Improved Plasticity and Failure models for Extruded MgProfiles in Crash Simulations

Gernot Oberhofer (Sp), Harry Dell, Dmitri Dell, Helmut Gese MATFEM Partnerschaft Dr. Gese & Oberhofer Horst Lanzerath, Jürgen Wesemann Ford Forschungszentrum Aachen Elke Hombergsmeier EADS Corporate Research Center, München The Crash Simulation of Magnesium Structures with Finite Element Methods demands the use of suitable material and failure models. An associated plasticity model describing the complex asymmetric yield behaviour in tension and compression of Mg extrusions has been developed during the InMaK-project (Innovative Magnesium Compound Structures for Automobile Frames) supported by the German Federal Ministry for Education and Research (BMBF). Differences to the material model 124 in LS-DYNA are exposed. In order to describe the failure behaviour of Mg extrusions under multiaxial loading in FEM crash simulation this constitutive model has been combined with a fracture model for ductile and shear fracture. The fracture model has been added to the user defined constitutive magnesium model in LS-DYNA. The experimental investigations carried out on model components are compared with numerical derived results. Experimental methods for fracture parameter evaluation are shown and general aspects of metal failure due to fracture as well as different modelling techniques are discussed.