Multiscale study of the dynamic friction coefficient due to asperity plowing

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 molecula...

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Bibliographic Details
Published in:Friction 2021-08, Vol.9 (4), p.822-839
Main Authors: Hu, Jianqiao, Song, Hengxu, Sandfeld, Stefan, Liu, Xiaoming, Wei, Yueguang
Format: Article
Language:English
Subjects:
Coefficient of friction
Corrosion and Coatings
Dependence
Engineering
Flat surfaces
Friction
Mechanical Engineering
Molecular dynamics
Multiscale analysis
Nanotechnology
Physical Chemistry
Plowing
Research Article
Statistical models
Surface roughness
Surfaces and Interfaces
Thin Films
Tribology
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Summary: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.
ISSN:2223-7690
2223-7704
DOI:10.1007/s40544-020-0438-4