在ST12冷轧板上用线切割加工出不同深度的狭缝来模拟钢板中缝类缺陷。采用一发一收方式在钢板上激励出兰姆波进行检测,用经验模态分解(EMD)技术对Lamb波与缺陷作用的响应信号进行处理,并用波形指数对响应信号的各阶固有模态函数(IMF)进行量化,定征了缺陷状态并客观判断了缺陷对Lamb波影响。结果表明:用波形指数的变化可较好地发现构件中材料的不连续特性,这一数字参数在小缺陷的检测以及客观评价方面将有较好的应用前景。 In the ST12 cold-rolled sheet with wire-cut into different depths of the slit to simulate steel plate seam defects. In this method, the Lamb wave is excited on the steel plate by one-shot-one-off method, the response signal of the Lamb wave and the defect is treated by Empirical Mode Decomposition (EMD), and the waveform intrinsic index Function (IMF) to quantify, characterize the defect status and objectively determine the impact of defects on the Lamb wave. The results show that the change of waveform index can find the discontinuity of the material well. This digital parameter will have better application prospect in the detection and objective evaluation of small defects.