基于离散小波变换的斜拉桥缆索断丝检测

Testing for Broken Cable Wires of Cable-stayed Bridges Based on Discrete Wavelet Transform

采用磁通量检测法对斜拉桥缆索进行无损检测试验。试验中为了降低工作环境中空间电磁场噪声对检测信号的影响,采用一个独立的基于二进小波变换的改进软阈值去除高斯白噪声的方法来分离检测缆索得到的磁通信号和噪声信号。为了准确获得缺陷位置,对缆索检测的磁通信号波形和李氏指数奇异点进行分析。试验结果表明,该检测方法可以准确获得缆索缺陷的大小和具体位置,对于斜拉桥缆索缺陷的检测和分析很有意义。

This paper carries out nondestructive testing for cables of cable - stayed bridges by means of magnetci flux testing method. In the test in order to reduce impact of the noise of spacial electromagnetic field in working environment on testing signals, the method of removing Gaussian white noise by means of an independent modified soft threshold based on binary wavelet transform is employed to separate magnet flux signals and noise signals obtained by testing cables. In order to acquire the positions of defects correctly, this paper analyzes the waeforms of magnetic flux signals and Lipschitz Exponent singularity of cable testing. The test results show that this testing method can correctly obtain magnitudes and specific positions of cable defects and is quite significant for testing and analysis of cable defects of cable - stayed bridges.