Homogeneity and packing structure of a 2D sheared granular system

This work focuses on the homogeneity and packing structure in a 2D granular system subjected to a novel bottom-assisted shear. While traditional boundary-driven shear experiments always induce inhomogeneities in the form of localized shear bands, our novel shear apparatus successfully prevents the formation of shear bands by incorporating a controlled deformable base and creatively utilizing the particle-base friction. We studied homogeneity of this sheared granular system using both non-affine particle displacements and the coarse-grained density field. Both methods present signatures of a homogeneous system, even under large amounts of shear. By applying Voronoi tesselation to the packing, we also determined local densities on the particle scale. The statistics of this Voronoi density are then studied, and under a simple scaling, a collapse of the local density distribution is found for different shear strains and different densities.