应变模态分析在机械结构损伤检测中的应用
发布时间：2018-11-03 19:54
【摘要】：机械结构在使用过程中,将会受到正常工作载荷的作用以及各种突发性外在因素影响而出现局部损伤。当局部损伤积累到一定程度时,会导致整体结构的突然失效。对于重要结构,损伤的发生以及机械结构的失效将引起重大的安全事故和经济损失。因此,为保证机械结构的安全与系统的正常工作,需要定期或在线对机械结构进行损伤检测,尽早地发现损伤发生的位置和程度,对结构实时进行修复或改进,避免灾难性事故的发生。 本文从工程实际应用出发,将应变模态方法与工作模态理论相结合应用于机械结构的损伤检测中。具体研究过程如下： 1、通过分析结构损伤识别方法的研究现状和存在的问题,结合具体研究对象对应变模态分析方法做了详细的研究。 2、通过间接损伤诊断数值仿真、实验研究,得出损伤位置、程度对模态参数(频率、阻尼、振型)的一般影响规律。 本文以应变模态振型和应变模态差为损伤识别指标对悬臂梁损伤进行了有效的识别。应变模态振型对非模态节点损伤非常敏感,尤其是对损伤发生在某阶模态峰值区附近时。在损伤附近应变模态发生突变,并且突变程度随损伤量的增加而增大。 3、由加速度信号推算应变模态。 根据材料力学纵应变理论,得出应变与位移的关系。位移信号可以由加速时信号经两次积分得到。从加速度信号推导出应变模态,并从误差的角度分析了这种方法的可行性。计算过程中主要误差来源为两测点信号相减过程中的相位误差。为了减小这种相位误差,提出了一种基于最小方差的处理方法,并通过实验验证了这种方法的可行性。该方法可以使以后的测试及诊断更加方便有效。 4、将应变模态与工作模态综合运用于结构的损伤检测中。 本文将应变模态和工作模态相结合,阐述了应变工作模态的基本原理及频域参数识别方法。针对应变模态与工作模态相结合的研究方法提出新的研究路径,并通过悬臂梁实验验证了这种方法的可行性 总体来说,本文将应变模态分析方法和工作模态的基本理论应用于机械结构的损伤检测中,通过理论的分析推导和实验验证,对所提方法的可行性和有效性进行了分析研究。
[Abstract]:In the process of use, the mechanical structure will be affected by the normal working load and a variety of sudden external factors, resulting in local damage. When the local damage accumulates to a certain extent, it will lead to the sudden failure of the whole structure. For important structures, the occurrence of damage and the failure of mechanical structures will cause serious safety accidents and economic losses. Therefore, in order to ensure the safety of the mechanical structure and the normal work of the system, it is necessary to detect the damage of the mechanical structure on a regular or online basis, to find out the location and extent of the damage as soon as possible, and to repair or improve the structure in real time. Avoid catastrophic accidents. In this paper, the strain mode method is combined with the working mode theory to detect the damage of mechanical structures. The specific research process is as follows: 1. By analyzing the present situation and existing problems of structural damage identification methods, the strain modal analysis method is studied in detail. 2. Through numerical simulation of indirect damage diagnosis and experimental study, the general influence of damage location and degree on modal parameters (frequency, damping, mode shape) is obtained. In this paper, the damage of cantilever beam is effectively identified by using strain mode and strain mode difference as damage identification index. The strain mode is very sensitive to the damage of the non-modal node, especially when the damage occurs near the peak value of a certain mode. A mutation occurs in the strain mode near the damage, and the degree of the mutation increases with the increase of the damage. The strain mode is calculated from the acceleration signal. According to the theory of longitudinal strain in mechanics of materials, the relationship between strain and displacement is obtained. The displacement signal can be obtained from the acceleration signal by two integrals. The strain mode is derived from the acceleration signal and the feasibility of this method is analyzed from the angle of error. The main source of error in the calculation process is the phase error in the process of signal subtraction between two measuring points. In order to reduce the phase error, a processing method based on minimum variance is proposed, and the feasibility of this method is verified by experiments. This method can make the later test and diagnosis more convenient and effective. 4. The strain mode and the working mode are applied to the damage detection of the structure. In this paper, the basic principle of strain working mode and the identification method of frequency domain parameters are expounded by combining the strain mode with the working mode. A new research path is proposed for the combination of strain mode and working mode, and the feasibility of this method is verified by cantilever beam experiment. In this paper, the strain mode analysis method and the basic theory of working mode are applied to the damage detection of mechanical structures. The feasibility and validity of the proposed method are analyzed and studied by theoretical analysis and experimental verification.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH165.3
本文编号：2308840
[Abstract]:In the process of use, the mechanical structure will be affected by the normal working load and a variety of sudden external factors, resulting in local damage. When the local damage accumulates to a certain extent, it will lead to the sudden failure of the whole structure. For important structures, the occurrence of damage and the failure of mechanical structures will cause serious safety accidents and economic losses. Therefore, in order to ensure the safety of the mechanical structure and the normal work of the system, it is necessary to detect the damage of the mechanical structure on a regular or online basis, to find out the location and extent of the damage as soon as possible, and to repair or improve the structure in real time. Avoid catastrophic accidents. In this paper, the strain mode method is combined with the working mode theory to detect the damage of mechanical structures. The specific research process is as follows: 1. By analyzing the present situation and existing problems of structural damage identification methods, the strain modal analysis method is studied in detail. 2. Through numerical simulation of indirect damage diagnosis and experimental study, the general influence of damage location and degree on modal parameters (frequency, damping, mode shape) is obtained. In this paper, the damage of cantilever beam is effectively identified by using strain mode and strain mode difference as damage identification index. The strain mode is very sensitive to the damage of the non-modal node, especially when the damage occurs near the peak value of a certain mode. A mutation occurs in the strain mode near the damage, and the degree of the mutation increases with the increase of the damage. The strain mode is calculated from the acceleration signal. According to the theory of longitudinal strain in mechanics of materials, the relationship between strain and displacement is obtained. The displacement signal can be obtained from the acceleration signal by two integrals. The strain mode is derived from the acceleration signal and the feasibility of this method is analyzed from the angle of error. The main source of error in the calculation process is the phase error in the process of signal subtraction between two measuring points. In order to reduce the phase error, a processing method based on minimum variance is proposed, and the feasibility of this method is verified by experiments. This method can make the later test and diagnosis more convenient and effective. 4. The strain mode and the working mode are applied to the damage detection of the structure. In this paper, the basic principle of strain working mode and the identification method of frequency domain parameters are expounded by combining the strain mode with the working mode. A new research path is proposed for the combination of strain mode and working mode, and the feasibility of this method is verified by cantilever beam experiment. In this paper, the strain mode analysis method and the basic theory of working mode are applied to the damage detection of mechanical structures. The feasibility and validity of the proposed method are analyzed and studied by theoretical analysis and experimental verification.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH165.3
【参考文献】
相关期刊论文 前9条
1 王文静,刘志明,缪龙秀;基于实验模态的结构应变模态分析[J];北方交通大学学报;2000年04期
2 陈淮,禹丹江;基于曲率模态振型进行梁式桥损伤识别研究[J];公路交通科技;2004年10期
3 刘晖,瞿伟廉,袁润章;基于应变能耗散率的结构损伤识别方法研究[J];工程力学;2004年05期
4 郭国会,范培生,易伟进;基于振型变化的框架结构破损评估[J];重庆建筑大学学报;1998年06期
5 李德葆,诸葛鸿程,王波;实验应变模态分析原理和方法[J];清华大学学报(自然科学版);1990年02期
6 瞿伟廉,陈超,魏文辉;基于应变模态的钢结构构件焊缝损伤定位方法的研究[J];世界地震工程;2002年02期
7 李中付,华宏星,宋汉文,陈之炎;非稳态环境激励下线性结构的模态参数辨识[J];振动工程学报;2002年02期
8 姜德生,罗裴,梁磊;光纤布拉格光栅传感器与基于应变模态理论的结构损伤识别[J];仪表技术与传感器;2003年02期
9 顾培英;陈厚群;李同春;邓昌;;基于损伤应变模态的结构损伤识别直接指标法[J];自然科学进展;2007年02期
相关博士学位论文 前1条
1 顾培英;基于应变模态技术的结构损伤诊断直接指标法研究[D];河海大学;2006年
，本文编号：2308840
本文链接：https://www.wllwen.com/kejilunwen/jixiegongcheng/2308840.html
