臺灣博碩士論文加值系統

本文主要是以ABAQUS 有限元素分析軟體建構一套模擬流程，分析鋁合金板片（A5052P-H32）在圓形模穴內進行U-型彎曲之應力及變形行為。模穴直徑60mm，U 型彎曲深度50.8 mm，厚度1/32" (0.794 mm)。分析模擬考慮的變數包含板金的寬度（20 mm 至50 mm）衝頭衝壓平均速度（63 mm/sec 及151 mm/sec），以及衝壓過程胚料下方有無支撐板支持等不同條件。本文並選擇曲柄式衝床進行一系列彎曲加工實驗，包括應用動力計（Kistler 9257B）量測衝壓力的變化等，以比較及驗證本文建構的模擬分析流程之正確性。由模擬及實驗結果顯示：（1）U 型彎曲無使用支撐板時，隨著板寬的增加，成品（底面）翹曲更加嚴重，當板寬50 mm時，翹曲達6 mm 左右；（2）衝頭拉回後，U 型成品回彈角隨板寬減少而加大，板寬於20 mm 時，回彈角達10.3 度左右；（3）當有支撐板支持的情況下可有效阻止翹曲現象並減少回彈角大約50%左右；（4）使用較高衝頭速度，經模擬及實驗顯示可有效改善回彈角。

This study mainly develops a simulation algorithm to analyze the stresses and deformation behavior of aluminum sheet metal (A5052P-H32) going on U-shape bending in a circular die cavity using ABAQUS finite element programs. The diameter of the round die is 60 mm, depth of U-shape bending is 50.8 mm, and the thickness of sheet material is 1/32" (0.794 mm). The variables considered for bending simulation include different width of sheet metal ranging from 20 mm to 50 mm, two average punching speeds (63 mm/sec and 151 mm/sec), and with or without using stripper under the bottom surface of sheet metal during punching. In this study, we choose single crank type press to proceed a set of bending experiments, and use dynamometer (Kistler 9257B) to measure the varying punching forces for the purpose of comparison with present simulation results. The simulation results are very close to experimental results, and they show some features as follows: (1) When punching without using stripper, the bottom side of finished U-shape part warps more as the sheet blank increases its width, iii e.g. as the blank is 50 mm wide, the warping may reach approximately 6 mm high. (2)
After retracting punch, the springback angle of U-shape part increases as the blank decreases its width, e.g. for 20 mm blank width, the springback angle is up to about 10.3
degrees. (3) The warping phenomenon and springback angle can be effectively improved or reduced when bending with stripper. (4) It can improve springback angle if we use higher punch speed.

摘 要 i
ABSTRACT ii
誌 謝 iv
目 錄 v
表目錄 vii
圖目錄 viii
第一章 緒論 1
1.1 前言 1
1.2 文獻回顧 1
1.3 研究動機與目的 3
1.4 論文架構3
第二章 有限元素法與ABAQUS 5
2.1 平衡方程式與虛功原理 5
2.2 基本有限元素方程 7
2.3 彈塑性有限元素增量分析 8
2.4 ABAQUS 金屬成形分析解法 9
2.4.1 隱式(Implicit)求解法 10
2.4.2 顯式(Explicit)求解法 11
2.4.3 隱式及顯式比較 13
2.5 有限單元的元素描述14
2.5.1 殼體厚度和截面點(Section Point) 15
2.5.2 殼法線和殼面 16
第三章 實驗與模擬步驟 18
3.1 衝壓實驗模具設計 20
3.2 實驗儀器設備與材料 22
3.2.1 彎曲實驗設備 22
3.2.2 衝壓力量測及數據擷取系統 23
3.2.3 材料 25
3.3 實驗步驟 26
3.4 ABAQUS 模擬分析流程 27
3.4.1 基本假設 29
3.4.2 分析步驟 29
第四章 U 形彎曲模擬與實驗結果 32
4.1 衝頭負荷33
4.1.1 Ａ設計(無支撐板) 34
4.1.2 B 設計(有支撐板) 34
4.2 接觸力分佈41
4.2.1 Ａ設計(無支撐板) 41
4.2.2 Ｂ設計(有支撐板) 41
4.3 應力分佈63
4.3.1 Ａ設計(無支撐板) 63
4.3.2 B 設計(有支撐板) 63
4.4 厚度分佈82
4.4.1 Ａ設計(無支撐板) 82
4.4.2 Ｂ設計(有支撐板) 83
4.5 回彈現象97
4.6 翹曲現象101
第五章 結論107
5.1 結論107
5.2 未來展望108
參考文獻109

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