Adhesive wear and interaction of tangentially loaded micro-contacts

TL;DR

This paper develops a physical model for adhesive wear at the microscale, considering elastic interactions of micro-contacts, and uses simulations to predict wear regimes based on energetic criteria.

Contribution

It extends existing models by incorporating elastic interactions among multiple micro-contacts and provides criteria to assess wear particle formation.

Findings

Model predicts critical micro-contact size for debris formation.

Elastic interactions influence the transition between wear regimes.

Simulations validate the energetic criteria for wear outcomes.

Abstract

Current engineering wear models are often based on empirical parameters rather than built upon physical considerations. Here, we look for a physical description of adhesive wear at the microscale, at which the interaction between two surfaces comes down to the contact of asperities. Recent theoretical work has shown that there is a critical micro-contact size above which it becomes energetically favorable to form a wear particle. We extend this model by taking into consideration the elastic interaction of multiple closely-spaced micro-contacts in 2D, with different sizes and separation distances. Fundamental contact mechanics solutions are used to evaluate the elastic energy stored by shearing the micro-contacts, and the stored energy is compared to the energy needed to detach a single joined debris particle or multiple debris particles under the micro-contacts. Molecular dynamics simulations are used to test the predictions of the outcome for various sets of parameters. Our model provides simple criteria to evaluate the energetic feasibility of the different wear formation scenarios. Those criteria can be used to rationalize the transition between mild and severe wear regimes and help define the notion of asperity.

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