Influence of surface elliptical dent defects on thermal elastohydrodynamic lubrication performance in ball-tripod universal joints

Herein, the effects of elliptical dent defects on the properties of oil films formed in point-contact thermal elastohydrodynamic lubrication were examined through numerical modelling and ANSYS-based finite element analysis. Peak pressure and temperature of an oil film increase steeply with increasing depth on both sides of a dented edge, resulting in oil thickness variations across the dent and high stress concentration along the edge. Furthermore, peak pressure and temperature increase with the aspect ratio of elliptical dents, accompanied by shifts in subsurface stress directionality. Lubrication performance degrades with increasing dent direction angle and is the lowest when the dent’s long axis aligns with the entrainment direction. These findings highlight the detrimental effects of surface dents on joint lubrication performance.