4a impetus - efficient evaluation of material cards for non-reinforced and reinforced thermoplastics

LS-DYNA© has included plenty of material cards, each of them offering different scalability and complexity to describe the behavior of non- reinforced thermoplastics. The consideration of the strain rate behavior is included in many material cards, e.g. in the well known MAT_PICEWISE_LINEAR_PLASTICITY. More complex material models can also handle varying compression and tension behavior as well as unloading by using damage functions. One of the recent development results is MAT-SAMP-1 by Du Bois, Kolling, Feucht and Haufe. This specially developed material model for polymers includes a yield surface out of different loading cases and a damage function for better description of unloading. For better use of the above mentioned models a huge amount of tests have to be carried out, to determine the material parameters and to represent the thermoplastic characteristics in crashworthiness simulations. 4a impetus builds up an efficient and reliable process, starting with realistic tests and finally ending up with a validated material card. Recent developments of new test methods for 4a Impetus are presented, that satisfy the needs of complex material models as well as the expectations with regard to easy and favorable testing. Limits and opportunities of different test methods and material card implementations are shown and compared to each other especially focused on typical polymer behavior. Finally the influence of fiber reinforcement is discussed and solutions to determine material parameters by using micro mechanic models (4a MicroMec) are shown.