表面裂纹是危害很大且普遍存在的一种缺陷,严重影响到特种设备的安全运行。对表面裂纹尺寸的测量一直未得到很好的解决,由于Raylegh波能量主要集中在深度一个波长的范围内,当传播过程中和裂纹相互作用时,其频谱会发生变化,一部分高频波将会被吸收,吸收频率的大小与裂纹的深度密切相关。此时裂纹起了一个类似低通滤波器的作用,这点对于裂纹深度检测具有指导意义。 Surface cracks is a serious and ubiquitous defect, seriously affecting the safe operation of special equipment. The measurement of the surface crack size has not been well solved. Since the energy of Rayleigh wave is mainly concentrated in the depth of one wavelength range, the spectrum will change when it interacts with the crack during the propagation and some high frequency waves will be absorbed The frequency of absorption is closely related to the depth of the crack. In this case, the crack plays a similar role as the low-pass filter, which is of guiding significance for the crack depth detection.