4a impetus is a system especially designed for characterization of materials that are dynamically loaded. After evaluation of the test results dynamic material cards can be generated regarding complex material behavior such as strain rate dependency and tension/compression-asymmetry. The material characterization is done by reverse engineering. The procedure is as follows:
The measurement setup is built up as FE-model and the material card is parameterized for the simulation. In the simulation the test is calculated in such a way that the difference between test and simulation is continuously decreased by optimizing the parameters of the material card. If a minimum is reached the resulting material parameters are the best for your material.
When creating a material card for foams that are tested by compression tests a meta model is generated by a neuronal network. Cuts of the meta model at constant strain rates give you the material card. The picture shows an example for such a meta model.