框架结构模态辨识及损伤诊断方法的改进与应用
发布时间：2019-01-09 16:01
【摘要】：工程结构的模态参数辨识及损伤诊断是结构健康监测的核心技术与理论基础。结构的地震损伤可以通过结构物理参数及动力特性的变化来估计，，这样就可用模态参数辨识方法来评估结构的地震损伤。结构地震损伤评估为震后结构的安全性评定及加固修复提供理论依据，具有较重要的工程实用价值。本文首先提出了结构模态参数辨识与损伤诊断的方法，进而对结构地震损伤进行评估，主要研究内容归纳如下： ①简要介绍了相关的研究背景和意义，对结构模态参数辨识方法、结构损伤诊断方法及地震损伤评估方法的国内外研究现状进行了阐述。 ②针对经验模式分解存在的缺点，提出了将数字滤波器和经验模式分解结合的ARMA法、SRCE法、STD法，针对四层钢框架试验模型、BHM Benchmark试验模型和仿真模型进行了模态参数辨识。辨识结果表明，所提方法能有效分离密集模态，避免了单独使用经验模式分解可能出现的模态混叠问题，免除了ARMA法、SRCE法、STD法定阶问题的困扰。进一步与随机子空间法的模态参数辨识结果进行了对比。 ③结合模态应变能变化率指标法和直接解析法的优点，提出了一种新的两阶段损伤诊断方法：第一阶段使用模态应变能变化率指标进行损伤定位，第二阶段使用直接解析法对损伤单元进行损伤定量。数值分析结果表明：所提方法不仅大大降低了直接解析法损伤未知量的求解数目，而且大大降低了损伤识别所需的模态阶数，仅需结构的低阶模态就能准确地进行损伤诊断，这样在理论上更加接近于工程实用。 ④通过计算结构地震损伤前后模态参数的变化量，并建立这种变化与结构损伤状态参数的关系，提出了一种实用的结构地震损伤评估方法。利用IDARC对五层钢筋混凝土框架结构进行地震反应分析，绘出结构各层的损伤指数时程曲线来对结构地震响应进行分段，运用随机子空间方法识别出完好状态和破坏状态下的模态参数。通过改变输入地震动的加速度峰值来获得结构在不同损伤程度下的模态参数，从而建立结构整体损伤指数与模态参数变化的关系，并拟合了经验公式。这样就可以由模态参数变化得到的结构整体损伤指数来评估结构的地震损伤状态。
[Abstract]:Modal parameter identification and damage diagnosis of engineering structures are the core technology and theoretical basis of structural health monitoring. The seismic damage of structures can be estimated by the changes of physical parameters and dynamic characteristics of structures, so the modal parameter identification method can be used to evaluate the seismic damage of structures. Seismic damage assessment of structures provides a theoretical basis for the safety assessment and reinforcement and repair of post-earthquake structures, which is of great practical value in engineering. In this paper, a method of structural modal parameter identification and damage diagnosis is put forward, and then the seismic damage of structure is evaluated. The main research contents are summarized as follows: 1 the research background and significance are briefly introduced. The research status of structural modal parameter identification method, structural damage diagnosis method and seismic damage assessment method at home and abroad are described. (2) aiming at the shortcomings of empirical mode decomposition, ARMA method, SRCE method and STD method are proposed to combine digital filter and empirical mode decomposition. Modal parameter identification is carried out for, BHM Benchmark test model and simulation model of four-layer steel frame test model. The identification results show that the proposed method can effectively separate the dense modes, avoid the problem of modal aliasing which may occur by using empirical mode decomposition alone, and eliminate the problem of ARMA method, SRCE method and STD order problem. The results are compared with the modal parameter identification results of the stochastic subspace method. (3) combining the advantages of modal strain energy change rate index method and direct analytical method, a new two-stage damage diagnosis method is proposed. In the first stage, the modal strain energy change rate index is used to locate the damage. In the second stage, direct analytical method was used to quantify the damage. The results of numerical analysis show that the proposed method not only reduces the number of damage unknowns solved by direct analytical method, but also reduces the number of modal orders required for damage identification. In theory, it is closer to engineering practice. 4. By calculating the variation of modal parameters before and after earthquake damage, and establishing the relationship between this change and structural damage state parameters, a practical method for structural seismic damage assessment is proposed. The seismic response of five-story reinforced concrete frame structure is analyzed by IDARC, and the damage index time-history curve of each layer is drawn to segment the seismic response of the structure. The random subspace method is used to identify the modal parameters in the intact state and the failure state. The modal parameters of the structure with different damage degree are obtained by changing the acceleration peak of the input ground motion, and the relationship between the structural damage index and the modal parameters is established, and the empirical formula is fitted. In this way, the seismic damage state of the structure can be evaluated by the damage index of the whole structure obtained from the variation of the modal parameters.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU317;TU375.4
[Abstract]:Modal parameter identification and damage diagnosis of engineering structures are the core technology and theoretical basis of structural health monitoring. The seismic damage of structures can be estimated by the changes of physical parameters and dynamic characteristics of structures, so the modal parameter identification method can be used to evaluate the seismic damage of structures. Seismic damage assessment of structures provides a theoretical basis for the safety assessment and reinforcement and repair of post-earthquake structures, which is of great practical value in engineering. In this paper, a method of structural modal parameter identification and damage diagnosis is put forward, and then the seismic damage of structure is evaluated. The main research contents are summarized as follows: 1 the research background and significance are briefly introduced. The research status of structural modal parameter identification method, structural damage diagnosis method and seismic damage assessment method at home and abroad are described. (2) aiming at the shortcomings of empirical mode decomposition, ARMA method, SRCE method and STD method are proposed to combine digital filter and empirical mode decomposition. Modal parameter identification is carried out for, BHM Benchmark test model and simulation model of four-layer steel frame test model. The identification results show that the proposed method can effectively separate the dense modes, avoid the problem of modal aliasing which may occur by using empirical mode decomposition alone, and eliminate the problem of ARMA method, SRCE method and STD order problem. The results are compared with the modal parameter identification results of the stochastic subspace method. (3) combining the advantages of modal strain energy change rate index method and direct analytical method, a new two-stage damage diagnosis method is proposed. In the first stage, the modal strain energy change rate index is used to locate the damage. In the second stage, direct analytical method was used to quantify the damage. The results of numerical analysis show that the proposed method not only reduces the number of damage unknowns solved by direct analytical method, but also reduces the number of modal orders required for damage identification. In theory, it is closer to engineering practice. 4. By calculating the variation of modal parameters before and after earthquake damage, and establishing the relationship between this change and structural damage state parameters, a practical method for structural seismic damage assessment is proposed. The seismic response of five-story reinforced concrete frame structure is analyzed by IDARC, and the damage index time-history curve of each layer is drawn to segment the seismic response of the structure. The random subspace method is used to identify the modal parameters in the intact state and the failure state. The modal parameters of the structure with different damage degree are obtained by changing the acceleration peak of the input ground motion, and the relationship between the structural damage index and the modal parameters is established, and the empirical formula is fitted. In this way, the seismic damage state of the structure can be evaluated by the damage index of the whole structure obtained from the variation of the modal parameters.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU317;TU375.4
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