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南京理工大學泰州科技學院
畢業(yè)設計(論文)外文資料翻譯
系 部: 機械工程系
專 業(yè): 機械工程及自動化
姓 名: 王忠賢
學 號: 0501510141
外文出處:Advance in FEM Simulation and its
Related Technologies in Sheet Metal Forming (July 2001, p641-648)
附 件: 1.外文資料翻譯譯文;2.外文原文。
指導教師評語:
該英文翻譯經(jīng)過幾次修改后語句較通順,語義較正確,基本能正確表達原文的內(nèi)容。這反映了該生通過本英文翻譯基本掌握了科技文獻的閱讀方法和常用專業(yè)詞匯的翻譯方法,但仍需加強學習,基本達到了外文資料翻譯的目的。
簽名:
2009 年 3 月 16 日
附件1:外文資料翻譯譯文
板料成形中有限元仿真及相關技術的研究進展
1理研和光材料制造實驗室 ,日本
2法國國家科學研究中心,法國
3 IIS,東京大學,六本木,東京都港區(qū),日本
摘要 本文概述了汽車制造商和鋼板供應商采用的板料成形仿真及相關技術的現(xiàn)狀。為此,作者調(diào)查了歐洲、日本和美國的行業(yè),與工程師和研究人員討論上述問題。各行業(yè)中使用的軟件如表所示,行業(yè)用戶對有限元素的評價也歸納在表中。根據(jù)這些信息提出在這領域的研究方法。
關鍵詞 板料沖壓成形,仿真,有限元法,計算機輔助設計
1 導言
汽車行業(yè)面臨著全球范圍嚴重的挑戰(zhàn):激烈的市場競爭和嚴格的政府環(huán)境保護法規(guī)。汽車制造商為迎接這些挑戰(zhàn)而采取的戰(zhàn)略是有時稱為3R的策略:縮短上市時間,降低開發(fā)成本以贏得競爭,減少車輛重量以提高燃料效率。來實現(xiàn)三個目標的解決方案必不可少的要在產(chǎn)品開發(fā)和進程設計中采用基于CAD / CAE / CAM系統(tǒng)集成技術。
這一努力最顯著的部分在于減少沖壓車身面板相關的加工費用和提前期,甚至在增加技術難度,如使用鋁合金和高強度鋼,和要求沖壓件高幾何精度情況下。為處理這趨勢所帶來的超越過去的經(jīng)驗的問題,板料成形仿真的數(shù)值方法顯得越來越重要。它由計算機試錯取代了物理沖壓試錯。
成功的數(shù)值仿真主要取決于成形仿真軟件的進展,但其他相關的技術的進展也很重要。相關技術的例子有能迅速構建和修改加工表面的CAD系統(tǒng),或多或少在CAD表面自動創(chuàng)建有限元網(wǎng)格的現(xiàn)代網(wǎng)格生成器,使用戶能夠掌握大量的數(shù)據(jù)的可視化的硬件和軟件以及最后在合理的時間內(nèi)處理大型仿真的計算機硬件。本文的目的在于總結(jié)業(yè)界金屬板料成形仿真和相關技術實現(xiàn)現(xiàn)狀,并對未來的研究方向提出建議。在80 和90年代關于金屬板料成形仿真已舉辦了許多國際會議并發(fā)表了許相關文章。然而,通過這些信息還不足以解決上述問題。由于這個原因,,作者決定訪問調(diào)查歐洲、日本和美國的汽車行業(yè)和鋼板供應商,與工作在模具沖壓車間和企業(yè)沖壓部門的工程師和研究人員來討論這些具體課題。
2 歷史背景
本世紀中葉對板料成形過程的分析研究已經(jīng)開始,在60年代,數(shù)值程序(有限差分方法)被應用于軸對稱拉伸過程分析中。雖然這種工作對于金屬成形分析理論貢獻巨大,但是它還不能應用于實際生產(chǎn)。
非線性有限元仿真打開了真實工業(yè)沖壓過程仿真之路,1985年在安阿伯密歇根州的板材成形過程計算機建模專題討論會提出了使用殼單元的彈塑性有限元方法對三維汽車車身面板成形過程建模。研究中,對升降機窗口外形的拉伸過程和甲板蓋的壓邊圈夾緊過程進行了仿真,但它們尚處于測試和評價的階段。因此,在這個會議中,幾何建模方法[ 10月12日]和簡化的力學建模方法更受到業(yè)界贊賞,發(fā)表了許多關于成形仿真的文章,其中兩個重要方向?qū)⑹拱辶铣尚畏抡嫣嵘揭粋€新的水平,一個是動力顯式軟件的應用,另一個是一步法的提出。在文獻【16】中昂納克和Mattiasson證明采用DYNA3D可對一個油底殼和散熱器部分深拉深,可獲得用靜態(tài)顯式軟件ABAQUS無法獲得的的深拉深形狀,包括凸緣起皺。會后,一些用于板料成形仿真的動力顯式軟件如 PAM-STAMP 和OPTRIS 被開發(fā)出來,并且許多汽車企業(yè)開始嘗試使用這些軟件。
另一方面,開發(fā)了基于Batiste al李和常[18]理念提出的一步法,其中使用一個大時間步長值,逆變形板料從最終的零件配置到最初的板料配置。這個方法的主要好處是計算時間非常短,并且,根據(jù)這個方法開發(fā)了許多軟件,主要在歐洲如ISOPUNCH、SIMEX、FAST FORM3D和AUTO FORM ONE STEP。
與此同時進行了根據(jù)靜態(tài)隱式增量方法,這也許是仿真金屬板變形的最適當?shù)姆椒ǎM行軟件開發(fā)。那些成果在汽車制造業(yè)NUMISHEET’3 和NUMISHEET 6的三維金屬板料有限元仿真的國際專題討論會上被提出了。在我們訪問的企業(yè)所用的靜態(tài)隱式增量軟件是MTLFRM和AUTO FORM。為了避免在靜態(tài)隱式方法遇到的收斂問題,開發(fā)了靜態(tài)顯式軟件lTAS3D。在最近十年期間,由于這些非常密集的研究,板料成形仿真發(fā)生了顯著的變化,如表1所示。有幾個獨立的研究小組在10年前開發(fā)他們自己的有限元軟件并且使用自己的軟件解決他們的問題。然而,在今天,情況已顯著改變了。有三組人: 研究員、軟件開發(fā)商和軟件用戶。CIRP成員也許是屬于研究員小組,而多數(shù)工作在汽車制造商和板料供應商那里的工程師屬于軟件用戶小組。當軟件開發(fā)商和用戶建立了一個非常強的聯(lián)系時,這兩個小組之間的聯(lián)系卻相當弱了。
研究員軟件用戶
軟件用戶
軟件開發(fā)商
研究員
1988
1998
圖1 最近十年期間金屬板材成形仿真的趨勢。
3 企業(yè)中使用的軟件
我們走訪了列于表1至3 的12家公司。地區(qū)和公司的選擇是基于我們的興趣,而非基于系統(tǒng)化戰(zhàn)略。
表1 在歐洲用于汽車制造商和板料供應商的軟件
公司名稱
戴姆勒奔馳
雷諾汽車
沃爾沃汽車
Sollac
訪問的地方
Sindelfingen Plant
德國
Guyancourt Technocenter
法國
Olofstrom Engineering
瑞典
Montataire Centred' tudes et de Development
法國
仿真軟件
AUTO FORM
LS-DYNA3D
LS-N I KE3D
OPTRIS
INDEED
ISOPUNCH
AF ONE STEP
SIMEX
OPTRIS
PAM-STAMP
AF ONE STEP
AUTO FORM
LS- DY NA3D
ISOPUNCH
AUTO FORM
PAM-STAMP
OPTRIS
CAD系統(tǒng)
CATIA
SYRKO(內(nèi)部)
I-DEAS
EUCLID
CATIANAMOS
網(wǎng)格生成器
MEDINA
DELTA MESH
TRANSK
HYPER MESH
DELTA MESH
AMORA
DELTA MESH
TRANSK
表2 在日本用于汽車制造商和板料供應商的軟件
公司名稱
馬自達
日產(chǎn)
豐田
新日本制鋼
訪問的地方
Headquarters
Hiroshima
Technical Center
Atsugi
Motomachi Plant
Toyota
Research Center
Futtsu
仿真軟件
PAM-STAMP
ITAS3D
AUTO-FORM
PAM-STAMP
LS-DYNA3D
JOH-NIKE3D
PAM-STAMP
ITAS3D
CAD系統(tǒng)
I-DEAS
GNC(內(nèi)部)
PUNCH(內(nèi)部)
Integrated CAD(內(nèi)部)
Pro-ENGINEER
PRO-ENGINEER
網(wǎng)格生成器
GNC
I-DEAS
FEMB
PATRAN
K-SWAD
CADISCT
表3 在美國用于汽車制造商和板料供應商的軟件
公司名稱
克萊斯勒汽車
福特汽車
國家鋼鐵
美國鋼鐵
訪問的地方
Technical Center
Auburn Hills, Michigan
Research Laboratory
Dearborn, Michigan
Product Application Center
Livonia, Michigan
Troy, Michigan
仿真軟件
LSDYNA 3D
AUTO FORM
MTLFRM
OPTRIS
AUTO FORM(EU)
DYNA 3D
FAST-FORM3D
DYNA 3D
CAD系統(tǒng)
CATIA
I-DEAS(PDGS)
CATIA
網(wǎng)格生成器
DELTA MESH
DYNAFORM
HYPER MESH
I-DEAS (模具表面) 自帶板料網(wǎng)格軟件
DYNA FORM
HYPER MESH
3.1歐洲工業(yè)
( 1 )戴姆勒奔馳公司
盡管1994年戴姆勒奔馳公司就引進了板料成形仿真,但在模具車間由受過訓練的制造工程師生產(chǎn)化利用它從1996年1月開始的。如表1所示,目前金屬成形團隊正在使用7種軟件。ISOPUNCH和AOTO FORM ONE FORM用于快速預先優(yōu)化在零件設計部分零件形狀,而不是用作幾何工具。AUTO FORM更多地被用于評估幾何工具原型的模具設計和系列模具設計。有時LS-DYNA3D或OPTRIS被用于執(zhí)行更加確切的優(yōu)化。INDEED和LS-DYNA3D被用于預測反彈。在Shindelfingen工廠,相當多的工程師已經(jīng)被訓練使用仿真軟件, 其中有14 名AUTO FORM 工程師和 4名 OPTRlS 工程師。
( 2 )雷諾汽車
在80年代期間,雷諾通過與各大學和研究機構合作在開發(fā)板料成形仿真的數(shù)值方法上付出很大的努力。其中最重要的成果之一是開發(fā)基于單步法的SIMEX軟件。雷諾正在在模具設計部門使用此軟件,并試圖與SIMTEC軟件公司進一步開發(fā)新的功能。其中一個功能是自動優(yōu)化模具設計,另一個功能是能對影響成形過程的疲勞極限的評價。為了更準確地對形成效應的評價,在1993年,引入了 OPTRIS和PAM的編碼。SIMEX和OPTRIS融入了FICTURE處理器,因此,這兩個仿真軟件可用于同一用戶界面。
( 3 )沃爾沃汽車公司
在1989年,沃爾沃,第一次表明了動態(tài)顯式軟件DYNA3D對鈑金成形過程的仿真的適用性,并在經(jīng)過5年的研究后,在沖壓車間引入該軟件實際使用。沃爾沃公司目前在產(chǎn)品設計和沖壓工藝/模具設計中使用三種有限元軟件:AUTOFORM ONE STEP、AUTO FORM 和LS-DYNA3D。所有仿真軟件綜合成CATIA/NAMOS ,這是一個專用于汽車制造的計算機輔助設計軟件。目前11個訓練有素的工程師能夠使用這一系統(tǒng)執(zhí)行仿真。
( 4 )Sollac公司
作為鋼板供應商,Sollac利用有限元軟件向金屬板材用戶提供技術服務。Solace開發(fā)了單步求解器ISOPUNCH并對其商業(yè)化。對于Solace而言,作為一種提供技術服務的途徑,仿真已逐漸變得重要了。
3.2日本產(chǎn)業(yè)
( 1 )馬自達
在1990年,通過與ESI和IBM的合作,馬自達開始了評估PAM-STAMP可應用性的初步研究。對于日本汽車制造商在板料沖壓部門使用有限元軟件這是最早的嘗試。雖然馬自達內(nèi)部模具的CAD系統(tǒng)可以提供信息以便優(yōu)化模具表面,但是系統(tǒng)無法跟上快速變化的技術趨勢,因此馬自達決定引入使用有限元仿真。與歐洲汽車制造商不同,馬自達只使用PAM-STAMP作為仿真軟件,兩名工程師在仿真環(huán)境中深入開展高級仿真。
( 2 )日產(chǎn)汽車
于1994年,日產(chǎn)汽車開始使用ITAS3D,稍候再模具設計車間引入了PAMSTAMP和AUTO FORM。通過與Rilk合作,日產(chǎn)公司已經(jīng)開發(fā)出了專業(yè)版本的ITAS3D,打算在早期階段沖壓作業(yè)中以獲取正確的變形形狀;變形由于重量和壓邊圈夾緊產(chǎn)生。大多數(shù)計算機試錯都是在早期設計階段進行,即在零件設計后使用大致接近模具面的幾何圖形。四個工程師從事零件仿真工作和仿真系統(tǒng)的開發(fā)。
( 3 )日本豐田汽車
由于豐田汽車有一個非常先進的幾何建模軟件,模具的計算機輔助設計,和訓練有素的模具設計工程師,對引進仿真他們沒有太多的熱情。然而,在鍛壓車間,高強度鋼板和新面板形狀被使用,如大型規(guī)模做片斷側(cè)面板,迫使豐田使用有限元仿真技術。LS-DYNA3D測試于1993年并被使用,豐田汽車公司自己擁有“虛擬試錯系統(tǒng)”,其中包括友好的用戶界面、LS-DYNA3D和一個新開發(fā)的數(shù)據(jù)庫。目前四個仿真工程師在從事此系統(tǒng)的開發(fā)和應用。
( 4 )新日本制鋼
在日本,日本深沖壓研究小組( JDDRG )在促進汽車和鋼鐵公司之間的密切聯(lián)系。新日本制鋼已主要是基于這個框架內(nèi)與汽車公司開展了合作調(diào)研工作。在1991年,開發(fā)出了lTAS3D,而于1994年,又開發(fā)了出PAM-STAMP。有限元仿真主要優(yōu)點是減少實驗次數(shù),這項技術手段在被正式使用之前主要用于解決薄板用戶所提出的問題。
3.3美國工業(yè)
( 1 )克萊斯勒汽車公司
在美國,作為三大汽車制造商之一,克萊斯勒是最后使用仿真的。然而,于1994年,克萊斯勒開發(fā)的最先進的仿真系統(tǒng)采用了CATIA和LS- DYNA3D,成為生產(chǎn)模具進程的主流設計。所有主要的重要的面板都使用它仿真。使克萊斯勒采用當前先進的動態(tài)軟件仿真的關鍵原因是計算機硬件和可視化工具開發(fā)與應用。
( 2 )福特汽車公司
MTLFRM 是唯一用于板料成形仿真的靜態(tài)隱式軟件,早在70年代,由Tang和他的同事開發(fā),并在福特廣泛使用。這個軟件主要優(yōu)點是能夠預測幾乎所有成形瑕疵包括缺陷回彈,但缺點是計算時間長。然而,最近,通過引進先進的直接矩陣方法求解MTLFRM ,計算時間大大減少。動態(tài)顯式軟件運作也可以用于該工具設計階段。
( 3 )國家鋼鐵
在1996年,在北美洲,汽車制造商和金屬板供應商之間有一個合作研究方案,叫做“汽車鋼鐵伙伴關系”,并在 1996年,國家鋼鐵決定利用有限元仿真技術與汽車制造商合作建造有共同技術的汽車制造基地,并使用了LS-DYNA3D和FASTFORM3D。這些軟件被廣泛應用于支持客戶活動,如管狀液壓和拼焊板的形成。
( 4 )美國鋼鐵公司
美國鋼鐵公司通過“汽車和鋼鐵伙伴關系”和“回彈項目”與汽車制造商密切合作。鋼板使用性能的評估是一個重要的課題。例如,通過使動態(tài)代碼和靜態(tài)代碼相結(jié)合來仿真面板局部凹痕抗力的形成過程。
附件2:外文原文(復印件)
Advance in FEM Simulation and its Related Technologies in Sheet Metal Forming
1 Material fabrication Lab., RIKEN, Wako, Japan
2 LPMTM-CNRS, University Paris Nerd, Valentines, France
3 IIS, The University of Tokyo, Roping, Minato-key, Tokyo, Japan
Abstract This paper presents an overview of the current state of sheet metal forming simulation and related technologies employed by automakers and steel sheet suppliers. For this purpose the authors visited industries in Europe, Japan, and the United States, to discuss the above-mentioned issues with engineers and researchers. Soft wares used in each industry are shown in tables and evaluations of finite element cods from industrial users are also summarized in a table. Based on that information the future direction of research in this field is suggested.
Key words sheet metal forming, simulation, finite element method, CAD
1 INTRODUCTION
The automotive industry faces world-wide serious challenges: fierce market competition and strict governmental regulations on environment protection. The strategies of the automakers to meet these challenges are sometimes called the 3R Strategy: Reduction in time-to market, reduction in development costs to gain competitiveness, and reduction in the vehicle weight to improve fuel efficiency. The solutions to achieve this triple goal are essentially based on the implementation of CAD/CAE/CAM technologies in product development and process design.
A very significant component of this endeavor is focused on the reduction of the tooling costs and the lead-time related to the stamping of auto body panels, even under increasing technological difficulties such as the use of aluminum alloys and high-strength steels, and requirements for higher geometrical accuracy of stamped parts. To deal with the problems brought about by these trends, which are beyond past experience, numerical methods for sheet forming simulation become more and more important, replacing the physical tryout of stamping dies by a computer tryout.
The success of numerical simulation depends mainly on the advances in forming simulation codes, but progress in other related technologies is also important. Examples of related technology are the CAD systems that rapidly construct and modify tool surfaces, modern mesh generators to, more or less automatically, create Famishes CAD surfaces, visualization hardware and software, which enables users to grasp the huge data, and, finally, the computer hardware, which makes it possible to perform large scale simulations within reasonable time. The objective of the paper is to present an overview of the current state of sheet metal forming simulation and related technologies realized in industries, and to suggest the future directions of research. Many international conferences have been held and numerous papers are published related to sheet metal forming simulation in the 1980’and 1990’. However, the information obtained through these events is not sufficient to address the above issues. For this reason the authors decided to visit automotive industries and sheet steel suppliers in Europe, Japan and the United States to discuss these specific topics with engineers and researchers working at die shops and in sheet stamping sections of industries.
2. HISTORICAL BACKGROUND
Analytical study of sheet metal forming process was already started in the middle of this century [1, 2] and numerical procedures (finite difference methods) were applied to analyze ax symmetric drawing process in the 1960’ [3].Although such work contributed greatly to develop the theory of sheet metal forming analysis, this kind of approach could not be applicable to the actual production parts. Non-linear finite element methods opened the path for the simulation of real industrial stamping processes [4-6]. A symposium on computer modeling of sheet metal forming process was held in Ann Arbor, Michigan in 1985 [7], in which three dimensional auto-body panel forming processes are modeled by elastic-plastic finite element methods using shell elements[8-9]. In these studies drawing process of a lift window outer and binder wrapping process of a deck-lid were simulated, but they were in the stage of testing and evaluation, since finite element.
Simulation was still an extremely time consuming and unreliable tool to the engineer in the press shop. So that, in this symposium, geometric modeling methods [10-12] and simplified mechanical modeling methods [13-14] were much more appreciated by participants from industries. In NUMIFORM' 9[15], numerous papers concerning the sheet forming simulation were presented, and among them two important directions were suggested which brought sheet forming simulation to a new horizon; one was the application of a dynamic explicit code[16] and the other was the proposal of the one step method. In[16]Honaker and Madison demonstrated the deep drawing of an oil-pan and a radiator part by using DYNA3D,obtaining deeply drawn shapes including wrinkle on the flange, which was not possible by using the static implicit code ABAQUS. After this conference several dynamic explicit codes specialized to the sheet forming simulation, such as PAM-STAMP and OPTRIS, were developed, and many automotive industries started to try these codes. On the other hand the one step method proposed by Batiste al. was developed based on idea of Chang and Lee, in which a single large time step was used, deforming the sheet inversely from the final part configuration to the initial blank configuration. A major advantage of this method is the very short computation time, and thus, based on this strategy, many codes have been developed mainly in Europe. These are ISOPUNCH, SIMEX, and FAST FORM3D and AUTO FORM ONE STEP. Meanwhile there were several activities to develop codes based on the static implicit incremental approach, which may be the most appropriate method for sheet metal forming simulation. Those endeavors are presented at the International Symposium on FE-Simulation of 3-D Sheet Metal Forming Processes in Automotive Industry [19], NUMISHEET’3 [20] and NUMISHEET' 6[21].The static implicit incremental codes used in the industries, visited by us, are MTLFRM, INDEED [2, 3] and AUTO FORM [24-26] In order to avoid the convergence problem in the static implicit approach, the static explicit code lTAS3D was developed [27, 28]. Due to these very intensive activities, the trend of sheet forming simulation has undergone significant change during the last decade, which may be able to be illustrated like Fig.1. There existed several independent research groups, 10 years before, which developed their own FE codes and solved their problems using their own codes. However, today, the situation has dramatically changed. There are three groups of people; researchers, software developers and software users. Carp members may belong to the group of researchers and most engineers working in automakers and sheet suppliers may belong to the group of software users. There is a rather thin relationship between these two groups, while a very strong relationship has been established between software developers and users.
3. SIMULATION CODES USED IN INDUSTRIES
We visited 12 companies listed in Table 1 to 3. Choice of regions and choice of companies are based on our interest, and not on some systematic strategy.
3.1 European Industries
(1) Daimler Benz AG
Although in 1994 sheet metal forming simulation was introduced in Daimler Benz, the productive use of it in die shop by trained tool engineers was since January 1996. As shown in Table 1, currently seven codes are being used by the metal forming team. ISOPUNCH and AUTO FORMONE STEP are used for a fast pre-optimization of shape of parts at the parts design section without tool geometry. AUTO FORM is most intensively used to evaluate the tool geometry for the prototype die design and also the series die design. Sometimes LS-DYNA3D or OPTRIS is employed to perform a more exact Optimization. INDEED and LS-NIKE3D are used for prediction of the spring backed shape. A rather large number of engineers have been trained to use the simulation codes.
(2) Renault Automobile
Renault made significant efforts to develop numerical method for sheet metal forming simulation during the1980' .in cooperation with universities and research institutes. One of the important results from these attempts was the development of the code SIMEX based on the one step approach. Renault is utilizing this code in the die design section and is trying to develop further new technological features in cooperation with the software company SIMTEC. One feature is the auto maticoptimization of tool design [29]and the other is evaluation of fatigue limit taking into account the effect of a forming process PO].In order to perform more accurate evaluation of the forming defect, OPTRIS and PAM-STAMP codes were introduced in 1993. SIMEX and OPTRIS are integrated into the pre and post processor FICTURE, so that both simulation codes can be used in the unified user interface.
(3) Vivo Car Corporation
Volvo, for the first time, demonstrated the applicability of dynamic explicit code DYNA3D to the simulation of sheet metal forming process in 1989 [16], and after 5 years of research, the code was introduced in the press shop for actual use. Volvo currently uses three FE codes, AUTOFORM ONE STEP, AUTO FORM and LS-DYNA3D. All the simulation codes are integrated into CATIANAMOS, which is specialized CAD software for automakers. Currently 11 trained engineers are able to perform simulations using this system.
(4) Solace
As a steel sheet supplier, Solace uses FE codes to provide technical services to the sheet metal users. Solace developed a one step solver ISOPUNCH [23] and commercialized it. Simulation has become increasingly important for Solace as a means to provide technical services.
3.2 Japanese industries
(1) Mazda
Mazda began a preliminary study to evaluate the applicability of PAM-STAMP in cooperation with ESI and IBM in 1990. This was the earliest attempt, for Japanese automakers, to employ a FE code to the sheet stamping section. Although Mazda had an in-house die face CAD system which could provide information for optimizing the die face geometry, the system could not keep pace with the rapid changes in the technical trends and therefore Mazda decided to introduce FE simulation. In contrast to the European automakers, Mazda use only PAM-STAMP as the simulation code, and two engineers are intensively engaged in simulations.
Advanced - simulation
(2) Nissan Motor
Nissan started the use of ITAS3D in 1994, and PAMSTAMP and AUTO FORM were introduced a little later to the tool design section. Nissan has developed the special version of ITAS3D in cooperation with Rilke intending to obtain a correct deformation shape at the early stages of stamping operation; the deformation due tow eight and the binder wrapping. Most of the computer tryouts are performed during the early design stage, just after part design, using the roughly approximated die face geometry. Four engineers are engaged in simulation of new parts and also in the development of the simulation system.
(3) Toyota Motor
Since Toyota had very advanced geometric modeling software, Die Face CAD, and well trained die design engineers, they were not much enthusiastic for introduction of the simulation. However, the increase usage of high strength steel sheet in the press shop and introduction of new panel shapes, such as a large-size done-piece side panel, forced Toyota to employ FE simulation. LS-DYNA3D was tested in 1993 and introduced. Now, Toyota has their own “Virtual Tryout System”, which consists of well defined user interface, LS-DYNA3D and a newly developed data base. Currently four simulation engineers work on this system.
(4) Nippon Steel
The Japan Deep Drawing Research Group (JDDRG) facilitates a close relationship between the automotive and steel companies in Japan. Mainly based on this framework, Nippon Steel has carried out cooperative research works with automotive companies.lTAS3D was introduced in1991, and PAM-STAMP in 1994. The main advantage of FEM simulation is the reduction in the number of experiments, which was the main technical means to solve problems asked by the sheet metal users, before the introduction of FEM.
3.3 US industries
(1) Chrysler Corporation
Among the big three automakers in US, Chrysler was the last to introduce the simulation. However, Chrysler developed a most advanced simulation system using CATIA and LS-DYNA3D in 1994, which became the mainstream in the design of production die process. All major significant panels are simulated by it. The key reasons which made Chrysler adopt simulation were there cent advances in the dynamic code, the computer hardware and the visualization tool.
(2) Ford Motor Company
MTLFRM, the only incremental static implicit code used for panel forming simulation, was being developed as early as the end of the 1970' by Tang and coworkers [6-9] and is used exclusively at Ford. A major advantage of this code is its ability to predict almost all the forming defects including the spring back, while the drawbacks are long computation time. However, recently, by introducing an advanced direct space matrix solver into MTLFRM, computation time was significantly reduced. The dynamic explicit code OPTRIS is also used in the tool design stage.
(3) National Steel
In North America there is a cooperative research program betwee
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