基于响应面法的桥梁结构有限元模型修正与应用

发布时间：2018-11-14 09:11

【摘要】：有限元分析法已被广泛的应用于桥梁结构分析中,一个精准的有限元模型对于结构的静动力分析、损伤识别、健康监测等起着至关重要的作用。通常依设计图纸建立的初始有限元模型与实际结构存在着一定差异,要获得精准模型必须对初始模型进行修正。即结合实测的静动载数据修正初始模型中的结构参数,使修正后的模型更好的反应结构的实际受力状态。目前常用的基于灵敏度的修正方法存在一定的弊端,如:筛选参数不准确、构建出病态的灵敏度矩阵,导致收敛速度慢甚至不收敛等。考虑到响应面法存在较多优点,本文研究了响应面法在桥梁结构有限元模型静动力修正中的应用,该方法不仅计算量小、修正效率高,而且修正后的模型能够作为健康监测、损伤识别等的基准模型。首先,对有限元模型修正理论进行了简要概述,阐述了有限元模型修正的基本原理,基本过程,以及模型修正过程中的关键问题。然后对响应面法进行了重点介绍,介绍了应用响应面法进行模型修正的基本原理,并对该方法的每个步骤进行了阐述,其中重点介绍了试验设计和优化算法,详细对比分析了各试验设计和优化算法的优缺点及适用条件。其次,应用响应面法,结合某单梁荷载试验的实测数据,对该单梁初始模型进行了静力修正,其修正结果证实了该方法的可行性。最后,以黄弓大桥为工程实例,以实测的挠度和结构频率作为响应值,采用响应面法对该桥的初始模型进行静动力修正,与初始模型计算值相比,其修正后的计算值更接近实测值,其中修正前后频率的误差由10%左右降至1%左右,挠度误差由20%左右降至2%左右。随后利用其它工况的实测数据对修正后的模型进行验证,其结果误差明显减少,由此验证了运用响应面法对有限元模型进行静动力修正的可靠性。
[Abstract]:Finite element analysis has been widely used in bridge structure analysis. A precise finite element model plays an important role in static and dynamic analysis, damage identification, health monitoring and so on. The initial finite element model based on the design drawings is usually different from the actual structure, so it is necessary to modify the initial model in order to obtain the accurate model. That is, the structure parameters in the initial model can be corrected by using the measured static and dynamic load data, so that the modified model can better reflect the actual stress state of the structure. At present, there are some drawbacks in the commonly used sensitivity-based correction methods, such as the inaccuracy of screening parameters, the construction of ill-conditioned sensitivity matrix, which leads to slow or even non-convergent convergence rate and so on. Considering the advantages of response surface method, this paper studies the application of response surface method in static and dynamic modification of finite element model of bridge structure. Benchmark model for damage identification, etc. Firstly, the theory of finite element model modification is briefly summarized, and the basic principle, basic process and key problems in the process of model modification are expounded. Then the response surface method is introduced emphatically, and the basic principle of model modification by response surface method is introduced, and each step of the method is described, in which the experimental design and optimization algorithm are emphatically introduced. The advantages and disadvantages and applicable conditions of each experimental design and optimization algorithm are compared and analyzed in detail. Secondly, the response surface method is applied to the static modification of the initial model of a single beam with the measured data of a single beam load test. The result of the correction proves the feasibility of the method. Finally, taking the Huanggong Bridge as an engineering example and taking the measured deflection and structural frequency as the response values, the initial model of the bridge is modified by the response surface method, which is compared with the calculated value of the initial model. The calculated value is closer to the measured value. The error of frequency before and after correction is reduced from about 10% to about 1%, and the error of deflection from about 20% to about 2%. Then the modified model is verified by the measured data of other working conditions, and the error of the result is obviously reduced, which verifies the reliability of the static and dynamic modification of the finite element model by using the response surface method (RSM).
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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