Stress-induced ordering of two-dimensional packings of elastic spheres

TL;DR

This study investigates how stress influences the organization of deformable elastic spheres in two-dimensional packings under compression, revealing a sequence of ordered structures driven by stress-induced elastic instabilities.

Contribution

It introduces a model showing stress as a key factor in ordering 2D packings of elastic spheres, uncovering a sequence of complex arrangements under compression.

Findings

Particles form regular packings under compression

Sequence of structures includes triangular, square, and pentagonal arrangements

Stress acts as an ordering field influencing particle organization

Abstract

Packing of particles in confined environments is a common problem in multiple fields. Here, based on the two-dimensional Hertzian particle model, we study the packing of deformable spherical particles under compression, and reveal the crucial role of stress as an ordering field in regulating particle arrangement. Specifically, under increasing compression, the squeezed particles spontaneously organize into regular packings in the sequence of triangular and square lattices, pentagonal tessellation, and the reentrant triangular lattice. The rich ordered patterns and complex structures revealed in this work suggest a fruitful organizational strategy based on the interplay of external stress and intrinsic elastic instability of particle arrays.