基于子结构模态综合法识别桥面板柔度的理论和试验研究

发布时间：2018-04-20 05:14

本文选题：结构识别 + 模态柔度　；参考：《湖南大学》2015年硕士论文

【摘要】：钢-混凝土组合结构是桥梁结构中的一种常见形式,对其进行结构识别研究有着重要的意义。本文在总结之前研究成果的基础上,对一块实验室钢-混凝土组合桥面板和一座钢-混凝土组合结构桥梁进行静动载试验及子结构模态柔度识别研究。具体研究内容如下:(1)在理论上总结了两种模态柔度计算方法,提出两种模态识别方法在本质上进行模态柔度的求解是一致的。利用两种方法相互转化的特点,可以得到结构的质量归一振型。同时,提出了利用分片测试获取结构整体模态柔度的理论。其过程是对子结构质量归一振型进行拼接得到扩充的整体振型,再利用拼接的振型计算结构的整体柔度矩阵。(2)对一混凝土板有限元模型和一实验室钢-混凝土组合板进行脉冲锤击测试实验,表明单点输入单点输出(SISO),单点输入多点输出(SIMO)和多点输入多点输出(MIMO)等方法均能较为准确地获取模态柔度系数,并能通过子结构振型拼接的方法获得与静力方法相差很小的模态柔度矩阵。通过对一座实际桥梁的脉冲锤击法分片测试,验证了该方法在实际运用的可行性。同时,进行了随机振动测试下的振型质量归一研究。通过有限元数值试验和实验室的随机振动试验表明,基于集中质量矩阵假设,可以利用随机振动测试获取结构的模态柔度,其结果比实际结构要柔。(3)基于模态柔度方法进行结构损伤识别研究。首先,设计了支座刚度变化、连接件损伤和横向支撑破坏这三种损伤工况用来模拟实际桥梁结构可能出现的损伤状况。通过对比结构损伤前后的模态柔度位移信息,成功实现了组合板的损伤识别。结果表明模态柔度是极好的损伤指标,其对损伤的敏感程度比频率和振型大得多。其次,通过静力加载造成试验板的静力损伤,并利用模态柔度方法成功地识别出静力损伤的位置和损伤程度。(4)基于Strand7有限元软件和Mat lab应用程序的API交互访问技术对钢-混凝土组合板结构进行有限元模型修正。首先,比较了三种不同建模方式的钢-混凝土有限元模型,结果表明壳-实体模型能够很好地反映出组合结构的真实静动力性能。然后,基于静动力数据对基准模型的物理参数进行灵敏度分析,选取灵敏度高的4个参数进行多参数模型校验。最后,基于获得的静动力试验数据和Strand7模型分析结果,通过引入Teughels损伤函数识别出了试验板的刚度退化分布。
[Abstract]:Steel-concrete composite structure is a common form of bridge structure. It is of great significance to study the structure identification of steel-concrete composite structure. Based on the previous research results, the static and dynamic load tests and modal flexibility identification of a laboratory steel-concrete composite deck slab and a steel-concrete composite structure bridge are studied in this paper. The main contents of this paper are as follows: (1) two modal flexibility calculation methods are summarized theoretically, and two modal identification methods are proposed to solve the modal flexibility in essence. Using the characteristics of the two methods to transform each other, the quality of the structure can be obtained. At the same time, the theory of obtaining the overall modal flexibility of the structure by piecewise test is put forward. The process is to splice the substructure mass normalized mode to obtain the expansion of the integral mode. Then the finite element model of a concrete slab and a laboratory steel-concrete composite slab are tested by pulse hammer test using the integral flexibility matrix of the jointed mode calculation structure. The results show that SISO, SIMO and MIMOM) can obtain the modal flexibility coefficient more accurately than the other methods, such as single-point input and single-point output (SISO), single-point input multi-point output (SIMO) and multi-point input multi-point output (MIMOO). The modal flexibility matrix with small difference from the static method can be obtained by the substructure mode splicing method. The feasibility of using this method in practical application is verified by testing the pulse hammer method of a practical bridge. At the same time, the model quality normalization under random vibration test is carried out. The finite element numerical test and the random vibration test in laboratory show that the modal flexibility of the structure can be obtained by random vibration test based on the assumption of lumped mass matrix. The result is more flexible than the actual structure. Firstly, three kinds of damage conditions, such as stiffness change of support, joint damage and transverse bracing failure, are designed to simulate the possible damage conditions of actual bridge structures. By comparing the modal flexibility and displacement information before and after structural damage, the damage identification of composite plate is successfully realized. The results show that modal flexibility is an excellent damage index and its sensitivity to damage is much greater than that of frequency and mode shape. Secondly, the static damage of the test plate is caused by static loading. The static damage location and damage degree are identified successfully by modal compliance method. The finite element model of steel-concrete composite slab structure is modified based on the API interactive access technique of Strand7 finite element software and Mat lab application program. Firstly, three kinds of steel-concrete finite element models with different modeling methods are compared. The results show that the shell-solid model can well reflect the real static and dynamic performance of composite structures. Then, based on the static and dynamic data, the physical parameters of the benchmark model are analyzed, and the four parameters with high sensitivity are selected to verify the multi-parameter model. Finally, based on the obtained static and dynamic test data and the results of Strand7 model analysis, the stiffness degradation distribution of the test plate is identified by introducing the Teughels damage function.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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