在石化工廠、發電廠及燃氣工業中，貯存流體的儲存槽是相當基本的設備。在長期的使用下，因人為或天然環境等因素造成的損傷將影響儲存槽結構之強度，進而發生洩漏導致停工檢修。近年來國內針對儲存槽底板之檢測而開始引進音洩法，其優點是可在非開槽下進行大範圍檢測。然而，音洩法在儲存槽底板上缺陷的聲源定位依舊受到質疑，其原因是由於腐蝕、裂痕成長和塑性變形等不同類型的缺陷，均會產生音洩訊號並形成多種波傳的模態於儲存槽中傳遞，使聲源定位變得難以判讀。
本研究係針對儲存槽底板之腐蝕，分析自由邊界下零階蘭姆波之波傳類型及行為，利用有限元素模擬波傳變化，藉由模擬結果來選定可有效判斷腐蝕訊號之音洩參數，於實驗證實其音洩參數可增加判斷聲源定位之可信度。再者，以理論計算不同黏滯性流體之邊界條件下零階蘭姆波之波速，並利用有限元素模擬得其洩漏蘭姆波的波傳行為。最後，於充滿不同黏滯性流體之小尺寸儲存槽中進行實驗，並將利用小波分析其蘭姆波與洩漏蘭姆波對聲源定位之影響。
本論文由實驗與模擬確認腐蝕產生的音洩訊號，其訊號之波傳類型為零階非對稱蘭姆波，並可藉由訊號的上升時間、平均頻率及振幅來增加聲源定位之可信度。研究結果顯示，當儲存槽內為低黏滯性流體時，可利用洩漏到流體中之波傳做為聲源定位訊號；反之，為高黏滯性流體時，則需以非對稱蘭姆波做為聲源定位的撞擊訊號。此外，本研究採用小波轉換分析波傳模態，能有效地界定出音洩訊號中的第一個模態，進而瞭解儲存槽底板腐蝕的聲源定位依據，提高音洩法對儲存槽底板的檢測能力。

The storage tank is a general equipment in petrochemical industry, power plant and gas industry. Long-term usage of storage tank, the artificial and natural defect will cause structural damage. Recently, Acoustic Emission (AE) Testing was introduced to tank bottom corrosion inspection. The advantage of using Acoustic Emission Testing is a large range inspection of tank bottom without opening the tank. However, positioning of acoustic source is always be the problem of AE testing. The reason is that corrosion, crack growth and plastic deformation will produce numerous mode of wave making trouble for positioning of the defects.
This study analyzed corrosion on the tank bottom will generate mode and behaviors of zeroth Lamb wave, and utilized Finite element method for analyzing wave propagation which judged position of the source with AE parameters. Furthermore, the theoretical velocity of Lamb wave with different viscous fluid boundary was calculated and wave propagation of Leaky Lamb wave was simulated. Finally, Lamb wave and Leaky Lamb wave effect on positioning the AE source using Wavelet Transform analysis result of the small tank filled with different viscous fluids.
The study confirmed corrosion producing AE signal which is A0 mode by experiment and simulation. And using rise time, average frequency and amplitude will help to recognize position the AE source. The results showed that Leaky Lamb wave propagated in the low viscous fluid for positioning the AE source. On the country, A0 Lamb wave propagated on the bottom plate with high viscous fluid for positioning the AE source. The Wavelet analysis was used successfully to define the wave mode in the first arrival wave packet. Interpret the wave modes and wave propagation behavior as positioning the AE source of corrosion, and improve the ability of corrosion inspection on tank bottom.

中文摘要 i
英文摘要 ii
目錄 iv
表目錄 vii
圖目錄 ix
第一章 緒論 1
1.1前言 1
1.2研究動機與目的 2
1.3文獻回顧 4
1.4研究方法 7
1.5論文結構 8
第二章 基本理論 10
2.1音洩法 10
2.2平板蘭姆波理論 13
2.2.1平板蘭姆波波傳之特徵方程式 13
2.2.2頻散曲線圖 16
2.2.3波型結構 17
2.3小波轉換法 18
第三章 平板實驗之波傳類型 26
3.1 音洩工作平台操作 26
3.1.1硬體設備 26
3.1.2軟體操作 27
3.1.2.1撞擊訊號設定 28
3.1.2.2聲源定位設定 29
3.2實驗設定 32
3.2.1平板實驗 32
3.2.2實驗結果 34
3.2.3波傳行為 36
3.3聲源分類 38
3.3.1斷芯與球撞球訊號 40
3.3.2腐蝕訊號 42
第四章 儲存槽實驗與模擬 90
4.1頻散曲線 90
4.2有限元素模擬 91
4.2.1儲存槽為無內裝流體 92
4.2.1.1結構的暫態分析 92
4.2.1.2建立儲存槽模型 92
4.2.2儲存槽內裝為不同黏滯性流體 94
4.2.2.1流體聲學原理 94
4.2.2.2黏滯性流體設置 95
4.2.2.3儲存槽內裝為水之模擬 96
4.2.2.4儲存槽內裝為混合油之模擬 97
4.3儲存槽實驗 98
4.3.1聲源定位結果 99
4.3.2小波時頻分析 101
4.3.2.1連續小波 101
4.3.2.2離散小波 102
4.3.3波速修正後定位 105
4.3.4撞擊訊號之音洩參數 106
第五章 結論與未來展望 152
5.1結論 152
5.2未來展望 153
參考文獻 154
附件A：音洩聲源之定位推導 157
附件B：洩漏蘭姆波推導 159

　1.委國油廠大火，他山之石，可供借鏡。高市勞檢處公安快訊。2012年8月30日，取自http://jms.cla.gov.tw/show_article.php?fma_no=428。
　2. 俞清雲，中油公司橋頭供油中心甲苯儲槽火災事故。聯合新聞網。2008 年11月5 日。取自http://udn.tkec.com.tw/info/detail/%E6%B2%B9%E6%A7%BD%E7%81%BD/2623752。
　3. 洪臣宏，達成聚化苯乙烯外洩擴大，36 人送醫。自由時報，2014 年7 月4 日，取自http://news.ltn.com.tw/news/society/breakingnews/1047025。
　4. H. Nakamura, Study on Evaluation of Corrosion for Oil Storage Tank Floors by AE Method, Ph.D Thesis, the Yokohama National University, 2008.
　5. J. Kaiser, A Study of Acoustic Phenomena in Tensile, Ph. D Thesis, the Technical University of Munich, 1950.
　6. I. A. Viktorov, Rayleigh and Lamb wave: Physical Theory and Applications, New York: Plenum Press, 1967.
　7. A. Tobias, “Acoustic Emission Source Location in Two Dimensions by an Array of Three Sensors,” Non-Destructive Testing, Vol. 9, No. 1, pp. 9-12, 1976.
　8. M. R. Gorman, “Plate Wave Acoustic Emission,” The Journal of the Acoustical Society of America, Vol. 90, No. 1, pp. 358-364, 1991.
　9. Z. Zhu and J. Wu, “The Propagation of Lamb Waves in a Plate Bordered with a Viscous Liquid,” The Journal of the Acoustical Society of America, Vol. 98, No. 2, pp. 1057-1064, 1995.
　10. A. Maji and D. Satpathi, “Acoustic Emission Source Location using Lamb Wave Modes,” Journal of Engineering Mechanics, Vol. 123, No. 2, pp. 154-161, 1997.
　11. W. H. Prosser, M. D. Seale and B. T. Smith, “Time-Frequency Analysis of the Dispersion of Lamb Modes,” The Journal of the Acoustical Society of America, Vol.105, No. 5, pp. 2669-2676, 1999.
　12. K. M. Holford and D. C. Carter, “Acoustic emission source location,” Key Engineering Materials, Vol. 167-168, pp. 162-171, 1999.
　13. H. Nakamura, T. Arakawa and M. Yamada, “Examination of AE Wave Propagation Routes in a Small Model Tank,” Journal of Acoustic Emission, Vol. 23, pp.243-248, 2005.
　14. W. H. Weng, “Evaluation of Acoustic Emission Method for Detecting Corrosion of Aboveground Tank Floor,” Journal of Petroleum, Vol. 42, No. 1, pp. 73-81, 2006.
　15. H. Cho, T. Matsuo and M. Takemoto, “Long Range Inspection of Wall Reduction of Tank Utilizing Zero-th Order Symmetric Mode Lamb Wave: Performance Demonstration of the Method Proposed,” The Japanese Society for Non-Destructive Inspection, Vol. 48, No. 6, pp. 1179-1183, 2007.
　16. S. K. Lee, S. Bamerjee and A. Mal, “Identification of Impact Force on a Thick Plate Based on the Elastodynamic and Higher-order Time-frequency Analysis,” Journal of Mechanical Engineering, Vol. 221, No. 11, pp. 1249-1263, 2007.
　17. J. Jingpin, W. Bin and H. Cunfu, “Acoustic Emission Source Location Methods using Mode and Frequency Analysis,” Structural Control and Health Monitoring, Vol. 15, No. 4, pp. 642-651, 2008.
　18. G. Du, J. Li, W.K. Wang, C. Jiang and S.Z. Song, “Detection and characterization of stress-corrosion cracking on 304 stailess steel by electrochemical noise and acoustic emission techniques,” Corrosion Science, Vol. 53, pp. 2918-2926, 2011.
　19. J. Xu, X. Wu and E. H. Han, “Acoustic Emission during Pitting Corrosion of 304 Stainless Steel,” Corrosion Science, Vol. 53, No. 4, pp. 1537-1546, 2011.
　20. ASTM E976, “Standard Guide for Determining the Reproducibility of Acoustic Emission Sensor Response,” ASTM International, West Conshohocken, Pennsylvania, USA, 2012.
　21. European Standard EN 15856, “Non-destructive Testing – Acoustic Emission –General Principles of AE Testing for the Detection of Corrosion within Metallic Surrounding Filled with Liquid, ” European Committee for Standardization, Brussels, 2010.
　22. B. Pavlakovic, M. Lowe, D. N. Alleyne and P. Cawley, “DISPERSE: A General Purpose Program for Creating Dispersion Curve,” Review of Progress in Quantitative Nondestructive Evaluation, Vol. 16, pp. 185-192, 1997.
　23. DiSP with AEwin user’s manual, New Jersey: Physical Acoustics Ltd., 2003.
　24. 王芳、丁振君、祝彥、王偉，「金屬腐蝕聲發射信號小波去噪」，河北大學學報，第30 卷，第5 期，頁580-584，2010。
　25. API 650, “Welded Tanks for Oil Storage,” American Pertroleum Institute, USA,2013.
　26. ASTM E1930/1930M, “Standard Practice for Examination of Liquid-filled Atmospheric and Low-pressure Metal Storage Tanks using Acoustic Emission,” ASTM International, West Conshohocken, Pennsylvania, USA, 2012.
　27. P. Wilcox, M. Evans, O. Diligent, M. Lowe and P. Cawley, “Dispersion and Excitability of Guided Acoustic Waves in Isotropic Beams with Arbitrary Cross Section,” Review of Progress in Quantitative Nondestructive Evaluation, Vol. 21, pp.203-210, 2002.
　28. 戈浩、蔡桂喜、劉暢、董瑞琪，「基於模態識別與分離的鋁板激光超聲檢測」，應用聲學，第32 卷，第5 期，頁341-347，2013。
　29. 劉晉奇、褚晴暉，有限元素分析與ANSYS 的工程應用，滄海書局，台中，2006。