臺灣博碩士論文加值系統

金屬板材之剪切與伸張加工是常用於製作金屬元件的成形技術，其變形過程複雜，材料成形極限預測困難。因此，發展精準的破壞預測方法一直受到廣泛的重視。本研究應用有限元素軟體DEFORM，分別進行純鈦板材之剪切與伸張成形之模擬，並與實驗結果比較，預估Normalized Cockcroft and Latham、Rice and Tracey與Ayada破壞準則之臨界值。
本研究使用厚度為0.05mm、0.1mm及0.25mm之純鈦板材，分別進行微剪切與微伸張之成形實驗與模擬。微剪切成品斷面利用光學顯微鏡與影像軟體，分析其光滑面與厚度之比值，並與模擬結果比較，預估破壞臨界值。微伸張成形則以發生破裂之衝程做為破壞臨界值預估之依據。
研究結果顯示，三種破壞準則可預估微剪切之破斷面形狀與微伸張成形之破裂位置，但其破壞臨界值隨板厚與成形方式而改變，這顯示材料之初始條件與變形路徑和破壞之發生有密切關聯。

The shearing and drawing processes of sheet metals are common techniques to produce metal components. The processes involve complex forming behaviors. It is difficult to predict the forming limit of sheet metals. Therefore, it is widely interested in developing methods which are able to accurately predict the facture. This study used a finite element package, DEFORM, to simulate micro shearing and micro drawing processes of pure titanium sheets. By comparing the simulated results with experimental ones, the critical values were estimated for three damage criteria which are Normalized Cockcroft and Latham, Rice and Tracey, and Ayada criteria.
This study used titanium sheets with different thicknesses of 0.05 mm, 0.1 mm and 0.25 mm in the experiments and simulations of micro shearing and micro drawing processes. The sections of the sheared sheets were examined by an optical scope and analyzed by imaging software. The ratio of burnished land to thickness was used as a reference for estimating the critical values of the damage criteria. In the case of the micro drawing process, the stroke at the fracture was employed to estimate the critical values.
The results show that the used damage criteria are able to predict the fracture profiles in the micro shearing processes and the fracture locations in the micro drawing processes. However, their critical values vary with the thickness of the sheet and the type of the forming process. The results imply that the facture is highly associated with the initial conditions of materials and the path of deformation.

摘要....................................i
ABSTRACT...............................ii
致謝....................................iii
表目錄..................................vi
圖目錄..................................vii
符號表..................................ix
一、緒論.................................1
1.1 前言................................1
1.2 文獻回顧.............................2
1.2.1剪切加工............................2
1.2.2成形極限............................4
1.3研究動機與目的.........................6
1.4論文架構..............................6
二、基本理論..............................8
2.1金屬成形概論...........................8
2.2剪切加工基本理論........................8
2.2.1剪切加工原理.........................8
2.2.2剪切過程............................9
2.2.3剪切之斷面形狀.......................10
2.3引伸成形基本理論.......................11
2.3.1引伸成形原理........................11
2.4延性破壞準則..........................13
2.5破壞臨界值...........................16
三、材料試驗.............................17
3.1材料機械性質..........................17
3.2單軸拉伸試驗..........................17
3.3強度係數(K值)與加工硬化指數(n值)........27
四、模具設計與實驗流程....................30
4.1模具設計............................30
4.1.1微剪切模具........................30
4.1.2微伸張成形模具.....................30
4.2實驗設備............................33
4.2.1電子式沖壓機.......................33
4.2.2光學顯微鏡.........................33
4.2.3精密表面輪廓儀......................33
4.3實驗流程.............................36
4.4評估破壞之方法........................37
4.4.1微剪切製程.........................37
4.4.2微伸張成形.........................38
五、成形模擬分析.........................39
5.1有限元素分析軟體(DEFORM)介紹...........39
5.2收斂性分析...........................42
5.2.1微剪切製程.........................42
5.2.2微伸張成形.........................44
5.3成形模擬.............................46
5.3.1微剪切製程之2D模擬..................46
5.3.2微伸張成形之2D模擬..................52
六、結果與討論...........................57
6.1微剪切製程...........................57
6.1.1微剪切斷面之光滑面與板厚比............57
6.1.2模擬與實驗之行程負荷比較.............63
6.2微伸張成形..........................65
6.2.1微伸張成形破裂時之沖頭行程...........65
6.2.2模擬與實驗之行程負荷比較.............71
6.3微剪切製程與微伸張成形之破壞臨界值比較...73
6.4 Rice and Tracey破壞準則...........75
七、結論與未來展望......................77
7.1結論...............................77
7.2未來展望............................78
參考文獻...............................79
附錄..................................81
附錄-1微剪切模具圖......................81
附錄-2微伸張成形模具圖...................90
簡歷..................................98

[1]E. Taupin, J. Breitling, W. B. Bae, 1996, Material fracture and burr formation in blanking results of FEM simulation and comparison with experiments, Journal of Materials Processing Technology.
[2]R. Hambli, M. Reszka, 2002, Fracture criteria identification using an inverse technique method and blanking experiment, Journal of Materials Processing Technology.
[3]G. Fang, P. Zeng, L. Lou, 2002, Finite element simulation of the effect of clearance on the forming quality in the blanking process, Journal of Materials Processing Technology.
[4]N. Hatanaka, K. Yamaguchi, N. Takakura, 2003, Finite element simulation of the shearing mechanism in the blanking of sheet metal, Journal of Materials Processing Technology.
[5]H. K. Shim, S. K. Lee, B. S. Kang, S. M. Hwang, 2004, Investigation on blanking of thin sheet metal using the ductile fracture criterion and its experimental verification, Journal of Materials Processing Technology.
[6]S. Thipprakmas, M. Jin, M. Murakawa, 2007, An investigation of material flow analysis in fineblanking process, Journal of Materials Processing Technology.
[7]林明宏，2007，微衝剪之成形模擬與剪斷面品質之研究，國立高雄用科技大學，碩士論文。
[8]S. Yu, X. Xie, J. Zhang, Z. Zhao, 2007, Ductile fracture modeling of initiation and propagation in sheet-metal blanking processes, Journal of Materials Processing Technology.
[9]鄭軒州，2008，精微薄板精密剪切參數特性之研究，國立成功大學，碩士論文。
[10]W. F. Fan, J. H. Li, 2009, An investigation on the damage of AISI-1045 and AISI-1025 steels in fine-blanking with negative clearance, Materials Science and Engineering A.
[11]J. Xu, B. Guo, C. Wang, D. Shan, 2012, Blanking clearance and grain size effects on micro deformation behavior and fracture in micro-blanking of brass foil, International Journal of Machine Tools & Manufacture.
[12]H. Takuda, K. Mori, N. Hatta, 1998, The application of some criteria for ductile fracture to the prediction of the forming limit of sheet metals, Journal of Materials Processing Technology.
[13]F. Ozturk, D. Lee, 2004, Analysis of forming limits using ductile fracture criteria, Journal of Materials Processing Technology.
[14]Z. J. Wang, Y. Li, J. G. Liu, Y. H. Zhang, 2007, Evaluation of forming limit in viscous pressure forming of automotive aluminum alloy 6k21-T4 sheet, Trans. Nonferrous Met. Soc. China.
[15]H. Liu, Y. Yang, Z. Yu, Z. Sun, Y. Wang, 2009, The application of a ductile fracture criterion to the prediction of the forming limit of sheet metals, Journal of Materials Processing Technology.
[16]Y. Lou, H. Huh, Y. Ko, J. Ha, 2010, Comparative study of ductile fracture criteria on the prediction of FLDs for aluminum alloys.
[17]林儷伊，2011，晶粒尺寸對SUS304不鏽鋼微鼓脹成形之影響，國立高雄應用科技大學，碩士論文。
[18]戴宜傑，1999，沖壓加工與沖模設計，修正版，新陸書局股份有限公司。
[19]劉福興、鄭偉盛，2002，衝壓模設計，新文京開發出版有限公司。
[20]T. Etienne, B. Wu, W. T. Wu, A. Taylan, 1996, Material fracture and burr formation in blanking results of FEM simulations and comparison with experiments, Journal of Materials Processing Technology.
[21]J. R. Rice, D. M. Tracey, 1969, On the ductile enlargement of voids in triaxial stress fields, Journal of Mechanics and Physics of Solids.
[22]李榮顯，1986，塑性加工學，三民書局。
[23]蘇貴福，1993，薄板之沖床加工，全華科技圖書股份有限公司。
[24]R. Hambli, A. Potiron, 2000, Finite element modeling of sheet-metal blanking operation with experimentals verification, Journal of Materials Processing Technology.
[25]賴袁璋，2001，精密剪斷之有限元素分析，國立交通大學，碩士論文。
[26]邱冠華，2002，商業用純鈦薄板沖壓成形性之研究，國立台灣大學，碩士論文。
[27]U. Engel, R. Eckstein, 2002, Microforming-from basic research to its realization, Journal of Materials Processing Technology.
[28]余俊德，2003，附V型壓環之精密剪斷有限元素分析，國立交通大學，碩士論文。
[29]S. S. Kim, C. S. Han, Y. S. Lee, 2005, Development of a new burr-fee hydro-mechanical punching, Journal of Materials Processing Technology.
[30]Z. Tekiner, M. Nalbant, H. Gurun, 2006, An experimental study for the effect of different clearances on burr, smooth-sheared and blanking force on aluminium sheet metal, Materials and Design.
[31]陳建宏，2008，黃銅微引伸成形加工條件對引伸伸度之影響，國立高雄應用科技大學，碩士論文。
[32]謝典霖，2009，鋁箔微衝孔之模擬與實驗，國立高雄應用科技大學，碩士論文。