Evolution of the force distributions in jammed packings of soft particles

Abstract

The evolution of the force distributions during the isotropic compression of two dimensional packings of soft frictional particles is investigated numerically. Regardless of the applied deformation, the normal contact force distribution can be fitted by the product of a power-law, and a stretched exponential, while the tangential force distribution is fitted well by a Gaussian. With increasing strain, the asymptotic behavior at large forces does not change, but both normal and tangential distributions exhibit a broadening, even though, when scaled with the average forces, their widths decrease. Furthermore, the distribution of friction mobilization is a decreasing function of the mobilization, except for an increased probability of fully mobilized contacts. The excess coordination number of the packings increases with the applied strain, indicating that the more a packing is compressed the more stable it becomes.