Abstract: A cross-shaped array which was composed of piezoelectric sensors was used for the excitation and reception of Lamb wave signals. A two-dimensional multiple signal classification (2D-MUSIC) method was proposed to locate and detect defects in aluminum plates. Firstly, the appropriate excitation frequency was selected for the generation of a single mode signal to avoid the influences of multi-mode and reduce the dispersion of Lamb waves. Then, received signals were segmented by 2D-MUSIC algorithm. Finally, reflected signals and 2D steering vectors were combined to locate the defects in the aluminum plate. The results show that the proposed 2D-MUSIC algorithm is more accurate than traditional multiple signal classification algorithm for defecting locations in aluminum plates.

Key words: Lamb wave； piezoelectric transducer； array； wavelet transform； imaging, aluminum plates

摘要： 采用由压电传感器组成的十字形阵列进行Lamb波信号的激励和接收，提出一种二维多重信号分类（2D-MUSIC）方法对铝板中的缺陷进行定位检测。选用合适的频率激励产生单一模态信号，可避免多模态的影响，降低Lamb波的频散；利用2D-MUSIC算法对接收信号进行分段处理，并结合反射信号和二维导向矢量对铝板中的缺陷进行定位。结果表明，提出的2D-MUSIC算法对铝板中的缺陷定位比传统MUSIC算法更精准。

关键词: Lamb波, 压电传感器, 阵列, 小波变换, 成像, 铝板