Free volume under shear

TL;DR

This study investigates how shear influences free volume distribution in hard-particle packings, revealing self-organization towards jammed states and contrasting thermal effects on structural features.

Contribution

It demonstrates that shear induces jammed-like free volume features in athermal packings, and thermalization erases these structural signatures, highlighting the role of shear and temperature.

Findings

Free volumes develop jammed-like features under shear.

Thermalization erases structural features.

Particle dynamics show a crossover from ballistic to diffusive.

Abstract

Using an athermal quasistatic simulation protocol, we study the distribution of free volumes in sheared hard-particle packings close to, but below, the random-close packing threshold. We show that under shear, and independent of volume fraction, the free volumes develop features similar to close-packed systems -- particles self-organize in a manner as to mimick the isotropically jammed state. We compare athermally sheared packings with thermalized packings and show that thermalization leads to an erasure of these structural features. The temporal evolution, in particular the opening-up and the closing of free-volume patches is associated with the single-particle dynamics, showing a crossover from ballistic to diffusive behavior.