EMD与小波阈值联合滤波方法的改进及其在泄流结构振动分析中的应用  

An improved filtering method based on EMD and wavelet-threshold and its application in vibration analysis for a flood discharge structure

作　　者：李成业[1] 练继建[1] 刘昉[1] 马斌[1] 

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300072

出　　处：《振动与冲击》2013年第19期63-70,110,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金青年科学基金项目(51209158);国家重点基础研究发展计划(973)计划(2013CB035905_1);天津市应用基础及前沿技术研究计划(青年基金项目)(12JCQNJC04600)

摘　　要：泄流结构在水流荷载作用下的实测振动响应中常混有各种噪声,影响结构振动响应分析的精度。通过研究EMD与小波阈值联合的滤波降噪方法,提出了含噪信号EMD分解后各分量中噪声标准差的确定方法,解决了小波阈值计算中噪声标准差计算难的问题。同时,分析了泄流结构水流激励荷载的特点,将NExT+HHT的模态参数识别方法应用到泄流结构中。将该方法应用到二滩拱坝、映秀湾水电站拦河闸结构实测振动响应的滤波分析中,取得了较好的应用效果。Due to the influence of noise mixed into vibration responses of a flood discharge structure, the analysis precision of its vibration responses is reduced. Here, through studying the filtering and denoising method based on EMD and wavelet-threshold, the calculation method for noise standard deviation of each IMF after EMD decomposition of a noisy vibration signal was proposed. Then, the features of flood ambient excitation were analyzed, and a method based on NExT and HHT was adopted to identify the modal parameters of a flood discharge structure. Finally, the presented method was used to filter and analyze the actually measured vibration responses of Ertan arch-dam and Yingxiuwan hydropower station sluice structures, respectively. The results showed that the proposed method is applicable for vibration analysis of a flood discharge structure.

关 键 词：泄流结构 滤波降噪 白噪声 小波阈值 模态识别 

分 类 号：TV65[水利工程—水利水电工程]