Modeling and analysis of sliding wear based on fractal surface reconstruction in line contact mixed lubrication

In mixed lubrication, the direct rough contact between the two contact surfaces causes material wear and lead to the variation of the surface micro-topography. In turn, the variation of the micro-topography affects the lubrication state between the two contacting surfaces. For the better comprehension of the interaction of lubrication and wear on rough surfaces in mixed lubrication, in this paper, a coupled model of fluid flow, rough contact, and surface wear was established, with fractal theory being applied to predict the changes in surface microtopography. Furthermore, the effects of fractal dimension, roughness direction, contact load and slide-roll ratio on the surface contact area ratio, accumulated wear, film thickness and friction coefficient are analyzed. The results demonstrated that surfaces with large fractal dimension have denser roughness peaks, resulting in larger contact areas and more severe wear. Transverse roughness surfaces exhibit better lubrication and wear performance compared to longitudinal and isotropic surfaces. In addition, increasing the contact load and slip-roll ratio increases the contact area ratio, resulting in lower lubricating performance and increased wear.