| Nowadays, researchers have conducted lots of theoretical and experiment researches about how to improve the friction performance of artificial human joint. After millions of years of evolution, the elytra of beetle shows special non-smooth surface textures. Large amount of experimental studies have shown its superior ability of wear-resistance and lubrication, so it has been used in the research of artificial human joint.An observation with Keyence was made, the results showed that the elytra have a non-smooth surface, including furrow-like grooves, flake-like polygon, eye-like pits and other micro pit structures. Positive hex and negative circle structure were designed in this paper.Numerical solution was made under hydrodynamic lubrication condition based on Reynolds equation to investigate the effect of two kinds of surface textures on the hydrodynamic pressure generation. Based on the friction coefficient, the optimum structure was obtained according to the average film pressure and coefficient.The base was produced after different processing including polishing, photoetching, electroforming, then the UHMWPE samples were prepared by pre-press and hot press process, the parameters are showed as follows: pit-diameter(100 ?m), pit-depth(5 ?m), pit-ratio(10.4%), hexlength(55 ?m), hex-height(5 ?m), hex-ratio(10.4%).Ball-on-plane friction experiment was carried out by using the sodium hyaluronate solution as lubricant. By comparing the coefficient of different textures, the circle texture showed the lowest coefficient, which testify the correctness of theoretical research.An ball-on-plane elastic-hydrodynamic lubrication model was established. By multi-grid numerical methods, the film pressure and film thickness distribution was analysed and the minimum film thickness was also calculated. Empirical formula was used to calculate the minimum film thickness of ball-on-socket. The results showed great consistency with the numerical methods. |
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