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提出一种基于Lamb波和字典库为Chirplet原子的匹配追踪方法的板结构损伤定位方法。首先针对Lamb波监测的特点,提出了匹配追踪方法的快速实现方案,将信号分解为多个Chirplet原子的线性组合;然后建立了Lamb的弥散效应与Chirplet原子的调频斜率之间的关系,表明Chirplet原子能准确地匹配失真变形的窄带脉冲信号,并能识别Lamb波的模态;根据损伤前与损伤后的信号差,提出了一种可以分辨多损伤散射信号的损伤定位方法。最后通过数值仿真、各向同性板结构实验和蜂窝夹层复合材料结构实验,验证了该方法的可行性和有效性。
A new method for damage detection of plate structure based on the matching pursuit method of Chirplet atom based on Lamb wave and dictionary is proposed. First of all, according to the characteristics of Lamb wave monitoring, a fast implementation of matching pursuit method is proposed, which decomposes the signal into a linear combination of multiple Chirplet atoms. Then the relationship between the dispersion effect of Lamb and the chirplet atom’s frequency modulation slope is established. The atom can accurately match the narrow-band pulse signal with distorted deformation and can recognize the mode of Lamb wave. According to the signal difference between pre-damage and post-damage signal, a new method of locating damage signals is proposed. Finally, the feasibility and effectiveness of this method are verified by numerical simulation, isotropic plate structure experiment and honeycomb sandwich composite structure experiment.