Linking the macro-scale response of granular materials during drained cyclic loading to the evolution of micro-structure, contact network and energy components
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Published version
Author(s)
Sassel, Tara
Patino-Ramirez, Fernando
Hanley, Kevin
O'Sullivan, Catherine
Type
Journal Article
Abstract
This study has considered the behaviour of granular materials subjected to drained cyclic loading under constant mean effective stress. Using the discrete element method, cubical, isotropically compressed samples were subjected to 50 loading cycles at different values of mean stress (p′=
100, 200, 300 kPa) and different loading amplitudes (ζ=
5%, 10% and 20% of p′
). At low cycle numbers, the deformation mechanism is controlled by contractive volumetric strains, before transitioning to the ratcheting regime, characterised by the persistent accumulation of plastic strains. An energy/work analysis showed that the volumetric work per cycle decreased as hysteresis loops tighten. During ratcheting, most boundary work was dissipated by contact sliding. The mechanical response was controlled by ζ
, with little to no influence of p′
. For ζ=5%
, deformations were confined to the elastic range, with no increase in secant stiffness Gsec
or shear strength after cyclic loading. For ζ=10%
, Gsec
and the shear strength increased after cyclic loading, although no significant expansion of the yield surfaces was observed. The largest loading amplitude (ζ=20%
) induced yielding at low cycles, leading to significant changes in the fabric, volume and yield surfaces of the samples, and a significant increase of shear strength and Gsec
. At the micro-scale, graph theory was used to quantify the evolution of the contact network. After ∼20
loading cycles, the network reached a steady-state of constant but persistent topology changes in the material, with most of the topology retained between loading cycles.
100, 200, 300 kPa) and different loading amplitudes (ζ=
5%, 10% and 20% of p′
). At low cycle numbers, the deformation mechanism is controlled by contractive volumetric strains, before transitioning to the ratcheting regime, characterised by the persistent accumulation of plastic strains. An energy/work analysis showed that the volumetric work per cycle decreased as hysteresis loops tighten. During ratcheting, most boundary work was dissipated by contact sliding. The mechanical response was controlled by ζ
, with little to no influence of p′
. For ζ=5%
, deformations were confined to the elastic range, with no increase in secant stiffness Gsec
or shear strength after cyclic loading. For ζ=10%
, Gsec
and the shear strength increased after cyclic loading, although no significant expansion of the yield surfaces was observed. The largest loading amplitude (ζ=20%
) induced yielding at low cycles, leading to significant changes in the fabric, volume and yield surfaces of the samples, and a significant increase of shear strength and Gsec
. At the micro-scale, graph theory was used to quantify the evolution of the contact network. After ∼20
loading cycles, the network reached a steady-state of constant but persistent topology changes in the material, with most of the topology retained between loading cycles.
Date Issued
2023-05
Date Acceptance
2023-01-09
Citation
Granular Matter, 2023, 25 (2), pp.1-19
ISSN
1434-5021
Publisher
Springer
Start Page
1
End Page
19
Journal / Book Title
Granular Matter
Volume
25
Issue
2
Copyright Statement
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
License URL
Identifier
https://link.springer.com/article/10.1007/s10035-023-01308-z
Publication Status
Published
Article Number
23
Date Publish Online
2023-03-02