Molecular Modeling and Continuum Analyses of Thin Film InterfacesPublic Deposited
The combined trends of decreasing application size and increasing requirements for energy efficiency have driven a need for improved understanding and better predictive tools for thin film lubricated systems. Research on such systems is complicated by the involvement of both larger scale phenomena such as fluid flow, material deformation, and material wear, as well as behaviors that are typically only significant on the molecular scale such as solvation pressure, interface slip, and unique thin film fluid properties. Thin film lubricated systems can be investigated by combining traditional lubricated contact models with a molecular scale characterization of thin film behavior. However, this type of integrated research requires a foundation of fundamental understanding of both continuum models for describing a lubricated interface as well as the molecular models that can be used to characterize behaviors of a confined fluid. This dissertation describes the building of that foundation through research performed from the continuum and molecular perspectives individually. Continuum simulation-based studies include formulation of a thermoelastic displacement model with convection, development of a method for rapid prediction of maximum subsurface stress, and evaluation of a mixed elastohydrodynamic lubrication wear model. A molecular simulation that models a lubricated interface was developed and then employed to investigate thin film behaviors and properties including density, solvation pressure, interface slip, and viscosity. Finally, potential areas of overlap between the continuum and molecular models are discussed, and the initial phases of an integration plan for the two models are proposed.