The calibration of the MMC damage model under various hardening models and yielding criterions for DP800 steel

The use of Finite Element Analysis (FEA) in sheet metal forming processes has been increasing day by day. In recent studies, damage models that feature the effects of Lode angle parameter and stress triaxiality have been widely used in predicting fracture onset in sheet metals. However, the selection of the hardening model and yielding criterion can have significant impacts on the created fracture surface, and if not calibrated accurately, it can lead to erroneous fracture predictions. In this study, Modified Mohr-Coulomb (MMC) damage model has been calibrated for DP800 steel by using two different hardening models (Hollomon and Voce) and two different yielding criterions (Von-Mises and Hill-48). The effects of the hardening models and the yielding criterions on the predicted fracture surface of MMC have been investigated. Their prediction capability of the force-displacement curves for different deformation modes (uniaxial tension, plane strain and shear) have been compared. According to the results, it has been shown that both hardening models are accurate in their predictions up to 6% error, however, in addition to its accuracy in predicting force-displacement behaviours, the Voce hardening model has also been more successful in its fracture surface predictions.