悬索桥有限元模型修正的响应面方法

发布时间：2019-06-21 04:05

【摘要】：一个准确的有限元模型是桥梁结构健康监测中传感器优化布设、损伤识别、安全评定以及状态预测的基础。响应面方法已经在结构的优化设计、简单桥梁结构有限元模型修正中得到应用。本文将响应面方法应用于超大跨悬索桥梁的有限元模型修正中,研究内容和结论如下： (1)分析了以健康监测为目标的桥梁结构三维有限元模型的建模需求和建模策略。详细阐述了超大跨悬索桥的受力特征、主缆线形的计算理论以及破坏形式,以减小建模过程中的不确定性,并以此为基础建立了某超大跨悬索桥的三维有限元模型,并对该模型做了简要的静力和动力特性分析。 (2)详细阐述了基于径向基函数响应面方法的有限元模型修正方法,并详细介绍了基于灵敏度分析方法的待修正参数的选取、特征信息的选取要求、目标函数的构建方法以及优化方法的选取等。把上述方法应用于实验室钢桁架模型有限元模型修正中,并以实验数据验证了该方法的有效性,修正结果表明,修正后的各修正参数依然能够保持原有的物理意义,并且修正后的有限元模型的特征信息能够反映真实结构的特征信息。 (3)把基于径向基函数响应面的有限元模型修正方法应用于超大跨悬索桥有限元模型修正中,以获得能反映结构真实状态的超大跨悬索桥基准有限元分析模型。首先利用灵敏度分析方法选取待修正参数和可用的特征量信息,以中心复合试验设计方法构造不同摄动水平下的待修正参数样本,通过有限元模型的静动力分析计算不同参数水平下的特征量样本；然后,以待修正参数样本和特征量样本为结构系统输入和输出,建立能逼近大型结构系统设计参数与特征量之间复杂隐式函数关系的径向基响应面模型,最后,基于建立的响应面模型以及目标函数,采用优化算法对结构有限元模型进行修正。结果表明：修正后的有限元模型能够更真实的反映结构的物理状态,较好的体现了该桥梁结构的真实静动力特性。该方法具有较高的计算效率和精度,适用于超大跨悬索桥的有限元模型修正。 (4)对修正后的悬索桥有限元模型进行了静力实验验证,验证的结果表明,修正后的有限元模型的静载分析结果能够较好地与实际监测结果吻合,修正后的有限元模型具有较高的精度。
[Abstract]:An accurate finite element model is the basis of sensor optimization, damage identification, safety assessment and state prediction in bridge structural health monitoring. The response surface method has been applied in the optimization design of structures and the modification of finite element model of simple bridge structures. In this paper, the response surface method is applied to the finite element model modification of super-large span suspension bridge. The research contents and conclusions are as follows: (1) the modeling requirements and modeling strategy of 3D finite element model of bridge structure aiming at health monitoring are analyzed. In order to reduce the uncertainty in the modeling process, the stress characteristics of the super-large span suspension bridge, the calculation theory of the main cable alignment and the failure form are described in detail, on the basis of which the three-dimensional finite element model of a large-span suspension bridge is established, and the static and dynamic characteristics of the model are briefly analyzed. (2) the finite element model correction method based on radial basis function response surface method is described in detail, and the selection of parameters to be modified based on sensitivity analysis method, the selection requirements of feature information, the construction method of objective function and the selection of optimization method are introduced in detail. The above method is applied to the modification of the finite element model of the laboratory steel truss model, and the effectiveness of the method is verified by the experimental data. The modified results show that the modified parameters can still maintain the original physical meaning, and the feature information of the modified finite element model can reflect the characteristic information of the real structure. (3) the finite element model modification method based on radial basis function response surface is applied to the finite element model modification of super-long span suspension bridge in order to obtain the reference finite element analysis model which can reflect the real state of the structure. Firstly, the parameters to be modified and the available characteristic information are selected by using the sensitivity analysis method, and the samples of the parameters to be modified under different perturbation levels are constructed by the central composite test design method, and the characteristic samples at different parameter levels are calculated by the static and dynamic analysis of the finite element model. Then, taking the parameter samples and feature samples to be modified as the input and output of the structural system, the radial basis response surface model which can approximate the complex implicit function relationship between the design parameters and the feature quantity of the large-scale structural system is established. Finally, based on the established response surface model and objective function, the finite element model of the structure is modified by using the optimization algorithm. The results show that the modified finite element model can reflect the physical state of the structure more truly and better reflect the real static and dynamic characteristics of the bridge structure. This method has high computational efficiency and accuracy and is suitable for finite element model modification of super-large span suspension bridges. (4) the modified finite element model of suspension bridge is verified by static experiment. The results show that the static load analysis results of the modified finite element model are in good agreement with the actual monitoring results, and the modified finite element model has high accuracy.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.25

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