Stress response inside perturbed particle assemblies

TL;DR

This study investigates how structural disorder affects stress transmission in 3D particle assemblies using simulations, revealing a transition from anisotropic to isotropic elastic responses as disorder increases.

Contribution

It provides a detailed simulation-based analysis of stress response evolution from weakly disordered to fully disordered particle packings.

Findings

Weakly disordered packings show double-peak force transmission.

Peak widths scale linearly with distance from perturbation source.

Fully disordered packings exhibit single-peak, isotropic response.

Abstract

The effect of structural disorder on the stress response inside three dimensional particle assemblies is studied using computer simulations of frictionless sphere packings. Upon applying a localised, perturbative force within the packings, the resulting {\it Green's} function response is mapped inside the different assemblies, thus providing an explicit view as to how the imposed perturbation is transmitted through the packing. In weakly disordered arrays, the resulting transmission of forces is of the double-peak variety, but with peak widths scaling linearly with distance from the source of the perturbation. This behaviour is consistent with an anisotropic elasticity response profile. Increasing the disorder distorts the response function until a single-peak response is obtained for fully disordered packings consistent with an isotropic description.