利用遙場渦電流檢測技術檢測管束之腐蝕缺陷時，主要原理是利用低頻交流電通過探頭激發線圈所產生之磁場與探頭接收線圈之感應磁場交互作用。將接收線圈上之感應電壓繪製為訊號圖，由訊號圖之形狀、角度判定缺陷之存在與深淺，因此探頭之結構與檢測之準確度息息相關。然而在實際檢測中，探頭表面因覆蓋一層外殼，拆卸不易，因此較少人針對探頭部分結構進行分析。
本論文針對探頭上之結構進行對檢測影響之分析。主要以有限元素法模擬檢測探頭之軸對稱模型，並改變激發線圈和接收線圈之間距、結構以及激發線圈之電流大小、頻率與擋板之結構、材料…等性質，以達到分析探頭結構對檢測之影響。藉由此模擬技術的建立，可增加對遙場渦電流檢測技術的了解，更可使探頭透過模擬具有更高之靈敏度以提高檢測之準確度及降低由探頭部分所造成誤差因素之影響。

While evaluating the depth of corrosive defect of the pipe through Remote Field Eddy Current (RFEC) Testing technology, the critical principle of the process is to use the interaction of the magnetic field. Generally, exciter coils in the low-frequency alternating current and detector coils can generate the magnetic field. The signal curve can be transformed by receiving and plotting the induction voltage of detector coils. In addition, the signal curve can be used to identify the existence and the depth of corrosive defect from the shape and angle of the curve. Thus, the structure of the detector has a great influence on the exactitude of the testing. However, in the real experiment, RFEC probe is covered by shell and hard to disassemble. Thus, few people doing the research to analyze the structure of the RFEC probes.
This research is based on two-dimensional axial-symmetry models and using Finite Element Method to simulate different structures or designs, such as the distance between exciter coils and detector coils, the amplitude and frequency of current in exciter coils, and even the material and size of shield. The simulation results show the influences of changing these important characteristics. Therefore, with these scenarios, the RFEC testing technology can be understood more completely and be improved the accuracy and reliability of the experiment by optimizing the sensibility of the RFEC probe.

謝誌 ----------------------------------------------------------------------------- Ⅰ
目錄 ----------------------------------------------------------------------------- Ⅱ
表目錄 -------------------------------------------------------------------------- Ⅴ
圖目錄 -------------------------------------------------------------------------- Ⅵ
中文摘要 -------------------------------------------------------------------- ⅩⅠ
英文摘要 -------------------------------------------------------------------- ⅩⅡ
一、 緒論 ---------------------------------------------------------------------- 1
1.1 前言 ----------------------------------------------------------------------- 1
1.2 文獻回顧 ----------------------------------------------------------------- 2
1.3 遙場渦電流簡介 -------------------------------------------------------- 4
1.4 研究動機與目的 -------------------------------------------------------- 6
1.5 使用軟體介紹 ----------------------------------------------------------- 6
1.5.1 FEMLAB (v2.3) ----------------------------------------------------- 7
1.5.2 MATLAB (v6.51) --------------------------------------------------- 7
1.6 研究分析流程 ----------------------------------------------------------- 8
二､理論分析 ------------------------------------------------------------------- 10
2.1 電磁理論基礎方程式 ------------------------------------------------ 10
2.2 能量方程式與有限元素法 ------------------------------------------ 12
2.3 遙場渦電流線圈電壓方程式 --------------------------------------- 15
三､遙場渦電流探頭之有限元素分析 ------------------------------------- 16
3.1 有限元素模型之建立 ------------------------------------------------ 16
3.1.1 渦電流模型初始假設條件 ------------------------------------- 16
3.1.2軸對稱模型之建立 ----------------------------------------------- 17
3.1.3 邊界條件之設定 ------------------------------------------------- 17
3.1.4 材料性質之設定 ------------------------------------------------- 18
3.1.5 有限元素模型之分割 ------------------------------------------- 18
3.1.6 有限元素計算與電磁分佈圖 ---------------------------------- 19
3.2 訊號圖之建立與分析流程 ------------------------------------------ 19
3.3 有限元素分析 --------------------------------------------------------- 20
3.3.1 模擬實驗文獻分析----------------------------------------------- 20
3.3.2 激發與接收線圈 ------------------------------------------------- 21
3.3.3 電流頻率 ---------------------------------------------------------- 21
3.3.4 電流大小 ---------------------------------------------------------- 21
3.3.5 激發與接收線圈間距 ------------------------------------------- 22
3.3.6 擋板 ---------------------------------------------------------------- 22
四､有限元素模擬結果 ------------------------------------------------------- 25
4.1 實驗與模擬之比較與分析 ------------------------------------------ 25
4.1.1 非導磁性管材 ---------------------------------------------------- 25
4.1.2 導磁性管材 ------------------------------------------------------- 26
4.2 激發線圈與接收線圈尺寸大小 ------------------------------------ 26
4.2.1 厚度變化 ---------------------------------------------------------- 26
4.2.2 寬度變化 ---------------------------------------------------------- 27
4.3 電流頻率 --------------------------------------------------------------- 28
4.4 電流大小 --------------------------------------------------------------- 29
4.5 激發與接收線圈間距 ------------------------------------------------ 29
4.6 擋板 --------------------------------------------------------------------- 31
4.6.1 擋板尺寸 ---------------------------------------------------------- 32
4.6.2 擋板材質 ---------------------------------------------------------- 33
五､結論 ------------------------------------------------------------------------- 35
5.1 結論與建議 ------------------------------------------------------------ 35
5.2 未來展望 --------------------------------------------------------------- 37
附錄 ----------------------------------------------------------------------------- 89
附錄1 FEMLAB計算程式 --------------------------------------------- 89
附錄2 MATLAB電壓轉換程式 --------------------------------------- 95
參考文獻 ----------------------------------------------------------------------- 97

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