Multiscale study of the dynamic friction coefficient due to asperity plowing  

作　　者：Jianqiao HU Hengxu SONG Stefan SANDFELD Xiaoming LIU Yueguang WEI 

机构地区：[1]State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China [2]School of Engineering Science,University of Chinese Academy of Sciences,Beijing 100049,China [3]Institute for Advanced Simulation,IAS-9:Materials Data Science and Informatics Forschungszentrum Juelich GmbH,Juelich 52425,Germany [4]Department of Mechanics and Engineering Science,College of Engineering,Peking University,Beijing 100871,China

出　　处：《Friction》2021年第4期822-839,共18页摩擦（英文版）

摘　　要：A macroscopically nominal flat surface is rough at the nanoscale level and consists of nanoasperities.Therefore,the frictional properties of the macroscale-level rough surface are determined by the mechanical behaviors of nanoasperity contact pairs under shear.In this work,we first used molecular dynamics simulations to study the non-adhesive shear between single contact pairs.Subsequently,to estimate the friction coefficient of rough surfaces,we implemented the frictional behavior of a single contact pair into a Greenwood-Williamson-type statistical model.By employing the present multiscale approach,we used the size,rate,and orientation effects,which originated from nanoscale dislocation plasticity,to determine the dependence of the macroscale friction coefficient on system parameters,such as the surface roughness,separation,loading velocity,and direction.Our model predicts an unconventional dependence of the friction coefficient on the normal contact load,which has been observed in nanoscale frictional tests.Therefore,this model represents one step toward understanding some of the relevant macroscopic phenomena of surface friction at the nanoscale level.

关 键 词：multiscale friction asperity plowing dislocation plasticity size/velocity effect crystal orientation statistical model 

分 类 号：TH117.1[机械工程—机械设计及理论]