臺灣博碩士論文加值系統

本論文主要解析不鏽鋼雙極板螺旋式微流道衝壓製程的胚料成形性與微觀尺寸效應影響。雙極板是質子交換膜燃料電池中關鍵零組件之一，但市面上使用傳統石墨雙極板成本昂貴且需要幾微米厚度，所以金屬雙極板因而產生。本文使用有限元素分析程式模擬不銹鋼雙極板螺旋式微流道衝壓製程，胚料長與寬度皆為25mm，厚度0.05mm 的不銹鋼薄板(SUS304)，以剛性衝頭對材料進行微衝壓製程，在其雙極板上衝出六條螺旋式流道，流道寬度和深度分別為0.75mm和0.75mm，探討微衝壓製程最佳成形性及微觀尺寸效應影響。本文有限元素法是運用Prandtl-Reuss之塑流法則，結合有限元素變形理論與updated Lagrangian formulation(ULF)觀念，進而模擬金屬雙極板微流道之成形製程。本論文中亦運用選擇性減化積分法SRI (slective reduced integration)與四節點四邊形退化殼元素所推導之形狀函數至剛性矩陣中。



本文研究重點，經由微衝壓製程來驗證模擬與分析之全部變形履歷資料、衝頭負荷與衝程之關係、應力與應變分布、厚度分布、截面深度及截面厚度，其胚料選用SUS304薄板進行微衝壓成形之實驗，再與模擬結果作比對以驗證本分析程式之可靠性。另外，加入不同參數變化如：變化摩擦係數、變化模具倒角半徑、變化胚料厚度、變化螺旋流道數等，進行微衝壓製程分析。變化不同螺旋式流道數的胚料成形性，經分析模擬後得知八條螺旋流道數也可順利成形，但衝頭負荷會大幅度上升；在衝程方面，除了衝程到達0.45mm能順利成形以外，在模擬時發現衝程只要高於0.45mm在螺旋流道中央處就會有裂痕之情形，此情況與實際衝壓出之成品相符合；越接近胚料中央處的成形流道越深，而越外圍的流道會受到胚料翹曲的影響，使流道成形深度越淺。本文建立有限元素分析模式，亦比較傳統巨觀材料模型與比例因子修正後的材料模型，結果指出修正後的材料模型較能符合實際成形情況，該比例因子修正法亦可運用於SUS304不銹鋼微觀任意厚度的修正，以省略繁複的拉伸試驗。
本論文所提出之方法能夠有效地模擬不銹鋼金屬雙極板之微流道衝壓製程。因此，可廣泛應用在各種流道形狀的衝壓製程上，建立完善分析數據及預估微衝壓過程中產生的各式問題，有利降低試誤損失及增進生產速率，進而使得燃料電池可朝向更精確微小化之發展。

The purpose of this study was to analysis stainless steel spiral micro flow channel bipolar plate stamping process for effect of blank formability and microscopic size effect. Bipolar plate is a key component for proton exchange membrane fuel cell. But it is very expensive and need micro thickness if using conventional graphite bipolar plate. A metal bipolar plate is another choice. This study use finite element analysis method (FEA) to analysis program and simulation stainless steel spiral micro flow channel bipolar plate stamping process. Blank length and width are 25mm, 0.05mm thick stainless sheet (SUS304).Use the rigid punch to machining material to achieve micro stamping process. Punch out of the six spiral flow channel on bipolar plate. Channel width and depth are 0.75mm respectively, discussion the micro-stamping process optimization formability and microscopic size effect. This finite element analysis method (FEA) use the Prandtl-Reuss of plastic flow theorem, combination with the finite element deformation theory and updated Lagrangian formulation (ULF) concept, and then simulate metallic bipolar plates the micro fluidic channel forming processes. This study also uses selective reduction of the integration method SRI (selective reduced integration) and four-node quadrilateral degenerated shell element shape function derivation from the stiffness matrix.This study is focus on during the micro-stamping process to verification simulation and analysis all deformation history data, punch load and stroke relationships, stress and strain distribution, thickness distribution, section depth and section thickness, SUS304 blank sheets were used in the experimental micro-stamping process, and comparison with the simulation results to verify the reliability of the analysis program. In addition, adding different parameters such as: changes coefficient of friction, changes mold chamfers radius, Changes the thickness of the blank, etc., for micro-stamping process analysis. Variation different spiral flow channel number blank formability, after analysis simulation, we get that eight spiral flow channel number can also be formed smoothly, but also increase punch load, In stroke part, except stroke achieve 0.45mm can success forming, In simulation, if stroke is more than 0.45mm, the spiral flow channel center have crack, is same with the experimental results. If close the blank center forming flow channel is deep, outside flow channel during blank warping effect, because the flow channel forming deep shallow. This study construct the finite element analysis mode, compare with conventional macroscopic material model and correct of scale factor after modify material mode, the result indicate the after modify material mode can satisfied actually situation. The correct of scale factor method can be applied to any thickness SUS304 stainless steel. Omission complicated tensile test.

This study proposed the effectively method to simulation stainless steel spiral micro flow channel bipolar plate stamping process. It can widely applied on any flow channel shape micro-stamping process, construct and improve the analysis of data for micro stamping process produces all kinds of problems, it can reduce try and error loss and increases production rate, let proton exchange membrane fuel cell toward more precision and minimize.

致 謝 I
中 文 摘 要 II
英 文 摘 要 IV
目 錄 VI
表 目 錄 IX
圖 目 錄 X
符 號 說 明 XIII

第 一 章 緒論 1
1.1 前言 1
1.2 研究動機 2
1.3 燃料電池簡介 4
1.4 研究方法 11
1.5 文獻回顧 13
1.6 論文架構 24
第 二 章 有限元素分析理論 25
2.1 基本假設 25
2.2 剛性統制方程式 25
2.3 虛功原理之離散化 28
2.4 ETA-DYNAFORM簡介 29
2.4.1 ETA-DYNAFORM簡介 29
2.4.2 LS-DYNA算法 30
2.4.3 ETA-DYNAFORM軟體分析流程 31
2.4.4 ETA-DYNAFORM軟體結構 32
2.5 ETA-DYNAFORM數值模擬基本流程 35
2.5.1 建立模型並儲存數據 35
2.5.2 導入ETA-DYNAFORM前處理 36
2.5.3 單元網格類型的選擇 37
2.5.4 定義屬性，參數設定 38
2.5.5 提交求解 38
2.5.6 後處理 39
第 三 章 螺旋式微流道雙極板衝壓實驗與數值分析 40
3.1 螺旋式微流道雙極板衝壓實驗與模擬簡介 40
3.2 研究步驟 42
3.3 板材拉伸試驗 43
3.3.1 拉伸試驗 43
3.3.2 試驗結果 44
3.4 比例因子修正之微觀彈塑性材料模型 46
3.5 材料參數 49
3.6 實驗設備與微衝壓模具建構 51
3.6.1 實驗設備 51
3.6.2 微衝壓模具建構 53
3.7 改變衝程之實驗成品比較 55
3.8 螺旋式微流道雙極板衝壓製程之數值分析 57
3.8.1 有限元素網格化處理 58
3.8.2 邊界條件 59
3.8.4 除荷處理 59
3.9 螺旋式微流道雙極板衝壓實驗與模擬之結果分析 60
第 四 章 螺旋式微流道雙極板衝壓製程參數分析 70
4.1 螺旋流道數對衝壓金屬雙極板之影響 70
4.1.1 中央與外圍流道之外型比較 70
4.1.2 變化螺旋流道數對衝頭負荷與衝程之關係 74
4.1.3 變化螺旋流道數對胚料厚度 74
4.2 摩擦係數對衝壓金屬雙極板之影響 77
4.2.1 變化摩擦係數對衝頭負荷與衝程之關係 77
4.2.2 變化摩擦係數與最薄厚度之關係 78
4.2.3 變化摩擦係數與最大應力之關係 79
4.2.4 變化摩擦係數與最大應變之關係 79
4.3 胚料厚度對衝壓金屬雙極板之影響 80
4.3.1 變化胚料厚度對衝頭負荷與衝程之關係 81
4.3.2 變化胚料厚度與最薄厚度之關係 81
4.3.3 變化胚料厚度與最大應力之關係 82
4.3.4 變化胚料厚度與最大應變之關係 83
4.4 模具倒角半徑對衝壓金屬雙極板之影響 84
4.4.1 變化模具倒角半徑對衝頭負荷與衝程之關係 85
4.4.2 變化模具倒角半徑與最薄厚度之關係 85
4.4.3 變化模具倒角半徑與最大應力之關係 86
4.4.4 變化模具倒角半徑與最大應變之關係 87
第 五 章 結果與討論 89
5.1 結論 89
5.2 未來展望 91
參 考 文 獻 92

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