Validation of advanced material models using the crossdie test

The crossdie test, i.e. deepdrawing with cross shaped tools, is used in industry to asses the formability of the sheet material. The strain path of the material in this test is non-proportional. The effect of strain path changes can be modelled with the Teodosiu & Hu model. Therefore this model is applied to describe the Bauschinger and cross hardening effects present in the crossdie test to improve the simulation results. Less ductile materials, such as high strength steels or aluminium, show already ductile damage before necking. Therefore damage should be included in the material models to predict failure accurately. An anisotropic continuum damage model is used to simulate the crossdie test. In this model damage is not a scalar but a second order tensor, which means that the softening has a different effect in different directions. Results of simulations using both advanced material models and a simple material model will be compared with a set of experimental data. The predictions of forming processes can be improved further if both damage and strain path changes are included in the simulations.