Consistent Modelling of Plasticity and Failure in the Process Chain of Deep Drawing and Crash with User Material Model MF-GenYld + CrachFEM for LS-DYNA

In automotive industry the need to build light weight structures with increased demands for passenger safety can be significantly supported by numerical simulation. However a correct material description is essential. For a correct prediction of failure behaviour of metallic materials in the crash simulation it can be necessary to consider the complete process chain of forming and crash. Today crash analysis cannot be performed with the same degree of discretization like in forming simulation. In order to transfer results between different meshes a mapping process of the relevant element variables has to be introduced. The user material model MF GenYld + CrachFEM has been developed at MATFEM as an universal material model which can be combined with finite element code LS-Dyna and other finite element codes with explicit-dynamic time integration scheme. The module MF GenYld describes the elastoplastic material behaviour. It has a modular structure which allows to combine different yield loci with a variety of hardening models. Besides different models for isotropic hardening, it includes advanced models for isotropic-kinematic hardening and anisotropic hardening. The comprehensive failure model CrachFEM allows to predict material failure due to localized necking (for shell discretization), ductile fracture and shear fracture. The models for ductile and shear fracture can be used consistently for shell and solid discretization. As the algorithm Crach for the prediction of localized necking requires information about the complete deformation history of an elementan orthotropic mapping is inevitable. Within this investigation the application of material model MF-GenYld+CrachFEM for forming and crash simulations is discussed. The technical background for the mapping of the deformation history is introduced.