Particle scale anisotropy controls bulk properties in sheared granular materials

The bulk dynamics of dense granular materials arise through a combination of particle-scale and mesoscale effects. Theoretical and numerical studies have shown that collective effects are created by particle-scale anisotropic structures such as grain connectivity, force transmission, and frictional mobilization, all of which influence bulk properties like bulk friction and the stress tensor through the Stress-Force-Fabric (SFF) relationship. To date, establishing the relevance of these effects to laboratory systems has remained elusive due to the challenge of measuring both normal and frictional contact forces at the particle scale. In this study, we perform experiments on a sheared photoelastic granular system in a quasi-2D annular cell. During these experiments, we measure particle locations, contacts, and normal and frictional force vectors during loading. We reconstruct the angular distributions of the contact and force vectors, and extract the corresponding emergent anisotropies fo..., , # Particle scale anisotropy controls bulk properties in sheared granular materials

Dataset DOI: [10.5061/dryad.m905qfvds](10.5061/dryad.m905qfvds)

## Description of the data and file structure

This repository contains four folders corresponding to the data (at different stages of processing) of a full rotation of the shear on an annular shear cell.

### Files and variables

#### File: rawdata.zip

**Description:** The data in this folder contains 3 files named as centers_tracked.txt, Adjacency_list.txt, and annulusgeometry.txt

**centers_tracked.txt:** This file contains the particle position information and radius.

The columns are: [frame, particleID, x, y, r, edge]

*frame:* image number corresponding to a strain step

*particleID:* individual id of one particle that should persist from frame to frame

x: x position of particle, in pixels

y: y position of particle, in pixels

r*:* radius of particle, in pixels

edge*:* boolean edge flag, 0 not near an edge, -1 near the inner bou...,