环境激励下基于奇异谱互熵的结构损伤诊断方法  

A METHOD OF STRUCTURAL DAMAGE DIAGNOSIS BASED ON SINGULAR-SPECTRUM CROSS ENTROPY UNDER AMBIENT EXCITATION

作　　者：李睿[1] 于德介[1] 曾威[1] 

机构地区：[1]湖南大学振动测试研究中心,湖南长沙410082

出　　处：《工程力学》2007年第6期142-146,90,共6页Engineering Mechanics

基　　金：湖南省交通厅科技项目(200223)资助

摘　　要：环境激励下的结构响应是一个随机过程,结构发生破损时其响应将随之变化,因而可将描述随机过程特性的参数作为评判结构状况的指标。熵是测量随机过程不确定性的一个比较方便的方法,能够用于高斯及非高斯分布的情况。在相空间重构与奇异值分解的基础上建立了奇异谱互熵的概念,提出了一种环境激励下用奇异谱互熵诊断结构损伤的方法。以ASCE学会提出的基准结构为对象进行研究,利用NExT技术获得响应,采用伪邻近法确定相空间的嵌入维数,讨论了不同工况及噪声对诊断结果的影响,分析结果验证了该方法的有效性和鲁棒性。The structural response under ambient excitation is a stochastic process. The response changes with damage, so does the stochastic process. From this fact, the parameters demonstrating the characteristics of stochastic process can be recommended to evaluate the state of structure. Entropy is a suitable measurement of stochastic process uncertainty, either for Gaussian or non-Gaussian for distributed data . According to those principles, the concept of singular-spectrum cross-entropy is proposed based on the techniques of phase space reconstruction and singular value decomposition. It is then used as an index for damage diagnosis under ambient excitation. The method was tested on the benchmark model designed by ASCE task group, the response of which was acquired by NExT technique. The embedding dimension of phase space was obtained with false neighbor technique. The influences of operational conditions and noise on diagnosis were analyzed, the results of which confirm the effectiveness and robustness of the proposed method.

关 键 词：结构损伤 奇异谱互熵 环境激励 相空间重构 NExT技术 

分 类 号：O329[理学—一般力学与力学基础]