Application oriented failure modeling and characterization for polymers in automotive pedestrian protection

In the development process of automotive pedestrian protection (PedPro) for upper- and lower leg impact, the failure of polymer components plays an important role. To influence impact kinematics, fractures can either be advantageous or undesirable. Simulation based design is a challenge for material modeling and hence characterization, particularly for failure of polymer components. An application-oriented concept for failure modeling in FEM simulations of polymer components in pedestrian protection is presented. The boundary conditions for polymer failure in PedPro are investigated. Failure models are evaluated and selected by referring to special component tests, scanning-electron microscopy (SEM) of failure areas and simulative analysis of continuum mechanical parameters. The approach of capturing the material’s behavior and consecutive modeling including parametrization is presented as well. Here a polymer blend (PC-PET) is exemplarily characterized in the highly dynamic domain. This is mainly done by using innovative pendulum tests. The parametrization of a modified Bai-Wierzbicki failure approach is performed by a numerical optimization process. The model validation is done with more complex test samples by pendulum testing.