非平稳环境激励下结构工作模态参数识别法  

Operational modal parameter identification of structures for non-stationary ambient excitation

作　　者：陆秋海[1] 李连友 向律楷[3] 王波[1] 

机构地区：[1]清华大学航天航空学院,应用力学教育部重点实验室,北京100084 [2]中国路桥工程有限责任公司,北京100011 [3]中铁二院工程集团有限责任公司,成都610031

出　　处：《清华大学学报（自然科学版）》2013年第3期389-393,共5页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金项目(10802040)

摘　　要：为了研究非平稳环境激励下只根据响应信号识别系统的模态参数的问题,首先将自然激励技术(natural excitation technique,NExT)法的应用范围从理想白噪声扩展到了MA(q)模型。假设非平稳激励由(d-1)阶多项式趋势项与MA(q)模型之和构成,将其d阶差分后变成MA(q+d)阶模型;导出了基于激励和响应差分数据的运动方程,建立了非平稳环境激励下模态参数识别NExT法。用该方法对龙潭河大桥进行模态参数识别。识别的结果与有限元计算值一致,并且在非平稳环境激励下,该方法能够比标准NExT方法获得更好的模态参数识别结果。Structural modal parameters are identified using only response data from non-stationary ambient excitations with the white noise excitation assumption for natural excitation technique （NEXT） extended to a MA（q） model assumption in an extended NExT method. The model then assumes that the non stationary excitation is composed of a （d - 1）-th order polynomial and a MA（q） model. Taking the d-th order difference of the non-stationary excitation yields a MA（q＋d） model which satisfies the assumption of the extended NExT method. The motion equation based on difference excitation data and response data is then used in a modal parameter identification algorithm based on NExT for structures with non-stationary ambient excitation. Identification results from the method are compared with standard NExT results for a finite element model of the Longtanhe Bridge. The results show that thismethod gives better system modal parameters for non-stationary ambient excitation than the standard NExT method.

关 键 词：自然激励技术 模态参数识别 非平稳激励 移动平均模型 

分 类 号：O327[理学—一般力学与力学基础]