摘要
利用小波变换的线性变换特性,结合Morlet小波的性质和结构振动系统自由响应信号的形式,构造了一组小波族,并通过利用2-范数对结构响应信号的小波变换进行归一化以及小波变换局部极大值的计算,获得了结构的模态频率与模态振型。仿真结果表明,Morlet连续小波变换不同尺度之间重叠的冗余性,使得利用尺度与信号频率的变换关系来进行准确的密集模态参数辨识比较困难,而本文方法简单有效,比直接利用Morlet小波更为直观、方便和准确,对压电柔性结构的低频密集模态频率和模态振型能够很好地辨识。
The method of modal decoupling and identification for piezoelectric flexible structures with closely spaced modes is given by using linear wavelet transform. The relationship between Morlet wavelet and impulse response coming from dynamical vibration systems is investigated, and a family of wavelet functions is introduced based on the characteristics of transient responses of vibration system and Morlet wavelet. Modal frequencies for piezoelectric flexible structures are obtained by normalizing the wavelet transform coefficient using 2-norms, and corresponding mode shapes are obtained by computing local maxima of wavelet transform. The simulation results show that the method is simple and effective in telling the closely spaced modes accurately, which cannot be implemented by using the relationship between Morlet wavelet scales and signal frequencies due to the information redundancy resulting from scale overlapping.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2008年第6期231-236,共6页
Journal of Mechanical Engineering
基金
陕西省自然科学基金(D7010418)
国防预研基金(51421060505DZ0155)资助项目
关键词
压电柔性结构
模态参数辨识
小波变换
Piezoelectric flexible structures Modes identification Wavelet transform
