Fix_Abrasion: Plastic wear of arbitrarily shaped surfaces and particles in LAMMPS

The bulk dynamics of granular systems are significantly affected by the shape of the constituent particles. [1][2][3] As an added, but necessary, complication, particle shape can change over time through the process of abrasion. [4] However, the current LAMMPS implementation does not allow for abrasion to be captured. This represents a major shortcoming, and area of interest, as in reality all granular particles abrade and change shape to some extent. [5] Hence, this current research proposes to implement abradable non-spherical particles into LAMMPS through a new fix abrasion. Here, particle topologies are represented using the existing LAMMPS data structures - vertices by discrete spherical atoms, edges by bonds, and facets by angles. To model the abrasion, atoms are displaced normally to the particle’s surface, when subject to a force exceeding a material yield criterion, altering its shape and reducing its volume. [6] In this presentation, the current implementation is summarised and preliminary results are presented for a single non-spherical particle abraded isotropically by thousands of impacting spherical grains.

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