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arXiv · 2607.02762

Shear and crystallization in deformable granular packings: why don't auxetics order?

Joel T. Clemmer·Nicholas W. Hackney·Gary S. Grest
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Abstract

Shear of three-dimensional, highly compressed granular packings is simulated using a bonded particle approach that explicitly resolves elastic deformation. Varying Poisson's ratio $\nu$ produces significant changes in rheology, packing structure, and grain morphology. During flow, conventional systems ($\nu > 0$) readily crystallize while auxetics ($\nu < 0$) resist ordering. This duality reflects the fact that conventional grains develop polyhedral-like facets but conserve volume while auxetics behave oppositely, demonstrating an unexpected interaction between elasticity, geometry, and crystallization.

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Joel T. Clemmer, Nicholas W. Hackney, Gary S. Grest. 2026-07-02. Shear and crystallization in deformable granular packings: why don't auxetics order?. https://arxiv.org/abs/2607.02762

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