Parametric Modelling of Simplified Car Models for Assessment of Frontal Impact Compatibility

The aim of the FIMCAR project (co-funded by the European Commission within the 7th Framework Programme) is to develop and validate a frontal impact assessment approach that considers self and partner protection. In order to assess the influence of different test procedures and metrics on car- to-car compatibility a huge simulation programme is envisaged. However, car-to-car simulations with models of different car manufacturers are almost impossible because of confidentiality. In addition the detailed models of the car manufacturers are complicated to optimise for different assessment procedures and are consuming considerable computational efforts. In order to overcome these problems, parametric car models were built allowing fast modifications. By simplifying the models, computational efforts are reduced. Due to the rapid increase of the calculation power the level of detail in car models has reached a very high level. At the same time the number of discretised parts drops and smaller structures are considered in the meshing process. However, only a few structures are mainly responsible for the frontal crash behaviour of the vehicle. A high variability of mounting positions, connections and stiffness of parts of a car’s front–end offers a big potential in investigations of frontal impact vehicle structures. However, the modification of these criteria is time consuming, especially the modification of a given FE-mesh or geometry model. The software SFE CONCEPTTM offers the possibility to establish an implicit parametric car model in an easy and fast way. A variable geometric model is created by the specification of base lines and cross sections for the different parts. The modification of a structure with respect to connected parts is one of the advantages of SFE CONCEPTTM. Through manipulation of the implicit parameters, new structure concepts and /or small variations of a part’s dimensions can be established. After all the software is able to mesh the geometry and export the data for different solvers like LS-Dyna. In that way it is possible to generate a manifold number of structures, in a fast and certain way which is necessary for the investigations of the influence of these structures in frontal impact compatibility. The set up of the FE model is adapted to the export data structure of SFE CONCEPTTM. This way the models can be simulated directly after modification without further post-editing.