关键词: 模态参数辨识, 小波变换, 压电柔性结构, 磨损性能, 碳/碳复合材料, 泄漏性能, 指尖密封, 轴间密封

Abstract: 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.

Key words: Modes identification, Piezoelectric flexible structures, Wavelet transform, Carbon-Carbon composite, Intershaft seal, Leakage performance, Wear performance, Finger seal