導波法能快速並大範圍的針對管線進行整體性檢查，如果管線為埋地或包覆，僅需開挖部分檢測坑或拆除局部包覆材來架設環狀陣列探頭，即可對整體管線做評估。但若此時檢測點架設於管線表面呈現均勻腐蝕之位置時，導波的背景訊號會增加而干擾檢測訊號的辨別，尚且均勻腐蝕也會使導波能量衰減，影響檢測距離。
本文以實驗及有限元素法數值模擬來進行比較研究，主要探討探頭下方均勻腐蝕對訊號的影響與均勻腐蝕區段中包含嚴重局部腐蝕之波傳行為。首先以有限元素模擬導波波傳，採用時域訊號、波傳圖與二維傅立葉轉換分析，探討管線上有均勻腐蝕時，導波之入射、反射與穿透等波傳現象。接著探討不同程度均勻腐蝕區段，於不同檢測頻率時，對於均勻腐蝕與波傳衰減之關係，並於均勻腐蝕中加入局部腐蝕進一步研究兩者之間的關聯性。研究結果顯示：探頭架設於均勻腐蝕區進行檢測時，其表面腐蝕使探頭激振面積減少，所激振出的能量較乾淨管路為低；利用二維傅立葉轉換分析，可知非均勻對稱的接觸面將導致非對稱模態的產生；導波的能量雖仍集中於T(0,1) 扭矩模態，但伴隨之非對稱模態易使訊號混雜難以判讀。針對均勻腐蝕訊號模擬分析可得知，腐蝕深度或檢測頻率的提高，將使波傳的衰減率上升，如深度為2 mm之均勻腐蝕其衰減率於20 kHz時為-1.09 dB/m，於40 kHz時達到-3.01 dB/m；深度為4 mm之均勻腐蝕其衰減率於20 kHz時為-5.76 dB/m，於40 kHz時達到-23.19 dB/m，將降低可檢測之距離，甚至影響其它特徵辨別。均勻腐蝕所造成的背景訊號同樣會隨著腐蝕深度上升而升高，易使嚴重局部腐蝕訊號埋沒其中而不易辨別，但隨著檢測頻率上升，造成散射情形越加嚴重，反使接收的訊號減小，均勻腐蝕所產生的背景訊號下降，此時嚴重局部腐蝕的回波特性隨頻率的提高而上升，則有利於檢出均勻腐蝕區內的嚴重局部腐蝕，如模擬中2 mm深均勻腐蝕所造成之背景訊號值，於20 kHz時為-23.67 dB，於40 kHz時為-35.44 dB，而軸長為20 mm深為3.5 mm之缺陷反射訊號於20 kHz時為-26.34 dB，於40 kHz時為-26.94 dB，即高頻時易因背景訊號值的降低有利於此缺陷訊號的凸顯。以上結論可提供實務檢測者瞭解探頭架設於腐蝕區對檢測所造成的影響以及判別均勻腐蝕中嚴重缺陷訊號之參考。

The guided wave method can inspect pipelines very quickly and widely. For instance, it can inspect the overall pipelines by digging several detection pits or removing part of coating material to set the array ring. However, it will make the guided wave attenuate more seriously and make the signals hard to identify when setting the array ring on the general corrosion.
In this study, the wave propagation will be discussed when the general corrosion is under the array ring and the severe localized corrosion is inside the general corrosion via experiment and finite element method. In finite element method, time-domain signal analysis, wave propagation and the two-dimensional Fourier transform are used to explore the guided wave incident, reflection, transmission and other wave propagation phenomena. Furthermore, the relationship between wave propagation, attenuation and localized corrosion on the general corrosion were discussed by different detection frequencies.
The results showed that the excitation energy will be lower when the array ring set on the pipe surface with the general corrosion. By two-dimensional Fourier transform analysis, its non-uniform contact surface will increase asymmetric modal and mix signals. The energy attenuation will increase when the corrosion depth is deepened or the inspection frequency is risen. For example, the 2 mm deep general corrosion will attenuate -1.09 dB/m at 20 kHz and attenuate -3.01 dB/m at 40 kHz; the 4 mm deep general corrosion will attenuation -5.76 dB/m at 20 kHz and attenuation -23.19 dB/m at 40 kHz. However, the coherent signals which were caused by the general corrosion will decay with increasing frequency. For example, the coherent signals of 2 mm deep general corrosion are -23.67 dB at 20 kHz and -35.44 dB at 40 kHz; then, the 20 mm long and 3.5 mm deep localized corrosion which signal is -26.34 dB at 20 kHz and -26.94 dB at 40 kHz will be detected easily at high frequency. It can provide detectors to understand the impact when the array ring set on the area of general corrosion and the way to distinguish the localized corrosion which is inside the area of general corrosion.

論文審定書 i
誌謝 ii
中文摘要 iii
英文摘要 iv
目錄 vi
表目錄 viii
圖目錄 ix
第一章緒論 1
1.1前言 1
1.2腐蝕介紹 2
1.3研究動機與目的 3
1.4文獻回顧 4
1.5研究方法 6
1.6論文結構 7
第二章基本理論 10
2.1導波基本理論與分析 10
2.1.1導波於圓管之波動方程式 10
2.1.2頻散曲線 12
2.1.3波形結構 14
2.2有限元素法 15
2.3二維傅立葉快速轉換法 16
第三章模擬設定與分析 25
3.1有限元素法導波波傳模擬 25
3.1.1模型設定與網格劃分 26
3.1.2圓管導波激發與施加負載情形 27
3.1.3訊號擷取 28
3.2均勻腐蝕區的模型建立 30
3.3扭矩模態於不同腐蝕區之影響 31
3.3.1 於乾淨管面激振扭矩模態 31
3.3.2 於均勻腐蝕表面激振扭矩模態 33
3.3.3 於加長之均勻腐蝕表面激振扭矩模態 36
3.4模擬導波檢測均勻腐蝕區域的訊號情形與特性 37
3.4.1均勻腐蝕模擬結果與討論 37
3.4.2局部缺陷模擬結果與討論 40
3.4.3均勻腐蝕加入局部缺陷之模擬討論 43
第四章實驗架構與量測結果 91
4.1儀器系統 91
4.2實驗架設 94
4.3實驗結果與討論 96
4.3.1導波法探頭架設於均勻腐蝕上進行檢測之結果 96
4.3.2導波法對均勻腐蝕檢測之結果 98
4.3.3模擬與實驗結果比較與討論 100
第五章結論與未來展望 129
5.1結論 129
5.2未來展望 130
參考文獻 132

參考文獻
1.D. N. Alleyne and P. Cawley, “The Interaction of Lamb Waves with Defects,” IEEE Trans Ultrason Ferroelectr Freq Control, Vol. 39, pp. 381-97, 1992.
2.M. J. S. Lowe, D. N. Alleyne and P. Cawley, “Defect Detection in Pipes using Guided Waves,” Ultrasonics, Vol. 36, pp. 147-54, 1998.
3.P. Cawley and D. N. Alleyne, “The Use of Lamb Waves for the Long Range Inspection of Large Structures,” Ultrasonics, Vol. 34, pp. 287-90, 1998.
4.鮮祺振、劉國橋，金屬腐蝕及其控制，台北，財團法人徐氏基金會，1995。
5.揚武、願濬祥，金屬的局部腐蝕，北京，化學工業出版社，1997。
6.張銘坤， “調查石化廠管線腐蝕偵測方法與防治技術，” 論文，行政院勞工委員會勞工安全衛生研究所，新北市，1998年。
7.台灣高雄氣爆事故。2014年10月2號，取自http://zh.wikipedia.org/wiki/2014年台灣高雄氣爆事故
8.J. A. Mcfadden, “Radial Vibrations of Thick-walled Hollow Cylinders,” Journal of the Acoustical Society of America, Vol. 26, pp. 714-715, 1954.
9.P. M. Naghdi and R. M. Cooper, “Propagation of Elastic Wave in Cylindrical Shells. Including the Effect of Transverse Shear and Rotatory Intertia,” Journal of the Acoustical Society of America, Vol. 28, pp. 56-63, 1956.
10.D. C. Gazis, “Three-dimensional Investigation of the Propagation of Waves in Hollow Circular Cylinders. I. Analytical Foundation,” Journal of the Acoustical Society of America, Vol. 31, pp. 568-573, 1959.
11.D. C. Gazis, “Three-dimensional Investigation of the Propagation of Waves in Hollow Circular Cylinders.Ⅱ. Numerical Results,” Journal of the Acoustical Society of America, Vol. 31, pp. 573-578, 1959.
12.D. N. Alleyne and P. Cawley, “A Two-dimensional Fourier Transform Method for the Measurement of Propagating Multimode Signals,” Journal of the Acoustical Society of America, Vol. 89, pp. 1159-1168, 1991.
13.M. Castasing and P. Cawley, “The Generation, Propagating, and Detection of Lamb Waves in Plates Using Air-coupled Ultrasonic Transducer,” Journal of the Acoustical Society of America, Vol. 100, pp. 3070-3077, 1996.
14.D. N. Alleyne, P. Cawley and M. Lowe, “The Mode Conversion of a Guided Wave by a Part-Circumferential Notch in a Pipe,” Journal of Applied Mechanics, Vol. 65, pp. 649-656, 1998.
15.P. Cawley, M. J. S. Lowe, F. Simonetti, C. Chevalier and A. G. Roosenbrand, “The Variation of the Reflection Coefficient of Extensional Guided Waves in Pipes from Defects as a Function of Defect Depth, Axial Extent, Circumferential Extent and Frequency,” Journal of Mechanical Engineering Science, Vol. 216, pp. 1131-1143, 1998.
16.S. P. Pelts, D. Jiao and J. L. Rose, “A Comb Transducer for Guided Wave Generation and Mode Selection,” IEEE Conference, San Antonio, TX, November 3-6, 1996.
17.H. J. Shin and J. L. Rose, “Guided Wave Tuning Principles for Defect Detection in Tubing,” Journal of Nondestructive Evaluation, Vol. 17, pp. 27-36, 1998.
18.J. L. Rose, S. Pelts and M. Quarry, “A Comb Transducer Model for Guided Wave NDE,” Ultrasonics, Vol. 36, pp. 163-168, 1998.
19.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.
20.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, pp. 457-464, 2001.
21.P. Wilcox, M. J. S. Lowe and P. Cawley, “The Effect of the Dispersion on Long-Range Inspection using Ultrasonic Guided Waves,” NDT＆E International, Vol. 34, pp. 1-9, 2001.
22.W. Zho, “An FEM Simulation for Guided Elastic Wave Generation and Reflection in Hollow Cylinders with Corrosion Defects,” Journal of Pressure Vessel Technology, Vol. 124, pp. 108-117, 2002.
23.A. Demma, P. Cawley, M. J. S. Lowe, A. G. Roosenbrand and B. Pavlakovic, “The Reflection of Guided Waves From Notches in Pipes: A Guide for Interpreting Corrosion Measurement,” NDT&E International, Vol. 37, pp. 167-180, 2004.
24.R. Carandente, J. Ma and P. Cawley, “The Scattering of the Fundamental Torsional Mode from Axi-symmetric Defects with Varying Depth Profile in Pipes,” Journal of the Acoustical Society of America, Vol. 127, pp. 3340-3348, 2010.
25.X. Wang, P. W. Tse, C. K. Mechefske and M. Hua, “Experimental Investigation of Reflection in Guided Wave-Based Inspection for the Characterization of Pipeline Defects,” NDT&E International, Vol. 43, pp. 365-374, 2010.
26.A. Løvstad and P. Cawley, “The Reflection of the Fundamental Torsional Guided Wave from Multiple Circular Holes in Pipes,” NDT&E International, Vol. 44, pp. 553-562, 2011.
27.R. Carandente and P. Cawley, “The Effect of Complex Defect Profiles on the Reflection of the Fundamental Torsional Mode in Pipes,” NDT&E International, Vol. 46, pp. 41-47, 2012.
28.R. Carandente, A. Løvstad and P. Cawley, “The Influence of Sharp Edges in Corrosion Profiles on the Reflection of Guided Waves,” NDT&E International, Vol. 52, pp. 57-68, 2012.
29.ASTM Standard G46, “Standard Guide for Examination and Evaluation of Pitting Corrosion,” ASTM International, West Conshohocken, PA, 2005.
30.蘇俊吉， “設備和管線包覆層下腐蝕問題之風險鑑別與預防，” 中油技術報告，頁1-27，2009年。
31.A. C. Cobb, H. Kwun, L. Caseres and G. Janega, “Torsional Guided Wave Attenuation in Piping from Coating, Temperature, and Large-area Corrosion,” NDT&E International, Vol. 47, pp. 163-170, 2012.
32.Obtaining Credit for Guided Wave as a Buried Pipe Direct Examination. EPRI, Palo Alto, CA: 2013.
33.O. Bareille, M. Kharrat, W. Zhou and M. N. Ichchou, “Distributed Piezoelectric Guided-T-wave Generator, Design and Analysis,” Mechatronics, Vol. 22, pp. 544-551, 2012.
34.Wavemaker G3 Procedure Based Inspector Training Manual, Guided Ultrasonics Ltd., Nottingham, UK, 2007.
35.J. L. Rose, Ultrasonic Waves in Solid Media, New York: Cambridge University Press, 1999.
36.A. H. Meitzler, “Mode Coupling Occurring in the Propagation of Elastic Pulses in Wires,” Journal of the Acoustical Society of America, Vol. 33, pp 435-145, 1961.
37.J. Jr. Zemanek, “An Experimental and Theoretical Investigation of Elastic Wave Propagation in Cylinder,” Journal of the Acoustical Society of America, Vol. 51, pp 265-283, 1972.
38.M. G. Silk and K. P. Bainton, “The Propagation in Metal Tubing of Ultrasonic Wave Modes Equivalent to Lamb Waves,” Ultrasonics, Vol. 17, pp. 11-19, 1979.
39.H. Nishino, S. Takashina, F. Uchide, M. Takemoto and K. Ono, “Modal Analysis of Hollow Cylindrical Guided Waves and Applications,” The Japan Society of Applied Physics, Vol. 40, pp. 364-370, 2001.
40.P. Cawley, D. N. Alleyne and M. J. S. Lowe, “The Reflection of Guided Waves From Circumferential Notches in Pipe,” Journal of Applied Mechanics, Vol. 65, pp. 635-641, 1998.
41.B. Pavlakovic, M. J. S. 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.
42.劉晉奇、禇晴暉，有限元素分析與ANSYS的工程應用，滄海書局，2006。
43.B. Pavlakovic, Leaky Guided Ultrasonic Wave in NDT, Imperial College, 1998.
44.P. Wilcox, M. Evans, O. Diligent, M. Lowe and P. Cawley, “Dispersion and Excitability of Acoustic Waves in Isotropic Beams with Arbitrary Cross Section,” in D. Thompson and D. Chimenti, eds., Review of Progress in Quatitative NDE, edited by D. Thompson and D. Chimenti (Plenum, New York), Vol.11B, pp. 203-210, 2002.