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研究生： 李奇勳
Chi-Hsun Lee
論文名稱： 非結構化四邊形網格自動建構研究
指導教授： 賴景義
Jiing-Yih Lai
口試委員:
學位類別： 碩士
Master
系所名稱： 工學院 - 機械工程學系
Department of Mechanical Engineering
論文出版年： 2024
畢業學年度： 112
語文別： 中文
論文頁數： 186
中文關鍵詞： 模流分析 、自動化非結構四邊形網格建構 、狹長角度 、邊長過長及過短 、局部品質不佳 、網格生成錯誤及封閉 、Paving演算法
外文關鍵詞： mold flow analysis, automated unstructured quadrilateral mesh construction, narrow angles, side lengths that are too long and too short, poor local quality, mesh generation errors and closure, Paving algorithm
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    • 模流分析應用於各種射出成型產品，有助於生產高質量的零件，它針對塑料件的射出、保壓、冷卻及翹曲等過程進行有限元素分析，且透過實體網格進行模擬分析，因此進行模流分析前，需將IC CAD模型轉換為實體網格，再由求解器計算。其中六面體網格被視為品質最佳的網格型式，而建構六面體網格的前提是生成四邊形網格，然而，自動化的四邊形網格建構難度較高，通常需透過人工方式進行建構，而人工方式進行建構需耗費大量時間，為此本實驗室致力於開發自動化的非結構四邊形網格建構技術，在發展階段中，需面臨網格具有狹長角度、網格邊長過長及過短、局部網格品質不佳、網格生成錯誤與網格封閉等情況。為了應對以上情況，本研究基於Paving演算法，對演算法進行改良，並完善網格的建構流程，且各項函式中完善的偵測方法與網格修正方法為針對IC CAD模型廣泛測試而得，也進而確保其程式執行上的穩定性，並針對函式中各項參數的探討，比較參數改變的影響一併得出最佳參數組合。

    Mold flow analysis is used in various injection molding products to help produce high-quality parts. It performs finite element analysis on the injection, pressure holding, cooling and warping processes of plastic parts, and through the solid network Grid is used for simulation analysis, so before conducting mold flow analysis, the IC CAD model needs to be converted into a solid mesh, and then calculated by the solver. Among them, hexahedral mesh is regarded as the best quality mesh type, and the prerequisite for constructing hexahedral mesh is to generate quadrilateral mesh. However, automatic quadrilateral mesh construction is more difficult and usually requires manual construction. Manual construction takes a lot of time. Therefore, our laboratory is committed to developing automated unstructured quadrilateral mesh construction technology. During the development stage, we need to face the problems of meshes with narrow angles, mesh side lengths that are too long or too short, Poor local mesh quality, mesh generation errors, mesh closure, etc. In order to cope with the above situation, this study improves the algorithm based on the Paving algorithm and improves the grid construction process. The perfect detection methods and grid correction methods in each function are developed for extensive testing of IC CAD models. In order to ensure the stability of the execution of the program, various parameters in the function are discussed, the effects of parameter changes are compared, and the best parameter combination is obtained.

    目錄 摘要 i Abstract ii 致謝 iii 圖目錄 viii 表目錄 xiv 第一章 緒論 1 1.1 前言 1 1.2 文獻回顧 2 1.3 研究目的與方法 4 1.3.1 研究目的 4 1.3.2 研究方法 6 1.4 論文架構 7 第二章 非結構化四邊形網格自動建構流程 9 2.1 前言 9 2.2 非結構化四邊形網格自動建構整體流程說明 9 2.2.1 初始尖角與微小圓弧處理(S2) 9 2.2.2 初始迴圈自交偵測處理(S10) 11 2.2.3 計算節點角度(S3)、計算節點型態(S4) 11 2.2.4 Type 2節點型態轉換(S5) 11 2.2.5 Type 1與5偏置點預設(S6) 13 2.2.6 新一層節點計算與網格建立(S7) 13 2.2.7 狹長角度網格修正(S8) 13 2.2.8 迴圈間網格相交預測與迴圈合併(S9) 13 2.2.9 迴圈內網格自交預測與迴圈分割(S10) 13 2.2.10 邊太短網格修正(S11)、邊太長網格修正(S12) 14 2.2.11 迴圈邊界平滑化(S13) 14 2.2.12 Types 1與2節點相鄰網格成長(S14) 14 2.2.13 迴圈封閉檢查(S15) 15 2.3 網格平滑化 15 2.4 狹長角度網格修正方法 15 2.4.1 狹長角度網格修正偵測方法 15 2.4.2 狹長角度網格修正情況 18 2.5 邊太短網格修正方法 32 2.5.1 邊太短網格修正偵測方法 32 2.5.2 邊太短網格修正情況 32 2.6 邊太長網格修正方法 36 2.6.1 邊太長網格修正偵測方法 36 2.6.2 邊太長網格修正情況 42 2.7 迴圈邊界平滑化方法 42 2.8 Types 1與2節點相鄰網格成長方法 46 2.8.1 Types 1與2節點相鄰網格成長偵測方法 50 2.8.2 Types 1與2節點相鄰網格成長情況 56 2.9 迴圈封閉檢查方法 63 第三章 非結構化四邊形網格比較 68 3.1 前言 68 3.2 四邊形網格自動建構錯誤結果 68 3.3 「狹長角度網格修正」修改方式測試 74 3.3.1 探討不同接縫連法的影響 74 3.3.2 探討不同接縫預設角度的影響 88 3.4 「邊太短網格修正」修改方式測試 88 3.5 「邊太長網格修正」修改方式測試 91 3.6 「Types 1與2節點相鄰網格成長」修改方式測試 98 3.6.1 常見Case修正前後對比 101 3.6.2 節點數剩餘6點與8點 106 3.6.3 探討i_skip功能的影響 113 3.6.4 探討不同參數的影響 113 3.7 「迴圈封閉檢查」修改方式測試 124 第四章 非結構化四邊形網格測試結果分析 126 4.1 前言 126 4.2 四項函式之參數影響探討 126 4.2.1 「狹長角度網格修正」接縫連法影響 126 4.2.2 「狹長角度網格修正」接縫預設角度影響 127 4.2.3 「邊太短網格修正」邊長比例影響 127 4.2.4 「邊太長網格修正」參數影響 129 4.2.5 「Types 1與2節點相鄰網格成長」參數影響 129 4.3 非結構化四邊形網格自動建構測試結果分析 132 4.4 問題討論 134 第五章 結論與未來展望 162 5.1 結論 162 5.2 未來展望 163 參考文獻 165

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