Laser-Induced Fluorescence (LIF) Method-Based Research on the Influence of Textured Water-Lubricated UHMWPE Bearing Tribological Performance

The surface texturing of water-lubricated ultra-high molecular weight polyethylene (UHMWPE) bearing has the advantages of enhancing the hydrodynamic effect, capturing wear debris, reducing secondary friction, and storing water, and is one of the research hotspots in tribology. However, the influence of the surface texture of water-lubricated UHMWPE bearing on the friction performance of bearing is still unclear. Based on the laser induced fluorescence (LIF) method, this study developed an in situ-visualization observation system for water film on the friction interface of non-metallic bearing with the help of transparent glass friction pair. The typical textures with different area ratios, aspect ratios and distribution angles were used as the research objects. The water film thickness, friction coefficient and surface morphology of the friction interface of UHMWPE bearing with different textures under low-speed and heavy-load conditions were analyzed. The results show that elongated textures with a reasonable area ratio and length-to-width ratio, arranged along the direction of friction, are more likely to form hydrodynamic effects and create strong support points at the friction interface. Additionally, the divergent and convergent spaces formed at the inlet and outlet of the textured units cause the lubrication pressure at the inlet to be lower than that at the outlet, resulting in severer wear at the inlet compared to the outlet. The overall trends and the mechanism discussed in this research may be considered as a guideline for the design and optimization of surface texture of water-lubricated UHMWPE bearing.