Contact between representative rough surfaces

TL;DR

This paper presents a numerical analysis of frictionless contact between rough elastic surfaces, revealing universal behavior in contact area evolution independent of surface roughness details, and introduces a universal law for this evolution.

Contribution

It identifies the lower cutoff wavenumber as a key parameter and proposes a universal law governing contact area evolution beyond infinitesimal contact fractions.

Findings

Real contact area evolution is universal for representative surfaces.

The lower cutoff wavenumber controls surface representativity.

A universal law with three constants describes contact evolution.

Abstract

A numerical analysis of mechanical frictionless contact between rough self-affine elastic manifolds was carried out. It is shown that the lower cutoff wavenumber in surface spectra is a key parameter controlling the representativity of the numerical model. Using this notion we demonstrate that for representative surfaces the evolution of the real contact area with load is universal and independent of the Hurst roughness exponent. By introducing a universal law containing three constants, we extend the study of this evolution beyond the limit of infinitesimal area fractions.