Alignment and anisotropy of stresses in disordered granular media

Aashish K. Gupta; Christopher Ness; Sina Haeri

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arXiv · 2506.06498

Alignment and anisotropy of stresses in disordered granular media

Aashish K. Gupta·Christopher Ness·Sina Haeri

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Abstract

Characterizing the degeneracy of local stress states is a central challenge in obtaining the complete statistical mechanics of disordered media. Here, we introduce a minimal force-balance model for isolated granular clusters to probe the structure of the stress space through principal stress orientation and stress anisotropy. We further show that when complemented by physically motivated pairwise constraints, the model produces predictions for the stress alignment in packings of repulsive hard spheres. We compare these predictions against simulation data for grains in hopper and simple shear flows, finding quantitative agreement. This demonstrates the promise of modeling bulk athermal disordered systems through the combinatorics of few primitive geometric motifs.

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Aashish K. Gupta, Christopher Ness, Sina Haeri. 2025-06-06. Alignment and anisotropy of stresses in disordered granular media. https://arxiv.org/abs/2506.06498

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