracy of the proposed two coupled damage models are discussed.