Observation of strain-rate softening behavior in jammed granular media

Fuente: arXiv
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Main Authors: Liu, Mingchao, Mao, Weining, Zhao, Yiqiu, Xu, Qin, Gan, Yixiang, Wang, Yifan, Hsia, K Jimmy
Format: Preprint
Published: 2024
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author Liu, Mingchao
Mao, Weining
Zhao, Yiqiu
Xu, Qin
Gan, Yixiang
Wang, Yifan
Hsia, K Jimmy
author_facet Liu, Mingchao
Mao, Weining
Zhao, Yiqiu
Xu, Qin
Gan, Yixiang
Wang, Yifan
Hsia, K Jimmy
contents The strain-rate sensitivity of confined granular materials has been widely explored, with most findings exhibiting rate-strengthening behaviors. This study, however, reveals a distinct rate-softening behavior across a certain strain rate range based on triaxial tests on particle clusters of various materials with different surface properties, particle sizes, shapes, and stiffness. This softening effect is especially pronounced in the case of common rice particles. By examining the behavior of rice particles under different confining pressure and surface conditions, and directly measuring the frictional coefficient across various loading rates, we find that the reduction in surface frictional coefficient with the increasing strain rate predominantly contributes to this rate-softening behavior. This conclusion is validated by results from Finite Element Method (FEM) simulations. Additionally, we identify confining pressure as a critical factor regulating the normal stress between particles, and thereby enhancing frictional behavior. Rheometer tests reveal that the shear modulus exhibits a similar rate-softening trend. This study of rate-softening behavior in granular materials enhances our understanding of the mechanisms during their deformation under confining pressure. It also suggests that local inter-particle tribology significantly impacts overall granular behavior.
format Preprint
id arxiv_https___arxiv_org_abs_2404_19321
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Observation of strain-rate softening behavior in jammed granular media
Liu, Mingchao
Mao, Weining
Zhao, Yiqiu
Xu, Qin
Gan, Yixiang
Wang, Yifan
Hsia, K Jimmy
Soft Condensed Matter
Applied Physics
The strain-rate sensitivity of confined granular materials has been widely explored, with most findings exhibiting rate-strengthening behaviors. This study, however, reveals a distinct rate-softening behavior across a certain strain rate range based on triaxial tests on particle clusters of various materials with different surface properties, particle sizes, shapes, and stiffness. This softening effect is especially pronounced in the case of common rice particles. By examining the behavior of rice particles under different confining pressure and surface conditions, and directly measuring the frictional coefficient across various loading rates, we find that the reduction in surface frictional coefficient with the increasing strain rate predominantly contributes to this rate-softening behavior. This conclusion is validated by results from Finite Element Method (FEM) simulations. Additionally, we identify confining pressure as a critical factor regulating the normal stress between particles, and thereby enhancing frictional behavior. Rheometer tests reveal that the shear modulus exhibits a similar rate-softening trend. This study of rate-softening behavior in granular materials enhances our understanding of the mechanisms during their deformation under confining pressure. It also suggests that local inter-particle tribology significantly impacts overall granular behavior.
title Observation of strain-rate softening behavior in jammed granular media
topic Soft Condensed Matter
Applied Physics
url https://arxiv.org/abs/2404.19321