基于OMA试验模态参数的砌体结构有限元建模及修正  

Finite element modeling and model updating of brick masonry structure based on modal parameters obtained from operational modal analysis

作　　者：管晓明[1] 傅洪贤[1] 王梦恕[1] 崔堃鹏[1] 林凡涛[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《振动与冲击》2014年第14期181-187,210,共8页Journal of Vibration and Shock

基　　金：国家自然科学基金项目(51278042);国家自然科学基金项目(L1222021);铁道部重点课题(2010G016-L-1)

摘　　要：依托重庆新红岩隧道工程，选典型2层砌体结构进行隧道施工爆破振动激励的OMA试验，采用等效体积单元法建立能准确反映砌体结构真实动力特性的有限元模型；探讨砌体用不同材料模型所得分析频率与实测频率误差及二者振型相关性；据OMA试验模态参数，基于砌体与混凝土材料参数的结构固有频率灵敏度分析，选择合适的修正参数进行有限元模型修正研究。结果表明，二层砌体结构前4阶固有频率位于9～25 Hz；较用各向同性模型而言，砌体采用各向异性模型时计算所得前4阶频率与实测频率值更接近，振型相关性更好；修正有限元模型中材料密度、弹性模量、剪切模量后频率与实测频率间误差明显减小，结构模型动力特性更符合实际，正交各向异性材料模型修正最准确。Based on the engineering background of New Hongyan Tunnel in Chongqing,an operational modal analysis was carried out on a typical 2-story brick masonry structure under tunnel blast excitation.An accurate finite element model which could reflect the actual dynamic characteristics of the brick masonry structure was built by using the representative volume element. Furthermore, the numerical structural natural frequencies and modal shapes were compared with the experimental modal data.According to the first four modal parameters obtained from the operational modal analysis （OMA ） and based on the structural natural frequencies sensitivity analysis of masonry and concrete material parameters,the appropriate modifying parameters were selected and the model of the brick masonry structure was updated.The first four natural frequencies of the brick masonry structure are in 9 ~25Hz.The analysed natural frequencies by using anisotropic model match much better with the experimental modal parameters than by using isotropic model for the brick masonry.Besides,the correlation between the analyzed and experimental modal shapes is good.After updating the parameters of density,elastic modulus and shear modulus in the finite element model,the errors between analyzed frequencies and experimental results are reduced,and the dynamic characteristics parameters of the model are more close to the true values.The updating of the finite element model by using orthogonal anisotropic model for masonry is more accurate.

关 键 词：砌体 有限元模型 模态试验 模型修正 正交各向异性 等效体积单元 

分 类 号：TU311[建筑科学—结构工程]