Friction and adhesive wear behavior caused by periodic impact in mixed-lubricated point contacts

Xin Pei,Ying Zhang,Jialong Yang,Wei Pu

doi:10.1177/1687814020901666

Abstract

Periodic impact is a common phenomenon experienced by functional components. The mechanisms governing the adhesive wear growth caused by the periodic impact are not well understood, which limits the development of antiwear and lubricating behavior. In this work, the periodic impact action caused by rubbing surface velocity and contact load is studied in the sliding wear process under mixed lubrication condition. At each wear simulation circle, the material removal at each asperity contact location is evaluated and the surface topography is renewed correspondingly. The evolutions of friction and wear track are revealed during wear process. We find that the friction coefficient changes periodically caused by the periodic speed, and the wear rate increases almost linearly with either speed period or speed amplitude. The load impact results in an abrupt variation in friction coefficient, while it appears to be limited in adhesive wear state compared to speed, highlighting the critical role of velocity impact in wear formation.

Highlights

Wear, the loss of material in a solid surface, is a major surface failure resulted from a surface being stressed mechanically, thermally, or chemically
Hu and Zhu[8] and Zhu and Hu9 have proposed a numerical solution of deterministic mixed lubrication model, which solves both hydrodynamic lubrication and surface contact problems simultaneously, and predicts the distribution of pressure, film thickness, asperity deformation, friction, and so on as functions of location and time
The effects of load impact, shifting impact, and variable slide-to-roll ratio (SRR) on wear are studied in mixed lubrication conditions

Summary

Introduction

The loss of material in a solid surface, is a major surface failure resulted from a surface being stressed mechanically, thermally, or chemically. The surface roughness height is generally equal to or larger than the oil film thickness; thereby, asperity contact is inevitable due to rough peaks.[1] Many models have been proposed to study the complicated wear processes, among which the adhesive wear model developed by Archard[2] is the most widely used. Hu and Zhu[8] and Zhu and Hu9 have proposed a numerical solution of deterministic mixed lubrication model, which solves both hydrodynamic lubrication and surface contact problems simultaneously, and predicts the distribution of pressure, film thickness, asperity deformation, friction, and so on as functions of location and time. Zhu et al.[1] published a full numerical simulation of sliding wear under lubricated point contacts based on their previous work. The effects of load impact, shifting impact, and variable slide-to-roll ratio (SRR) on wear are studied in mixed lubrication conditions

Research methodology

Conclusion