光弹技术在弹流润滑测试中的应用研究

发布时间：2018-04-01 13:18

本文选题：弹流润滑实验　切入点：光弹性　出处：《华南理工大学》2014年博士论文

【摘要】：弹流润滑摩擦副接触区内部及摩擦副间油膜压力、温升和接触区亚表层的应力测量是弹流润滑领域的基础问题，研究表明虽然弹流润滑的理论建模及数值模拟分析水平已经达到了很完善的水平，建立的理论模型能计算出弹流润滑的膜厚、压力及温升分布，但弹流润滑实验测量问题尚未完全解决，弹流润滑接触区的油膜压力、温升和接触区亚表层的应力分布尚无理想的测量方法。结合当前光弹性测试技术发展，作者首次提出了用光弹性方法进行弹流润滑油膜压力分布、温升和接触区亚表层压力分布测量研究。研究成果对进一步阐明弹流油膜承载机制，揭示摩擦副的失效机理，对摩擦学设计、摩擦材料的制备及润滑设计的性能评价具有重要的指导意义。通过对目前的弹流润滑膜厚测量技术的优缺点进行逐一分析，对弹流润滑的压力和温度测量技术进行综述，指出目前的弹流润滑测试技术主要是膜厚测量技术，而弹流润滑压力测试技术存在不足。颈缩现象和二次压力峰是弹流润滑的重要特征，而通过实验测量颈缩和二次压力峰也是弹流实验的一大难点，经过众多弹流研究科学家的努力，多年来尚无特别完善的实验测量方法。本文首次提出应用光弹技术，利用光弹性材料制作摩擦副，进行弹流润滑压力测量。主要研究工作包括以下几点： 1)通过对光弹应力分析理论基础的介绍，分析光弹性理论中条纹级数与入射光波长的关系，结合弹流润滑接触区的压力分布及尺度特点，从理论上证明了可以应用光弹性技术来测量弹流润滑压力。 2)搭建了弹流润滑光弹测量实验台，并通过实验台进行了弹流润滑压力的测量，实验结果初步证实了通过光弹性进行弹流润滑压力测试实验的可行性。分析了此实验台存在的不足，对实验台进行了结构、加载方式、光源等改进，通过对比白炽灯、荧光灯及LED照明光源的实验效果，确定了采用荧光灯为实验台的照明光源，并引入了菲涅尔透镜作为准直镜。 3)对不同工作压力和滑动、滚动速度状态的润滑压力分布进行了试验，并对实验结果进行了分析对比。光弹性实验结果的应力条纹需要进行定级，而弹流润滑应力区的条纹级数通常较高。尽管进行条纹定级的方法很多，但是人工神经网络在进行光弹条纹定级方面有着独特的优势。通过人工神经网络对弹流润滑光弹实验结果进行了条纹的定级。 4)光弹技术应用于弹流润滑测量实验结果为应力差，为进一步分析，需要进行主应力的分离。光弹应力分离方法包括数值法、实验方法和混合法等三大类，数值法主要是剪应力差及基于LAME-MAXWELL方程的应力分离法、解补偿方程法；实验方法有：钻孔法、斜射法、条带法和条纹涂层法及划线法；混合法主要是基于求等和线法的各类方法和近期出现的数字散斑相关法和红外热成像法。通过分析各种光弹应力分离技术的优缺点，指出目前大部分的光弹应力分离技术均无法直接应用于光弹性弹流润滑压力测量实验，只有红外热成像技术可以较方便地进行弹流润滑光弹实验主应力的分离。 5)最后研究了基于红外成像技术的热应力分析原理，总结了由红外热成像信号到实验试样内部应力和的相关计算公式的推导。搭建了基于红外成像技术的弹流润滑时变热分析实验系统，采用光弹实验进行纯滑动摩擦方式，，进行了石蜡油、二甲基硅油和润滑脂三种不同粘度系数的润滑剂润滑下的动载摩擦热测量实验，获得了不同载荷和滑动线速度实验条件下的摩擦区表面及亚表层温升数据。通过对比分析实验结果，可以认为实验结果正确地反映了载荷对温升的影响趋势，证明了基于红外热成像仪的弹流润滑热应力分析是可行的。
[Abstract]:The stress measurement of the oil film pressure , temperature rise and the sub - surface layer of the contact zone is the basic problem in the field of elastohydrodynamic lubrication . The research results show that the theoretical model and the numerical simulation analysis level of the elastohydrodynamic lubrication have reached a perfect level . The theoretical model can calculate the film thickness , pressure and temperature rise distribution of the elastohydrodynamic lubrication .

This paper reviews the advantages and disadvantages of current elastohydrodynamic lubrication film thickness measurement technology , and summarizes the pressure and temperature measurement techniques of elastohydrodynamic lubrication . It is pointed out that the present technology of elastohydrodynamic lubrication is mainly the film thickness measurement technology , and there is not enough test method for elastohydrodynamic lubrication .

1 ) Based on the theoretical foundation of the light elastic stress analysis , the relationship between the fringe series and the wavelength of incident light is analyzed , and the pressure distribution and the scale characteristic of the contact zone are combined .

2 ) The experiment table of elastohydrodynamic lubrication is set up , and the experimental results show that the feasibility of the experiment of elastohydrodynamic lubrication pressure test is carried out by means of the experimental bench . The experimental results of the experiment show that the experiment table is not enough , the structure , the loading mode and the light source are improved . By comparing the experimental results of the incandescent lamp , the fluorescent lamp and the LED lighting source , the illumination light source with fluorescent lamp as the experimental bench is determined , and the Fresnel lens is introduced as the collimating mirror .

3 ) The distribution of lubricating pressure in different working pressure and sliding and rolling speed states is tested , and the experimental results are compared . The stress stripes of the light elastic experimental results need to be graded , and the number of stripes in the elastic stress region of the elastic flow is usually higher .

4 ) Photoelastic technique is applied to the experimental results of elastohydrodynamic lubrication measurement . For further analysis , it is necessary to separate the main stress . The method includes numerical method , experimental method and mixing method . The numerical method is mainly the shear stress difference and the stress separation method based on the LAME - MAXWELL equation , the solution compensation equation method ;
The experimental methods are : drilling method , oblique beam method , strip method , stripe coating method and scribing method ;
The mixed method is mainly based on the methods of finding and line method and the recent digital speckle correlation method and infrared thermal imaging method . By analyzing the advantages and disadvantages of various techniques of light elastic stress separation , it is pointed out that most of the light elastic stress separation techniques can not be directly applied to the light elastic elastohydrodynamic lubrication pressure measurement experiment , and only the infrared thermal imaging technology can be used to separate the main stress of the elastohydrodynamic lubrication .

5 ) In the end , the principle of thermal stress analysis based on infrared imaging technology is studied , and the formulas for calculating the internal stress and the internal stress of the test specimens are derived . The experimental system for thermal analysis of elastohydrodynamic lubrication based on the infrared imaging technology is established . The experimental results of dynamic load friction measurement under the lubrication of three different viscosity coefficients of paraffin oil , dimethyl silicone oil and lubricating grease are carried out by using the light elastic experiment . The friction zone surface and the subsurface temperature rise data under different load and sliding speed experiment conditions are obtained .

By comparing the experimental results , it can be concluded that the experimental results accurately reflect the influence tendency of the load on the temperature rise , and it is proved that the thermal stress analysis of the elastohydrodynamic lubrication based on the infrared thermal imager is feasible .

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH117.2

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