连杆齿形配合面微动疲劳损伤研究

发布时间：2018-01-26 21:39

本文关键词： 齿形配合面微动疲劳损伤有限元裂纹预测　出处：《天津大学》2012年硕士论文　论文类型：学位论文

【摘要】：本文针对连杆齿形配合面在服役过程中过早出现裂纹的现象，从微动疲劳角度出发，进行裂纹萌生位置和扩展方向的观察统计，并运用有限元软件建立齿形配合面的接触模型，展开应力场与位移场的数值模拟和裂纹萌生位置的预测，最终提出减缓微动疲劳损伤的建议措施，，为工程应用提供一定的理论依据。本文主要包括以下工作和研究成果： 1.对工程应用中因齿形配合面发生失效的一批连杆进行裂纹位置的统计，得出损伤重点部位为齿形面；从某一典型失效连杆上切割得到齿形面部位，进行裂纹萌生位置和扩展方向的进一步观察，总结微动疲劳损伤的特点；化学成分、力学性能和金相组织等一系列试验检测得到连杆材料性质，其中力学性能为后续有限元分析提供数据支持。 2.根据连杆的动力学分析计算结果，应用非线性有限元分析软件ABAQUS对连杆进行多工况接触分析；在全局模型的基础上，运用子模型技术建立适于微动研究的齿形配合面精细有限元模型，分析齿面应力、位移分布特点。 3.提出累计Ruiz准则法，考虑各个工况载荷大小和作用时间的不同进行加权，将单一工况的Ruiz准则统计值乘以相应的加权系数，最终得到一个工作循环的累计微动疲劳损伤参数，在对比短臂端预测结果与实际损伤位置吻合程度较高后，进行了长臂端齿形面的裂纹位置预测，为连杆的改进设计和损伤评估提供参考。 4.针对螺栓预紧力、配合面摩擦系数、连杆结构设计和表面工程，提出减缓齿形配合面微动损伤的改进措施，为工程应用提供指导。
[Abstract]:In view of the phenomenon that cracks appear prematurely in the service process of the tooth fitting surface of connecting rod, from the angle of fretting fatigue, the observation and statistics of crack initiation position and propagation direction are carried out in this paper. The contact model of tooth fit surface is established by using finite element software, the numerical simulation of stress field and displacement field and the prediction of crack initiation position are carried out. Finally, the suggested measures to reduce fretting fatigue damage are put forward. This paper mainly includes the following work and research results: 1. According to the statistics of the crack position of a batch of connecting rods which have failure due to the failure of the tooth fitting surface in engineering application, it is concluded that the key site of the damage is the tooth shape surface; The tooth profile face position was obtained from the cutting of a typical failure connecting rod. The crack initiation position and propagation direction were observed further, and the characteristics of fretting fatigue damage were summarized. A series of tests such as chemical composition, mechanical properties and metallographic structure are used to test the properties of connecting rod materials, among which the mechanical properties provide data support for the subsequent finite element analysis. 2.According to the dynamic analysis results of the connecting rod, the contact analysis of the connecting rod under multiple working conditions is carried out by using the nonlinear finite element analysis software ABAQUS. On the basis of the global model, the fine finite element model of tooth fit surface is established by using submodel technique, and the distribution characteristics of stress and displacement of tooth surface are analyzed. 3. The accumulative Ruiz criterion method is put forward, considering the different load size and working time of each working condition, the statistical value of Ruiz criterion is multiplied by the corresponding weighting coefficient. Finally, the cumulative fretting fatigue damage parameters of a working cycle are obtained. After comparing the predicted results of short arm end with the actual damage location, the crack location of the tooth surface of the long arm end is predicted. It provides reference for the improved design and damage assessment of connecting rod. 4. Aiming at the pretightening force of bolt, friction coefficient of fit surface, design of connecting rod structure and surface engineering, the improvement measures of reducing fretting damage of tooth fitting face are put forward, which can provide guidance for engineering application.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH114;TH133.5

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