Disentangling microstructural elements of shear thickening suspensions via computer simulations of a minimal model

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Main Authors: Buchholtz, William C. J., Blair, Daniel L., Urbach, Jeffrey S., Vinutha, H. A., Del Gado, Emanuela
Format: Preprint
Published: 2026
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author Buchholtz, William C. J.
Blair, Daniel L.
Urbach, Jeffrey S.
Vinutha, H. A.
Del Gado, Emanuela
author_facet Buchholtz, William C. J.
Blair, Daniel L.
Urbach, Jeffrey S.
Vinutha, H. A.
Del Gado, Emanuela
contents We use a minimal model for a dense suspension undergoing thickening and thinning to investigate microstructural changes in 2d simulations. Our simulations show that in steady flow the contact network contains distinct building blocks which are clearly signaled by sharp peaks in the radial distribution function, similar to what is observed in granular jamming. These structures {deform} during thinning. Non-Gaussian stress fluctuations that only emerge during thickening are associated to power law tails in the distribution of local contact forces, which tend to emerge when the flow-induced building blocks form large spanning assemblies. The subset of the contact network characterized by strong contact forces and connectivity large enough to be rigid or over-constrained is increasingly likely to percolate as the system starts to thicken, and to percolate over larger strain windows during thickening. The tendency of these structures to span the sample and to persist is dramatically reduced during thinning, where instead their deformation allows for a more homogeneous spatial redistribution of contact forces, significantly reducing the fluctuations of the macroscopic stress over time.
format Preprint
id arxiv_https___arxiv_org_abs_2604_12107
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Disentangling microstructural elements of shear thickening suspensions via computer simulations of a minimal model
Buchholtz, William C. J.
Blair, Daniel L.
Urbach, Jeffrey S.
Vinutha, H. A.
Del Gado, Emanuela
Soft Condensed Matter
We use a minimal model for a dense suspension undergoing thickening and thinning to investigate microstructural changes in 2d simulations. Our simulations show that in steady flow the contact network contains distinct building blocks which are clearly signaled by sharp peaks in the radial distribution function, similar to what is observed in granular jamming. These structures {deform} during thinning. Non-Gaussian stress fluctuations that only emerge during thickening are associated to power law tails in the distribution of local contact forces, which tend to emerge when the flow-induced building blocks form large spanning assemblies. The subset of the contact network characterized by strong contact forces and connectivity large enough to be rigid or over-constrained is increasingly likely to percolate as the system starts to thicken, and to percolate over larger strain windows during thickening. The tendency of these structures to span the sample and to persist is dramatically reduced during thinning, where instead their deformation allows for a more homogeneous spatial redistribution of contact forces, significantly reducing the fluctuations of the macroscopic stress over time.
title Disentangling microstructural elements of shear thickening suspensions via computer simulations of a minimal model
topic Soft Condensed Matter
url https://arxiv.org/abs/2604.12107