中文摘要：

对兰姆波在铝合金薄板中传播的频散曲线进行了理论分析。采用任意波形信号发生器和单一传感器发射超声波，用非接触式激光测振仪、数字示波器和计算机，接收并处理超声波信号，并采取时频联合分析，运用短时傅里叶变化的方法，获得了兰姆波在三组合有不同缺陷的铝合金薄板中的传播模式。试验结果表明，超声兰姆波在无缺陷的硬铝合金薄板中传播时模式为A0，在含有空孔型的铝合金薄板传播时，没有产生新的频率成分，但是由A0模式转换成A1模式；而在含有线切割缝隙的铝合金薄板传播中，兰姆波产生了新的频率，即二次谐波，并且兰姆波的模式变成了A0和S0两种。

英文摘要：

The dispersion curve of Lamb wave transmitting in aluminum alloy plate was analyzed theoretically.A signal generator instrument and an electronics sensor were used for generating ultrasonic signals. A laser vibrometer, a digital oscilloscope and a computer were used for receiving signals and making signal processing and STFT signal processing was adopted to analyze lamb wave transmission mode. Three group of experimental results showed that there was A0 mode in a nondestructive plate, and when lamb wave transmits in an aluminum alloy plate with small hole, no extra frequency produces and mode A0 changed into mode A1, and in an aluminum alloy plate with cutting line, a new frequency appears and lamb wave mode changed from A0 to mode A0 and S0.