Transmission des forces dans un milieu compos\'e de grains non sph\'eriques

TL;DR

This study investigates how non-spherical (pentagonal) particles influence force transmission in dense granular packings, revealing unique anisotropy behaviors and force network structures compared to circular particles.

Contribution

It provides the first detailed comparison of force networks in pentagonal versus circular particle packings, highlighting shape effects on anisotropy and force chain characteristics.

Findings

Pentagon packings exhibit lower structural anisotropy than disk packings.

Higher force anisotropy compensates for lower structural anisotropy, enhancing shear strength.

Presence of a large class of very weak forces mainly carried by vertex-to-edge contacts.

Abstract

We perform a detailed analysis of the contact force network in a dense confined packing of pentagonal particles simulated by means of the contact dynamics method. The effect of particle shape 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 counterintuitive finding of this work is that, under steady shearing, the pentagon packing develops a lower structural anisotropy than the disk packing. We show that this weakness is compensated by a higher force anisotropy, leading to enhanced shear strength of the pentagon packing. We revisit "strong" and "weak" force networks in the pentagon packing, but our simulation data provide also evidence for a large class of "very weak" forces carried mainly by vertex-to-edge contacts. The strong force chains are mostly composed of edge-to-edge contacts with a marked zig-zag aspect and a decreasing exponential probability distribution as in a disk packing.