Topography Evolution · Rough surfaces in sliding contact: A combined atomistic/continuum investigation of topography evolution

Summary - Mechanical systems have moving parts which dissipate energy at surfaces sliding with respect to each other. Energy efficient devices need interfaces that are tailored to consume little to no energy. This requires a fundamental understanding of frictional dissipation processes. The evolution of the topography of the two surfaces that are in contact is a crucial component of sliding friction: Processes such as fracture and plastic flow dissipate energy and contribute to the macroscopic coefficient of friction. Using molecular dynamics and continuum methods, the surface structure evolution during plastic deformation is investigated for three isotropic model materials. This hybrid atomistic/continuum approach is aimed to reveal at which length-scale the continuum theory starts to fail in its description of the basic plastic processes and what new phenomena occur below this scale. Besides gaining insights into frictional dissipation processes, this will clarify how to extrapolate atomistic results to the continuum. Since continuum theories are typically used for the design of macroscopic devices, this also constitutes a first step towards the incorporation of surface structure as a design element in the engineering process.