AUTHOR=Zhou Yunong , Müser Martin H. 

TITLE=Effect of Structural Parameters on the Relative Contact Area for Ideal, Anisotropic, and Correlated Random Roughness

JOURNAL=Frontiers in Mechanical Engineering

VOLUME=Volume 6 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/mechanical-engineering/articles/10.3389/fmech.2020.00059

DOI=10.3389/fmech.2020.00059

ISSN=2297-3079

ABSTRACT=The relative contact area between an initially flat, adhesion- and frictionless, linearly elastic body and a variety of rough, rigid counterbodies is studied using Green's function molecular dynamics. The indenter's height profiles range from ideal random roughness through roughness with a moderate amount of correlation to periodically repeated, single-asperity indenters having perfect phase coherence. At small reduced pressures, p* := p/(E*/g) << 1, sufficiently large systems are consistent with a linear aC = kappa p* relation. Here, p is the pressure, E* is the contact modulus, g the root-mean-square height gradient, and kappa a unitless proportionality coefficient. However, the parameter g must be evaluated over the real contact area for the linear relation to hold if the random roughness is correlated or the interfacial dimension reduced. No single unitless structural parameter--- including the Nayak parameter--- correlates in a significant fashion with kappa.