A two-scale model of granular materials using a coupled DE-FE approach

Granular materials are typically modeled as continuum by describing their mechanical behavior in terms of phenomenological constitutive equations. While this approach enables the solution of engineering scale problems via e. g. the Finite Element Method (FEM), it is inappropriate to model localizations where the deformation concentrates in small domains. An alternative approach is the Discrete Element Method (DEM) which models the individual grains’ motion resulting from their interactions via mechanical contact but suffers from high computational costs. Within this work a two-scale model is developed which combines the advantages of both approaches by modeling localization domains by the DEM and the remaining domains by the FEM. The two-scale model is based on a coupling scheme which enables a smooth transition of the fields between the discrete and the continuous domains and which does not disturb the force-chain microstructure within the discrete part.