Résumé
Numerous materials are made of a disordered arrangement of soft grains, a characteristic preva-lent in various substances such as food products, metal powders, colloidal suspensions, and clays.Unlike hard-grain models, the interaction between disorder and grain deformations in these materialsresults in unique physical and mechanical properties. The notable deformability of soft grains underlow confining pressure enables packing fractions to exceed the random close packing of hard grains.Consequently, rheological properties like compressibility and shear strength, as well as microstructurecharacteristics, are governed by a combination of grain rearrangements, and grain shape and volumechanges. Indeed, the diverse forms of the microstructure depend on grain properties (compressibility,plasticity...) and interaction forces (friction, adhesion...) between grains.In this work, to model the rheology and microstructure of soft granular systems, we use theMaterial Point Method (MPM) to compute the grain deformations and the Contact Dynamics Method(CDM) for the treatment of inter-grain interactions [1, 2, 3, 4]. An example of a deformed sample isshown in Fig. 1. We apply this approach to investigate the compaction of an assembly of elastic orplastic particles. In particular, we are interested in the behavior beyond the jamming state as a functionof material parameters including the friction and cohesion between grains, and the strain rate loading.