Contributions of Molecular Dynamics Simulations to Elastohydrodynamic Lubrication

Abstract

The prediction of friction under elastohydrodynamic lubrication (EHL) conditions remains one of the most important and controversial areas of tribology. This is mostly because the pressure and shear rate conditions inside EHL contacts are particularly severe, which complicates experimental design. Over the last decade, molecular dynamics (MD) simulation has played an increasingly significant role in our fundamental understanding of molecular behaviour under EHL conditions. In recent years, MD simulation has shown quantitative agreement with friction and viscosity results obtained experimentally, meaning that they can, either in isolation or through the use of multiscale coupling methods, begin to be used to test and inform macroscale models for EHL problems. This is particularly useful under conditions that are relevant inside machine components, but are difficult to obtain experimentally without uncontrollable shear heating.