基于DIC与NExT-ITD的结构运行模态测试新方法  

A New Method for Structural Operational Modal Test Based on DIC and NExT-ITD

作　　者：李君[1,2] 蔡子峥 徐飞鸿 Li Jun;Cai Zizheng;Xu Feihong(Hunan Province Engineering Laboratory of Bridge Structure(Changsha University of Science&Technology),Changsha 410114,Hunan,China;School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,Hunan,China)

机构地区：[1]桥梁结构安全控制湖南省工程实验室(长沙理工大学),湖南长沙410114 [2]长沙理工大学土木工程学院,湖南长沙410114

出　　处：《工程与试验》2023年第4期11-14,共4页Engineering and Test

基　　金：长沙理工大学桥梁结构安全控制湖南省工程实验室开放基金资助项目(基金编号14KD07)。

摘　　要：传统的结构运行模态测试采用接触式测量并在频域进行模态参数识别,存在测量不便捷、计算繁复等问题。针对此问题,本文提出了基于数字图像相关方法与自然激励技术-Ibrahim时域法相结合的模态测试新方法。运用工业相机获取结构在环境激励下的散斑图像,通过数字图像相关方法计算结构的平稳响应信号,然后根据自然激励技术-Ibrahim时域法,以互相关函数代替脉冲响应函数,构造响应矩阵并建立数学模型,计算结构的模态参数。以某简支梁模型为例进行数值模拟和试验测试,结果表明,该方法可由结构的散斑图像直接识别模态参数,识别精度高,抗噪能力强。该方法实现了非接触式测试,尤其适用于高温高压等工程环境;在时域内进行参数识别,避免了繁复的频域分析,简化了计算。The traditional structural operational modal test adopts contact measurement and carries out modal parameter identification in the frequency domain,which has the problems of inconvenient measurement and complicated calculation.Aiming at this problem,a new modal test method based on Digital Image Correlation method and Natural Excitation Technology-Ibrahim Time Domain method is proposed.The industrial camera is used to obtain the speckle image of the structure under environmental excitation,and the stationary response signal of the structure is calculated by Digital Image Correlation method.Then,according to the Natural Excitation Technology-Ibrahim Time Domain method,the cross-correlation function is used to replace the impulse response function,and the response matrix is constructed to establish the mathematical model and calculate the modal parameters of the structure.Taking a simply supported beam model as an example,the numerical simulation and experimental test are carried out.The results show that the method can directly identify the modal parameters from the speckle image of the structure,with high recognition accuracy and strong anti-noise ability.The non-contact test is realized,especially suitable for high temperature and high pressure engineering environment.Parameter identification in the time domain avoids complicated frequency domain analysis and simplifies the calculation.

关 键 词：数字图像相关方法 环境激励 运行模态测试 

分 类 号：TU311.3[建筑科学—结构工程]