Scaling of discrete element model parameters for cohesionless and cohesive solid

TL;DR

This paper investigates how to scale discrete element model parameters to enable larger, computationally efficient simulations of cohesionless and cohesive solids without losing accuracy in bulk mechanical response.

Contribution

It introduces scaling laws for contact stiffness and adhesive forces that maintain scale-independent predictions in DEM simulations of cohesive materials.

Findings

Contact stiffness scales linearly with particle size.

Adhesive force scales with the square of particle size.

Scaling laws enable larger simulations to replicate small-particle behavior.

Abstract

One of the major shortcomings of discrete element modelling (DEM) is the computational cost required when the number of particles is huge, especially for fine powders and/or industry scale simulations. This study investigates the scaling of model parameters that is necessary to produce scale independent predictions for cohesionless and cohesive solid under quasi-static simulation of confined compression and unconfined compression to failure in uniaxial test. A bilinear elasto-plastic adhesive frictional contact model was used. The results show that contact stiffness (both normal and tangential) for loading and unloading scales linearly with the particle size and the adhesive force scales very well with the square of the particle size. This scaling law would allow scaled up particle DEM model to exhibit bulk mechanical loading response in uniaxial test that is similar to a material comprised of much smaller particles. This is a first step towards a mesoscopic representation of a cohesive powder that is phenomenological based to produce the key bulk characteristics of a cohesive solid and has the potential to gain considerable computational advantage for industry scale DEM simulations.