Continuum thermo-mechanical surrogate modeling of frictional contact at atomic length scales

点击翻译按钮获取中文摘要

We propose to develop a computational multiscale methodology for the systematic determination of continuum thermo-mechanical friction models based on the underlying atomistic contact behavior. The work is motivated by a demand for effective continuum friction models that are computationally efficient and simple to scale up, yet still based directly and exclusively on the underlying atomistic contact behavior. Our particular focus is on sliding contact between two solid bodies, onehard and one soft, where an interfacial medium such as water can also bepresent. Our approach is an extension of an existing multiscale methodology developed jointly by our research groups, which uses molecular dynamics (MD) simulations to develop the constitutive models needed for finite-element contact models of interfacial systems, including multicomponent systems such as self-assembled monolayers and thin films. This existing methodology allows for a systematic, bottom-up determination of continuum models that can accurately predict the normal contact behavior of the original molecular model. The work proposed here will extend the methodology by incorporating thermal effects to properly characterize the tangential contact behavior during frictional sliding. The methodology involves setting up and running a series of "virtual experiments" with MD simulations as well as extracting appropriate mechanical and thermal variables needed for the information transfer to the continuum level. Based on those experiments, suitable continuum models are formulated, implemented and validated against the molecular behavior in a set of benchmark cases. We restrict ourselves here to contact between polymeric and crystalline solids, considering only the contact behavior (but not the bulk behavior) to be dissipative. The methodology itself, however, will be formulated in general terms to readily admit other material pairings.