Generation of Porous Particle Structures using the Void Expansion Method

TL;DR

This paper introduces the void expansion method, an efficient technique for generating porous spherical particle structures with controlled microstructures and volume fractions using the discrete element method.

Contribution

The paper presents the void expansion method, a novel approach for creating porous particle packings with adjustable microstructures and volume fractions.

Findings

Transition in coordination number correlates with void radius.

Stiffness ratio affects the transition point and smoothness.

Method efficiently generates diverse porous structures.

Abstract

The newly developed "void expansion method" allows for an efficient generation of porous packings of spherical particles over a wide range of volume fractions using the discrete element method. Particles are randomly placed under addition of much smaller "void-particles". Then, the void-particle radius is increased repeatedly, thereby rearranging the structural particles until formation of a dense particle packing. The structural particles' mean coordination number was used to characterize the evolving microstructures. At some void radius, a transition from an initially low to a higher mean coordination number is found, which was used to characterize the influence of the various simulation parameters. For structural and void-particle stiffnesses of the same order of magnitude, the transition is found at constant total volume fraction slightly below the random close packing limit. For decreasing void-particle stiffness the transition is shifted towards a smaller void-particle radius and becomes smoother.