Microscopic origin of granular ratcheting

TL;DR

This paper explains that granular ratcheting arises from path-dependent contact potentials in common models, and proposes an alternative force calculation method to eliminate this effect.

Contribution

It identifies the microscopic origin of granular ratcheting as path-dependent contact energy and introduces a new force calculation method to prevent it.

Findings

Granular ratcheting is caused by path-dependent contact potentials.

An alternative force calculation method removes ratcheting.

The study links microscopic contact properties to macroscopic deformation.

Abstract

Numerical simulations of assemblies of grains under cyclic loading exhibit ``granular ratcheting'': a small net deformation occurs with each cycle, leading to a linear accumulation of deformation with cycle number. We show that this is due to a curious property of the most frequently used models of the particle-particle interaction: namely, that the potential energy stored in contacts is path-dependent. There exist closed paths that change the stored energy, even if the particles remain in contact and do not slide. An alternative method for calculating the tangential force removes granular ratcheting.