Multiscale modelling of metal anisotropy using the viscoplastic self-consistent (VPSC) approach as a user-defined material model (UMAT) within LS-DYNA

Directional deformation processes of primary material, such as rolling and extrusion, lead to anisotropic mechanical properties of a workpiece. Such can be observed because of reoriented crystallographic grains, i.e. texture, along directions of preferred orientations. The anisotropy can strongly influence follow-up processes like deep drawing of metal sheets. Considering such properties in numerical simulations allows to investigate the effects of texture-dependent defects in forming processes. However, current applications of the finite-element (FE) method in forming simulations either neglect anisotropic material properties or incorporate a fixed texture by special material models. Often this is the case, because full-field crystal-plasticity (CP) FE models are too computationally demanding for industrial-relevant part sizes. This presentation shows the use of the visco-plastic self-consistent (VPSC) model as an efficient way of modelling a metal’s developing texture and mechanical response. Applying a multiscale approach by incorporating VPSC as a user-defined material model (UMAT) in the FE-solver LS-DYNA allows to consider texture evolution in large scale metal forming simulations. The resulting material properties of some simulated metal deformation processes are compared to experimental data to highlight the accuracy of the coupled FE-VPSC simulation model.