环境激励下检测桥梁结构损伤的柔度灵敏度方法研究

发布时间：2018-01-12 16:01

本文关键词：环境激励下检测桥梁结构损伤的柔度灵敏度方法研究　出处：《河北工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：桥梁结构的损伤识别对于大型结构的安全使用是至关重要的,在损伤识别过程中如何更加准确地对损伤程度和位置进行判定成为研究热点。本文提出了一种以环境激励下的结构柔度灵敏度为理论基础的损伤识别方法,通过对结构的现场动力检测得到结构损伤后的振型矩阵,以及根据图纸建立其原始的有限元模型进行模态分析得到其未损伤的振型矩阵,利用通过理论推导得到的公式可以计算出结构单元级别的损伤程度。本文主要的研究内容有:1.介绍了一种利用环境激励下的模态数据监测结构损伤的柔度灵敏度方法,对于环境激励下所得的不归一化的振型引入振型归一化系数,并且将这些系数作为新的未知量,通过对柔度灵敏度方程做适当的变形,并利用矩阵的拉直运算和广义逆,把各单元的损伤参数和各振型归一化系数一并予以求解。2.以简支梁为简单模型,根据有限元模型建立的法则进行建模,并且对其某一单元修改弹性模量以模拟结构的损伤,进行模态分析后得到损伤前后的振型,利用提出的柔度灵敏度方法进行损伤识别,以此验证此理论的科学性和实用性。本文对简支梁模型进行了单损伤情况和多损伤情况的对比。针对实际情况的数据不完备性作了模拟分析,验证了实际检测数据不完备时此方法是可行的。3.以承德某大桥为实际工程示例,根据图纸建立原始有限元模型,从而得到质量归一化下的振型矩阵;另外,根据对其进行的实际模态测试以得到该桥梁结构的环境激励下的非质量归一化的模态数据;利用振型归一化系数环境激励下的非质量归一化数据转化为质量归一的数据;最后,将振型归一化系数和损伤参数均视为未知量,通过对柔度灵敏度方程的适当变形,利用广义逆运算进行求解。
[Abstract]:The damage identification of bridge structures is very important for the safe use of large structures. In the process of damage identification, how to determine the damage degree and location more accurately has become a hot topic. In this paper, a damage identification method based on the sensitivity of structural flexibility under environmental excitation is proposed. The mode matrix of the damaged structure is obtained by the field dynamic detection of the structure, and the undamaged mode matrix is obtained by modal analysis of the original finite element model based on the drawing. The damage degree of structural element level can be calculated by the formula derived from theory. The main contents of this paper are as follows:. 1. A flexibility sensitivity method for structural damage monitoring using modal data under ambient excitation is introduced. The normalized mode coefficients are introduced to the non-normalized modes under ambient excitation, and these coefficients are regarded as new unknown variables, and the flexibility sensitivity equation is deformed appropriately. Using the straightening operation of the matrix and generalized inverse, the damage parameters of each element and the normalized coefficient of each mode are solved simultaneously. 2. The simple supported beam is taken as the simple model, and the model is established according to the rule of the finite element model. The elastic modulus is modified to simulate the damage of the structure and the modal analysis is carried out to obtain the mode before and after the damage. The proposed flexibility sensitivity method is used to identify the damage. In order to verify the scientific and practical nature of the theory, this paper makes a comparison between single damage and multiple damage in the simply supported beam model, and simulates and analyzes the data incompleteness of the actual situation. It is proved that this method is feasible when the actual test data is not complete. Taking Chengde Bridge as an example, the original finite element model is established according to the drawing, and the mode matrix under mass normalization is obtained. In addition, according to the actual modal test, the non-mass normalized modal data of the bridge structure under ambient excitation are obtained. The non-quality normalized data is transformed into the quality normalized data under the ambient excitation of the mode normalization coefficient. Finally, the normalized mode coefficients and damage parameters are regarded as unknown variables, which are solved by the generalized inverse operation through the proper deformation of the flexibility sensitivity equation.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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