基于声发射的起重机回转支承裂纹检测技术研究
发布时间：2018-08-30 16:17
【摘要】：起重机回转支承工作环境恶劣，裂纹难以避免。目前，针对旋转机械发展较为成熟的振动诊断法对低速重载回转支承裂纹难以实现有效检测。裂纹发生部位通常较为隐蔽，常规巡检与在线检测技术难以有效发现。针对起重机回转支承在故障诊断特别是早期故障诊断领域所面临的难点问题，，本论文通过对早期裂纹形成机理、声发射信号传播规律及常用材料声发射特性进行分析，探讨采用声发射技术对回转支承进行裂纹检测时声源定位和严重程度识别等方面的问题。论文研究内容主要包括： （1）裂纹形成机理及声发射检测可行性分析。利用疲劳接触理论研究了回转支承裂纹形成机理及裂纹扩展形式，并在弹性波动理论及声发射检测基本原理的基础上，分析了利用声发射技术对回转支承裂纹进行检测的可行性。 （2）声发射信号传播规律及常用材料声发射特性研究。运用显式算法在ANSYS/LS-DYNA中建立了声发射信号传播模型，研究声发射信号在回转支承套圈中传播时传播路径、动力响应、能量衰减等规律；利用拉伸试验和三点弯曲试验对起重机回转支承常用材料的声发射特性进行了试验研究。 （3）基于声发射技术的裂纹源定位及严重程度识别。建立了基于线性时差的回转支承裂纹源定位方法，采用平滑伪Wigner-Ville分布对阈值时差估计法进行了修正，对定位效果进行了模拟试验验证；利用从拉伸试验全过程中获取到的声发射波形信号，建立了基于小波包能量谱和支持向量机的声发射信号严重程度识别模型。 （4）回转支承裂纹检测试验研究及工程应用研究。在起重机回转支承结构健康检测试验平台上进行了回转支承裂纹检测试验研究，验证了声发射检测在回转支承裂纹检测方面的可行性及准确性。在此基础上开展了起重机回转支承裂纹检测的工程应用研究。
[Abstract]:The working environment of the crane slewing support is bad, and the crack is difficult to avoid. At present, it is difficult to detect the crack of low speed heavy load slewing bearing by vibration diagnosis method which is mature for rotating machinery. The location of cracks is usually concealed, and it is difficult to find the conventional inspection and on-line detection techniques. Aiming at the difficult problems of crane slewing bearing in the field of fault diagnosis, especially in the field of early fault diagnosis, this paper analyzes the mechanism of early crack formation, the propagation law of acoustic emission signal and the characteristics of acoustic emission of common materials. In this paper, acoustic emission technology is used to detect the crack of rotary bearing. The problems of sound source location and severity identification are discussed. The main contents of this paper are as follows: (1) the mechanism of crack formation and feasibility analysis of acoustic emission detection. Based on the theory of elastic wave and the basic principle of acoustic emission detection, the mechanism of crack formation and crack propagation in slewing bearing are studied by using fatigue contact theory. The feasibility of using acoustic emission technology to detect cracks in rotary bearing is analyzed. (2) the propagation law of acoustic emission signal and the characteristics of acoustic emission of common materials are studied. The acoustic emission signal propagation model in ANSYS/LS-DYNA is established by using explicit algorithm. The propagation path, dynamic response and energy attenuation of acoustic emission signal propagating in the ring of slewing bearing are studied. The acoustic emission characteristics of the materials commonly used in crane slewing support are studied by tensile test and three-point bending test. (3) crack source location and severity identification based on acoustic emission technology. A method for locating crack source of slewing bearing based on linear time difference is established. The method of threshold time difference estimation is modified by using smooth pseudo-Wigner-Ville distribution, and the localization effect is verified by simulation test. Using the acoustic emission waveform obtained from the whole process of the tensile test, The acoustic emission signal severity recognition model based on wavelet packet energy spectrum and support vector machine is established. (4) the experimental research and engineering application research on crack detection of slewing bearing. The crack detection of slewing bearing is studied on the health test platform of crane slewing bearing structure, and the feasibility and accuracy of acoustic emission detection in the detection of slewing bearing crack are verified. On this basis, the engineering application research of crane slewing bearing crack detection is carried out.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH165.3
[Abstract]:The working environment of the crane slewing support is bad, and the crack is difficult to avoid. At present, it is difficult to detect the crack of low speed heavy load slewing bearing by vibration diagnosis method which is mature for rotating machinery. The location of cracks is usually concealed, and it is difficult to find the conventional inspection and on-line detection techniques. Aiming at the difficult problems of crane slewing bearing in the field of fault diagnosis, especially in the field of early fault diagnosis, this paper analyzes the mechanism of early crack formation, the propagation law of acoustic emission signal and the characteristics of acoustic emission of common materials. In this paper, acoustic emission technology is used to detect the crack of rotary bearing. The problems of sound source location and severity identification are discussed. The main contents of this paper are as follows: (1) the mechanism of crack formation and feasibility analysis of acoustic emission detection. Based on the theory of elastic wave and the basic principle of acoustic emission detection, the mechanism of crack formation and crack propagation in slewing bearing are studied by using fatigue contact theory. The feasibility of using acoustic emission technology to detect cracks in rotary bearing is analyzed. (2) the propagation law of acoustic emission signal and the characteristics of acoustic emission of common materials are studied. The acoustic emission signal propagation model in ANSYS/LS-DYNA is established by using explicit algorithm. The propagation path, dynamic response and energy attenuation of acoustic emission signal propagating in the ring of slewing bearing are studied. The acoustic emission characteristics of the materials commonly used in crane slewing support are studied by tensile test and three-point bending test. (3) crack source location and severity identification based on acoustic emission technology. A method for locating crack source of slewing bearing based on linear time difference is established. The method of threshold time difference estimation is modified by using smooth pseudo-Wigner-Ville distribution, and the localization effect is verified by simulation test. Using the acoustic emission waveform obtained from the whole process of the tensile test, The acoustic emission signal severity recognition model based on wavelet packet energy spectrum and support vector machine is established. (4) the experimental research and engineering application research on crack detection of slewing bearing. The crack detection of slewing bearing is studied on the health test platform of crane slewing bearing structure, and the feasibility and accuracy of acoustic emission detection in the detection of slewing bearing crack are verified. On this basis, the engineering application research of crane slewing bearing crack detection is carried out.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH165.3
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