桥梁安全状态评估有限元模型修正方法  

A method for modifying bridge security condition evaluation FEA model

作　　者：康俊涛[1] 张亚州[1] 秦世强[1] 

机构地区：[1]武汉理工大学土木工程与建筑学院

出　　处：《中国安全科学学报》2016年第11期99-103,共5页China Safety Science Journal

基　　金：国家自然科学基金资助(51608408);湖北省自然科学基金资助(2015CFB393)

摘　　要：桥梁结构的长期健康监测和安全状态评估需要一个能真实反映结构静动力特性的有限元(FEA)模型,而初始有限元模型与实际结构往往存在误差。提出一种有限元模型修正方法:首先进行环境激励测试,然后用随机子空间(SSI)识别,最后用粒子群算法(PSO)进行优化。以一座模型斜拉桥为例,利用布置在桥梁上的拾振器,测试环境激励下的桥梁的振动信号;采用SSI法对测得的信号模态识别,并用PSO修正有限元模型。结果表明,经过修正,桥梁有限元模型的第1,3,4和5阶频率值与实测信号分析值的误差均减小,能真实反映结构的静动力特性,可用于桥梁安全状态评估。Long-term health monitoring and condition evaluation of a bridge structure system need a finite element model which can reflect actual static and dynamic characteristics of the system. Typically, the initial finite element model（FEA） needs revision due to the differences between it and the actual structure.A method was worked out by the authors for modifying the model. Firstly, the bridge was tested based on ambient vibration, secondly the stochastic subspace identification method was used to identify modes, finally the finite element model was modified by PSO. Through vibration pickups set on the model bridge, response signals of the bridge under ambient excitation were collected. Next vibration modes of the bridge were identified from the processed signals using the method of stochastic subspace identification（SSI）. Then, the finite element model can be modified using the method of PSO. The results show that modal parameters of the structure can be well obtained using stochastic subspace identification method accompanied with stabilization diagram, that the modifying amplitude of the density of the steel tower is the greatest, that after modifying, the errors of 1st, 3rd, 4~ and 5th modal data are decreased, and that the modified finite element model can better reflect static and dynamic characteristics of the structure and be used for the security condition evaluation.

关 键 词：桥梁工程 环境激励 模态识别 粒子群算法(PSO) 模型修正 

分 类 号：X913.4[环境科学与工程—安全科学]