小波分析在钢丝绳无损检测中的应用

The Application of Wavelet Analysis in Nondestructive Testing of Wire Ropes

本文论述了采用漏磁通法检测钢丝绳局部损伤的原理和方法，并将小波理论有效地用于检测信号的处理中，用来确定局部损伤的位置，识别内外部断丝。

This paper describes the principles and methods of detecting localized flaws in wire ropes by measuring leakage flux.The theory of wavelets is applied for the process of detected signals.The method of locating localized flaws and recognizing internal and external broken wires is presented. LF(Localized Flaws)signal has much noise by the traditional flux leakage method,because the inspection is on the condition that the wire rope is magnetically saturated in the longitudinal direction.In order to improve signal to noise ratio,we use hinged differential sense coils to inspect the wire rope after magnetizing it.The wavelet transform is very suitable for analyzing the LF signals which are nonstationary signals.By using a discrete dyadic wavelet transform,we can transform the LF signal into a sequence of signals along a well defined sequence of scales.The zero crossings of this wavelet transform give a complete characterization of broken wires.Features can be found at different resolutions to recognze internal and external broken wires.The zero crossings can also be used to locate the localized flaws in the wire rope.