挖掘机履带链轨节刚柔耦合仿真及疲劳失效分析

发布时间：2018-07-10 02:32

本文选题：履带 + 链轨节　；参考：《吉林大学》2017年硕士论文

【摘要】：履带链轨节作为履带行走装置的重要组成零件,常处于恶劣的工作环境中,所受载荷复杂多样,易出现裂纹并导致失效而影响整个履带行走装置的正常工作。论文结合校企合作项目“XE60CA液压挖掘机履带底盘性能分析及故障机理研究”对履带链轨节进行了失效原因探究。为确定裂纹类型,本文首先对链轨节进行极限静强度校核,同时对裂纹进行扫描电镜实验,结合静强度校核结果和电镜图像,判断了链轨节出现的裂纹为疲劳裂纹。为进一步探究链轨节形成疲劳裂纹的原因,对履带行走装置模型中的一对链轨节进行柔性化处理并进行刚柔耦合动力学仿真,基于仿真得到链轨节的载荷时间历程,在此基础上对链轨节进行了疲劳分析。在查阅国内外相关文献的基础之上,综述了履带链轨节失效相关的国内外研究现状。建立了履带行走装置虚拟样机模型,并通过挖掘机典型工况试验验证了模型的正确性。根据挖掘机虚拟样机仿真获得的载荷,针对挖掘机可能出现的三种极端工况,通过有限元法对链轨节进行了计算,结果表明链轨节的静强度满足要求。为了探究链轨节出现疲劳裂纹的原因,本研究通过RecurDyn软件中的疲劳分析模块对链轨节进行疲劳失效分析。基于虚拟样机模型,先对XE60CA挖掘机履带行走装置中的一对链轨节进行柔性化处理,针对直线行驶、爬坡以及原地转向三种典型工况进行刚柔耦合仿真,得到各工况下履带链轨节的载荷时间历程。将履带链轨节在典型工况下的载荷时间历程导入到疲劳分析模块,对载荷时间历程进行雨流计数、平均应力修正,设置材料的S-N曲线,最后对链轨节进行疲劳失效分析。结果显示,链轨节易疲劳失效的区域为链轨节前销轴孔与底部的连接处,与链轨节的实际裂纹位置相吻合,验证了本文所采用研究方法的正确性。本文通过有限元静强度校核结合裂纹断口扫描电镜图像判断了链轨节的失效类型,基于刚柔耦合仿真所获得的载荷时间历程对链轨节进行了疲劳寿命分析。论文所采用的研究方法以及得出的相关结论对履带链轨节的研究与设计提供了有效参考,对优化链轨节结构设计,提高其使用寿命具有一定意义。
[Abstract]:As an important part of the crawler walking device, the track joint of the track is often in a bad working environment, and the loads are complex and varied, which can easily lead to cracks and lead to failure, which will affect the normal work of the whole crawler walking device. In this paper, the failure reasons of track joint of XE60CA hydraulic excavator are studied in combination with the project "performance analysis and fault mechanism study of track chassis of XE60CA hydraulic excavator". In order to determine the crack type, the ultimate static strength of the rail joint is checked, and the crack is tested by scanning electron microscope (SEM). Combined with the static strength checking result and the electron microscope image, the fatigue crack of the chain rail joint is judged. In order to further explore the cause of fatigue crack in the chain rail joint, the flexible treatment of a pair of chain rail joints in the crawler walking device model and the dynamic simulation of rigid-flexible coupling are carried out. Based on the simulation, the load time history of the chain rail joint is obtained. On this basis, the fatigue analysis of the rail joint is carried out. On the basis of consulting related literatures at home and abroad, this paper summarizes the research status of track joint failure related to crawler chain at home and abroad. The virtual prototype model of crawler walking device is established, and the correctness of the model is verified by the typical working condition test of excavator. According to the load obtained by the simulation of the excavator virtual prototype, aiming at the three extreme conditions that the excavator may appear, the finite element method is used to calculate the link of the rail. The results show that the static strength of the link meets the requirements. In order to investigate the cause of fatigue crack in the rail joint, the fatigue failure analysis of the rail joint is carried out by the fatigue analysis module of RecurDyn software. Based on the virtual prototype model, the flexible processing of a pair of links in the track walking device of XE60CA excavator is first carried out, and the rigid-flexible coupling simulation is carried out for three typical conditions of straight line driving, slope climbing and in situ steering. The load time history of the track joint of the crawler chain under various working conditions is obtained. The load time history of track joint under typical working condition is introduced into the fatigue analysis module. The load time history is counted by rain flow, the average stress is corrected, the S-N curve of material is set up, and the fatigue failure analysis of the rail joint is carried out. The results show that the fatigue failure area of the link rail joint is the joint between the shaft hole and the bottom of the chain rail joint, which coincides with the actual crack position of the link rail joint, which verifies the correctness of the research method used in this paper. In this paper, the failure types of chain rail joints are judged by finite element static strength checking and scanning electron microscope image of crack fracture. The fatigue life of chain rail joints is analyzed based on the load time history obtained by rigid-flexible coupling simulation. The research methods adopted in this paper and the relevant conclusions provide an effective reference for the research and design of the crawler rail joint. It is of certain significance to optimize the structural design of the rail joint and to improve its service life.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU621

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