环境激励下基于快速贝叶斯FFT的实桥模态参数识别

发布时间：2018-01-12 03:34

本文关键词：环境激励下基于快速贝叶斯FFT的实桥模态参数识别　出处：《工程力学》2014年04期 　论文类型：期刊论文

【摘要】：近年来,贝叶斯理论逐步应用于工程结构的模态参数识别、有限元模型修正及状态评估等方面。基于快速贝叶斯FFT的模态参数识别方法是针对某一共振频率带的单个模态,通过一个四维的数值优化问题得到模态参数的最佳估计,并通过对数似然函数关于模态参数的二阶导数求得Hessian矩阵,使得基于贝叶斯的参数识别方法可以快速高效地进行。为了评估该方法在实际桥梁结构模态参数识别应用中的可行性及优越性,运用快速贝叶斯FFT方法对环境激励下一刚构-连续组合梁桥的竖向加速度响应进行了分析处理,识别了其模态参数的最佳估计,并根据模态参数的变异系数评估了其后验的不确定性。识别结果与随机子空间识别结果的对比表明,两种方法识别的频率和振型基本吻合,阻尼识别结果的差异仍然较大。
[Abstract]:In recent years, Bayesian theory has been gradually applied to the identification of modal parameters of engineering structures. The modal parameter identification method based on fast Bayesian FFT is aimed at a single modal of a total frequency band. The optimal estimation of modal parameters is obtained by a four-dimensional numerical optimization problem, and the Hessian matrix is obtained by the second derivative of the number likelihood function with respect to the modal parameters. In order to evaluate the feasibility and superiority of this method in the application of modal parameter identification of bridge structure, the Bayesian parameter identification method can be carried out quickly and efficiently. The vertical acceleration response of a rigid frame-continuous composite beam bridge under ambient excitation is analyzed by using fast Bayesian FFT method, and the optimal estimation of modal parameters is identified. The uncertainty of a posteriori is evaluated according to the coefficient of variation of modal parameters. The comparison between the identification results and the results of random subspace identification shows that the frequency and vibration pattern of the two methods are basically consistent. The difference of damping identification results is still large.
【作者单位】：兰州理工大学甘肃省土木工程防灾减灾重点实验室;兰州理工大学防震减灾研究所;
【基金】：甘肃省科技攻关项目(2GS057-A52-008) 甘肃省交通科技攻关项目(2010-19)
【分类号】：U441.3;U446
【正文快照】： 工程结构的健康监测和损伤诊断是近年来的研究热点,而这过程大多数需要获得结构的动力特性,进而确定损伤位置和损伤程度[1 5]。近些年来,由于不需要施加人工荷载、操作方便和费用低,环境激励下的动力测试已经成为应用于结构参数识别、有限元模型修正和状态评估的普遍方法。在

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