Fluctuating particle motion during shear induced granular compaction

TL;DR

This study uses a refractive index matching method to analyze particle trajectories in 3D granular packings under cyclic shear, revealing non-diffusive, cage-like motion and linking microscopic behavior to macroscopic compaction.

Contribution

It provides detailed microscopic insights into particle dynamics during shear-induced granular compaction, highlighting the transient cage effect and its relation to shear amplitude.

Findings

Particle trajectories show transient cage effects similar to colloidal glasses.

Step size between cycles is proportional to shear amplitude.

Microscopic particle motion correlates with macroscopic volume fraction changes.

Abstract

Using a refractive index matching method, we investigate the trajectories of particles in a three dimensional granular packing submitted to cyclic shear deformation. The particle motion observed during compaction is not diffusive but exhibits transient cage effect, similar to the one observed in colloidal glasses. We precisely study the statistics of the step size between two successive cycles and observe that it is proportional to the shear amplitude. The link between the microscopic observations and the macroscopic evolution of the volume fraction during compaction is discussed.