基于非局部摩擦的钢丝滚道球轴承接触仿真与实验研究

发布时间：2019-04-10 16:28

【摘要】：钢丝滚道球轴承是一种新型的非标准滚动轴承,具有径向尺寸大、轴向尺寸小的结构特点,受到世界各国科学家和工程技术人员的关注。近10年,钢丝滚道球轴承以其抗倾覆能力强和结构尺寸设计灵活等特点被广泛应用于建筑机械、医疗器械和飞行器仿真转台等领域。然而,钢丝滚道往往在循环交变的接触载荷作用下,导致接触疲劳与磨损,严重影响轴系的工作性能。为了探索钢丝滚道发生接触疲劳与磨损的特征和规律,本文将其视为接触问题进行对待,综合运用ANSYS有限元数值模拟方法和接触破坏实验方法对其进行研究。基于非局部摩擦理论模型,在微观尺度上,接触面某一点的摩擦效应不仅与该点的摩擦状态有关,而且与该点一定范围内其它点的摩擦状态也有关。因此本文首先考虑接触表面上微凸结构所引起的非局部摩擦效应,采用统计学方法确定钢丝滚道表面上非局部摩擦效应的作用半径,建立三维粗糙平面和三维粗糙圆柱面实体模型,基于三维粗糙表面建立钢丝滚道球轴承的接触分析模型,对滚动体与钢丝滚道之间的接触行为,在ANSYS中进行有限元数值模拟。三维粗糙表面接触模型对应力应变分布、摩擦应力分布,剪切应力分布,应力集中现象的描述更加接近于实际情况,仿真结果更加真实可信。滚动体与钢丝滚道在切向摩擦应力和循环交变的法向接触应力作用下,接触表面容易产生接触疲劳和磨损。接触破坏实验研究中,通过改变调整垫片的厚度实现接触载荷的精确加载,收集每一组接触载荷作用下的脱落颗粒,与最终发生接触破坏的钢球、钢丝滚道一起制作试样,在激光共聚焦显微镜和扫描电子显微镜下观察产生损伤的组织形貌。与有限元接触仿真结果对比,总结滚动体与钢丝滚道产生接触疲劳与磨损的特征和规律。实验结果表明:滚动体与钢丝滚道接触过程中,接触表面上的微凸结构首先发生接触,产生应力集中和塑性变形。最大剪切应力存在于接触区表层以下的某一深度处,循环交变应力作用下,接触疲劳裂纹在此处产生,然后向两侧或者表面扩展合并,最终脱落形成点蚀,同时加剧接触体间的磨损。本文的研究方法为钢丝滚道球轴承更广泛的应用提供理论支持和实验依据,同时对MEMS微机电系统、超精密加工等其它领域的微观接触问题提供了借鉴。
[Abstract]:Steel wire raceway ball bearing is a new type of non-standard rolling bearing, which has the structural characteristics of large radial size and small axial size, which attracts the attention of scientists and engineers all over the world. In recent 10 years, steel wire raceway ball bearings have been widely used in many fields such as construction machinery, medical devices and simulation turntables for aircraft due to their strong anti-overturning ability and flexible structural design. However, the steel raceway is often subjected to cyclic alternating contact loads, which results in contact fatigue and wear, which seriously affects the performance of the shafting. In order to explore the characteristics and rules of contact fatigue and wear of steel wire raceway, it is treated as contact problem in this paper. ANSYS finite element numerical simulation method and contact failure test method are used to study the contact fatigue and wear of steel wire raceway. Based on the non-local friction theory model, the friction effect of a point on the contact surface is not only related to the friction state of the point, but also to the friction state of other points within a certain range of the point. Therefore, this paper firstly considers the non-local friction effect caused by the micro-convex structure on the contact surface, and uses the statistical method to determine the action radius of the non-local friction effect on the surface of the steel wire raceway. The solid models of three-dimensional rough plane and three-dimensional rough cylindrical surface are established. Based on the three-dimensional rough surface, the contact analysis model of steel wire raceway ball bearing is established. The contact behavior between rolling body and steel wire raceway is simulated by finite element method in ANSYS. The three-dimensional rough surface contact model describes the stress-strain distribution, friction stress distribution, shear stress distribution and stress concentration phenomenon more closely to the actual situation, and the simulation results are more realistic and reliable. Under the action of tangential friction stress and cyclic alternating normal contact stress, contact fatigue and wear are easy to occur on the contact surface between roller and steel wire raceway. In the experimental study of contact failure, the contact load can be accurately loaded by changing the thickness of the gasket, and each group of shedding particles under the action of contact load is collected, and the specimens are made together with the steel ball and steel wire raceway that finally occur contact failure. The morphology of the damaged tissue was observed under laser confocal microscope and scanning electron microscope. Compared with the finite element contact simulation results, the characteristics and rules of contact fatigue and wear between rolling body and steel wire raceway are summarized. The experimental results show that during the process of contact between the roller and the steel wire raceway, the micro-convex structure on the contact surface first occurs contact, resulting in stress concentration and plastic deformation. The maximum shear stress exists at a certain depth below the surface of the contact zone. Under the action of cyclic alternating stress, the contact fatigue cracks occur here and then expand and merge to both sides or surfaces, finally falling off to form pitting corrosion. At the same time, it aggravates the wear and tear between contact bodies. The research method in this paper provides theoretical support and experimental basis for the wider application of steel wire raceway ball bearings and provides reference for micro-contact problems in other fields such as MEMS micro-electromechanical system ultra-precision machining and so on.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH133.3

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