Mechanic model of water-based boundary lubricated contact based on surface force effects

In water-based boundary lubrication regime, the contact gaps (or boundary lubricated film thickness) and surface pressure distribution must be determined to really understand the boundary lubricated contact mechanism. However, the accurate determination of these parameters is limited. In this study, a mechanical model based on boundary lubricated contact involving surface force effects is developed. The surface force distribution characteristics, normal force vs. central film thickness curve, and macroscale water-based boundary lubricated contact are investigated numerically. The results show that hydration directly affects surface force interaction. The accurate boundary lubricated film thickness and surface pressure distribution can be obtained using this model in point contact. Furthermore, the mechanism of macroscale water- based liquid boundary lubricated contact is investigated, in which a water-based boundary lubricated film is formed under appropriate operating conditions based on surface force effects during running-in. This study can reveal the water-base boundary lubricated contact behavior and the carrying capacity of the surface force effect, and provides important design guidance for the surface force effect to achieve liquid superlubricity in water-based boundary lubricated contacts.