小波降噪在钢绞线缺陷检测中的应用

在对钢铰线进行的超声导波检测试验中，使用一对自行研制的磁致伸缩式传感器在公称直径17.80 mm的7芯钢铰线中激励接收了最低阶纵向模态L(0,1)模态导波。采用以40阶Daubechies小波为母小波的多层离散小波分解及单支重构的方法对检测信号进行降噪处理，能有效地提高信噪比。在此基础上对钢绞线外围钢丝上的刻痕缺陷进行检测，经小波降噪后的信号中能够提取出缺陷信息。这种利用小波降噪对信号处理的方法为超声导波技术应用于钢绞线健康检测奠定了基础。

Application of Wavelet Denoise in Defect Inspection of Steel Strands

In the inspection test on steel strands by using ultrasonic guided waves, the lowest longitudinal mode, L(0,1) mode, is excited and received by a pair of developed magnetostrictive sensors in a seven-wire, 17.80 mm nominal diameter steel strands. Then, the signal is denoised by using the method of multi-level discrete wavelet decomposition and single branch reconstruction. The daubechies wavelet of order 40 is used as the mother wavelet for the decomposition. This wavelet denoise method improves the signal-to-noise ratio. Furthermore, a steel strands with 3.00 mm depth notch on peripheral wire is inspected, the information of the defect is extracted from the signal by using the wavelet denoise. This signal processing method of wavelet denoise provide foundation for application of ultrasonic guided waves technique to health monitoring of steel strands.