Flow-Arrest Transitions in Frictional Granular Matter

TL;DR

This study investigates the transition between flowing and arrested states in frictional granular matter using simulations, revealing critical shear stress thresholds, bifurcations, and the influence of friction on arrest unpredictability.

Contribution

It introduces a detailed simulation analysis of shear arrest in granular matter, highlighting friction-dependent critical stresses and the statistical nature of arrest times.

Findings

Critical shear stress and density depend on friction.

Two steady states: shear flow and shear arrest.

Heavy-tailed distribution of arrest times with diverging mean and variance.

Abstract

The transition between shear-flowing and shear-arrested states of frictional granular matter is studied using constant-stress discrete element simulations. By subjecting a dilute system of frictional grains to a constant external shear stress and pressure, friction-dependent critical shear stress and density are clearly identified with both exhibiting a crossover between low and high friction. The critical shear stress bifurcates two nonequilibrium steady states: (i) steady state shear flow characterized by a constant deformation rate, and (ii) shear arrest characterized by temporally decaying creep to a statically stable state. The onset of arrest below critical shear stress occurs at a time $t_{c}$ that exhibits a heavy-tailed distribution, whose mean and variance diverge as a power law at the critical shear stress with a friction-dependent exponent that also exhibits a crossover between low and high friction. These observations indicate that granular arrest near critical shear stress is highly unpredictable and is strongly influenced by interparticle friction.