Impact of friction and grain shape on the morphology of sheared granular media

TL;DR

This study investigates how particle shape and friction influence the structural evolution of sheared granular materials, revealing complex behaviors like dilatancy, compaction, and morphological inhomogeneity.

Contribution

It provides new insights into the effects of friction and grain shape on particle alignment and packing density in sheared granular media.

Findings

Higher aspect ratio particles exhibit dilatancy or compaction under shear.

Particle alignment correlates with morphological inhomogeneity.

Dilatancy or compression dominates within shear bands depending on conditions.

Abstract

The interplay between dilatancy and particle alignment in sheared granular materials composed of non-spherical particles leads to morphological inhomogeneity. Dilatancy, driven by interparticle friction, causes the packing to expand, while particle alignment tends to densify it. We examine the influence of friction, particle aspect ratio, and initial packing conditions on the steady-state particle alignment and packing density. Unlike spherical particles, non-spherical particles with higher AR exhibit either dilatancy or compaction under shear, leading to spontaneous heaping or depression formation. We analyzed the evolution of packing density to identify whether dilatancy or compression prevails within the shear band.