Incorporating rolling resistance and contact anisotropy in micromechanical models of granular media

Recent findings from non-invasive experiments have shown that rolling resistance and contact anisotropy have a significant influence on the bulk behaviour of granular media. To date, however, there has been no generalised continuum model that accounts for both of these factors. In this paper, we propose a method by which rolling resistance and contact anisotropy may be introduced in a micropolar model of granular media. To capture key microstructures like shear bands, a homogenisation procedure on the scale of a particle and its local void space is developed.