基于振型相關(guān)性的結(jié)構(gòu)模態(tài)參數(shù)頻域自動識別*
徐琪澤1，吳金志1,2，張毅剛1,2
- 摘 要
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（1 北京工業(yè)大學空間結(jié)構(gòu)研究中心，北京 100124； 2 北京工業(yè)大學城市與工程安全減災省部共建教育部重點實驗室，北京 100124）［摘要］環(huán)境激勵下，頻域分解法(FDD)具有良好的結(jié)構(gòu)模態(tài)頻率和振型識別能力，但識別過程中需要基于頻率準則人為判斷奇異值曲線的峰值，無法準確識別出現(xiàn)近頻交疊或重頻情況的結(jié)構(gòu)模態(tài)參數(shù)，而且不能自動進行模態(tài)參數(shù)的識別。對此，提出了基于振型相關(guān)性的MAC-FDD模態(tài)參數(shù)識別方法，該方法能自動搜索目標模態(tài)所對應的頻率范圍，并利用反映實測振型與理論振型良好相關(guān)性的最大模態(tài)置信準則（MAC) 值判斷和識別結(jié)構(gòu)真實振型。給出了該方法的具體實現(xiàn)過程，對平面桁架和空間網(wǎng)架算例進行了模態(tài)參數(shù)識別。結(jié)果表明，該方法能夠準確識別出各階模態(tài)頻率和振型，可以有效避免模態(tài)遺漏，且具有很強的抗噪能力。該方法彌補了常規(guī)FDD的不足，適用于對頻率密集或具有重頻現(xiàn)象的空間網(wǎng)格結(jié)構(gòu)的模態(tài)參數(shù)識別，且其過程便于編程實現(xiàn)。［關(guān)鍵詞］模態(tài)參數(shù); 頻域分解法; 振型相關(guān)性; 自動識別; 網(wǎng)格結(jié)構(gòu)中圖分類號：TU393.3 文獻標識碼：A 文章編號：1002-848X(2015)05-0039-05An automated frequency domain modal identification method based on modal assurance criterionXu Qize1, Wu Jinzhi1,2, Zhang Yigang1,2（1 Space Structures Research Center, Beijing University of Technology, Beijing 100124, China; 2 Key Lab of Urban Security and Disaster Engineering, MOE, Beijing University of Technology， Beijing 100124, China）Abstract: Frequency domain decomposition (FDD) is known as one of the most powerful techniques for mode shape and frequency identification of structures subject to ambient excitation. However, the classical implementation of the technique requires user interaction by picking peaks as frequencies in singular vectors, thus it can not differentiate closely spaced or repeated modal parameter and carry out modal parameter identification automatically. An automated modal parameter identification procedure was proposed, namely MAC-FDD, which could be carried out automatically to search the target frequency range without any user interaction. And with the maximum modal assurance criterion (MAC) which could reflect the good correlation between measured and theoretic vibration modes, the real structure vibration modes were judged and identified. The implementation of the procedure and its application to two numerical examples, a planar truss and a spatial grid, were presented. The results indicate that MAC-FDD is capable to extract accurate mode shapes and frequencies without mode absence, showing great anti-noise capability. This friendly MAC-FDD method can be applied to modal parameter identification of spatial grid structures with closely spaced or repeated frequencies and can be easily implemented in programming to cover the shortage of the classical FDD.Keywords: modal parameter; frequency domain decomposition (FDD); modal correlation; automated identification; grid structure*國家自然科學基金項目(51278009)。通訊作者：吳金志，博士，副教授，Email：kongjian@bjut.edu.cn。參考文獻［1］傅志方，華宏星. 模態(tài)分析理論與應用［M］. 上海：上海交通大學出版社，2000.［2］ZHANG L M, BRINCKER R, ANDERSEN P. An overview of operational modal analysis: major development and issues［C］//Proceedings 1st IOMAC. Copenhagen, Denmark, 2005.［3］續(xù)秀忠，華宏星，陳兆能. 基于環(huán)境激勵的模態(tài)數(shù)辨識方法綜述［J］. 振動與沖擊，2002，21(3)：1-5.［4］沈方偉，杜成斌. 環(huán)境激勵下結(jié)構(gòu)模態(tài)參數(shù)識別方法綜述［J］. 電子測試，2013 (5)：178-181.［5］BRINCKER R, ZHANG L M, ANDERSEN P. Modal identification from ambient response using frequency domain decomposition［C］//Proceedings of the 18th IMAC. San Antonio, Texas, USA, 2000:625-630.［6］BRINCKER R, ZHANG L M, ANDERSEN P. Modal identification of output only systems using frequency domain decomposition［J］. Smart Materials and Structures, 2001, 10 (3)： 441-445.［7］TARINEJAD R, DAMADIPOUR M. Modal identification of structures by a novel approach based on FDD-wavelet method［J］. Journal of Sound and Vibration, 2014,333（3）：1024-1045.［8］ZHANG L M, WANG T, YUKIO TAMURA. A frequency-spatial domain decomposition (FSDD) method for operational modal analysis［J］. Mechanical Systems and Signal Processing, 2010, 24(5)：1227-1239.［9］高維成，于巖磊，劉偉. 在役鋼結(jié)構(gòu)游泳館的結(jié)構(gòu)安全性檢測研究［J］. 建筑結(jié)構(gòu)學報，2009，30(4)：38-46.［10］王卓，閆維明，葉列平. 網(wǎng)殼結(jié)構(gòu)運行模態(tài)分析的模型試驗［J］. 清華大學學報:自然科學版，2011，51(6)：755-759.［11］BRINCKER R, ANDERSEN P, JACOBSEN N J. Automated frequency domain decomposition for operational modal analysis［C］//Proceedings of the 25th IMAC. Orlando, Florida, USA, 2007.［12］ALLEMANG R J. The modal assurance criterion-twenty years of use and abuse［J］. Sound and Vibration, 2003, 37(8): 14-23.［13］KAMMER D C. Sensor placement for on-orbit modal identification and correlation of large space structures［J］. Journal of Guidance, Control, and Dynamics, 1991,14 (2): 251-259.
