Numerical Prediction of Wear Process of an Initial Line Contact in Mixed Lubrication Conditions

In mixed lubrication, wear is inevitable under the sliding condition due to the existence of the asperity contacts that bear partial normal load. This study proposes a numerical approach to predict the wear process of a cylinder sliding over a ring disk in mixed lubrication. Elastohydrodynamic lubrication of the rough contact, which is a line contact at the beginning of the sliding and gradually becomes a flatten cylinder/disk contact with the wear progress, is simulated with the three-dimensional finite element method. The elastic–plastic asperity contact model is adopted to calculate the asperity contact pressure. Based on the asperity contact load, the cylinder wear is computed with the Archard’s wear law. The wear process is simulated step by step, starting from an initial line contact configuration. In each calculation step, the cylinder geometry profile is updated, and the balance of the externally applied load with the elastohydrodynamic and the asperity contact loads is achieved. Variations of the cylinder geometry profile, the lubricant film thickness, and the friction coefficient are obtained for the whole rubbing process. Reasonable agreements on the changes of the wear scar width and the friction coefficient during the rubbing process between the simulation and the experiment results are obtained.