行星架过盈连接结构的微动滑移计算

发布时间：2018-03-20 13:42

本文选题：过盈连接　切入点：微动滑移　出处：《大连理工大学》2012年硕士论文　论文类型：学位论文

【摘要】：风力发电的行星架与法兰采用过盈连接,在风力载荷作用下,过盈配合的接触表面会产生小幅的相对滑动,该现象被称之为微动滑移。微动滑移将导致表面磨损、萌生裂纹甚至可能产生微动疲劳失效。本文采用有限元软件Workbench,建立该结构的有限元模型,编写后处理程序,考虑初始装配和工作载荷下,计算前后过盈配合的微动滑移结果,并分析滑移原因、探讨结构形状参数对微动滑移的影响,最后提出改进方案。首先,介绍有限元接触分析基础。在对接触的定义、摩擦模型、接触类型简要说明后,本文从算法原理和典型算例出发,比较各个接触算法在计算滑移量方面的差异。其次,建立准确且经济的有限元模型。包括：模型简化,忽略不必要的结构特征；轴承等效,因为该结构尺寸较大,其结构刚度接近轴承刚度,所以前后轴承不再视为刚性约束,而是采用弹簧等效；网格划分,选择高阶单元,且在过盈连接区域布置细密网格,达到兼顾精度和效率的目的；将整个分析过程分解为装配、预紧和加载三个分析步,模拟原结构的实际工况；网格划分大小敏感度分析。再次,考虑到Workbench只能输出基于初始状态的合成滑移量,所以需要自行编写后处理程序计算滑移矢量,其主要流程：提取各个接触单元在自然坐标系下的微动滑移,经过坐标变换、节点结果平均,得到全局坐标下的滑移结果,然后根据形函数插值获得接触区域的滑移场。采用该后处理程序,逐个分析研究三个分析步：装配阶段、预紧阶段和加载阶段,分别计算各个分析步的滑移结果,并分析不同网格单元大小对滑移幅值的影响。最后,分析滑移原因和结构影响因素,并据此提出改进方案。从结构形式、载荷形式和滑移结果等角度,分析引起后端滑移的原因,并据此提出对微动滑移有影响的若干结构形状参数,采用上述算流程分析其影响大小。根据影响因素分析结果,提出结构改进方案。改进后,后端过盈的最大滑移幅值从原来的40.0μm降低至8.8μm。
[Abstract]:When the planetary frame of wind power is connected with flange by interference, the contact surface of interference fit will produce small relative sliding under the action of wind load, which is called fretting slip. Fretting slippage will lead to surface wear. Crack initiation may even cause fretting fatigue failure. In this paper, the finite element model of the structure is established by using the finite element software Workbench, and the post-processing program is compiled to calculate the fretting slip results of the interference fit under the initial assembly and working load. The influence of structural shape parameters on fretting slip is analyzed and the improvement scheme is put forward. First of all, the basic of finite element contact analysis is introduced. After a brief description of the definition of contact, friction model and contact type, this paper compares the differences between the contact algorithms in calculating the slip amount from the principle of the algorithm and the typical examples. Secondly, an accurate and economical finite element model is established, which includes: simplification of the model and neglect of unnecessary structural characteristics; bearing equivalence, because the structure is larger in size and its structural stiffness is close to that of the bearing. Therefore, the front and rear bearings are no longer regarded as rigid constraints, but are equivalent to the spring; the mesh is divided, the high-order element is selected, and the fine mesh is arranged in the interference connection area to achieve the purpose of taking into account the accuracy and efficiency; the whole analysis process is decomposed into assembly. Preload and preload are three analytical steps to simulate the actual working conditions of the original structure and the sensitivity analysis of mesh size. Thirdly, considering that Workbench can only output the synthetic slippage based on the initial state, it is necessary to write a post-processing program to calculate the slip vector. The main process is to extract the fretting slippage of each contact unit in the natural coordinate system. After coordinate transformation, the node results are averaged, and the slip results under the global coordinate are obtained. Then the slip field of the contact region is obtained by interpolation according to the shape function. By using the post-processing program, three analytical steps are analyzed and studied one by one: the assembly stage. The slip results of each analysis step are calculated and the effects of different mesh sizes on the slip amplitude are analyzed respectively in the preloading and preloading stages. Finally, the causes of slippage and the factors affecting the structure are analyzed, and an improved scheme is put forward. The causes of the back-end slippage are analyzed from the aspects of structure form, load form and slip result, etc. Based on the above analysis, some structural shape parameters which have influence on fretting slip are put forward, and the influence is analyzed by the above calculation process. According to the analysis results of influencing factors, the scheme of structural improvement is put forward. The maximum slip amplitude of back-end interference is reduced from 40.0 渭 m to 8.8 渭 m.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH131.7

【参考文献】