Sensitivity of the stress response function to packing preparation

TL;DR

This study demonstrates that the macroscopic stress response of granular materials is highly sensitive to microscopic packing configurations and preparation history, affecting symmetry and isotropy, with implications for non-intrusive testing.

Contribution

It introduces a novel experimental and numerical method to analyze how packing preparation influences the stress response and symmetry in granular assemblies.

Findings

Stress profiles depend strongly on preparation procedures.

Preparation history affects macroscopic symmetry and isotropy.

Method applicable in both two and three dimensions.

Abstract

A granular assembly composed of a collection of identical grains may pack under different microscopic configurations with microscopic features that are sensitive to the preparation history. A given configuration may also change in response to external actions such as compression, shearing etc. We show using a mechanical response function method developed experimentally and numerically, that the macroscopic stress profiles are strongly dependent on these preparation procedures. These results were obtained for both two and three dimensions. The method reveals that, under a given preparation history, the macroscopic symmetries of the granular material is affected and in most cases significant departures from isotropy should be observed. This suggests a new path toward a non-intrusive test of granular material constitutive properties.