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論文名稱 Title |
以小波轉換法改善導波檢測時之同調雜訊 Using Wavelet Analysis to Improve the Effect of Coherent Noise for Guided Wave Inspection |
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系所名稱 Department |
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畢業學年期 Year, semester |
語文別 Language |
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學位類別 Degree |
頁數 Number of pages |
103 |
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研究生 Author |
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指導教授 Advisor |
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召集委員 Convenor |
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口試委員 Advisory Committee |
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口試日期 Date of Exam |
2009-01-14 |
繳交日期 Date of Submission |
2009-02-09 |
關鍵字 Keywords |
導波檢測、縱向焊接支撐架、小波轉換 wavelet analysis, guided wave, weld support |
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統計 Statistics |
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中文摘要 |
利用導波檢測法可以克服傳統超音波在檢測時,採用點對點的量測方法,造成相當費時又耗人力的問題,對於石化工業廠區內動輒數百公尺的管線檢測工程,導波檢測技術已大為採用與發展。利用收發合置系統激振蘭姆波於管線上傳遞以進行快速且大範圍檢測,擷取與分析其回波訊號判別腐蝕位置所在。但管線特徵,如彎管、管線支撐架等處若發生腐蝕時,腐蝕回波訊號往往會被管線特徵回波訊號覆蓋住,著實造成訊號判讀的困難。為了提升導波法對於管線特徵區具腐蝕之檢測能力,針對管線縱向焊接支撐架此特徵,本文目標在於以離散小波轉換法,分別對3吋管件上架設焊接支撐架之實驗與有限元素模擬所得之反射訊號做進一步的分析,探討以小波轉換法改善管線特徵所產生之同調雜訊其可行性研究。由本研究成果可見,比較原始管線支撐架、人工均勻腐蝕支撐架,與加深切凹槽支撐架之實驗回波訊號,由原始時域訊號並無法分辨出其差異;若比較經小波轉換後之三組高頻訊號,則可分辨出缺陷與支撐架訊號之訊號波形分離,並在分析加深切凹槽支撐架之回波訊號振幅比之趨勢有明顯的差異。在有限元素軟體ANSYS模擬以兩種不同模型、五個頻率進行模擬,並將模擬之結果載入小波轉換分析,其分析之結果亦有類似實驗分析結果之趨勢。針對正常支撐架與腐蝕支撐架,本文成功地藉由小波轉換分析,擷取出不同之訊號特性,未來可加以應用於現場檢測結果分析上,以提高導波於管線特徵區腐蝕檢測之能力。 |
Abstract |
Using ultrasonic guided waves improve a problem of time-consuming and laborious with conventional ultrasonic method involving point–by-point inspection. In order to measure of hundreds meters of pipeline in oil and chemical industries, guided waves inspection technique is used and developed widely. For fast and long range inspection, a pulse-echo system is used to excite Lamb waves propagating along the pipe. The collection and analysis of the returning echoes indicate the present of corrosion. But if the pipe features, like bends or supports, are corrosive, the signal of corrosions is often covered with echoes of pipe features. Then it causes the inspection more difficult. In this study, the pipe feature which discussed is the welded support. The focus of the advanced analysis, Discrete Wavelet Transform, of the echoes reflected from the welded support on a 3 inch pipe by experimental and finite element method, so as to improve the ability of corrosion inspection on pipe features. To study the feasibility of the improvement in the effect of coherent noise for guided wave inspection by Wavelet analysis. Results show that original signals can not be differentiated by comparing with signals of normal support, general corrosive support, and support with notch. But after processing these three signals by Wavelet analysis, the situation of the 3 type supports from the signals can be differentiated. The simulated results of two different models and five exciting frequencies show the similar trend to the experimental results after Wavelet transform processing. It is success on separating the signals of normal support and corrosive support with Wavelet Analysis, and this method of this study is useful to improve the effect of coherency noise for guided wave inspection. |
目次 Table of Contents |
中文摘要 ……………………………………………..………………………...I 英文摘要 ……………………………………………….…………………….III 目錄 ………………………………………….………………………………...V 表目錄 ………………………………………………………...………….…VIII 圖目錄 ……………………………………………………...………………...IX 第一章 緒論…………...……………………………………..………………...1 1.1研究背景…………………….………………….……………………….1 1.2文獻回顧……………………...…………………………………………3 1.3研究方法……………………..…………………………………….……6 1.4本文架構…………………….……………..……………………………6 第二章 基本理論……………………………………………..………………..8 2.1頻散曲線…………………….……………………….………………….9 2.2波形結構…………………….…………………………………………11 2.3波式轉換…………………….…………………………………………12 2.4小波轉換…………………….…………………………………………12 2.5連續小波轉換………………………………………………………….14 2.5.1尺度參數與頻率參數的關係….………………………….....….15 2.6離散小波轉換………………………………………………………….15 2.6.1近似空間與細節空間………….………………………………..16 2.6.2 Mallat 運演算法…………….…………………………………17 2.6.3正交基底……………………...…………………………………19 2.7傅立葉轉換…………………………………………………………….20 2.8 Gabor 轉換……………………………………………………………22 2.9小波轉換相較於傅立葉轉換的優勢………………………………….23 2.10小波轉換的應用………………..……….……………………………25 第三章實驗架設與模擬設定…………………………………………………33 3.1實驗架設……………………………………………………………….33 3.1.1實驗管線…………………………….……………………….….33 3.1.2實驗設備…………………………….…………………………..34 3.1.3實驗方法……………………………...…………………………36 3.2導波波傳模擬………………………………………………………….37 3.2.1圓管有限元素模型…………………….………………………..37 3.2.2激發與擷取訊號設定…………………...………………………38 3.3小波工具箱(Wavelet Toolbox)……………….………………………39 3.3.1小波圖形使用者介面(Graphical User Interface, GUI)…….….39 3.3.2 離散小波轉換……………………………………………….…40 第四章結果與討論…………………………………………………………....51 4.1研究結果…………………………………………………………..….51 4.1.1實驗結果…………………………………………………….…..51 4.1.2實驗結果討論..…………………………………………….……52 4.2有限元素模擬結果……………………………………………...……53 4.2.1以有限元素軟體ANSYS模擬檢測結果………………………..53 4.2.2截面積變化模擬結果……………………………………….…54 4.3小波分析……………………………………………………………….55 4.3.1小波函數選取原則…………………………………………...…55 4.3.2小波分析結果………………………………………………..….55 4.3.3結果討論……………………………………………………..….57 第五章結論與建議………………………………………………………..…..82 5.1結論…………………………………………………………………….82 5.2未來展望………………………………………………………..…….83 參考文獻……………………………………………………………….......….84 附錄A 導波於圓管中之波動方程式…………………………………………87 |
參考文獻 References |
01. D.C. Worlton, “Ultrasonic Testing with Lamb Waves,” Non-destructive Testing, Vol. 15, pp. 218-222, 1957. 02. W. Mohr and P. Hoeller, “On Inspection of Thin-walled Tubes for Transverse and Longitudinal Flaws by Guided Ultrasonic Waves,” IEEE Transactions on Sonics and Ultrasonics, Vol. 23, pp. 369-374, 1976. 03. G.M. Light, W.D. Jolly and D.J. Reed, “Detection of Stress Corrosion Cracks in Reactor Pressure Vessel and Primary Coolant System Anchor Studs,” Review of Progress in Quantitative Nondestructive Evaluation, Vol. 3, pp. 811-818, 1984. 04. G.M. Light, N.R. Joshi and S.N. Liu, “Cylindrically Guided Wave Technique for Inspection of Studs in Power Plants,” Materials Evaluation, Vol. 44, p. 494, 1986. 05. W. Boettger, H. Schneider and W. Weingarten, “Prototype EMAT System for Tube Inspection with Guided Ultrasonic Waves,” Nuclear Engineering and Design, Vol. 102, pp. 369-376, 1987. 06. S.P. Pelts, D. Jiao and J.L. Rose, “A Comb Transducer for Guided Wave Generation and Mode Selection,” IEEE Conference, San Antonio, TX, pp. 3-6, 1996. 07. H.J. Shin and J.L. Rose, “Guided Wave Tuning Principles for Defect Detection in Tubing,” Journal of Nondestructive Evaluation, Vol. 17, No. 1, pp. 27-36, 1998. 08. J.L. Rose, S. Pelts and M. Quarry, “A Comb Transducer Model for Guided Wave NDE,” Ultrasonics, Vol. 36/1-5, pp. 163-168, Feb., 1998. 09. J.J. Ditri and J.L. Rose, “Excitation of Guided Elastic Wave Modes in Hollow Cylinders by Applied Surface Tractions, ” Journal of Applied Physics, Vol. 72, pp.2589-2597, 1992. 10. H.J. Shin and J.L. Rose, “Guided Waves by Axisymmetric and Non-Axisymmetric Surface Loading Hollow Cylinders,” Ultrasonics, Vol. 37, pp. 355-363, 1999. 11. J. Li and J.L. Rose, “Excitation and Propagation of Non-axisymmetric Guided Waves in a Hollow Cylinder,” Journal of the Acoustical Society of America, Vol. 109, No. 2, pp. 457-464, 2001. 12. J. Li and J.L. Rose, “Implementing Guided Wave Mode Control by Use of a Phased Transducer Array,” Ultrasonics, Ferroelectrics & Frequency Control, Vol. 48, No. 3, pp. 761-768, May, 2001. 13. J. Li and J.L. Rose, “Angular-Profile Tuning of Guided Waves in Hollow Cylinders Using a Circumferential Phased Array,” IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Vol. 49, pp. 1720-1729, 2002. 14. T. Hayashi, K. Kawashima, Z. Sun and J.L. Rose, “Analysis of Flexural Mode Focusing by a Semianalytical Finite Element Method,” Journal of Acoustical Society of America, Vol. 113, pp. 1241-1248, 2002. 15. 黎文明,快速傅立葉轉換,復漢出版社,台灣,1985。 16. J.S. Bendat, Random Date Analysis and Measurement Procedure, WILEY Singapore, 1991. 17. Y. Meyer, Wavelets Algorithms and Application, S.I.A.M., Inst. Universitaire de France, 1993. 18. S. Mallat, A Wavelet Tour of Signal Processing, Academic Press, USA , 1998. 19. H. Oehlmann, “A Method For Analysis Gearbox Faults Using Time -Frequency Representation,” Mechanical Systems and Signal Processing, Vol. 11(4), pp. 530-545, 1997. 20. B.A. Papy, “Artificial Neural Networ Based Fault Diagnostics Of Rotating Machinery Using Wavelet Transform as A Preprocessor,” Mechanical Systemsand Signal Processing, Vol. 11(5), pp. 752-756, 1997. 21. 王智中,「小波理論應用於旋轉機器故障診斷之分析」,國立成功大學造船暨船舶機械工程研究所,碩士論文,中華民國八十八年六月。 22. 劉承揚,「小波理論應用於結構自然頻率與阻尼比分析之研究」,國立成功大學造船暨船舶機械工程研究所,碩士論文,中華民國九十年六月。 23. A. Trochidis, E. Douka and S. Loutridis, “Crack Identification in Plates Using Wavelet Analysis,” Journal of Sound and Vibration Vol. 27, pp. 279-295, 2004. 24. M.H.S. Siqueira, C.E.N. Gatts, R.R. da Silva and J.M.A. Rebello, “The Use of Ultrasonic Guided Waves and Wavelets Analysis in Pipe Inspection,” ULTRASONICS,Vol.41, pp. 785-797, 2004. 25. F. He, Y. Gao, Z. Zhou, amd J. Bai, “An Overview of Testing Applications of Wavelet in Guided Waves,” Auckland, New Zealand 12th A-PCNDT 2006. 26. B. Pavlakovic, M. Lowe, D. N. Alleyne and P. Cawley, “DISPERSE: A General Purpose Program for Creating Dispersion Curve,” in Review of Progress in Quantitative Nondestructive Evaluation, edited by D. Thompson and D. Chimenti (Plenum, New York), Vol. 16, pp.185-192,1997. 27. J. L. Rose, Ultrasonic Waves in Solid Media, Cambridge University, 1999. 28. 葛哲學、沙威,小波分析理論與MATLAB R2007實現,電子工業出版社,中國大陸北京,2007。 29. 胡昌華,基於MATLAB 的系統分析與設計:小波分析,西安電子科技大學出版社,中國大陸,1999. 30. GUL, Wavemaker G3 Procedure Based Training, Nottingham,UK. 31. M. Lowe, D.N. Alleyne and P. Cawley, “Defect Detection in Pipes Using Guided Waves,” Ultrasonics, Vol. 36, pp. 147-154, 1998. 32. D.N. Alleyne, P. Cawley and M. Lowe, “The Reflection of Guided Waves From Circumferential Notches in Pipes,” J. Appl. Mech., Vol. 65, pp. 635-641, 1998. 33. D.N. Alleyne, P. Cawley and M.J.S. Lowe, “The Mode Conversion of a Guided Wave by a Part-Circuferential Notch in a Pipe,” J. Appl. Mech., Vol. 65, pp. 649-656, 1998. 34. A. Demma, P. Cawley, M.J.S. Lowe, B. Pavlakovic and A.G. Roosenbrand, “The Reflection of Guided Waves from Notches in Pipes : a Guide for Interpreting Corrosion Measurements,” NDT&E Int, Vol. 37, No. 3, pp.167-180, 2004. 35. A. Demma, P. Cawley, M.L.S. Lowe and A.G. Roosenbrand, “The Reflection of the Fundamental Torsional Mode from Cracks and Notches in Pipes,” J. Acoust. Soc. Am., Vol. 114, No. 2, pp. 611-625, 2003. 36. 李傑弘,「導波經焊接管鞋之波式轉換現象」,國立中山大學機械與機電工程研究所,碩士論文,中華民國95年7月。 |
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