Dislocation Glides in Granular Media

TL;DR

This study investigates whether dislocation glide occurs in granular media, revealing that at low friction, dislocations move easily, reducing yield stress, with a linear relationship between friction and yield stress.

Contribution

It demonstrates for the first time that dislocation glide can occur in granular media and quantifies its dependence on interparticle friction.

Findings

Dislocation glide occurs at low interparticle friction.

Yield stress decreases with increasing dislocation mobility.

Linear relationship between interparticle friction and yield stress.

Abstract

Atomic crystals with dislocations deform plastically at low stresses via dislocation glide. Whether dislocation glide occurs in macroscopic frictional granular media has remained unknown. The discrete element method is employed to simulate the structural and mechanical responses of a granular crystal with an edge dislocation. We find that dislocation glide occurs at low interparticle friction, resulting in significantly lower yield stresses than in dislocation-free crystals. Yield stress varies linearly with interparticle friction, attributed to both Peierls stress and frictional effect.