Coarse-grained Molecular Dynamics Simulation of Fatty Acid Additives in Lubricating Oil in Corrugated Sliding Gap

Abstract

We constructed coarse-grained (CG) models for hematite surfaces, dodecane lubricating oil, and stearic acid additive. Compared with all-atom models, these CG models allow for molecular dynamics (MD) simulations with comparable accuracy and 40 times faster speed. Using the CG models, we performed MD simulations for confined shear of lubricating oil by solid surfaces bearing physically adsorbed additive films. In contrast to the case of smooth sliding surfaces, desorption and re-adsorption of additive molecules were observed at the convex portions of corrugated sliding surfaces. This demonstrates that roughness of sliding surfaces largely influences the dynamic behavior of additives in lubricating oil.