A coarse-grained discrete element method based on the principle of energy density mapping conservation: Efficient simulation of particle dynamic mixing and interaction using larger particles

A novel coarse-grained methodology has been developed, which is founded on the principle of energy density mapping conservation. Energy density conservation is maintained by this methodology throughout the particle size scaling, wherein kinetic, elastic strain, frictional, and damping energy densities are preserved. The methodology has been designed to address both dynamic particle flow and quasi-static interaction, whereby a comprehensive characterization model for microscopic parameters between particles in a coarse-grained system was established. The performance and accuracy were systematically evaluated through numerical simulations of rotating drum and direct shear tests. Excellent agreement with the original system was demonstrated by the numerical results in terms of particle mixing, Lacey mixing index, velocity field distribution, and stress field patterns. Significant improvements in shear rate distribution, force chain morphology, and force chain magnitude were observed in direct shear simulations when compared to the without coarse-grained system, by which the efficacy of the proposed methodology was substantiated.