Force network ensemble: a new approach to static granular matter

TL;DR

This paper introduces a novel ensemble framework for analyzing force distributions in static granular materials, effectively capturing behaviors in disordered and regular packings and revealing a shear-induced unjamming transition.

Contribution

It presents a new ensemble approach based on force and packing scale separation, with an a-priori flat measure under force constraints, advancing the understanding of granular force networks.

Findings

Realistic force distribution results for disordered packings

Successful modeling of regular 'snooker ball' configurations

Identification of a shear-induced unjamming transition

Abstract

An ensemble approach for force distributions in static granular packings is developed. This framework is based on the separation of packing and force scales, together with an a-priori flat measure in the force phase space under the constraints that the contact forces are repulsive and balance on every particle. We show how the formalism yields realistic results, both for disordered and regular ``snooker ball'' configurations, and obtain a shear-induced unjamming transition of the type proposed recently for athermal media.