外文翻譯=板料成形中有限元仿真及相關(guān)技術(shù)的研究進(jìn)展=4000字符

1、<p>　　南京理工大學(xué)泰州科技學(xué)院</p><p>　　畢業(yè)設(shè)計(jì)(論文)外文資料翻譯</p><p>　　系　　部： 機(jī)械工程系 </p><p>　　專 業(yè)： 機(jī)械工程及自動(dòng)化 </p><p>　　姓 名： 王忠賢

2、 </p><p>　　學(xué) 號(hào)： 0501510141 </p><p>　　外文出處：Advance in FEM Simulation and its </p><p>　　Related Technologies

3、 in Sheet Metal Forming (July 2001, p641-648) </p><p>　　附 件： 1.外文資料翻譯譯文；2.外文原文。 </p><p>　　附件1：外文資料翻譯譯文</p><p>　　板料成形中有限元仿真及相關(guān)技術(shù)的研究進(jìn)展</p><p>

4、;　　1理研和光材料制造實(shí)驗(yàn)室 ，日本 </p><p>　　2法國國家科學(xué)研究中心，法國 </p><p>　　3 IIS，東京大學(xué)，六本木，東京都港區(qū)，日本 </p><p>　　摘要 本文概述了汽車制造商和鋼板供應(yīng)商采用的板料成形仿真及相關(guān)技術(shù)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

5、對(duì)有限元素的評(píng)價(jià)也歸納在表中。根據(jù)這些信息提出在這領(lǐng)域的研究方法。</p><p>　　關(guān)鍵詞 板料沖壓成形，仿真，有限元法，計(jì)算機(jī)輔助設(shè)計(jì)</p><p><b>　　1 導(dǎo)言 </b></p><p>　　汽車行業(yè)面臨著全球范圍嚴(yán)重的挑戰(zhàn)：激烈的市場(chǎng)競(jìng)爭(zhēng)和嚴(yán)格的政府環(huán)境保護(hù)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(shí)稱為3R的策略

6、：縮短上市時(shí)間，降低開發(fā)成本以贏得競(jìng)爭(zhēng)，減少車輛重量以提高燃料效率。來實(shí)現(xiàn)三個(gè)目標(biāo)的解決方案必不可少的要在產(chǎn)品開發(fā)和進(jìn)程設(shè)計(jì)中采用基于CAD / CAE / CAM系統(tǒng)集成技術(shù)。</p><p>　　這一努力最顯著的部分在于減少?zèng)_壓車身面板相關(guān)的加工費(fèi)用和提前期，甚至在增加技術(shù)難度，如使用鋁合金和高強(qiáng)度鋼，和要求沖壓件高幾何精度情況下。為處理這趨勢(shì)所帶來的超越過去的經(jīng)驗(yàn)的問題，板料成形仿真的數(shù)值方法顯得越來越重要

7、。它由計(jì)算機(jī)試錯(cuò)取代了物理沖壓試錯(cuò)。 </p><p>　　成功的數(shù)值仿真主要取決于成形仿真軟件的進(jìn)展，但其他相關(guān)的技術(shù)的進(jìn)展也很重要。相關(guān)技術(shù)的例子有能迅速構(gòu)建和修改加工表面的CAD系統(tǒng)，或多或少在CAD表面自動(dòng)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(shí)間內(nèi)處理大型仿真的計(jì)算機(jī)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(guān)技術(shù)實(shí)現(xiàn)現(xiàn)狀，并對(duì)未來的研究方向提

8、出建議。在80 和90年代關(guān)于金屬板料成形仿真已舉辦了許多國際會(huì)議并發(fā)表了許相關(guān)文章。然而，通過這些信息還不足以解決上述問題。由于這個(gè)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(yīng)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。 </p><p><b>　　2 歷史背景 </b></p><p>　　本世紀(jì)中葉對(duì)板料成形

9、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(yīng)用于軸對(duì)稱拉伸過程分析中。雖然這種工作對(duì)于金屬成形分析理論貢獻(xiàn)巨大，但是它還不能應(yīng)用于實(shí)際生產(chǎn)。 </p><p>　　非線性有限元仿真打開了真實(shí)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(jì)算機(jī)建模專題討論會(huì)提出了使用殼單元的彈塑性有限元方法對(duì)三維汽車車身面板成形過程建模。研究中，對(duì)升降機(jī)窗口外形的拉伸過程和甲板蓋的壓邊圈夾緊過程

10、進(jìn)行了仿真，但它們尚處于測(cè)試和評(píng)價(jià)的階段。因此，在這個(gè)會(huì)議中，幾何建模方法[ 10月12日]和簡(jiǎn)化的力學(xué)建模方法更受到業(yè)界贊賞，發(fā)表了許多關(guān)于成形仿真的文章，其中兩個(gè)重要方向?qū)⑹拱辶铣尚畏抡嫣嵘揭粋€(gè)新的水平，一個(gè)是動(dòng)力顯式軟件的應(yīng)用，另一個(gè)是一步法的提出。在文獻(xiàn)【16】中昂納克和Mattiasson證明采用DYNA3D可對(duì)一個(gè)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(huì)后，一些用于

11、板料成形仿真的動(dòng)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。</p><p>　　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(gè)大時(shí)間步長(zhǎng)值，逆變形板料從最終的零件配置到最初的板料配置。這個(gè)方法的主要好處是計(jì)算時(shí)間非常短，并且，根據(jù)這個(gè)方法開發(fā)了許多軟件，主要在歐洲如ISOPUNCH、SIMEX、FAST FORM3D和

12、AUTO FORM ONE STEP。</p><p>　　與此同時(shí)進(jìn)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(dāng)?shù)姆椒?，進(jìn)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(huì)上被提出了。在我們?cè)L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

13、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(gè)獨(dú)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(yīng)商那里的工程師屬于軟件用戶小組。當(dāng)軟件開發(fā)商和用戶建立了一個(gè)非常強(qiáng)的聯(lián)系時(shí)，這兩個(gè)小組之間的聯(lián)系卻相當(dāng)弱了。 </p>

14、<p><b>　　1998</b></p><p>　　圖1 最近十年期間金屬板材成形仿真的趨勢(shì)。</p><p>　　3 企業(yè)中使用的軟件 </p><p>　　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。</p><p>　　表1 在歐洲用于汽車制造商和

15、板料供應(yīng)商的軟件</p><p>　　表2 在日本用于汽車制造商和板料供應(yīng)商的軟件</p><p>　　表3 在美國用于汽車制造商和板料供應(yīng)商的軟件</p><p><b>　　3.1歐洲工業(yè) </b></p><p>　?。?1 ）戴姆勒奔馳公司</p><p>　　盡管1994年戴姆勒奔馳公

16、司就引進(jìn)了板料成形仿真，但在模具車間由受過訓(xùn)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(tuán)隊(duì)正在使用7種軟件。ISOPUNCH和AOTO FORM ONE FORM用于快速預(yù)先優(yōu)化在零件設(shè)計(jì)部分零件形狀，而不是用作幾何工具。AUTO FORM更多地被用于評(píng)估幾何工具原型的模具設(shè)計(jì)和系列模具設(shè)計(jì)。有時(shí)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(yù)測(cè)反彈。在S

17、hindelfingen工廠，相當(dāng)多的工程師已經(jīng)被訓(xùn)練使用仿真軟件， 其中有14 名AUTO FORM 工程師和 4名 OPTRlS 工程師。 </p><p>　?。?2 ）雷諾汽車 </p><p>　　在80年代期間，雷諾通過與各大學(xué)和研究機(jī)構(gòu)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(shè)計(jì)部門使用此軟件，并試

18、圖與SIMTEC軟件公司進(jìn)一步開發(fā)新的功能。其中一個(gè)功能是自動(dòng)優(yōu)化模具設(shè)計(jì)，另一個(gè)功能是能對(duì)影響成形過程的疲勞極限的評(píng)價(jià)。為了更準(zhǔn)確地對(duì)形成效應(yīng)的評(píng)價(jià)，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(gè)仿真軟件可用于同一用戶界面。</p><p>　?。?3 ）沃爾沃汽車公司 </p><p>　　在1989年，沃爾沃，第一次

19、表明了動(dòng)態(tài)顯式軟件DYNA3D對(duì)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(shí)際使用。沃爾沃公司目前在產(chǎn)品設(shè)計(jì)和沖壓工藝/模具設(shè)計(jì)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(gè)專用于汽車制造的計(jì)算機(jī)輔助設(shè)計(jì)軟件。目前11個(gè)訓(xùn)練有素的工程師能夠使用這一系統(tǒng)執(zhí)行仿真。 </p><p>

20、　　（ 4 ）Sollac公司</p><p>　　作為鋼板供應(yīng)商，Sollac利用有限元軟件向金屬板材用戶提供技術(shù)服務(wù)。Solace開發(fā)了單步求解器ISOPUNCH并對(duì)其商業(yè)化。對(duì)于Solace而言，作為一種提供技術(shù)服務(wù)的途徑，仿真已逐漸變得重要了。</p><p><b>　　3.2日本產(chǎn)業(yè) </b></p><p><b>　　

21、（ 1 ）馬自達(dá) </b></p><p>　　在1990年，通過與ESI和IBM的合作，馬自達(dá)開始了評(píng)估PAM-STAMP可應(yīng)用性的初步研究。對(duì)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(dá)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(shù)趨勢(shì)，因此馬自達(dá)決定引入使用有限元仿真。與歐洲汽車制造商不同，馬自達(dá)只使用PAM-STAMP作為仿真軟件，兩

22、名工程師在仿真環(huán)境中深入開展高級(jí)仿真。</p><p>　　（ 2 ）日產(chǎn)汽車 </p><p>　　于1994年，日產(chǎn)汽車開始使用ITAS3D，稍候再模具設(shè)計(jì)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(jì)算機(jī)試錯(cuò)都是在早期設(shè)計(jì)階段進(jìn)行，即在

23、零件設(shè)計(jì)后使用大致接近模具面的幾何圖形。四個(gè)工程師從事零件仿真工作和仿真系統(tǒng)的開發(fā)。 </p><p>　　（ 3 ）日本豐田汽車 </p><p>　　由于豐田汽車有一個(gè)非常先進(jìn)的幾何建模軟件，模具的計(jì)算機(jī)輔助設(shè)計(jì)，和訓(xùn)練有素的模具設(shè)計(jì)工程師，對(duì)引進(jìn)仿真他們沒有太多的熱情。然而，在鍛壓車間，高強(qiáng)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(shù)。LS-DYNA3

24、D測(cè)試于1993年并被使用，豐田汽車公司自己擁有“虛擬試錯(cuò)系統(tǒng)”，其中包括友好的用戶界面、LS-DYNA3D和一個(gè)新開發(fā)的數(shù)據(jù)庫。目前四個(gè)仿真工程師在從事此系統(tǒng)的開發(fā)和應(yīng)用。 </p><p>　?。?4 ）新日本制鋼 </p><p>　　在日本，日本深沖壓研究小組（ JDDRG ）在促進(jìn)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(gè)框架內(nèi)與汽車公司開展了合作調(diào)研工作。在199

25、1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(diǎn)是減少實(shí)驗(yàn)次數(shù)，這項(xiàng)技術(shù)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。</p><p><b>　　3.3美國工業(yè)</b></p><p>　?。?1 ）克萊斯勒汽車公司 </p><p>　　在美國，作為三大汽車制造商之一，克萊斯勒是最后使用仿

26、真的。然而，于1994年，克萊斯勒開發(fā)的最先進(jìn)的仿真系統(tǒng)采用了CATIA和LS- DYNA3D，成為生產(chǎn)模具進(jìn)程的主流設(shè)計(jì)。所有主要的重要的面板都使用它仿真。使克萊斯勒采用當(dāng)前先進(jìn)的動(dòng)態(tài)軟件仿真的關(guān)鍵原因是計(jì)算機(jī)硬件和可視化工具開發(fā)與應(yīng)用。 </p><p>　　（ 2 ）福特汽車公司 </p><p>　　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

27、同事開發(fā)，并在福特廣泛使用。這個(gè)軟件主要優(yōu)點(diǎn)是能夠預(yù)測(cè)幾乎所有成形瑕疵包括缺陷回彈，但缺點(diǎn)是計(jì)算時(shí)間長(zhǎng)。然而，最近，通過引進(jìn)先進(jìn)的直接矩陣方法求解MTLFRM ，計(jì)算時(shí)間大大減少。動(dòng)態(tài)顯式軟件運(yùn)作也可以用于該工具設(shè)計(jì)階段。 </p><p>　?。?3 ）國家鋼鐵 </p><p>　　在1996年，在北美洲，汽車制造商和金屬板供應(yīng)商之間有一個(gè)合作研究方案，叫做“汽車鋼鐵伙伴關(guān)系”，并在

28、1996年，國家鋼鐵決定利用有限元仿真技術(shù)與汽車制造商合作建造有共同技術(shù)的汽車制造基地，并使用了LS-DYNA3D和FASTFORM3D。這些軟件被廣泛應(yīng)用于支持客戶活動(dòng)，如管狀液壓和拼焊板的形成。 </p><p>　?。?4 ）美國鋼鐵公司 </p><p>　　美國鋼鐵公司通過“汽車和鋼鐵伙伴關(guān)系”和“回彈項(xiàng)目”與汽車制造商密切合作。鋼板使用性能的評(píng)估是一個(gè)重要的課題。例如，通過使動(dòng)

29、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。</p><p>　　附件2：外文原文（復(fù)印件）</p><p>　　Advance in FEM Simulation and its Related Technologies in Sheet Metal Forming</p><p>　　1 Material fabrication Lab., RIKE

30、N, Wako, Japan</p><p>　　2 LPMTM-CNRS, University Paris Nerd, Valentines, France</p><p>　　3 IIS, The University of Tokyo, Roping, Minato-key, Tokyo, Japan</p><p>　　Abstract This pape

31、r 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, a

32、nd 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 summa

33、rized in a table. Based on that informatio</p><p>　　Key words sheet metal forming, simulation, finite element method, CAD</p><p>　　1 INTRODUCTION</p><p>　　The automotive industry

34、 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 Strateg

35、y: 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 t

36、he implementation of CAD/CAE/CAM tech</p><p>　　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, ev

37、en 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 th

38、ese trends, which are beyond past experience, numerical methods for sheet forming simulation become more and more import</p><p>　　The success of numerical simulation depends mainly on the advances in forming

39、 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

40、 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 larg</p><p

41、>　　2. HISTORICAL BACKGROUND</p><p>　　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 appl

42、ied 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 produ

43、ction parts. Non-linear finite element methods opened the path for the simulation of real industrial stamping pro</p><p>　　Simulation was still an extremely time consuming and unreliable tool to the engineer

44、 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], nu

45、merous 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 applic</p><p>

46、;　　3. SIMULATION CODES USED IN INDUSTRIES</p><p>　　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.<

47、;/p><p>　　3.1 European Industries</p><p>　　(1) Daimler Benz AG</p><p>　　Although in 1994 sheet metal forming simulation was introduced in Daimler Benz, the productive use of it in die

48、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

49、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 seri</p><p>　　(2) Renault Automobile</p&

50、gt;<p>　　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

51、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 cooperatio

52、n with the software company SIMTEC. One feature is the auto maticoptimization of</p><p>　　(3) Vivo Car Corporation</p><p>　　Volvo, for the first time, demonstrated the applicability of dynamic e

53、xplicit 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 ON

54、E 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 t</p>

55、<p>　　(4) Solace</p><p>　　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

56、. Simulation has become increasingly important for Solace as a means to provide technical services.</p><p>　　3.2 Japanese industries</p><p><b>　　(1) Mazda</b></p><p>　　M

57、azda 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

58、. 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

59、 decided to introduce FE simulation. In contrast to the Eur</p><p>　　Advanced - simulation</p><p>　　(2) Nissan Motor</p><p>　　Nissan started the use of ITAS3D in 1994, and PAMSTAMP

60、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

61、 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 geomet

62、ry. F</p><p>　　(3) Toyota Motor</p><p>　　Since Toyota had very advanced geometric modeling software, Die Face CAD, and well trained die design engineers, they were not much enthusiastic for intr

63、oduction 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 simulati

64、on. LS-DYNA3D was tested in 1993 and introduced. Now, Toyota has their own “Virtual Tryout System”, which consists of well defi</p><p>　　(4) Nippon Steel</p><p>　　The Japan Deep Drawing Research

65、 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.lTAS3

66、D 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, bef

67、ore the introduction of FEM.</p><p>　　3.3 US industries</p><p>　　(1) Chrysler Corporation</p><p>　　Among the big three automakers in US, Chrysler was the last to introduce the simul

68、ation. 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 i

69、t. The key reasons which made Chrysler adopt simulation were there cent advances in the dynamic code, the computer hardware and the visualization tool.</p><p>　　(2) Ford Motor Company</p><p>　　M

70、TLFRM, 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

71、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 int

72、o MTLFRM, computation time was significantly reduced. The dynam</p><p>　　(3) National Steel</p><p>　　In North America there is a cooperative research program between the automakers and sheet met

73、al suppliers, called " he Auto-Steel Partnership" National Steel decided to use FEM simulation to have common technical bases with the automakers, and introduces LS-DYNA3D and FASTFORM3D in 1996. These codes ar

74、e extensively used in customer support activities, such as the tubular hydro forming and the forming of tailor welded blanks.</p><p>　　(4) US Steel</p><p>　　US Steel also has close collaboration

75、 with automakers through cooperative activities such as the Auto-Steel Partnership and "he spring back project"[3-6]. Evaluation of service property of steel sheet is an important subject. For example, the dent