Quantifying microstructure and fabric chains in granular materials through X-ray CT experiments

Indian Institute of Science, Bangalore, India

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Published online: 1 December 2025

Abstract

The evolution of the contact network in granular materials plays a key role in stress transmission. This study investigates the evolution of fabric chains—pathways formed by maximally aligned inter-particle contacts—in an assembly of quartz particles subjected to one-dimensional compression. High-resolution synchrotron-based XRCT imaging captures the 3D microstructure at multiple loading stages. Fabric chains are extracted by iteratively tracking maximally aligned neighbors, and their network characteristics are quantified using fabric chain length, tortuosity coefficient, and participation index. The results reveal that chain lengths initially increase with loading, indicating the formation of more extensive pathways due to particle rearrangement. The tortuosity coefficient rises, reflecting the increasing curvature of chains as the contact network becomes more tortuous. The participation index highlights the degree of chain merging, with higher values indicating particles participating in multiple overlapping chains, signifying the emergence of an interconnected fabric chain network. These findings offer insights into the evolution of microstructure in granular materials under compressive loading conditions.