The contact of elastic regular wavy surfaces revisited

TL;DR

This paper provides a detailed analysis of elastic wavy surface contact, revealing new transition regimes and implications for modeling contact mechanics of rough surfaces through numerical and analytical methods.

Contribution

It uncovers previously overlooked transition regimes in elastic wavy surface contact and discusses their implications for modeling rough surface interactions.

Findings

Identification of new transition regimes in contact evolution.

Non-zero probability density of null contact pressures at full contact.

Insights into the applicability of existing models like Persson's and Westergaard's.

Abstract

We revisit the classic problem of an elastic solid with a two-dimensional wavy surface squeezed against an elastic flat half-space from infinitesimal to full contact. Through extensive numerical calculations and analytic derivations, we discover previously overlooked transition regimes. These are seen in particular in the evolution with applied load of the contact area and perimeter, the mean pressure and the probability density of contact pressure. These transitions are correlated with the contact area shape, which is affected by long range elastic interactions. Our analysis has implications for general random rough surfaces, as similar local transitions occur continuously at detached areas or coalescing contact zones. We show that the probability density of null contact pressures is non-zero at full contact. This might suggest revisiting the conditions necessary for applying Persson's model at partial contacts and guide the comparisons with numerical simulations. We also address the evaluation of the contact perimeter for discrete geometries and the applicability of Westergaard's solution for three-dimensional geometries.