Particle scale anisotropy controls bulk properties in sheared granular materials

Fuente: arXiv
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Autori principali: Lee, Carmen L., Bililign, Ephraim, Azéma, Emilien, Daniels, Karen E.
Natura: Preprint
Pubblicazione: 2024
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author Lee, Carmen L.
Bililign, Ephraim
Azéma, Emilien
Daniels, Karen E.
author_facet Lee, Carmen L.
Bililign, Ephraim
Azéma, Emilien
Daniels, Karen E.
contents The bulk dynamics of dense granular materials arise through a combination of particle-scale and mesoscale effects. Theoretical and numerical studies have shown that collective effects are created by particle-scale anisotropic structures such as grain connectivity (fabric), force transmission, and frictional mobilization, all of which influence bulk properties like bulk friction and the stress tensor through the Stress-Force-Fabric (SFF) relationship. To date, establishing the relevance of these effects to laboratory systems has remained elusive due to the challenge of measuring both normal and frictional contact forces at the particle scale. In this study, we perform experiments on a sheared photoelastic granular system in an quasi-2D annular (Couette) cell. During these experiments, we measure particle locations, contacts, and normal and frictional forces vectors during loading. We reconstruct the angular distributions of the contact and force vectors, and extract the corresponding emergent anisotropies for each of these metrics. Finally, we show that the SFF relation quantitatively predicts the relationship between particle scale anisotropies, the stress tensor components, and the bulk friction coefficient, capturing even transient behaviors. As such, this method shows promise for application to other dense particulate systems where fabric anisotropy can provide a useful measure of bulk friction.
format Preprint
id arxiv_https___arxiv_org_abs_2405_00653
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Particle scale anisotropy controls bulk properties in sheared granular materials
Lee, Carmen L.
Bililign, Ephraim
Azéma, Emilien
Daniels, Karen E.
Soft Condensed Matter
The bulk dynamics of dense granular materials arise through a combination of particle-scale and mesoscale effects. Theoretical and numerical studies have shown that collective effects are created by particle-scale anisotropic structures such as grain connectivity (fabric), force transmission, and frictional mobilization, all of which influence bulk properties like bulk friction and the stress tensor through the Stress-Force-Fabric (SFF) relationship. To date, establishing the relevance of these effects to laboratory systems has remained elusive due to the challenge of measuring both normal and frictional contact forces at the particle scale. In this study, we perform experiments on a sheared photoelastic granular system in an quasi-2D annular (Couette) cell. During these experiments, we measure particle locations, contacts, and normal and frictional forces vectors during loading. We reconstruct the angular distributions of the contact and force vectors, and extract the corresponding emergent anisotropies for each of these metrics. Finally, we show that the SFF relation quantitatively predicts the relationship between particle scale anisotropies, the stress tensor components, and the bulk friction coefficient, capturing even transient behaviors. As such, this method shows promise for application to other dense particulate systems where fabric anisotropy can provide a useful measure of bulk friction.
title Particle scale anisotropy controls bulk properties in sheared granular materials
topic Soft Condensed Matter
url https://arxiv.org/abs/2405.00653