Abradable DEM: A Novel Framework to Capture the Mechanistic Evolution of Particle Shape

Although various methods exist for modelling non-spherical particles in DEM, particles’ shapes are usually treated as immutable. However, particles often change shape gradually, e.g., due to abrasion or accrued plastic deformation. This manner of shape evolution has largely been neglected in DEM even though it can significantly influence bulk-scale behaviour. The following introduces an extendable framework for modelling the gradual and permanent evolution of particle shapes in DEM, focusing on abrasion/wear as an exemplar. By extending the existing LAMMPS rigid-body implementation, a comprehensive novel wear model is employed to simulate the abrasion of arbitrarily shaped dynamic particles. These abradable particles are represented as hollow shells of discrete spheres collated into a series of triangular facets. Following an impact exceeding a material yield criterion, spheres are displaced inwards along their normals. The result is a reduction in volume and a permanent change in shape. Following this, each abraded particle’s moment of inertia is recomputed and used to resolve future rigid-body dynamics. Thus, particle-level changes in shape affect the bulk dynamics of the system, which in turn informs all subsequent abrasion. Results exhibit particle shape evolution in agreement with a variety of abrasion scenarios in literature and showcase the resulting effect on the bulk dynamics of such systems. This research provides a versatile methodology for linking microscale abrasion mechanisms to macroscale system behaviour, with widespread applications in both natural processes and industrial particle-handling systems. Furthermore, the outlined framework can be readily adapted to other sources of mechanistic particle shape evolution in DEM.