外文翻譯--計算機輔助分析和設(shè)計金屬板料成形過程（節(jié)選）

1、<p><b>　　中文3125字</b></p><p><b>　　畢業(yè)設(shè)計外文翻譯</b></p><p>　　文獻名稱 計算機輔助分析和設(shè)計金屬板料成形過程 </p><p>　　第三部分：沖壓模具型面設(shè)計 </p>&

2、lt;p>　　學 院 機械工程學院 </p><p>　　專 業(yè) 機械工程及自動化 </p><p>　　班 級 </p><p>　　學 號 </p><p>　　姓 名

3、 </p><p>　　Technical report</p><p>　　Computer aided analysis and design of sheet metal forming processes:</p><p>　　Part III: Stamping die-face design</p>&l

4、t;p><b>　　M. Firat*</b></p><p>　　Department of Mechanical Engineering, The University of Sakarya, Adapazari, Turkey</p><p>　　Received 8 September 2005; accepted 31 January 2006<

5、/p><p>　　Available online 23 March 2006</p><p><b>　　Abstract</b></p><p>　　The finite element simulations of a sheet metal forming process help the methods and tooling engin

6、eer designing the forming interface for a stamping part by shifting the costly press shop try-outs to the computer aided design environment. The finite element models used in the sheet metal formability and stamping feas

7、ibility assessment studies are commonly based on the ideally rigid die-face design. This hypothesis is in general consistent with the present industrial experience even for large dra</p><p>　　Keywords: Sheet

8、 metal forming; Formability; Springback; Die design</p><p>　　1. Introduction</p><p>　　It is known that a crucial part of the production of a sheet metal stamping die is essentially the developme

9、nt of a die-face design aiming a tooling surface geometry that gives a fully developed blank shape a defect-free stamping form within the necessary quality constraints. The design of stamping tooling elements starts with

10、 the part geometry as the basic input data and the methods engineers try to determine the minimum number of operations for a given</p><p>　　stamping form in order to reduce the forming tooling costs while sa

11、tisfying the objective stamping criteria [1]. The methods engineer conducts various try-outs for the forming process design continuing up to the end of workshop try-outs until to the mass production phase of the stamping

12、 part. Since both the stamping die-face design and the plastic workability of the sheet metal determine the characteristics of blank deformations, additional care should be paid in the forming of high strength ste</p&

13、gt;<p>　　In this paper, following a short review of the stamping die design practice; a computational methodology is presented for the assessment and control of die-face deforma-</p><p>　　tions during

14、 the sheet metal forming processes. The proposed approach is employed in the forming process design for a cab body member based on the computer aided design and analysis concepts given in Part I and in Part II of this st

15、udy. The die-face deformations are taken into account in the computer aided design of the process tooling. The part formability analysis and springback deformations are conducted including the tooling deformations.The re

16、lative differences between the ideally rigid and</p><p>　　2. Die-face design concepts</p><p>　　The die-face design for a sheet metal forming die may be defined as the composition of a complete s

17、urface geometry that deforms a sheet metal blank plastically into a desired stamping shape by ensuring a rigid tooling construction. The design process starts with the part geometry as the basic input data, the methods e

18、ngineer firstly decides on the drawing direction by tipping the part to the most favorable axis, and eliminating the risk of an undercut. Then,using the material formability and min</p><p>　　and the amount o

19、f maximum stretching deformation, the maximum achievable drawing depth is estimated, and a set of drawbar and counter bar surfaces may be added to both punch and die in order to minimize the deformation gradient during t

20、he initial stage of the forming process.After deciding on the press operation type, the binder geometry is generated using a set of flat or developable surfaces, and usually integrating with the draw-bead and con-tra-bea

21、d elements in order to restraint the materia</p><p>　　After the creation of punch and binder interface, their geometric counterparts are developed usually by offsetting the surfaces with a clearance amount t

22、hat is typically a few percent larger than the sheet metal thickness using the CAD software. At this stage using the allowable thinning of the part, the amount of stretch, and the blank size estimate may be done</p>

23、;<p>　　using the volume constancy assumption.Once the methods engineer has createda entire geometric description of the blank and die faces in a CAD environment, the finite element analyses may be performed in ord

24、er to investigate the process feasibility in terms of the form-</p><p>　　ability, part geometry after springback and forming loads byassuming an ideally rigid die construction [6,7]. The finite element simul

25、ation of the stamping process is done usually</p><p>　　in two steps. A forming analysis is conducted to determine the metal deformation for a given punch and binder loading and, secondly, the springback defo

26、rmations following the removal of the tooling is computed with the forming stress distribution and the deformed geometry from the forming step as the inputs along with material thickness distributions [8]. Depending on t

27、he relative qualities of the process and material parameters, several virtual try-outs may be</p><p>　　necessary in order to reach the optimum tooling geometry and forming elements. At this point, the formin

28、g loads and the type of draw action is determined in accordance with the available press line specifications. Finally, the complete stamping tooling surface is approved and submitted to the draw die construction and manu

29、facturing department. In the automotive industries, the design and construction practice of stamping dies is adopted according to the sheet metal type and draw action in accord</p><p>　　rialselection forthed

30、ieelements includingthedetailedspec. </p><p>　　ificationofcastingandheattreatmentprocedures.Usingthe developed die-face design as the starting dimensions for the punch,upperandlow

31、erbinderelements,theguidelinesgiven</p><p>　　in the in-house standard are employed in the dimensioning and integration of the major structural elements, such as the lower and upper die adaptor plates, punch

32、and binder castings,guidepostandbushingsandwearplates.Additionally,byselectingpresstoolaction,thebolster–ramgeometry and punch stroke completely define the forming die con-</p><p>　　struction[4,10].Theuseofa

33、CADsystematthisphaseallowsthe design engineer to build a virtual prototype of the upper andlowerhalvesoftheformingdieusinganumberofgeom- etry parameters such as the inner ram shut height and the geometry of the adaptor p

34、late, punch and binder wall thicknessorpositionofblankholderbalanceblocks.Anumberofpositionanalysesofthepunch,dieandblankholderelements duringacompleteformingcycleareconductedtocontrolthe interference and overlap to elim

35、inate any inconsistency between the</p><p>　　3. The die-face shape control</p><p>　　The sheet metal forming process is a compound system made up of the stamping die and the blank, and involves13

36、12 M. Firat / Materials and Design 28 (2007) 1311–1320 a set of mechanical interactions with the press and the foun dation structure that provide the necessary forming energy [4,5,10,11]. Assuming an ideally rigid die co

37、nstruction connected to the ram and bolster plates of an ideally rigid pressand neglecting all die-face distortions help the methodsengineer designing the forming process</p><p>　　these mechanical systems in

38、 a computational model that is intended to simulate the sheet metal deformation response during the forming process. It is therefore the most practical approach to isolate the forming interface, i.e., the die-face design

39、 and the blank, from the remaining, and to model the blank deformations under the forming forces generated during the frictional contact with the purely geometric description of the die-face design. Moreover, this propos

40、i- tion has found widespread use </p><p>　　binder elements increasing the wear and distortion of guideposts. In these cases the deformations of the production tooling should be included in the computational

41、modeling</p><p>　　of the forming process. </p><p>　　Presently, building a computer model in order to simulate the complete process system is achievable considering the advancements in computer h

42、ardware and finite element software, nonetheless it is hardly feasible from an industrial perspective due to the high computer analysis times. Instead a rather simple but a practical engineering approach may be the decou

43、pling the stamping system in to the process-only part composed of the blank plus the die-face design and tooling-only part containing comp</p><p>　　based on the individual characteristics of the deformations

44、 experienced during a complete pressing-cycle, respectively. Considering process-only part, there are time-dependent interactions of the sheet metal blank and the forming inter- face bringing about large changes in the b

45、lank shape when compared with the scale of die-face distortions. Consequently, the process-only part should be simulated using afinite element formulation based on large-strain and finite incremental deformation theory d

46、u</p><p>　　Entities and the blank as an elastic–plastic deforming body, and the time-dependent displacement-driven binder and punch motion realize the forming process. The major out-</p><p>　　pu

47、ts are deformed geometry and production stress distribu- tions of the blank after springback and the forming load histories as well as the frictional contact stress distributions over the die-face elements. On the other

48、side, for the tooling-only part, the forming load histories are the basic input for the assessment of the die-face deformation analysis. The finite element analysis of the complete draw-die design for a given press cycle

49、 provides the displacements of dieface material points, an</p><p>　　材料與設(shè)計28 (2007) 1311–1320</p><p><b>　　科技報告篇</b></p><p>　　計算機輔助分析和設(shè)計金屬板料成形過程：</p><p>　　第三部

50、分：沖壓模具型面設(shè)計</p><p><b>　　作者：Firat</b></p><p>　　土耳其 莎卡里亞 啊達鉑扎勒大學機械工程學院</p><p>　　2005年9月8日接到，2006年1月31號接受</p><p>　　于2006年三月23號正式啟用</p><p><b>

51、　　摘要</b></p><p>　　用有限元的方法來模擬分析金屬板料沖壓成形過程能有效的幫助設(shè)計工程師在理論教學和實踐加工方面把沖壓件從昂貴的車間加工轉(zhuǎn)移到計算機輔助的設(shè)計環(huán)境來。有限元模型中使用的金屬薄板成形性和沖壓可行性評估研究通常是基于理想模型設(shè)計。這個假設(shè)是基于一般符合目前的工業(yè)生產(chǎn)經(jīng)驗甚至對于常用的鋼也能用于拉延模來分析。然而，對于中等厚度的高強度鋼形成的情況不一定可行因為高壓負荷所需的坯

52、料形狀仍然未知。因此，在成型過程中的模面變形的預測是必不可少的，根據(jù)估測值來判斷它可變形行的可能性以及回彈性，并且需要結(jié)合以前的生產(chǎn)實例緊密分析一般沖壓鍛模的設(shè)計程序。在這一部分的研究當中，從沖壓模具和模具型面的金屬板成型過程的結(jié)構(gòu)評估中就能夠得到一套工程學上的研究理論。利用計算機輔助分析和設(shè)計的概念在先前的第一部分和第二部分已經(jīng)給出介紹，該方法可以使得自動沖壓件和完整的模具結(jié)構(gòu)在設(shè)計界面中形成。結(jié)果表明該模具型面的相對優(yōu)點是容易鍛造成

53、型和回彈性好。</p><p>　　關(guān)鍵詞：金屬板材成形；成形；回彈；模具設(shè)計</p><p><b>　　1.介紹</b></p><p>　　眾所周知鈑金沖壓模具生產(chǎn)的一個重要組成部分是關(guān)于模面設(shè)計模具表面幾何形狀在必要的質(zhì)量約束下做出一個無缺陷的沖壓毛呸件的發(fā)展。設(shè)計沖壓模具的基本要素是開始以零件幾何作為基本的輸入數(shù)據(jù)和方法，工程師試圖確

54、定對于給定的操作的最小數(shù)量以沖壓形式來降低成形模具成本同時滿足目標的沖壓標準[1] 。該方法工程師用于成形工藝設(shè)計直到車間試驗結(jié)束，持續(xù)至沖壓部件進入批量生產(chǎn)階段為止。由兩個沖壓模面設(shè)計和金屬板的塑性加工性確定毛坯變形的特性，另外需要注意應保證高強度鋼的成形，以適應較低的成形性和較高的回彈變形[2]。在用在計算機輔助設(shè)計和分析模具試出階段可以進行的生產(chǎn)線的模擬并可靠地在計算機生成的虛擬設(shè)計環(huán)境，這樣的方法和模具設(shè)計需要采用有限元法是基

55、于仿真的優(yōu)點的并且可以預測模具的成形性，如裂紋，皺紋或過度變薄，涉及到的模面設(shè)計為給定的沖壓特點。這也是可以實現(xiàn)的微調(diào)操作，回彈變形后得到最終零件的幾何形狀。此工程方法假定在繪制過程中的模面的變形可以忽略不計并且工業(yè)實踐證明這一假設(shè)的有效性，即使大的內(nèi)板拉伸模具中的常規(guī)拉伸高品質(zhì)鋼[3]的情況也都一樣。作為一個理想的剛性拉伸模具結(jié)構(gòu)的概念，然而，當涉及到中等</p><p><b>　　2，模面的設(shè)計理

56、念</b></p><p>　　模面設(shè)計的板金成型用模具可以被定義為一個具有完整的表面幾何形狀和塑性變形的片狀金屬坯料成所需的組合物以確保剛性模具結(jié)構(gòu)沖壓形狀。設(shè)計一開始是以部件的幾何形狀為基本輸入數(shù)據(jù)，該方法工程師首先通過確定主軸再繪制出其余部分，同時也消除了一定的風險。然后，使用該材料的成形性和最小允許厚度，確定拉伸變形的量，并且估計出能夠拉伸的數(shù)量。設(shè)計人員利用CAD輔助環(huán)境將金屬板的圓角的尖銳

57、邊緣和凸緣部分偏移一定的厚度，用于沖壓成型。利用該材料的性能進行最大程度的拉伸變形時，估計可以達到最大的拉伸深度，通過一套牽引裝置安裝在沖裁面進行沖壓，盡量在模具成形的初始階段減少變形梯度。在決定操作類型之后，使用一組平面或者延生曲面通過與拉伸所結(jié)合，通常結(jié)合拉延筋把物質(zhì)約束在一個可以控制的方式上進行沖壓。創(chuàng)建沖頭和粘結(jié)劑界面后，它們的幾何同行被抵消表面通常開發(fā)具有間隙量，得出的結(jié)果比使用CAD軟件的金屬板厚度大百分之幾。在該階段使用該

58、部分的容許變薄拉伸，完全符合其預算大小使用量恒定的假設(shè)。</p><p>　　一旦工程師創(chuàng)造了一整個幾何空白的描述和方法在CAD環(huán)境里面，有限元分析可以為研究零件的成形工藝性的提供可行性分析，部分幾何回彈和成形載荷后分為一個理想的剛性模具結(jié)構(gòu)。有限沖壓過程的有限元仿真通常是在兩個步驟。進行成型性分析，確定金屬變形為一個給定的沖壓和粘合劑加載和，其次，回彈變形后對模具的去除應力而形成的力和幾何變形的形成步驟隨著材料

59、厚度的變化而分析[ 8 ]。根據(jù)工藝相對素質(zhì)和材料參數(shù)，可以設(shè)置多個虛擬測試為了達到最佳的模具幾何的構(gòu)成要素。在這一點上，成形載荷和動作類型是根據(jù)與現(xiàn)有的沖壓生產(chǎn)線的規(guī)格擬定的。最后，完整的沖壓模具表面被批準并報繪制模具結(jié)構(gòu)送往制造部。</p><p><b>　　3.模面形狀控制</b></p><p>　　金屬板材成形過程是由一個復雜系統(tǒng)控制沖壓模具和板料的變形，

60、并涉及到M.Firat/《材料與設(shè)計》28（2007）1311至1320一組材料和基礎(chǔ)機械相互作用的結(jié)果，機構(gòu)提供必要的成形力[4,5,10,11]。假設(shè)一個理想的剛性模具結(jié)構(gòu)連接加強了理想的剛性壓機板而忽略所有的模面變形面的輔助方法，工程師設(shè)計時只遵循純粹的形成過程幾何建模而不結(jié)合具體材料分析則會不符合要求。否則，它將是一個巨大的工程，包括所有的這些機械系統(tǒng)中的計算模型，該模型旨在模擬鈑金變形影響及采用相應的處理方式。因此，它最接近實

61、用，分離出形成界面，即在模面設(shè)計，從剩余空白處進行建模產(chǎn)生下形成勢力的空白變形在與純幾何的摩擦接觸的模面設(shè)計的描述。此外，這種生產(chǎn)理論已經(jīng)在行業(yè)中得到廣泛使用，即使大內(nèi)板拉伸模具在常規(guī)片的情況下都可以實施。一個理想的剛性平局，模具結(jié)構(gòu)的概念，不過，有可能成為可疑的，當涉及到所述的高強度鋼形成，由于較高的成形負荷需要。此外，一個所產(chǎn)生的大型結(jié)構(gòu)件與非對稱成形配置工件，可設(shè)計顯著高負荷的的平衡塊和上沖頭之間的耐磨板粘合劑元件增加的辦法， 磨

62、損和變形。在這些情況下，模具生產(chǎn)的變形應被包括在計算機建模成形</p><p>　　目前，建立的計算機模型，用來模擬完整過程的系統(tǒng)是可實現(xiàn)的，利用計算機硬件和有限元的先進軟件，不過它是從工業(yè)的角度來看幾乎不可行的由于電腦的分析使之成為可能。用軟件模型代替一個相對復雜的，實際的工程方法可以是在沖壓系統(tǒng)中分析的過程，只有一部分的坯件加含有完整拉伸模具設(shè)計的模面設(shè)計和模具僅部分構(gòu)成的基礎(chǔ)上，在一個特征的成型過程中由一個

63、完整的壓制循環(huán)體系分別變形?？紤]到過程的一部分，有金屬板的與時間有關(guān)的相互作用空并形成界面帶來大的變化，在空白形面上，應與模面扭曲變形進行比較。因此，這個過程部分應使用基于大變形和有限的增量變形理論的有限元計算，由數(shù)模變形的運動學特性仿真制造。另一方面，變形小的部分采用特征變大來表示變形拉伸量。把整體縮放為單個成形元素。因此，對于拉伸模結(jié)構(gòu)的小應變彈塑性有限元分析也是合適的。</p><p>　　兩者的計算方面的

64、相互作用可以用一個適當?shù)臄?shù)據(jù)傳輸例程來定義（圖1）。這個過程只是一部分，成形過程的模擬采用從模面設(shè)計為剛性曲面實體和空白面為彈性塑料變形體的幾何信息，并隨時間變化的驅(qū)動的粘合劑和沖壓成形過程的運動實現(xiàn)。主要輸出是幾何變形和回彈載荷是生產(chǎn)成型后的在毛坯上的應力分布以及分布在模面元素上摩擦接觸應力。另一方面，只有部分的模具，運用成形載荷的大小對模面變形進行分析和評價。對于一個給定的模具的位移，能夠完成拉延模設(shè)計的有限元分析，和更新模面設(shè)計，