基于非线性输出频率响应函数的转子裂纹故障诊断方法研究

发布时间：2017-12-31 07:03

本文关键词：基于非线性输出频率响应函数的转子裂纹故障诊断方法研究　出处：《郑州大学》2011年硕士论文　论文类型：学位论文

【摘要】：本论文在国家自然科学基金(50775208、51075372)、湖南省机械设备健康维护重点实验室开放基金(200904)和河南省教育厅自然科学基金(2008C460003)资助下,将非线性输出频率响应函数(Nonlinear output frequency response functions,简称为NOFRF)应用到转子裂纹的故障诊断中去,深入研究了基于NOFRF模型的转子裂纹故障诊断方法,并进行了仿真研究,取得了一些创新性成果。本文的主要内容包括：第一章,论述了本课题的提出及研究意义,综述了非线性系统辨识的国内外研究现状及其在故障诊断中的应用,并对转子裂纹故障的检测诊断方法及国内外的研究现状做了阐述。提出了本论文的主要内容与创新之处。第二章,论述了系统频率响应函数的定义和算法,在此基础上,将线性系统频率响应函数推广到非线性系统中,详细论述了非线性输出频率响应函数的理论,给出了基于非线性频率响应函数模型的故障诊断过程。本章内容是整篇论文的理论基础。第三章,详细讨论了裂纹轴的刚度计算,裂纹转子系统的振动表现出强烈的非线性,裂纹存在减小了转子的刚度,斜裂纹还会引起转轴刚度的相互耦合。本章首先介绍了常用的几种裂纹模型,而后依据断裂力学原理,详细推导了裂纹轴刚度的计算方法,并分析了裂纹位置,裂纹深度等参数变化时,裂纹轴刚度的变化规律,特别对斜裂纹转轴的刚度耦合进行了深入分析,合理解释了斜裂纹转子响应中出现的多频率耦合现象。第四章,非线性输出频率响应函数是在广义频率响应函数的基础上提出来的,是非线性系统Volterra级数模型的深入演化和扩展,它同样能反映系统的本质传递特征,也可以利用系统的输入输出辨识得到,最大优点在于它的表示形式是一维的,更容易理解。基于此,本章将非线性输出频率响应函数(NOFRF)应用到裂纹转子的故障诊断中,提出了基于NOFRF的转子裂纹故障诊断方法。辨识得到裂纹转子的NOFRF值,清楚的解释了系统高阶频率的产生；通过对比不同位置,不同深度的系统各阶NOFRF值,得出了NOFRF值随裂纹参数的变化关系,发现了对裂纹位置敏感的NOFRF值；通过检测敏感参数的变化,结合频域分析,可实现对裂纹故障的检测诊断。实验验证了该方法的有效性。第五章,转子上的斜裂纹引起了系统各方向的刚度耦合,振动特性更加复杂。本文对受水平,垂直,轴向,扭矩四个方向单位载荷情况的直斜裂纹转子系统,进行了动力学方程求解,对比分析了直斜裂纹转子系统的轴向和横向振动特征；辨识得到了斜裂纹转子系统的NOFRF模型各阶核值,分析了裂纹倾角不同时,系统各阶NOFRF值的变化情况,并对相同参数下的正常转轴,直裂纹轴,不同倾角的斜裂纹轴的非线性输出频率响应函数进行了对比研究,得到了斜裂纹故障的特征信息。实验结果表明,NOFRF值不仅能反映裂纹的存在,而且能反映裂纹的方向。第六章,对本文的工作进行了总结,并对非线性系统辨识在旋转机械故障检测与诊断领域的应用做了展望。
[Abstract]:In this paper, the National Natural Science Foundation (5077520851075372), Hunan Province health maintenance for mechanical equipment open fund of Key Laboratory (200904) and the Education Department of Henan Province Natural Science Foundation (2008C460003) funded by the nonlinear output frequency response function (Nonlinear output frequency response functions, referred to as NOFRF) is applied to the fault diagnosis of rotor crack, in-depth study of the fault diagnosis method for rotor crack based on NOFRF model, and the simulation research, some innovative results were achieved. The main contents of this paper include:
The first chapter discusses the background and significance of this topic, reviewed the research status of nonlinear system identification and its application in fault diagnosis, and the research status of detection and diagnosis methods at home and abroad on the rotor crack fault is described in detail. The main contents of this paper and innovation.
The second chapter discusses the definition and algorithm of frequency response functions, on this basis, the linear system frequency response function is extended to nonlinear system, discusses the nonlinear output frequency response function theory, gives the process of fault diagnosis based on the nonlinear frequency response function model. This chapter is the theoretical basis of the whole paper.
The third chapter, calculating the stiffness of the cracked shaft are discussed in detail, the cracked rotor system vibration shows strong nonlinearity, the existence of cracks reduces the stiffness of the rotor, the oblique crack will cause the coupling shaft stiffness. This chapter first introduces several commonly used crack model, and according to the principle of fracture mechanics, are derived in detail. The calculation method of the stiffness of the cracked shaft, and the analysis of the crack location, crack depth and other parameters change, change the stiffness of the cracked shaft, especially stiffness coupling on the inclined crack shaft is analyzed, a reasonable interpretation of the multi frequency coupling lines in response to rotor oblique fissure.
The fourth chapter, the nonlinear output frequency response function is proposed based on generalized frequency response function is the evolution and extension of nonlinear system Volterra series model deeply, it also can reflect the essence of the system transfer characteristics, can also use the input and output system identification, the biggest advantage is that it is a one-dimensional representation that is easier to understand. Based on this, this chapter will nonlinear output frequency response functions (NOFRF) is applied to the fault diagnosis of cracked rotor, the paper puts forward a fault diagnosis method for rotor crack based on NOFRF. The identified crack rotor NOFRF value, clearly explain the high order frequency of the system; through the comparison of different position. The NOFRF order system with different depth values, the variation between NOFRF and crack parameters, found on the crack position sensitive NOFRF value; detectingthesensitiveparameter, node In the frequency domain analysis, the detection and diagnosis of the crack fault can be realized. The validity of the method is verified by the experiment.
The fifth chapter, oblique crack on the rotor caused by the stiffness coupling of the direction of the system, the vibration characteristics are more complex. In this paper, by the horizontal, vertical, axial load, torque direction of four units of straight slant cracked rotor system, by solving the dynamic equation, comparison and analysis of the axial and transverse oblique crack rotor system vibration characteristics; identification by NOFRF model of rotor system of oblique crack of each order nuclear value, to analyze the crack angle is not at the same time, the changes of NOFRF value of each order system, and the normal axis with the same parameters, straight crack shaft, nonlinear output frequency response function of inclined crack shaft with different inclination angles were compared and studied. Get the characteristic information of the oblique crack fault. The experimental results show that NOFRF can not only reflect the existence of crack, and can reflect the direction of the crack.
In the sixth chapter, the work of this paper is summarized, and the application of nonlinear system identification in the field of fault detection and diagnosis of rotating machinery is prospected.

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH165.3

【相似文献】