A finite strain contact model for mixed lubricated surfaces in forming processes

The model is formulated with respect to a convected reference frame, so to make it amenable for large deformation simulations. The numerical integration scheme of the resulting initial constitutive value problem is presented and implemented into an explicit finite element code. The mechanisms of the interface model have been separately tested and the numerical results correlate well with the available experimental findings. Comparisons with the Coulomb friction model are also provided. The applicability of the model for forming simulations is then demonstrated by reproducing the manufacturing of a ridge on an aluminum tube for the cosmetic industry, using the hydroforming technique. Both an elastomer and the fluid have been employed as pressure medium, and their performance has been compared in terms of the stresses and deformations produced in the finished product.