第一作者张建伟男，博士，副教授，1979年生

一种适用于泄流结构振动分析的信号降噪方法

张建伟，江琦，赵瑜，朱良欢，郭佳

(华北水利水电大学水利学院，郑州450011)

摘要：针对低信噪比泄流结构振动信号有效信息难以提取问题，提出将小波阈值与经验模态分解(EMD)联合的信号降噪方法。利用小波阈值滤除大部分高频白噪声，降低EMD端点效应；进行EMD分解获得具有相对真实物理意义的固态模量(IMF)；通过频谱分析重构特征信息IMF获得降噪信号。构造仿真信号，将该方法与数字滤波、小波分析及EMD降噪效果进行对比。结果表明，该方法能精确滤除泄流结构的振动噪声保留信号特征信息，滤波降噪较优越。将其用于拉西瓦拱坝水弹性模型，精确分析坝体结构振动优势频率，为坝体结构的安全运行与在线监测提供基础，亦为大型泄流结构在强背景噪声下的结构有效信息提取提供捷径。

关键词：泄流结构；振动信号；低信噪比；小波与EMD联合降噪；优势频率

基金项目：国家自然科学基金(51009066)；河南省高等学校青年骨干教师资助计划(2012GGJS-101)；河南省科技攻关(142102310122，142300410177，132102310320)资助

收稿日期：2014-10-28修改稿收到日期：2015-04-27

中图分类号:TV31; TB53

文献标志码：A

DOI:10.13465/j.cnki.jvs.2015.20.030

Abstract:In view of the difficulty in extracting useful characteristics from the vibration signal of flood discharge structure with low signal to noise ratio, a novel de-noising method, combining wavelet threshold and empirical mode decomposition (EMD), was proposed. First of all, a part of white noises were filtered out with the wavelet threshold method, which can reduce the endpoint effect of EMD; then the signal was decomposed with EMD, to obtain a series of intrinsic mode functions (IMFs) which contains real physical meanings; finally the IMFs including characteristic information were reconstructed to achieve the de-noised signal through spectrum analysis. Constructing a simulation signal, and comparing the filtering effect of this method with the conventional method of digital filter, wavelet threshold and EMD on the signal, it is shown that, the method presented is a superior de-noising method, which can filter the vibration noise of flood discharge structure accurately and retain the characteristic information. It has been used in the Laxiwa arch dam hydro-elastic model test, analyzing the dominate frequency of dam structure precisely, and providing the basis for safe operation and on-line monitoring of the dam structure.

De-noising method for vibration signal of flood discharge structure

ZHANGJian-wei,JIANGQi,ZHAOYu,ZHULiang-huan,GUOJia(College of Water Conservancy, North China University of Water Conservancy and Electric Power, Zhengzhou 450011, China)

Key words:flood discharge structure; vibration signal; low signal to noise ratio; combination of wavelet threshold and EMD; dominant frequency

流体诱发的结构振动极其复杂，为二者相互作用现象。泄流结构的动力特性[1-2]为判断其运行状态、健康程度及振动危害的重要指标。泄流结构振动信号在获取、输送过程中会受环境激励的高频白噪声及低频水流脉冲噪声等不同程度干扰，从而影响结构健康状况及振动危害评价精度。……