Numerical modelisation of granular media by the bipotential approach

A 20 numerical simulation of the contact dynamics is presented: moving rigi d circular cylinders can run into themselves or into surrounding walls and are subjected to friction forces during these collisions. The interaction b etween cylinders is described by the unilateral contact law with Coulomb's friction. Using the contact bipotential leads to an algorithm of resolution based on a predictor-corrector scheme by projection on friction cone and a convergence criterion based on the estimator of relative error in constitu tive law. The applications show the convergence and the robustness of the a lgorithm. (C) Academie des sciences/Elsevier, Paris.