The properties of random surfaces of significance in their contact

TLDR

Engineering surfaces often exhibit random structures, as shown in recent studies. The authors model a surface profile as a random signal waveform defined by height distribution and autocorrelation, transform it into an asperity array with statistical height and curvature distributions, and validate the model against digitized surface profiles. The study demonstrates that this asperity‑array model enhances understanding of surface contact theory and informs surface finish measurement and characterization.

Abstract

In recent work it has been shown that many types of surfaces used in engineering practice have a random structure. The paper takes, as a representation of the profile of such a surface, the waveform of a random signal; this is completely defined by two parameters, a height distribution and an auto-correlation function. It is shown how such a representation can be transformed into a model, appropriate for the study of surface contact, consisting of an array of asperities having a statistical distribution of both heights and curvatures. This theory is compared with the results of an analysis of surface profiles presented in digital form. The significance of these findings for the theory of surface contact and for the measurement and characterization of surface finish is discussed.