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为降低Lamb波在复合材料结构中传播时存在的频散现象和各方向传播特性的不一致性给损伤监测带来的困难,提出一种利用Hilbert变换改进的空间滤波器对复合材料结构损伤进行成像的方法。分析了基于空间滤波器的信号合成成像原理,在此基础上利用Hilbert变换构造传感器时域响应信号的解析信号参与到信号合成成像过程中。通过对仿真声源的成像实验,验证了该方法的可行性,通过对碳纤维复合材料板结构上激励源和损伤的成像实验,验证了该方法的功能。研究表明该方法能够识别损伤相对于压电传感器阵列的角度位置和损伤散射信号的到达时刻。
In order to reduce the dispersion of Lamb waves propagating in composite structures and the inconsistency of propagation characteristics in all directions, it is difficult to monitor the damage. A spatial filter improved by Hilbert transform is proposed to image the damage of composite structures Methods. The principle of signal synthesis imaging based on spatial filter is analyzed. Based on this, the analytic signal of time-domain response signal of sensor is constructed by using Hilbert transform to participate in signal synthesis imaging. The feasibility of this method is verified through the imaging experiment of the simulated sound source. The experiment of the excitation source and damage on the carbon fiber composite plate is validated by this method. Research shows that this method can identify the angular position of the damage relative to the piezoelectric sensor array and the arrival time of the damage scattering signal.