Force networks and the dynamic approach to jamming in sheared granular media

TL;DR

This paper develops a rheological model for granular shear flow based on force chain networks, predicting flow regimes and scaling behaviors near the jamming transition, validated by simulations and experiments.

Contribution

It introduces a dynamic approach linking force networks to flow regimes and provides quantitative predictions for jamming behavior in granular media.

Findings

Identifies three flow regimes with distinct shear rate dependencies.

Quantitatively determines boundaries between flow regimes.

Predicts anomalous shear modulus scaling and shear strain at yield.

Abstract

Diverging correlation lengths on either side of the jamming transition are used to formulate a rheological model of granular shear flow, based on the propagation of stress through force chain networks. The model predicts three distinct flow regimes, characterized by the shear rate dependence of the stress tensor, that have been observed in both simulations and experiments. The boundaries separating the flow regimes are quantitatively determined and testable. In the limit of jammed granular solids, the model predicts the observed anomalous scaling of the shear modulus and a new relation for the shear strain at yield.