【作者】 李霞；

【导师】 郭峰；

【作者基本信息】 青岛理工大学 ， 机械设计及理论， 2014， 博士

【摘要】 流体动压润滑是摩擦副的基本润滑机制，承载量和摩擦力是其中的两个重要参数，被用来评价润滑性能。本课题基于面接触润滑膜光学测量系统，开发了承载量和摩擦力的测量技术，并将测量技术应用于生物润滑液的润滑学实验研究。完成的主要工作包括：(1)提出了一种润滑膜承载量测量的新方法。该方法应用光干涉技术在面接触流体润滑条件下测量得到膜厚-速度曲线，通过无量纲转换，得到承载量特性曲线（无量纲承载量-收敛比）。该方法避免了不同收敛比的人工调节和流体总压力的测量，有较高的测量效率。实测表明提出的方法可用于估算流体动压润滑薄膜承载能力；测量曲线同经典理论曲线呈现相同的变化趋势；更为重要的是，实验表明承载量的大小不仅仅依赖于收敛比的大小，经典的理论有待修正。针对高膜厚测量中级次丢失的现象，采用光干涉阶梯速度测量方法，实现了高膜厚的准确测量。设计了摩擦力测量系统，提出了测量值的修正方法，以实现流体动压润滑条件下较小摩擦力的精确测量。对测得的膜厚-速度进行变换，获得摩擦系数和收敛比的实验测量曲线。该曲线与同经典理论曲线呈现相同的变化趋势，但同时表明无量纲的摩擦系数并不如经典理论所预测的唯一由收敛比决定，而是受倾角及载荷等因素的影响。(2)对水基透明质酸溶液的流体润滑特性进行了实验研究，发现透明质酸水溶液有良好的润滑成膜特性和承载能力。在低速下，小间隙倾角对应高膜厚，这对于人工关节直径间隙的设计有参考意义。同时通过膜厚测量证实了透明质酸水溶液具有剪切稀化特性。为评价全膜润滑条件下透明质酸水溶液流变特性，提出了相对黏度的测量方法定量评价剪切稀化的水平。(3)利用面接触测量系统对蛋白质水溶液润滑特性进行了实验研究。通过光干涉图像对蛋白质表面吸附进行了在线观察。使用扫描电镜、原子力显微镜及表面形貌仪对滑块表面进行了分析，发现在流体润滑条件下蛋白质在钢块表面形成两种类型的吸附，一为连续的薄膜层，二为离散的蛋白质凝聚团簇。基于光学膜厚的计算，提出了一种双介质光干涉方法对蛋白质的吸附膜厚度进行估算，结果表明，吸附层的形成受润滑膜剪应变率和压力的影响，高的剪应变率和低的载荷有利于吸附膜的增长。实验同时证实了钢块表面微观腐蚀的存在。微腐蚀先在入口区发生并向出口区扩展，该腐蚀促进吸附膜的增长，实验表明微腐蚀的发生受速度、载荷及倾角等的影响。对多组分仿生滑液进行了实验研究，实验过程中发现微腐蚀及蛋白质吸附层的存在，吸附层的形成具有位置选择性。本课题以现有的光干涉面接触润滑膜测量系统为基础，开发了承载量和摩擦力的测量技术，利用改进的面接触测量系统实现了测量；对仿生滑液润滑特性的研究表明，该面接触润滑膜测量系统适用于生物滑液润滑特性的实验研究，为生物摩擦学的研究提供了一种新的手段。更多还原

【Abstract】 Hydrodynamic lubrication is a basic lubrication mechanism of friction pair.Load-carrying capacity and friction are two important parameters in study of lubricationwhich are often used to evaluate lubricating properties. This topic has developed themeasurement technologies of load-carrying capacity and friction based on theslider-on-disc lubricating film test system. And these technologies are applied to thelubricating experimental study of biological lubricants. The main work includes:(1) A new method has been put forward to measure the load-carrying capacity oflubricating film. The measured film thickness versus speed curve was measured usingoptical interference technology under hydrodynamic lubrication condition in conformalcontacts. The load characteristic curve (dimensionless load-carrying capacity versusconvergence ratio) was got using dimensionless transformation. This method does notneed to adjust convergence ratio by manual and measure total pressure of fluid whichhas high measuring efficiency. Experiments show the new method proposed can be usedto evaluate the load-carrying capacity of lubricating film. The experimental results andclassical theoretical formula present the same trend. Even more important, theexperimental results show that the load-carrying capacity does not exclusively dependon the convergence ratio, which is different from the theoretical prediction. Theclassical theory needs to be revised.The interference levels easily loss in the measurement of high film thickness, so thestep speed measuring method has been used, and accuracy measurement has beendirectly achieved.The system was designed to measure the friction. The method of correcting was putforward to finish the accurate measurement of smaller friction under hydrodynamiclubrication. To transform the parameters based on the measured curve of film thicknessand speed, the friction coefficient versus the convergence ratio curve was got. Theexperimental curve and the theoretical curve present the same trend. The results showthat the dimensionless friction coefficient does not exclusively depend on theconvergence ratio, which is different from the theoretical prediction. The dimensionlessfriction coefficient is affected by the inclination and load factors.(2) The experiments have been carried out to study the fluid lubrication characteristics of water-based hyaluronic acid solution. It is shown hyaluronic acidaqueous solution has the good lubricating properties and load-carrying capacity. Underlow speed, high film thickness is got when inclination is small, which has referencesignificance to the design of artificial joint diameter clearance. It is shown hyaluronicacid aqueous solution has the shear thinning property by measuring the film thickness.A new technology was used to measure the rheological properties of hyaluronic acidaqueous solution under full-film lubrication. The measuring method of relative viscosityhas been proposed to evaluate the shear thinning property quantitatively.(3) The lubricating properties of protein aqueous solution have been studied byexperiments using the conformal contact measurement system. Protein adsorption onsteel slider surface has been observed online using optical interference images. Thesurface of slider was analyzed using scanning electron microscope, atomic forcemicroscope and surface profilometer. Two types of adsorption were found. One is acontinuous thin layer adsorption, and the other is discontinuous clusters. The other wascontinuous adsorption. A new approach based on optical film thickness formed with twodifference media was proposed to measure the thickness of the protein adsorption film.The formation of adsorption layer is affected by the shear rate and pressure. High shearrate and low load favored the growth of adsorbed film. The experimental results showthe existence of micro-corrosion on surface of the steel slider. And the micro-corrosionwas happened firstly in the inlet. It grew from the inlet to the outlet and promoted thegrowth of adsorption. The experimental results show that the micro-corrosion is affectedby the speed, load, and inclination.The multicomponent simulated synovial fluid has been preliminarily studied byexperiments. The protein adsorption layer and micro-corrosion is found on the surfaceof steel slider. What interested us is that the layer formation demonstrates positionselectivity.This topic developed measuring technologies of load-carrying capacity and frictionbased on the lubricating film measurement system of optical interference. The testsystem of conformal contacts has been improved for measurements of load-carryingcapacity and friction. Researches of simulated synovial fluid showed this system is suitable for study of the lubricating properties of biological synovia. It provides a newmethod for the research of bio-tribology.更多还原