A data-driven virtual surface method for efficient DEM simulation of particle collisions with microstructured walls

Surface topography strongly influences particle-wall collision dynamics, affecting energy dissipation, adhesion, rebound velocity and angle, as well as rotational motion. To optimize granular processes, microstructuring techniques enable the fabrication of tailored surface topographies that can deliberately modify particle impact behavior. Achieving such targeted control requires a systematic investigation and quantitative characterization of the influence of surface microstructural features on collision dynamics. The Discrete Element Method (DEM) provides a powerful framework for studying these interactions. However, explicitly resolving microstructured surfaces in DEM simulations drastically increases computational costs due to the large number of resulting contact interactions. This work introduces a novel computationally efficient, reduced-order, data-driven DEM approach that accurately reproduces the rebound behavior of particles colliding with homogeneously microstructured surfaces. The proposed virtual surface (VS) method replaces explicit geometric modeling with a post-collision, data-driven correction based on precomputed, microstructure-specific parameters. The approach is validated through particle free-fall tests on two different microstructured surfaces manufactured via Direct Laser Writing. Compared to simulations with explicitly resolved geometries, the VS method reduces computational time by up to 85%, while incurring only a 31% increase relative to a flat wall.