Impact behaviour of microparticles with microstructured surfaces: Experimental study and DEM simulation

Abstract

The surface topography of a component influences lots of important macroscopic phenomena, for example friction, fatigue and wear behaviour. This study is focused on the effect of surface topography on the collision behaviour of fine particles. To obtain this behaviour an experimental study of the single particle impact with a microstructured substrate was performed. A novel experimental setup was developed to capture collisions of small particles with the surface three-dimensionally. The particle-wall collisions were performed with spherical polystyrene microparticles. As contact partners a polished and a microstructured stainless steel substrate were used. The surface microstructure was produced by a cold spray process with spherical stainless steel particles. The measured restitution coefficient significantly decreased after the microstructuring showing an additional energy dissipation due to topography. The particle impact was simulated using the Discrete Element Method. The surface topography was implemented in the model by reverse engineering and meshed with two different resolutions. The simulations were compared with the experiments regarding the energy dissipation and rebound behaviour. The calculated restitution coefficient was in good agreement with the experiments for a fine meshed surface, but deviated significantly with the coarsened mesh.