臺灣博碩士論文加值系統

在全球暖化日益嚴重下，節能減碳已是一個主要的議題，因此國際各大汽車產業均以輕量化為目標，且汽車安全法規越來越嚴格，促使先進高強度鋼板之開發，因其具有強度高之特性。但隨著鋼板強度的提高，其沖壓成形所面臨之破裂、回彈等成形缺陷相較於傳統低強度鋼更為嚴重，尤以回彈現象更不易克服。
因高強度鋼成形困難，在回彈補償的試模階段需耗費大量的金錢及時間成本，因此導入Computer Aided Engineering(CAE)分析技術，希望藉由CAE之準確分析，以達更精確的模具設計，可以大幅減少試模時間。而材料模型於CAE分析中是相當重要的一環，直接決定破裂、回彈等預測的準確性，其中先進高強度鋼之包辛格效應(Bauschinger effect)較傳統軟鋼更為明顯，因此材料模型需考慮使用包含包辛格效應之加工硬化準則。此外，對於複雜的板金成形，為多軸受力之狀態，因此需以雙軸拉伸試驗決定較適當之降伏準則，期望藉由瞭解材料的塑性變形特性，提升對於高強度鋼板沖壓成形特性分析與回彈預測之能力。
本論文首先針對目前常用之Hill48、Hill90、Barlat89、Barlat91和Yld2000-2d等降伏準則進行探討，此外，由文獻可知，包辛格效應對於提升回彈預測準確性有很大的幫助，因此本論文亦探討可以描述包辛格效應之Yoshida-Uemori材料模型，以及該材料模型所需之參數。
在確認材料模型之準確性後，接著討論板金成形之回彈改善方法。在目前許多使用高強度鋼之汽車結構件皆包含U形帽狀造型，而高強度鋼之U形帽狀引伸成形除了有側壁外開問題，還有嚴重的側壁捲曲。文獻顯示，以後拉伸(Post-Stretch)方式可以有效改善回彈，在實際沖壓過程中，主要以阻料條及變壓料力兩種方式可達到「後拉伸」之效果。因此本論文以1180級先進高強度鋼針對U形帽狀引伸成形進行變壓料力與可調式阻料條對於回彈改善之研究。研究顯示，變壓料力設計較容易且改善佳，因此以變壓料力之阻料力設計作為阻料條造型設計之參考。本論文分別建立兩種方式之參數設計流程，結果顯示，兩種方式皆可以有效改善回彈，並消除側壁捲曲。
本論文亦探討三種U形帽狀之兩道次彎曲方式。第一種方式可避免捲曲之產生，但仍有外開的問題。第二種為文獻提出的兩道次彎曲設計，可以有效改善回彈、捲曲問題，但側壁會產生S形現象，本論文針對其設計加以改善，設計出第三種兩道次彎曲方式，以CAM模改變沖壓方向，可以有更大的補償空間，以消除其S形現象。
本論文之變壓料力與阻料條之設計流程及優化後的兩道次彎曲設計，皆可能用於實際汽車結構件之沖壓設計上，期望以此對業界能有所貢獻。

Global warming is increasingly serious so Energy saving and carbon reduction is a main issue. Therefore many automotive industries aim for lightweight. Automotive safety regulations become more stringent, thus the development of advanced high-strength steels (AHSS) has been promoted. AHSS are high strength. With the increasing sheet metal strength, the stamping process of sheet metal faces some defects, such as rupture, springback, etc which are more serious than mild steel.
The stage of mold trial needs to consume a lot of money, manpower and time because of the forming difficult of AHSS. So the Computer Aided Engineering (CAE) has been introduced. Accurate analysis with CAE can reach accurately die design and reduce time of mold trial significantly. Material modal is a very important part in CAE analysis that deside accuracy of prediction of rupture and springback. Bauschinger effect in AHSS is more serious than mild steels so material modal need to use hardening rule including Bauschinger effect. Furthermore, multiaxial force in the complex metal forming need to use yield criterion including biaxial force. By understanding the plastic deformation characteristics of materials, to enhance abilities of the analysis of AHSS in the stamping and the prediction of springback.
The applicability of yield criteria, such as Hill48, Hill90, Barlat89, Barlat91 and Yld2000-2d for describing the plastic deformation of the advanced high strength steel were investigated first in this thesis. Also according to the literature survey conducted in this thesis, it reveals that the Yoshida-Uemori model is suitable to describe the Bauschinger’s effect and its model would improve the springback prediction.
After confirming the accuracy of the material model, the springback improvement method of sheet metal forming has been discussed. At present, many car structural parts that use AHSS contain U-hat shape section. The U-hat shape drawing that uses AHSS has serious defects of springback and side-wall curl. The literature shows that the “post-stretch” approach can effectively improve the springback. The use of drawbead and variable blank holder force can achieve the “post-stretch” effect in the actual stamping process. Drawbead and variable blank holder force used in U-hat shape drawing with 1180 grade AHSS have been study in this thesis. Research shows that the design of variable blank holder force is easier and better to improve springback, so the design of blank restraining force of variable blank holder force can be used as the reference of drawbead geomtry design. The parameter design flow of two methods have been established in this thesis. The result shows that both methods can effectively improve springback and eliminate side-wall curl.
Three ways of two-step bending process have been study in this thesis. The first way can avoid the occurrence of side-wall curl, but the side-wall springback remains unresolved. The two-step bending design in the literature is the second way that can effectively improve the springback, side-wall curl, but the side-wall will produce S-shaped defect. So the third two-step bending process has been designed to improve S-shaped defect in this thesis. The use of cam die can change stamping direction, thus the allowable compensation range is greater and S-shaped defect can be eliminated.
The design flow of the variable blank holder force and drawbead and optimized two-step bending design in this thesis may be used for the actual stamping design of car structural parts, hoping to contribute to the industry.

目錄 V
圖目錄 IX
表目錄 XVI
第1章 緒論 1
1.1 前言 1
1.2 研究動機與目的 3
1.3 文獻回顧 4
1.4 研究方法與步驟 15
1.5 論文總覽 16
第2章 先進高強度鋼板之材料模型研究 18
2.1 異向性材料降伏準則之介紹 18
2.1.1 Hill 48降伏準則之探討 18
2.1.2 Hill 90降伏準則之探討 21
2.1.3 Barlat 89降伏準則之探討 22
2.1.4 Barlat 91降伏準則之探討 24
2.1.5 Yld2000-2d降伏準則之探討 27
2.1.6 最適合先進高強度鋼成形之降伏準則 36
2.2 Yoshida-Uemori材料模型 36
2.2.1 Yoshida-Uemori材料模型參數之探討 39
2.2.2 加工硬化準則之準確性比較 45
第3章 變壓料力之回彈改善分析 46
3.1 U形帽狀引伸成形回彈分析 46
3.1.1 成形方式與造型說明 46
3.1.2 回彈機制探討 48
3.1.3 造型設計及材料參數對於回彈之探討 51
3.2 變壓料力之回彈改善分析 56
3.2.1 回彈改善機制 57
3.2.2 變壓料力參數設定與回彈之探討 60
3.2.2.1 變壓料力之參數設定 61
3.2.2.2 回彈與後拉伸之分析 63
3.2.2.3 小結 66
3.2.3 變壓料力曲線設計範圍建立 67
3.2.4 其他參數之探討 71
3.2.4.1 母模R角之影響 72
3.2.4.2 沖頭R角之影響 74
3.2.4.3 側壁角度之影響 76
3.2.4.4 材料強度之影響 78
3.2.4.5 板材厚度之影響 80
3.2.4.6 小結 81
3.2.5 變壓料力設計流程之建立 81
第4章 阻料條之回彈改善分析 83
4.1 阻料條之作用方式與收斂性測試 83
4.2 阻料條參數設定與回彈之探討 86
4.2.1 阻料條造型參數之搭配 86
4.2.2 第一組之回彈與後拉伸分析 87
4.2.3 第二組之回彈與後拉伸分析 91
4.2.4 第三組之回彈與後拉伸分析 94
4.2.5 第四組之回彈與後拉伸分析 97
4.2.6 小結 100
4.2.7 單一阻料條設計流程之建立 104
4.3 其他參數之探討 106
4.3.1 雙阻料條之設計與板厚1mm之回彈改善結果 106
4.3.2 沖頭R15mm之回彈改善結果 111
4.3.3 母模R9mm之回彈改善結果 112
4.4 雙阻料條設計流程建立 112
第5章 彎曲工法之回彈改善分析 115
5.1 一道次彎曲 115
5.2 兩道次彎曲(方式一)之探討 118
5.3 兩道次彎曲(方式二)之探討 121
5.3.1 回彈改善說明 121
5.3.2 側壁S形現象之產生機制探討 127
5.4 兩道次彎曲(方式三)之探討 129
5.4.1 工法改善說明 129
5.4.2 回彈改善結果 130
第6章 結論 133
參考文獻 134

[1]S. Keeler, M. Kimchi, amd P. J. Mconey, “Advanced high-strength steels application guidelines V6”, WorldAutoSteel, 2017.
[2]P. J. Armstrong and C. O. Frederick, “A mathematical representation of the multiaxial Bauschinger effect”, GEGB report RD/B/N731. Berkeley Nuclear Laboratories, Material at high temperatures, vol. 24, pp. 1-26, 1966.
[3]J. L. Chaboche, K. Dang-Van, and G. Cordier, “Modelization of the Strain Memory Effect on the Cyclic Hardening of 316 Stainless Steels”, SMiRT-5, Div. L, Paper No. L. 11/3, 1979.
[4]J. L. Chaboche and G. Rousselier, “On the plastic and viscoplastic constitutive equations”, part I and II. ASME Journal of Pressure Vessel Technology, vol. 105, pp. 153-164, 1983.
[5]F. Yoshida, T. Uemori, and K. Fujiwara, “Elastic-plastic behavior of steel sheet under in-plane cyclic tension-compression at large strain”, International Journal of Plasticity, vol. 18, pp. 633-659, 2002.
[6]F. Yoshida and T. Uemori, “A model of large-strain cyclic plasticity describing the Bauschinger effect and workhardening stagnation”, International Journal of Plasticity, vol. 18, pp. 661-686, 2002.
[7]Y. S. Suh, F. I. Saunders, and R. H. Wagoner, “Anisotropic yield functions with plastic-strain-induced anisotropy”, International Journal of Plasticity, vol. 12, pp. 417-438, 1996.
[8]D. C. Ahn, J. W. Yoon, and K. Y. Kim, “Modeling of anisotropic plastic behavior of ferritic stainless steel sheet”, International Journal of Mechanical Sciences, vol. 51, pp. 718-725, 2009.
[9]F. Barlat, J. C. Brem, J. W. Yoon, K. Chung, R. E. Dick, D. J. Lege, F. Pourboghrat, S. H. Choi, and E. Chu, “Plane stress yield function for aluminum alloy sheets-part1”, International Journal of Plasticity, vol. 19, pp. 1297-1319, 2003.
[10]J. W. Yoon, F. Barlat, R. E. Dick, K. Chung, and T. J. Kang, “Plane stress yield function for aluminum alloy sheets—part2”, International Journal of Plasticity, vol. 20, pp. 495-522, 2004.
[11]M. Janssson, L. Nilsson, and K. Simonsson, “On constitutive modeling of aluminum alloys for tube hydroforming applications”, International Journal of Plasticity, vol. 21, pp. 1041-1058, 2005.
[12]H. Wang, M. Wan, X. Wu, and Y. Yan, “The equivalent plastic strain-dependent Yld2000-2d yield function and the experimental verification”, Computational Materials Science, vol. 47, pp. 12-22, 2009.
[13]蘇柏銓, “先進高強度鋼板材料模型與成形工法之研究”, 國立台灣大學機械工程研究所碩士論文, 2015.
[14]R. G. Davies, ““Side-Wall Curl” in High-Strength Steels”, Journal of Applied Metalworking, vol. 3, pp. 120-126, 1984.
[15]R. A. Ayres, “SHAPESET: A process to reduce sidewall curl springback in high-strength steel rails”, Journal of Applied Metalworking, vol. 3, pp. 127-134, 1984.
[16]D. Schmoeckel and M. Beth, “Springback Reduction in Draw-Bending Process of Sheet Metals”, CIRP Annals-Manufacturing Technology, vol. 42, pp. 339-342, 1993.
[17]M. Traversin and R. Kergen, “Closed-loop control of the blank-holder force in deep-drawing: finite-element modeling of its effects and advantages”, Journal of Materials Processing Technology, vol. 50, pp. 306-317, 1995.
[18]M. Sunseri, J. Cao, A. P. Karafillis, and M. C. Boyce, “Accommodation of Springback Error in Channel Forming Using Active Binder Force Control: Numerical Simulations and Experiments”, Journal of Engineering Materials And Technology, vol. 118, pp. 426-435, 1996.
[19]J. Cao, B. Kinsey, and S. A. Solla, “Consistent and minimal springback using a stepped binder force trajectory and neural network control”, Journal of engineering materials and technology, vol. 122, pp. 113-118, 2000.
[20]S. Kitayama, K. Kita, and K. Yamazaki, “Optimization of variable blank holder force trajectory by sequential approximate optimization with RBF network”, The International Journal of Advanced Manufacturing Technology, vol. 61, pp. 1067-1083, 2012.
[21]S. Kitayama, S. Huang, and K. Yamazaki, “Optimization of variable blank holder force trajectory for springback reduction via sequential approximate optimization with radial basis function network”, Structural and Multidisciplinary Optimization, vol. 47, pp. 289-300, 2013.
[22]K. J. Weinmann, J. R. Michler, V. D. Rao, and A. R. Kashani, “Development of a Computer-Controlled Drawbead Simulator for Sheet Metal Forming”, CIRP Annals - Manufacturing Technology, vol. 43, pp. 257-261, 1994.
[23]M. L. Bohn, S. U. Jurthe, and K. J. Weinmann, “A New Multi-point Active Drawbead Forming Die: Model Development for Process Optimization”, SAE Technical Paper, 1998.
[24]R. Li and K. J. Weinmann, “Formability in Non-Symmetric Aluminium Panel Drawing Using Active Drawbeads”, CIRP Annals - Manufacturing Technology, vol. 48, pp. 209-212, 1999.
[25]Z. C. Xia and F. Ren, “An Investigation of Wall Curl Reduction Through Post-Stretch Forming”, ASME 2004 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, pp. 495-502, 2004.
[26]D. Zhou, C. Du, C. K. Hsiung, K. Schmid, F. Ren, and E. Liasi, “UHSS Springback Reduction with Post-Stretch”, AutoSteel, 2016.
[27]C. Y. Wang, X. Y. Zhang, C. Dai, S. Y. Wang, and F. F. Guo, “Controlling Spring Back of High-Strength Steel Based on Shape Adjustable Bead”, ADVANCED HIGH STRENGTH STEEL AND PRESS HARDENING: PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE (ICHSU2015), pp. 537-541, 2016.
[28]前田正幸 : Japan Patent JP10244324A, September 14, 1998.
[29]韓建波, 宋相軍, 梁繼才, 李義 : China Patent CN101259499A, September 10, 2008.
[30]李小平, 彭成允, 張俠, 唐麗文, 陳元芳, 呂琳, 胡建軍 : China Patent CN101530882A, September 16, 2009.
[31]李慧, 周杰, 陸演, 楊明 : China Patent CN102151752B, September 2, 2012.
[32]張懃 : China Patent CN202263837U, June 6, 2012.
[33]趙坤民, 胡平, 戴明華, 金榮, 黃波 : China Patent CN103341556A, October 9, 2013.
[34]A. Osumi, J. Iwaya, and T. Yamano : U. S. Patent US7213437A, May 8, 2007.
[35]佟國棟, 張昆, 閻德斌, 紀仕超, 杜祖椿, 劉濤: China Patent CN205551250U, September 7, 2016.
[36]W. Gan and R. H. Wagoner, “Die design method for sheet springback”, International Journal of Mechanical Sciences, vol. 46, pp. 1097-1113, 2004.
[37]R. Lingbeek, J. Huetink, S. Ohnimus, M. Petzoldt, and J. Weiher, “The development of a finite elements based springback compensation tool for sheet metal products”, Journal of Materials Processing Technology, vol. 169, pp. 115-125, 2005.
[38]X. A. Yang and F. Ruan, “A die design method for springback compensation based on displacement adjustment”, International Journal of Mechanical Sciences, vol. 53, pp. 399-406, 2011.
[39]R. Hill, “Constitutive modelling of orthotropic plasticity in sheet metals”, Journal of the Mechanics and Physics of Solids, vol. 38, pp. 405-417, 1990.
[40]F. Barlat and K. Lian, “Plastic behavior and stretchability of sheet metals. Part I: A yield function for orthotropic sheets under plane stress conditions”, International Journal of Plasticity, vol. 5, pp. 51-66, 1989.
[41]F. Barlat, K. Lian, and B. Baudelet, “Plastic behaviour and stretchability of sheet metals. Part II: Effect of yield surface shape on sheet forming limit”, International Journal of Plasticity, vol. 5, pp. 131-147, 1989.
[42]F. Barlat, D. J. Lege, and J. C. Brem, “A six-component yield function for anisotropic materials”, International Journal of Plasticity, vol. 7, pp. 693-712, 1991.
[43]彭彥安, “先進高強度鋼板材料模型特性對回彈影響之研究”, 國立台灣大學機械工程研究所碩士論文, 2014.
[44]蔡恒光, “先進高強度鋼板反覆拉壓與雙軸拉伸變形特性之研究”, 國立台灣大學機械工程研究所博士論文, 2012.
[45]ESI, “PAM-STAMP 2015.1 User’s Guide”, 2015.
[46]S. G. Xu, M. L. Bohn, and K. J. Weinmann, “Drawbeads in sheet metal stamping-A review”, SAE Technical Paper, 1997.
[47]張渭川, “沖壓加工資料集”, 全華科技圖書股份有限公司.