Dresden 2014 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
O: Fachverband Oberflächenphysik
O 84: Nanotribology
O 84.4: Talk
Thursday, April 3, 2014, 16:45–17:00, WIL B321
Plasticity during Contact of Rough Solids — •Tristan A. Sharp1, Lars Pastewka2, and Mark O. Robbins1 — 1Johns Hopkins University, Baltimore, USA — 2Fraunhofer-IWM, Freiburg, Deutschland
Surfaces of many solids exhibit multiscale roughness which has important consequences for contact area, contact stiffness, and friction. Continuum theories and simulations typically can not treat certain atomic-level features despite indications of their importance. For example, the atomic steps on the surface of crystalline solids can alter the contacting area predicted by continuum. Similarly, an appropriate model of yielding is necessary to capture the spatial distribution of surface pressure in the contact. Here, we use large-scale molecular dynamics simulation to study elastoplastic contact between self-affine rough solids. We observe that the elastic continuum result of linearity between contact area and load at small loads is preserved, but with a larger proportionality constant due to yielding. The spatial distribution of contact area is modified only at short length scales. Atomic steps concentrate the stress, increasing the amount of plasticity and contact area. The mean pressure of contacting regions is then given as a decreasing function of atomic step density.