基于响应面的刚构-连续组合梁桥有限元模型修正

FINITE ELEMENT MODEL UPDATING FOR A RIGID FRAME-CONTINUOUS GIRDERS BRIDGE BASED ON RESPONSE SURFACE METHOD

  • 摘要: 首先对响应面法在有限元模型修正中应用的主要问题,包括实验设计、参数筛选、响应面拟合及参数优化等进行了讨论,进而基于现场动力试验数据对一刚构-连续组合梁桥#x02014;靖远黄河大桥的有限元模型进行了修正。选取箱梁和桥墩的弹性模量以及连续墩顶支座及边跨联端支座的横向和竖向刚度为修正参数,采用中心复合设计法进行实验设计、计算样本值,分别构造两个响应面模型,其中一个考虑交互项的影响、一个不考虑交互项的影响,然后以这两个响应面模型代替初始有限元模型分别进行修正。修正结果表明,考虑和不考虑交互项的影响对修正后部分参数的取值有一定的影响,而对频率的修正精度影响不大。两种模型修正后的频率取值均与实测频率较吻合,修正后的模型能准确地反映桥梁的动力特性,可作为后续损伤识别及状态评估的基准模型。

     

    Abstract: The issues related to using the response surface method for finite element model updating such as experiment design, parameter selection, response surface regression and optimization are summarized firstly. Then the finite element model of a rigid frame-continuous girders bridge, Jingyuan Yellow River Bridge, is updated based on the in-situ dynamic test results. The elastic moduli of the box girder and the pier, transverse and vertical stiffness values of the bearings are selected to be the parameters for updating. The central composite design method is chosen to conduct the experimental design and calculate the sample values. Two response surface models with and without considering the influence of cross-terms are constructed respectively and used to be updated instead of updating the initial finite element model. It can be concluded that the cross-terms have less influence on the updating parameters and little influence on the modal frequencies. The analytical frequencies from the updated models are in good agreement with the identified frequencies based on dynamic test. The updated finite element model can accurately represent the dynamic characteristics of the bridge. Therefore it can serve as the benchmark model for further damage identification and condition assessment of the bridge.

     

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