针对多层板中缺陷的超声Lamb波检测，计算并分析了钢板-铝板-铜板多层结构的频散曲线以及位移波结构，提出了一种多层板结构中缺陷的检测方法，并进行了数值验证。数值计算表明，采用0.2 MHz的低频Lamb波检测时，多层板中各板层缺陷均产生反射信号；采用1 MHz的高频Lamb波A0模态检测时，只有铜板层中的缺陷产生反射信号，采用S0模态检测时，只有钢板层中的缺陷产生反射信号。因此，根据对多层板频散曲线和波结构的分析结果，可以选择频率与模态合适的Lamb波来实现对多层板中特定板层缺陷的检测。

Aiming at ultrasonic Lamb wave detection of defects in multi-layer plate, the dispersion curve and displacement wave structure of multi-layer structure of steel-aluminum-copper plate were calculated and analyzed. A defect detection method in multi-layer plate structure was proposed and verified by numerical simulation. The numerical calculation shows that when the low-frequency Lamb wave of 0. 2 MHz is used for detection, the defects of each layer in the multilayer plate produce reflected signals. When the A0 mode detection of 1 MHz high-frequency Lamb wave is adopted, only the defects in the copper plate layer produce the reflected signal, and when the S0 mode detection is adopted, only the defects in the steel plate layer produce the reflected signal. Therefore, according to the analysis results of the frequency dispersion curve and wave structure of multilayer plates, Lamb waves with appropriate frequency and mode can be selected to detect the defects of specific layers in multilayer plates.