Three-dimensional compaction of soft granular packings

Abstract

This paper analyzes the compaction behavior of assemblies composed of soft (elastic) spherical particles beyond the jammed state, using three-dimensional non-smooth contact dynamic simulations. The assemblies of particles are characterized...

Understanding slow compression and decompression of frictionless soft granular matter by network analysis

“…2 go as high as 0.9. Recent studies 56 have shown that classical DEM is not accurate at such high compression, due to extreme deformations, so that particles are not spherical anymore, with additional, multiple contacts established. Different methods, e.g.…”

“…Before closing this introduction, we point out that in the present work we also consider relative large volume fractions, that may lead to large particle deformations, which in turn could produce new contacts between particles. Recently, there have been a few studies to tackle the realistic behavior of highly deformable particles both numerically 51–56 and experimentally. 27,57–59 In the present paper the soft-DEM numerical approach is used to model the compaction of “soft” elastic grains; in this approach the change of shape of the grains is neglected.…”

Softer than soft: diving into squishy granular matter

“…Although many equations have been proposed in the last decades to try to link the confining pressure to the compactness [50,51,52,53], most of them are based on empirical strategies with no apparent physical bases, requiring several fitting parameters. Only recently, a systematic approach, based entirely on micromechanical parameters and free of any ad hoc parameters, has been proposed and numerically tested in the case of hyperelastic circular, polygonal, and spherical shapes under different frictionnal conditions [45,46]. This method was derived from the micromechanical expression of the granular stress tensor together with the approximation of the Hertz contact law between two particles at small strain and the theoretical solution of the hydro-static compaction of a single particle.…”

“…In the case (ii), the unilaterality of contacts (non-regularized laws) traduces the non-penetration of the particles. Both [20]), (b) using the meshless approach MPM (with permission of S. Nezamabadi et al [41]), (c) using the meshless "soft-DEM" approach (with permission of G. Mollon [64]), (d) using the 3D Non-Smooth Contact Dynamics approach by M. Cardenas-Barrantes et al [46]. (e) Example of a T1-event running from time t 1 to t 3 .…”

“…Some of them, based on the discrete element method (DEM), have allowed researchers to catch a glimpse of the behavior of multiparticle, highly deformable systems [41,20,42], but remain unsatisfactory in terms of material mimicking. Other methods based on finite-elements (FEM) are better at mimicking particles' materials, but have difficulties to properly take contact interactions into account [43,44,45,46]. In both cases, major improvements are necessary to simulate any squishy granular system.…”