Influence of particle shape on shear stress in granular media

TL;DR

This study investigates how particle shape influences shear stress in granular media, revealing that pentagonal particles exhibit lower structural anisotropy but higher force anisotropy, resulting in increased shear strength.

Contribution

It demonstrates that polygonal particle shape affects force chain structure and shear strength, providing new insights into granular material behavior based on particle geometry.

Findings

Pentagon packing has lower structural anisotropy than disk packing.

Pentagon packing exhibits higher force anisotropy, enhancing shear strength.

Force chains in pentagons are mainly edge-to-edge with zig-zag patterns.

Abstract

We analyze the contact and force networks in a dense confined packing of pentagonal particles simulated by means of the contact dynamics method. The particle shape effect is evidenced by comparing the data from pentagon packing and from a packing with identical characteristics except for the circular shape of the particles. A surprising observation is that the pentagon packing develops a lower structural anisotropy than the disk packing. We show in this work that this weakness is compensated by a higher force anisotropy that leads to enhanced shear strength of the pentagon packing. With the polygonal shape of the particles, the strong force chains are mostly composed of edge-to-edge contacts with a marked zig-zag aspect.