Scuffing failure analysis based on a multidisciplinary coupling model and experimental verification

Abstract

General reductions in lubricant viscosities and increased loads in many machine components mean that the role of tribofilms has become increasingly important to provide adequate surface protection against scuffing. However, the relationship between the scuffing process and the growth and removal of tribofilm has not been systematically demonstrated. In this study, a multidisciplinary coupling model, which includes hydrodynamic lubrication, asperity contact, thermal effect, tribochemistry reaction, friction, and surface wear, was developed to capture the initiation of surface scuffing. Simulations and experiments for a piston ring and cylinder liner contact were conducted following a step-load sequence under different temperature conditions. The results show that high temperature and extreme load could induce the lubricant film collapse, and then the tribofilm breakdown initiates due to the substantially increased removal process. The failures of both lubricant film and tribofilm progress instantaneously in a coupling way, which finally leads to severe scuffing.