Micromechanics of compressive and tensile forces in partially-bonded granular materials

Bulk material properties such as strength and stiffness are highly sensitive to changes in the degree of interparticle cohesion or the introduction of elongated particles, effects that are both associated with an increase in the average number of constraints per particle. By performing an ensemble of isotropic compression experiments, all starting from the same initial particle configuration but with varying fraction of bonded particles, we use photoelastic force measurements to identify the causes of this phenomenon at the particle-scale and meso-scale. By introducing a variable percentage of bonded dimers, we observe the expected decrease in the critical packing fraction at which jamming occurs. Above jamming, the local pressure increases predominantly for the bonded particles, measured relative to the unbonded case. The use of bonded dimers allows us to directly measure the relative contributions of tensile and compressive forces at the bond, which we observe occur with approximately..., , # Micromechanics of compressive and tensile forces in partially-bonded granular materials

Dataset DOI: [10.5061/dryad.s7h44j1p5]

## Description of the data and file structure

This repository contains analyzed data corresponding to the cyclic biaxial tests on cohesive granular ensemble comprising 832 photoelastic particles. The particles are bonded in pairs (dimers) at concentrations of 0, 10, 15, 20, 25 percent.

### Files and variables

#### File: BiAxial_test.zip

**Description:** This archive contains two types of files: *_preprocessing.mat and *_contacts.mat. These files exist for each dimer concentration: 0, 10, 15, 20, and 25 percent.

**_preprocessing.mat:** The primary fields in this file contain information about the particle position, radius, force-bearing contacts and bonded particles.

The fields are: [id, x, y, r, rm, color, fsigma, z, f, g2, forces, betas, alphas, neighbors, contactG2s, forceImage, synthImg, contactIs, bond, parBonded/bondedpar, bond_old]

* id: individ..., ,