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TESTING February 23, 2026

Linearised Identification of Mechanical and Structural Anisotropy of Granular Materials from Hollow-Cylinder Experiments

Authors

Mehdi Pouragha, Gertraud Medicus, Selvarajah Premnath, Siva Sivathayalan

Abstract

Anisotropy in granular materials arises from both the internal fabric and the directionality of the stress state, yet separating these effects experimentally remains challenging. This study develops a first-order linearisation of the incremental stress-strain response that isolates mechanical anisotropy from structural anisotropy using two independent orientation measures. The formulation enables both contributions to be quantified directly from macroscopic laboratory data. The method is applied to hollow-cylinder tests with systematically varied loading directions. Results show that both anisotropy components intensify as the stress state becomes more deviatoric; mechanical anisotropy is consistently stronger; and its relative dominance decreases with increasing deviatoric stress. Comparison with an isotropic hypoplastic model confirms that mechanically induced directional effects are captured even without fabric anisotropy. The framework offers a practical and physically transparent means for quantifying and comparing anisotropy mechanisms in granular materials.

Metadata

arXiv ID: 2602.19902
Provider: ARXIV
Primary Category: cond-mat.soft
Published: 2026-02-23
Fetched: 2026-02-24 04:38

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