A simulation of cold-roll forming for elastoplastic materials (Q1384338)

In our formulation, the metal sheet is considered as a thin shell, and its middle surface is described as a Coons patch depending on one geometrical parameter. Moreover, the material satisfies a constitutive rate equation in which the corotational rate of stress is used. We use the Prandtl-Reuss model, including the von Mises yield criterion and the normality flow rule. In order to integrate the elastoplastic constitutive equations, a radial return scheme is adapted so that the plastic power rate is calculated using a Gauss method. Its minimization gives the optimal shape for a strain hardening elastoplastic material, as well as the optimal velocity field. This approach has been implemented on a workstation and, as for rigid-plastic materials, it gives a very fast simulation of the cold-roll forming process.