摘要
渦電流檢測法是目前常見的非破壞性檢測法之一，常用以檢測較薄的金屬材料，其係藉由電磁感應作用，利用一激磁線圈，使被測物表面產生無數旋渦型局部小電流，這些局部電流稱之為渦電流。本法利用儀器檢測線圈阻抗，藉由觀察在阻抗平面訊號圖上的改變及其相位角的情形了解缺陷型態以及影響因素，以達到檢測的目的。
本文目的為探討在金屬管檢測時，激磁線圈與被測物幾何尺寸的影響。由於渦電流檢測係利用磁場相互作用達到檢測目的，因此磁場的影響大小係決定檢測準確率的重要因素。本文透過軟體建立一組三維電磁模型，以有限元素法分析在不同尺寸條件下檢測出的結果，藉由繪製線圈阻抗在阻抗平面訊號圖之變化及其深度-角度評估曲線，以觀察不同尺寸條件下之檢測結果對阻抗及相位角的影響，將其列入考慮以期降低檢測誤差。
本文將探討數個不同影響因素，藉由三維模型模擬分析，找出其影響之因素，確定趨勢，以期在往後渦電流檢測時，提高評估缺陷之準確度。

ABSTRACT

Eddy Current Test (ET) is one of the widely-used method in the nondestructive testing (NDT). It is used to examine thinner sheet metal. According to the theory of electromagnetic induction, the researcher used a coil to make the surface of the metal pipe bring much eddy current. In addition, he investigated the variations of the coil impendence by the interaction between the coil magnetic field and the eddy current magnetic field. By observing the variations of the phase angle and the impendence plane diagram, the researcher also found factors for different defects.

The purpose of this study is to research the influence of the diversity of the geometry when examining metal pipe. According to Eddy Current Test, the magnetic field is a major factor in testing. So the researcher generalized a 3-D electromagnetic model with software and analyzed the results of the magnetic field by the finite element method. By drawing the impendence plane diagram, evaluating curves and by observing the variations of the influence by diversity of the geometry, the researcher found the possibility of preventing the inaccuracy and errors in testing with a 3-D electromagnetic model. Later on, he found some influential factors, confirmed the tendency, and then increased the accuracy in examining thin sheet metal.

目錄
頁數
目錄……………………………………………………………………Ⅰ
表目錄…………………………………………………………………Ⅲ
圖目錄…………………………………………………………………Ⅳ
摘要……………………………………………………………………Ⅴ
英文摘要………………………………………………………………Ⅵ


第一章　緒論……………………………………………………………1
1.1前言…………………………………………………………1
1.2 研究動機與目……………………………………………2
1.3文獻回顧…………………………………………………2
1.4使用軟體簡介…………………………………………5
1.4.1 COMSOL Multiphysics…………………………………6
1.4.2 MATLAB…………………………………………………6
1.5文章架構………………………………………………7
第二章　研究理論………………………………………………………8
2.1渦電流基本原理……………………………………………8
2.2電磁理論……………………………………………………9
2.3有限元素法…………………………………………………12
2.4能量方程式與有限元素法…………………………………13
2.5 渦電流線圈阻抗方程式…………………………………14
2.6深度-角度評估曲線跨角經驗公式……………………15
2.7相位角計算方式…………………………………………16
第三章　渦電流模擬流程……………………………………………17
3.1三維模型的建構……………………………………………17
3.1.1 三維渦電流之模組初始條件設定…………………17
3.1.2 三維模組之繪製……………………………………18
3.1.3 統御域與邊界條件之設定……………………………22
3.1.4 網格化以及求解………………………………………23
3.1.5磁勢能與磁力線分佈圖………………………………24
3.2偏心率設定………………………………………………26
3.3 有限元素分析流程與訊號圖之建立………………………28
第四章　模擬結果與探討…………………………………………29
4.1 模型之準確性……………………………………………29
4.2配合比影響………………………………………………34
4.3厚度影響…………………………………………………41
4.4偏心模擬…………………………………………………47
4.4.1 360°環狀缺陷偏心模擬………………………………48
4.4.2 半環狀刻槽偏心模擬…………………………………52
4.5 偏心與缺陷之影響討論…………………………………57
第五章　結論與未來研究方向………………………………………61
5.1結論…………………………………………………………61
5.2未來研究方向………………………………………………62
參考文獻………………………………………………………………63

參 考 文 獻
[1]. M. D. Maclean, “Defect Characterization by the Remote Field EddyCurrent Technique in Small-Diameter Tubing,” Materials Evaluation, Vol. 47, No.1, pp. 24-28, 1989
[2]. D. D. Mackintosh, D.L. Atherton, and S. P. Sullivan, “Remote-FieldEddy Current Signal Analysis in Small-Bore Ferromagnetic Tubes, ” Materials Evaluation, Vol. 51, No.4, pp. 492-495, 1993
[3]. T. Kituta, J. L. Fisher, S. N. Rowland, and W. D. Jolly, “ Far-FieldEddy Current Model for Carbon Steel Gas Pipes, ” the 5(th) International Symposium on Offshore Mechanics and Arctic Engineering (OMAE), Dallas, TX, 1985
[4]. R. J. Kilgore and S. Ramchandran, “Remote-Field Eddy Current Testing of Small-Diameter Carbon Steel Tubes, ”Materials Evaluation, Vol. 47, No.1, pp. 32-36, 1989
[5]. C. V. Dodd, “Application of a Phase-Sensitive Eddy Current Instrument,” Materials Evaluation, Vol. 22, No. 6, pp.260-262, 1964
[6]. C. V. Dodd, “A Portable Phase –Sensitive Eddy Current Instrument,” Materials Evaluation, Vol. 26, No. 3, pp.33-36, 1968
[7]. C. V. Dodd, “ Solutions to Electromagnetic Induction Problems, ” Ph.D. dissertation, University of Tennessee, Knoxville, June, 1967
[8]. V. F. Muzhitskii, and A. S. Smirnov, “ Phase-Sensitive Method of Electromagnetic Flaw Detection, ” Soviet Journal of Nondestructive Testing, pp. 7-13, 1973
[9]. W. Lord, S. Nath, and Y. K. Shin, “ Pulsed RFEC Probe Response, ” IEEE Transactions on magnetics, Vol. 28, No. 2, pp.1430-1433, 1992
[10]. R. Palanisamy, “Finite Element Modeling of Eddy Current Nondestructive Testing Phenomena, ” Ph.D. dissertation, Colorado State University, 1980
[11]. N. Ida, R. Palanisamy, and W. Lord, “Eddy Current Probe Design Using Finite Element Analysis, ” Materials Evaluation, Vol. 41, No. 12, pp. 1389-1394, 1983
[12]. D. L. Atherton, B. Szpunar, and S. Sullivan, “The Application of Finite-Element Calculations to the Remote-Field Inspection Technique, ” Materials Evaluation, Vol. 45, No. 9, pp. 1083-1086, 1987


[13]. W. Lord, Y. S. Sun, S. S. Udpa, and S. Nath, “A Finite Element Study of the Remote-Field Eddy Current Phenomenon, ” IEEE Transactions on Magnetic, Vol. 24, No.1, pp. 435-438, 1988
[14]. D. L. Atherton and W. Czura, “Finite Element Calculations for Remote Field Eddy Current Inspection Tools, ” Electrosoft, Vol. 2, No. 2/3, pp.157-174, 1991
[15]. 申永吉(Shin Young-Kil), Member, IEEE, “Design of Encircling Remote Field Eddy-Current Probe, ” IEEE Transactions on magnetics, Vol. 38, No. 2, pp.1273-1276, 2002
[16]. 鄭錦智， Study on Reducing Evaluation Error of Remote Field Eddy Current Testing，國立中山大學機械與機電工程學系，博士論文，高雄，2002
[17]. 張淵俞，A Finite Element Study of the Influential Factors of Remote Field Eddy Current Testing，碩士論文，國立中山大學機械與機電工程學系，高雄，2004
[18]. 黃璽文，The Influence of Probe Structure on Remote Field Eddy Current Testing using Finite Element Analysis，碩士論文，國立中山大學機械與機電工程學系，高雄，2004
[19]. 林建宏，The Finite Element Analysis of Evaluation Curves and Errors in the Eddy Current Testing，碩士論文，國立中山大學機械與機電工程學系，高雄，2005
[20]. 林志生，The Finite Element Analysis of Influences of Varied Defects in Eddy Current Testing，碩士論文，國立中山大學機械與機電工程學系，高雄，2006
[21]. 許仁哲，The Finite Element Analysis of Three-Dimensional Defects in Eddy Current Testing，碩士論文，國立中山大學機械與機電工程學系，高雄，2008
[22]. COMSOL Documentation 使用手冊
[23]. 蒙以正，Matlab 入門與精進，儒林圖書有限公司，台北，2003
[24]. 王晟桓，A Study of Air Bearing for Micro Cooling Fans，碩士論文，國立成功大學航空太空工程學系，台南，2003
[25]. 李維仁，A Parametric Study for Finite-Width Journal Bearings Operating in the Turbulent Thermohydrodynamic Regime，碩士論文，國立成功大學航空太空工程學系，台南，2004
[26]. 余俊、全永昕、余夢生、張英會，機械設計(第二版)，亞東書局
[27]. 渦電流檢測法，陳必貫、余坤城、謝肇琨，財團法人中華民國非破壞檢測協會