A New Film Parameter for Rough Surface EHL Contacts with Anisotropic and Isotropic Structures

Abstract Numerous tribological contacts worldwide rely on adequate lubrication quality for proper functionality. Despite this, there is no existing approach to accurately predict the state of lubrication. The default model since introduced in 1960s—the $$\Lambda$$ ? -ratio, defined as oil film thickness over surface roughness height—is unpredictable and may yield erroneous results. Here, we put forward a framework new updated parameter, $${\Lambda }^{*}$$ ? , which accounts elasto-hydrodynamic (EHL) effects induced by irregularities microscopic scale (micro-EHL). This parameter was validated ball-on-disc tests with engineering surfaces comprising isotropic anisotropic structures. As expected, found experimentally measured true mixed full-film EHL regimes. ability mode represents major advance designing interfaces optimal efficiency durability.