Investigation on the impact-contact between droplet and rough surface in mechanical polishing using atomic modeling method

• Main Authors: Xuesong Han, Heming Ding
• Format: Article
• Language: English
• Published: SAGE Publishing 2017-07-01
• Series: Advances in Mechanical Engineering
• Online Access: https://doi.org/10.1177/1687814017710405

Investigation on the mechanism of impact-contact occurred at multiphase interface is of great importance in technique control of mechanical polishing as it is the basic dynamic process connected with mass transfer and interfacial pressure. Classical continuum mechanics is not fit for study the physical essence of complex dynamic behavior in the impact-spreading at nano length scale because of the small thickness of fluid film and the discrete property of surface morphology. Molecular dynamics method has already been proved to be one of the most efficient toolkit on atomic scale discrete phenomenon and thus being employed in this research to study the complex mechanism of nano-scale impact-spreading. The study shows that the liquid film behaves like a stretched membrane under the unbalanced forces and the real traverse spreading is an anisotropic process resulted by the anisotropic surface structure which also influences the nonuniform distribution of film. The result justifies that boundary lubrication at the interface is resulted by poor spreading behavior on rough surface and will affect the transportation of abrasive particle and materials removal rate. The results also justify that the mechanical similarity can be difficult to hold because of the complexity of surface texture (rough surface) and the different contour profiles resulted by random movement of molecule. Furthermore, energy distribution shows that physical adsorption plays an important role in the impact-contact process which is also justified by the adsorption structure of water. With the increasing of impact velocity, part of outer molecules breaks away the constraints generated by the surface tension and forming a free-state water layer.