4a Impetus II - Neue Wege in der Materialcharakterisierung für die dynamische Simulation am Beispiel eines Schaumwerkstoffes

In this presentation new possibilities for the material characterization of foams are shown. Especially the presentation focuses on the testing system 4a Impetus and its interaction with LS-OPT. To determine meta-models, that describe the stress, strain and strain rate dependency, two principal ways are shown. On measured results of confor blue foam the parameter identification of a material description is conducted. With this material description and material law *MAT_Fu_Chang_Foam the tests were simulated and compared to the measurement. This was also done for the second way of meta-model building. The starting point is the stress, strain and strain rate points of different tests with different impact velocity. These points were used in LS-OPT to build up a neuronal net as a meta-model. These two ways can be automatically done by 4a impetus testing system, so that a whole process from measurement to a final material card exists. Finally the two ways for building a meta-model are compared. There could be found a good correlation between simulated and measured forces. The neuronal net meta-model reproduces the initial impact behavior, which was effected by the fluid flow in the foam. The disadvantage of the neuronal net is the unforeseeable prediction in unknown areas. It is also shown, how to implement LS-DYNA into this whole process. So it is possible to include simulation software related influences- like mesh size or hour glassing- in the material card determination.