Adhesive wear regimes on rough surfaces and interaction of micro-contacts

TL;DR

This paper presents an analytical model for adhesive wear on rough surfaces, incorporating micro-contact interactions and surface roughness effects, resulting in a wear map that identifies different wear regimes based on load and material properties.

Contribution

The study introduces a novel analytical model that accounts for elastic interactions between micro-contacts and surface roughness, advancing understanding of wear regimes in unlubricated rough surfaces.

Findings

Identification of three distinct wear regimes.

Prediction of severe wear above a critical contact pressure.

Demonstration of micro-contact interactions influencing wear volume.

Abstract

We develop an analytical model of adhesive wear between two unlubricated rough surfaces, forming micro-contacts under normal load. The model is based on an energy balance and a crack initiation criteria. We apply the model to the problem of self-affine rough surfaces under normal load, which we solve using the boundary element method. We discuss how self-affinity of the surface roughness, and the complex morphology of the micro-contacts that emerge for a given contact pressure, challenge the definition of contact junctions. Indeed, in the context of adhesive wear, we show that elastic interactions between nearby micro-contacts can lead to wear particles whose volumes enclose the convex hull of these micro-contacts. We thereby obtain a wear map describing the instantaneous produced wear volume as a function of material properties, roughness parameters and loading conditions. Three distinct wear regimes can be identified in the wear map. In particular, the model predicts the emergence of a severe wear regime above a critical contact pressure, when interactions between micro-contacts are favored.