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

General reductions in lubricant viscosities and increasing loads in machine components highlight the role of tribofilms in providing surface protection against scuffing. However, the relationship between the scuffing process and the growth and removal of tribofilm is not well understood. In this study, a multiphysics 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, which in turn triggers the breakdown of the tribofilm due to the significantly increased removal process. The failures of both lubricant film and tribofilm progress instantaneously in a coupling way, which finally leads to severe scuffing.