A Macro-Micro-Fatigue approach for predicting fatigue life in mixed-EHL contact

Surface contact fatigue is one of the major failures that threaten the life of engineering components. A Macro-Micro-Fatigue approach for analyzing the effect of roughness on fatigue life in mixed elastohydrodynamic lubrication contact is developed and presented. This method involves two macro-micro approaches, a macro-micro mixed-lubrication approach for lubrication analysis and a macro-micro contact stress approach. The macro-micro approaches allow not only efficient modeling of pressure and film thickness distributions over the entire area of contact, but a detailed account of asperity interaction effects as well. A three-stage process is designed to comprise a rough-surface contact solver, a simplified mixed elastohydrodynamic lubrication solver, and a hydrostatic rough-contact stress solver. Subsurface stresses are calculated by means of the fast Fourier transform, and fatigue life is estimated using a version of the Zaretsky fatigue model. Typical point mixed-EHL contacts of rough surfaces are analyzed and results are presented on a comparative basis.