采用解析模态分解和小波变换的损伤识别方法

针对希尔伯特-黄变换(HHT)在信号处理中存在的模态混叠现象,引入解析模态分解定理(AMD)提取时变结构响应的一阶本征函数,并构建一阶本征函数能量比指标识别结构的损伤位置.从损伤位置处的响应信号出发,引入连续小波变换和时间窗思想,提出一阶本征函数小波能量变化率指标来预测结构的损伤演化过程.通过一个刚度突变和线性变化的三层剪切型结构数值算例,对一阶本征函数能量比和一阶本征函数小波能量变化率指标进行验证.结果表明:所提出的指标能够有效识别结构的损伤位置和损伤时间.

Structural Damage Detection Using Analytical Mode Decomposition and Wavelet Transform

Due to the problem of overlapping frequency existed in Hilbert-Huang transform(HHT), analytical mode decomposition theorem is introduced to extract the first order intrinsic mode function(IMF)from responses of time-varying structures, then the first order IMF energy ratio index is established to identify damage locations. Based on the response signal in damage location, continuous wavelet transform and time window are introduced to build the index of the first order IMF wavelet energy variation rate in order to predict the evolution of structural damage. A numerical example of three-story shear structure with abruptly and linearly varying stiffness is presented to verify the effectiveness of the two proposed indexes, and the results demonstrate that the proposed damage indexes can effectively detect the locations and time of structure damage.