Microstructure evolution of compressible granular systems under large deformations

TL;DR

This study uses advanced 3D particle mechanics calculations to analyze how the microstructure of elastic spherical granular materials evolves during high-density die-compaction, highlighting the influence of particle compressibility and force distributions.

Contribution

It introduces a nonlocal contact formulation that accurately predicts microstructure evolution at high confinement levels, bridging experimental observations with bulk behavior.

Findings

Coordination number depends on particle Poisson's ratio.

Contact force distributions differ significantly at full compaction.

Particle-wall force predictions match experimental data.

Abstract

We report three-dimensional particle mechanics static calculations that predict the microstructure evolution during die-compaction of elastic spherical particles up to relative densities close to one. We employ a nonlocal contact formulation that remains predictive at high levels of confinement by removing the classical assumption that contacts between particles are formulated locally as independent pair-interactions. The approach demonstrates that the coordination number depends on the level of compressibility, i.e., on the Poisson's ratio, of the particles. Results also reveal that distributions of contact forces between particles and between particles and walls, although similar at jamming onset, are very different at full compaction. Particle-wall forces are in remarkable agreement with experimental measurements reported in the literature, providing a unifying framework for bridging experimental boundary observations with bulk behavior.