Influence of thermal conductivity of contact bodies on perturbed film caused by a ridge and groove in point EHL contacts

The effects of a transverse ridge and groove in ceramics (Si3N4 and ZrO2) and steel circular contacts on the film thickness, pressure and temperature are discussed through transient non-Newtonian thermal EHL analyzes. The appearance time and the moving velocity of a perturbed film generated by a surface irregularity are mainly affected by the sign of slid-roll ratio, which relates directly to the thermal viscosity wedge effect, and the surface where the irregularity exists. The moving velocity of the perturbed film does not necessarily corresponds to the entrainment velocity. The perturbed film produced by the groove brings about a higher pressure at the ridge position depending on the relative position between the groove and the ridge.