Résumé
Soft particles can be described by their shape degrees of freedom, i.e. particle-level deformations,contrasting therefore the general approach used in the conventional DEM based on strains whcih areassumed to be localized at the contact points between particles. Many materials such as pharmaceuticaland food products are composed of soft particles that can deform elastically or plastically under lowconfining pressure. To model the rheology of soft-particle materials, we use the Material Point Method(MPM) to calculate the particle strains and the Contact Dynamics Method (CDM) for the treatment ofunilateral contact and Coulomb friction law. MPM is adapted for large deformations and makes it possibleto avoid cumbersome remeshing (in FEM) of particles close to the contact regions. We apply this approachto investigate the compaction of an assembly of elastic or plastic particles [1-4]. In particular, we areinterested in the behavior beyond the jamming state as a function of material parameters including thefriction coefficient between particles, the Poisson ratio, and the plastic hardening parameter.