Identifying Bridges from Asymmetric Load-Bearing Structures in Tapped Granular Packings

TL;DR

This study uses high-resolution x-ray tomography to analyze the structure of load-bearing bridges in tapped granular packings, revealing how gravity influences contact networks and how bridge cooperativity varies with packing density.

Contribution

It introduces a method to identify load-bearing contacts from structural data alone and characterizes the geometric properties of cooperative bridges in granular materials.

Findings

Gravity subtly alters load-bearing contacts.

Bridge cooperativity increases as packing fraction decreases.

Structural information can identify load-bearing contacts.

Abstract

Using high-resolution x-ray tomography, we experimentally investigate the bridge structures in tapped granular packings composed of particles with varying friction coefficients. We find that gravity can induce subtle structural changes on the load-bearing contacts, allowing us to identify the correct load-bearing contacts based on structural information alone. Using these identified load-bearing contacts, we investigate the cooperative bridge structures which are mechanical backbones of the system. We characterize the geometric properties of these bridges and find that their cooperativity increases as the packing fraction decreases. The knowledge of bridges can enhance our understanding of the rheological properties of granular materials.