Molecular Dynamics Study Of Lubrication,Friction At Nanoscale

The rocketing development of Micro-electronic mechanic system (MEMS) and Nano machine required urgently more and more fundamental research of nano-tribology. Hence the research of origin and mechanism of friction in molecular level is every meaningful to master the nature of friction and realize Ultra-solid lubrication. Meanwhile, the simulation of the property of ultra-thin film and the investigation about the dissimilarity and resemblance between it and macro continuous fluid is vital important to design future micro-flow pipe and establish the micro-flow theory.In this paper, the computer simulation tool– molecular dynamic simulation (MDs) is introduced at first and its special instruction in simulation of motion is listed as well.With MDs, the Couette model is used to research the oscillation of friction force. According to the result, The periods of the oscillation of friction force only has relations with velocity and the wall lattice length,moreover,they are linked with special function. Later we use MDs to investigate ultra-thin water film's lubrication under Couette model ,and we discover that the ultra-thin liquil film's solid-to-liquid ratio and the friction force aren't always show the same trend,the density of the wall's influence could not be neglected.Finally,we use simple model to reseach the nanoscale stick-slip phenomena by MDs, as a result, we find that all of the velocity,friction and the press of the sliding plank break among the stick-slip process.According to the simulation data ,we conclude that:The stick-slip motion has its origins in the formation and rupture of junctions that form between surfaces in contact.