Particle simulations as a microscopic approach to a Cosserat continuum

Granular materials are characterized by their internal structure which is determined by the shape and size of the individual gains. Even if the ratio of a characteristic length related to a large ensemble of particles (macroscopic scale) and the average diameter of the grains itself (microscopic scale) allow for the application of a continuum theory, the macroscopic response is influenced by the structure on the microscale. Therefore, two natural kinds of theoretical descriptions arise, namely a macroscopic continuum mechanical approach and a microscopic one based on molecular dynamics. The goal of the present contribution is to formulate both kinds of models and to compare the results obtained by the different approaches.