You can use linear elastic isotropic and bilinear von Mises plasticity material models. Unlike materials with linear elastic formulation, von Mises plastic materials can incur permanent deformation due to the impact. You can specify to use the small or large displacement formulation in the properties of the study. The default is to use large displacement formulation (nonlinear solution) for all studies. If all the materials are linear elastic, you can specify small displacement. The large displacement formulation is always used if you have any von Mises plastic materials in the model.