臺灣博碩士論文加值系統

　　本論文是以I-DEAS建立模型並且網格後，採用Prandtl-reuss塑流法則以及von Mises的降伏條件，加上增量型有限變形理論及Updated Lagrangian Formulation(ULF)的觀念使用DYNAFORM有限元素分析軟體模擬。
　　主要材料為冷軋鋼 (SPCC-SD)，並且經過材料拉伸試驗得到材料的各項數值做為模擬製程分析的準則，應用這些數值來模擬橢圓杯引伸成形以及橢圓孔凸緣成形，最後探討衝頭負荷與衝程之關係、變形歷程、工件厚度變化及成形極限，並且使用五十噸液壓成形機進行橢圓杯引伸製程及橢圓孔凸緣成形實驗，經由數據擷取系統得到實驗數據，將實驗數據與模擬數據進行比對，驗證理論的正確與可信度。
　　橢圓杯成形部分，工件最小厚度集中在工件與衝頭長軸接觸之區域，是因為料片在長軸處承受了最大拉伸應力，經由橢圓柱衝頭周長與初始料片周長所定義之極限引伸比得知，其橢圓杯引伸之極限引伸比為2.136，且在製程中，初始料片周長會影響鈑材之成形極限；而在橢圓孔凸緣方面，最大應力及最小厚度值在工件與衝頭長軸接觸之部分，是因為工件的內橢圓長軸孔周圍承受最大拉伸應力，使厚度明顯變薄，而短軸部分的曲率半徑較大，受到周向應力較小，所以厚度變化不大，經由橢圓柱衝頭周長與初始料片的最小橢圓形內孔周長所定義之極限引伸比得知，其橢圓孔凸緣貫穿之極限引伸比為1.463，且在製程中，料片的初始孔徑會影響鈑材之成形極限。
　　本論文結合I-DEAS模具設計與DYNAFORM有限元素分析軟體的應用，由分析結果得知真實性與可靠性，提供模具設計與製程分析之相關人員的需求，做為製程改良、模具設計及模擬分析的缺陷預估之參考。

This essay is base on I-DEAS to build a module and to grid computing, and adopting the conception of the Prandtl-reuss plasticity equations, the von Mises yield criterion, large deformation finite element model, and updated Lagrangian formulation (ULF) to use the DYNAFORM Finite Element Method, FEM simulator.
Using the values of tensile testing on cold rolled steel (SPCC-SD) to be the standard values of production procedure simulation analyzing, and simulating the deep drawing process of elliptical cup and the elliptical hole convex axis forming. Then the relationship of punch loading and stroke, deformation history, thickness change history, and forming limit.
Using 50-ton hydraulic machine to examine the deep drawing of elliptical cup and the elliptical hole-flanging process. And compare simulation values with examined values.
Regarding to the deep drawing process of cylindrical cup, the minimum thickness is at the contact area of parts and long punch axle. That is because the material Withstand the maximum tensile stress at this area.
From the limit drawing ratio of perimeter of Convex axis and perimeter of material, we can know that the limit drawing rate is 2.136. During process, the perimeter of material will affect the limit of forming,
Regarding to the elliptical hole-flanging forming, the maximum stresses and minimum thickness is at the contact area of parts and long punch axle. That is because the material withstand the maximum tensile stress at the area of internal elliptical hole, and force the thickness become thin. Regarding to short axle, the Radius of curvature is big, so the thickness is not changed.
From the limit drawing ratio of circumference of elliptical punch profile and the circumference of the minimal initial elliptical punch profile of the minimal initial elliptical hole of the blanks. We can know that the limit drawing rate of elliptical hole-flanging is 1.463. During process, the bore diameter of material will affect the material’s limit of forming,
This essay is base on I-DEAS module design and DYNAFORM finite element method, FEM simulator to analysis the authenticity and reliability. It can provide the reference for the staffs who are in mold design and process analysis field. As process improvement, mold design, and simulation analysis of defects estimated reference.

論文摘要 I
ABSTRACT III
致謝 V
符號索引 VI
圖目錄 VIII
表目錄 X
第一章 緒論 1
1-1 前言 1
1-2 研究動機與目的 2
1-3 文獻回顧 2
1-4 論文架構 4
第二章 基本理論 5
2-1 DYNAFORM數值模擬分析系統介紹 5
2-2 基本假設與理論 8
2-3 彈塑性有限元素法的構成關係式 8
2-4 動態顯性有限元素法 12
2-4-1 動態顯性有限元素法的基本步驟 13
2-4-2 中心差分法 15
第三章 有限元素法簡介與拉伸試驗 19
3-1 有限元素法簡介 19
3-2 拉伸試驗 19
3-3-1 真實應力-真實應變 20
3-4 材料拉伸試驗結果 20
3-4-1 塑性強度係數與加工硬化指數 20
3-4-2 冷軋鋼(SPCC-SD)之參數 21
第四章 金屬鈑材橢圓杯引伸成形製程之分析 25
4-1 前言 25
4-2 實驗設備與實驗步驟 25
4-3 橢圓杯引伸成形製程之數值分析 26
4-3-1 數值分析之流程 26
4-3-2 接觸與負載設定 27
4-4 實驗結果與數值分析之比較 27
4-4-1 橢圓杯引伸成形之衝頭負荷之比較 28
4-4-2 工件應力分佈之比較 28
4-4-3 工件厚度變化之比較 28
4-5 橢圓杯引伸成形極限分析 29
4-6 本章結語 31
第五章 金屬板材橢圓孔凸緣成形製程之分析 53
5-1 前言 53
5-2 實驗設備與實驗步驟 53
5-3 橢圓孔凸緣引伸成形製程之數值分析 54
5-3-1 數值分析之流程 54
5-3-2 接觸與負載設定 55
5-4 實驗結果與數值分析之比較 56
5-4-1 橢圓孔凸緣成形之衝頭負荷之比較 56
5-4-2 工件主應力分佈之比較 56
5-4-3 工件主應變之比較 57
5-5 工件厚度變化之比較 57
5-6 金屬鈑材橢圓孔凸緣成形極限分析 57
5-7 本章結語 58
第六章 結論 78
參考文獻 80

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