Einfluss der Materialbeschreibung bei kurzzeitdynamischen Simulationsvorgängen

Working with LS-DYNA during the development of a new car, many different simulation tasks have to be performed. The overall aim is to improve the capability of a car to withstand certain impact levels, i.e. the displacements or the accelerations at specified points shall stay below certain limits. The protection of occupants and pedestrians is of main importance. During the structural optimisation process, many model parameters have to be variied to achieve the defined goals. Today it is possible to model the CAD of a structure with a fine and detailed FE-mesh, taking into account the geometrical dimensions as well as the boundary conditions. But it is often difficult to get proper material data. In this paper the influence of the quality of material data on the results of LSDYNA simulations will be discussed. Two small examples will be used to demonstrate the influence of material data compared to the variation of other model parameters. A simplified crash-box model is simulated for which a ‘quasi-danner’ loadcase is modelled. In a second example, the head impact on a hood structure is investigated (‚pedestrian protection’). This shall support the simulation engineer to get a feeling of how large the influence of lack of material data knowledge is, compared to other model inconsistencies.