EMD信号分析方法的声发射管道泄漏检测研究

针对管道泄漏声发射检测信号的非平稳特征,提出了基于经验模态分解(EMD)的信号分析方法。该信号分析方法将管道泄漏产生的声发射信号通过EMD分解为多个平稳的固有模态函数(IMF)之和,选择包含声发射特征的若干IMF分量进行重构,可以提取到管道泄漏声发射信号的本质特征,消除噪声信号的干扰。通过对重构后的信号进行互相关分析计算,使基于声发射方法的管道泄漏检测的定位精度得到较大提高,验证了Hilbert-Huang变换是表征声发射信号的非平稳特征及信号参数提取的有效工具。

STUDY ON ACOUSTIC EMISSION DETECTION FOR PIPELINE LEAKAGE BASED ON EMD SIGNAL ANALYSIS METHOD

A signal analysis method based on empirical mode decomposition(EMD) is proposed aiming at extracting non-stationary characteristic of an acoustic emission (AE) signal result from pipeline leakage. The detected leakage signal can be decomposed into a sum of finite intrinsic mode functions (IMF) by EMD, some of IMFs embracing typical AE characteristic can be selected to be reconstructed. Thus, noise interference can be eliminated. The reconstructed signals are analyzed and their cross-correlation parameter is calculated. The locating accuracy of the leaking point calculated with the reconstructed signals is greatly increased. It is demonstrated that Hilbert-Huang transformation is an effective tool for demonstrating the unstable characteristic of acoustical signals and feature extraction of pipeline leak signals.