Generation of homogeneous granular packings: Contact dynamics method with coupling to an external pressure bath

TL;DR

This paper introduces a modified contact dynamics method coupled with an external pressure bath to generate homogeneous granular packings, enabling control over packing density and structure in simulations.

Contribution

It presents a novel coupling of contact dynamics with an external pressure bath inspired by Andersen dynamics for improved granular packing simulations.

Findings

Successful implementation of the coupled algorithm

Generation of homogeneous random packings

Insights into packing properties and structure

Abstract

The contact dynamics method (CD) is an efficient simulation technique of dense granular media where unilateral and frictional contact problems for a large number of rigid bodies have to be solved. In this paper we present a modified version of the contact dynamics to generate homogeneous random packings of rigid grains. CD is coupled to an external pressure bath, which allows the variation of the size of a periodically repeated cell. We follow the concept of the Andersen dynamics and show how it can be applied within the framework of the contact dynamics method. The main challenge here is to handle the interparticle interactions properly, which are based on constraint forces in CD. We implement the proposed algorithm, perform test simulations and investigate the properties of the final packings.