Comparison of three different ductile damage models for deep drawing simulation of high-strength steels

Abstract

High-strength steels are increasingly used in deep drawing for automotive parts due to their improved strength properties. To increase the formability and thus extend the process limits, a deep drawing process with additional force transmission has been developed. For a numerical optimisation of the considered process, an exact modelling of the failure behaviour is essential. The forming limit curve (FLC) is widely used to predict the onset of necking in sheet metal forming. However, the validity of the FLC is limited to the case of linear strain paths. Therefore, the scope of past investigations has been on failure modelling depending on the stress state. This article presents the experimental-numerical characterisation of the failure behaviour of the high-strength steels HCT600X and HX340LAD. Tensile tests with butterfly specimens were carried out under varying stress states and simulated with ABAQUS to parametrise the stress-based models Johnson-Cook (JC), Modified Mohr-Coulomb (MMC) and DF2016. An additional experiment was carried out to evaluate the models in terms of predicted outcome accuracies by comparing the onset of fracture in the simulation with the experimental findings. In future investigations, the improved damage modelling will be applied in a deep drawing simulation with additional force transmission to optimise the process design.