汽车工程专业外文翻译--传统车身与现代车身设计方法.pdf

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1、外文原文Traditional car body and modern car body design methodTraditional car body and modern car body design method1 1、Traditional car body design methodTraditional car body design methodThe autocar car body shape is one of the three greatest fractions that areparalleled with bedrock and engine in the

2、autocar structure,its development andcapacity preparation cycle is the longest,and the preparation work of chart paper andcraft is the biggest,and it is usually still need to remodel,unlike bedrock and engineattain which is easy to reach serialization and generalization.The characteristics of car bo

3、dy structure lies on the constitution of car bodyshape of each null parties be big for size more but shape complicated space curvedface(namely so-called person type overlay piece),these space curved faces can not beused ordinary machinery drawing method will it the complete earths surface appear,as

4、a result have to create stereoscopic pattern as basis.For making these chart paperand change a type tangibly express shape and structure of car body,need to pass acomplicated design process to complete.In the traditional car body design,the design information and the data of carbody deliver mainly b

5、y two-dimensional chart paper and principal mode type,thereare many design fraction of persons hand work.The defects that traditional designmethod can not overcome embody at as follows a few aspects:1、The manpower resource consume greatly.The traditional car body designs atapping requirement the art

6、 designing personnel,engineering the technical personneland its operative make a concerted effort,such as the creation and conservancy,molding tool of the two-dimensional engineering chart(the plot of car body graph),soil pattern design,production,grind togo together with and adjust to try,capacityp

7、repare medium process planning etc.s will expend a person quantitative manpowerand resource.2、Designing accuracy is low,the cycle is long.Accuracy low and main reasonslying in the information of each link that designs with born reserve to deliver is a kindof“move a shape,For example from lord drafti

8、on board manufacture principal modeXing,is carried on by the principal mode type to process craft supplement,productioncraft pattern,from convex of the craft pattern turn over into concave craft pattern,again is depended by the craft pattern anti to process trimming die,after the convert ofthese lin

9、ks,raw datas the error of various factitiousness unavoidable,cause themolding tool accuracy of processings canning not assure,only depend next move ofthe hand work grind to go together with to clinch.3、Car body already set over speedy and the incapability carry on proceedtogether design.Traditional

10、car bodys designing is basically a kind of one-way antireversible design status,product once already set,modification or remodel verydifficult,the universal turns,the series turn a degree low.In addition,the car body of the modern autocar null parts because of therequirement of structure and beauty,

11、the space curved face gradually complicates,traditional design method F very difficult satisfy design request.2 2、Modern car body design methodModern car body design methodAs design and modification of autocar car body shape request graduallyincreasing higher requirements,the parameter designment ma

12、tch more and comecloser to the conceptual design in modern CAD and proceed together design thought,and can develop the flexibility of design and analysis,therefore the parameter of thecar body craft shape design have already become a inevitable trend of vehicleproduction.The traditional hand work sh

13、ape method has already been replaced byComputer aided modeling method which is base on various of advanced modelingsoft wares,Parametric design technology can quickly absorb the foreign autocar carbody designs of advanced technique,quickly respond to a market,upgrading thecapability of independence

14、design and improving autocar product competitive powerin our country.Since 70s in last century,along with the increasing development ofcomputer aided geometric design and Computer graphics,the car body designsprocess mid for decide or the whole distances lead into calculator supporting system(CAD/CA

15、M software),the garbage sets up car body 3D digitize pattern,with”hat yousee is what you get of alternate mode the perfect design scheme is the main featuresof modern car body design method.The basic process is following:Afterinvestigating the market,forming a car type of whole request;Manufactureha

16、nd-drawing effect chart,also available calculator assistance the software draw;Thecreation shrinks ratio and principal mode type;Set up car body figure pattern by themode garbage of three coordinates scanning or laser scanning;Carry on a structuredesign,set up A class pattern;Born NC code produces a

17、 kind car.Draw an effect chartstep,can hand work plot also the available calculator assistance software plot,concrete according to personal condition of designer and then settle,but use calculatorplot can fasterly set up a car body figure pattern and make to modify an operate moreconvenient.But the

18、use hand work plot rework make to shrink scale model with 1:a,again scan by three coordinateness or the laser scan of the mode garbage set up carbody figure pattern,this is inner common use kind of method,because manufacturepattern in this way can even keep the style principle that the view earths s

19、urfacereaches to a designer.This is actually a process of contrary design.In a brief,thecontrary engineering is to point the product pattern conversion that will have beenalready had to design in the process and apply very extensively in the car body for theprocess of the pattern of digitize enginee

20、ring design in the calculator,equal hence 1kind make copy and have to develop a cycle short,designing the accuracy beinghigher and easy to progress structure designing/analyzing waiting merit.The famous soft wares,such as CATIA,IMAGEWARE and UG etc provided thestrong reversal the design function.The

21、 car body figure pattern cans share aftercreating and is advantageous to each segment realize to proceed together an operateand thus and consumedly shorten to design a cycle,and used for various CAD/CAMsystems of car bodydesign all according to3D solid pattern auto borntwo-dimensional car body chart

22、 paper and used for number to control the code oftransform,at the same time when the 3D pattern takes place arbitrarily minusculetransform,the systems will of oneself modify with of related chart the paper andnumber control a code.Use a far-ranging calculator to lend support to softwarecurrently CAT

23、IA is the most famous,it is a CAD/CAM/CAE software that is reachedSuo company and IBM by France to unite tapping,and the function is extremelystrong.CATIA provides to have perfect CLASSA(A class curved face,thisdenomination also from reach Suo to propose first)to set up function.CLASS the Acurved fa

24、ce is in a brief a car body shape,instrument board,inside decoration pieceetc.higher to curved face quality requirements type of curved face of parts,namelyand only agreeable requests higher type of curved face,since wanting a surface issmooth and links to transfer smooth satisfy aerodynamics princi

25、ple with thesignificant decrease air resistance,and then want to reserve the beauty of shape.Herepoint of A class curved face optics follow the sexual notion can in brief define frommathematics for:curve two ranks are several what continuous,have no redundancy toturn a dot,curvature change balance,t

26、he strain energy is smaller.Is a G2 at leastsequential(curvature continuous)to curved face,also namely two curved faces followpublic tie line to be placed in all directions to have common law curvature.Whileputtingtogetherconnecting,carbodyshapedifferentcurvedfaceslabscontinuousness have smooth requ

27、est to transfer,satisfy G2 at least,even G3continuous.The CLASS A curved face describes with the B kind method,the nodalpoint vector adopts tired the long parameter applying string turn a law;In the U,curved faces V direction last time count at 3-7 times of,the maximum was 9 times nobigger than.In t

28、he actual design can from as follows a few aspects to evaluate A classcurved face mass:the continuity,curved face whole cooperativeness,curved face ofthe inner mass,curved face of the design accuracy,curved face of curved face satisfycar body structure the design and car body make a request.Positive

29、 because garbageenergy such convenience,efficiently sets up CLASS A curved face,it just lets carbody solid the shape is accurate day by day and quick,design a personnel constructmore Be approached to reality,curved face mass higher car body 3D pattern.Garbagenot only can vs.car body external appeara

30、nce and inside decoration create figurepattern,and can vs.engine,bedrock etc.other null parts create pattern,and directlycarry on a limited kyat analysis,structure design/analysis,even conjecture assemblyand virtual air opening test etc.,making to design a personnel can set up virtualelectron kind w

31、ith the garbage car and carry on trial,can in advance discover theexistent question in the design before physically producing,raised an efficiency,lowered cost.Usually each kit pattern sort is depositing in a large data bank,hereaftercan go direct to match in the data bank while improving vs.the car

32、 type similar of nullparts,modify its related parameter then meet demand,have never needed to re-design,be advantageous to the series of car type to turn very much,produce company shouldto quick change of the capability of the market Be also strong to get poly.3 3、Domestic and international search p

33、resent conditionDomestic and international search present conditionCompare bigger autocar companies to widespread adopt the two-dimensionaldesign of CAD system progress car body in the world,like the generalarrangement(person machine engineering)of car body,inside the curved facestructure of the out

34、side overlay piece design,null parts structure and assembly design,molding tool design,and automatically born related design technique document.CAM/CAE is to apply to the CIMS technique also very universal.Each big autocarmanufacturing companies all own their huge car body tapping of oneself troops,

35、anddont hesitate to throw in the laboratory that the mint capital create a forerunner,develop or usher in the technical software progress car body design.Designing applied more earth of realm in the car body can the software mainlyhas the United States Auto studio of the ALIAS Company,CATIA of subsi

36、diaryDaussault of IBM Company,PRO/Engineer etc.of the UG of EDS Company,parameter Technique Company.These soft wares all belong to in general use machinedesign software and have stronger curved face design,parameter to turn designedcapacity or mix to design function,and can favor the machinery manuf

37、acturing wholeprocesses,then design a modelengineering analysis the transform make,someeven can better backing car body design of first step,namely conceptualdesign(Concept Design)step(is like Auto studio),and put together with model tiethrough a certain way it,design plane the convert as two-dimens

38、ional pattern.The local calculator is used for an autocar design to begin from 70s.The longspring vapor grinds agreeable procedure car body exclusive use function of the curvedface optics developed board,created its car body graphics used in design library,developed the autocar car body surface shap

39、e and structure design process system,thesystem had to draw car body soil draftion board and car body part drawing andprovide transform principal mode type NC data,manufacture the capability of soilpattern.The autocar motorcycle manufacturing company in Peking develops theBJA-BSM car body CAD system

40、,successfully is applied to BJ124,the BJ125 waitsthe car type of various new car type operate.Shanghai G.M.and Shanghai togetherhelped together Jie science and technology limited company etc.to design to developflow process to carry on to a little bit thoroughly study vs.the car body and forming amo

41、re perfect car body tapping procedure.But still exist a lot of problems that needsettle urgently in the aspects of clicking a data handling,curved face surface opticsbeing agreeable,mathematical models converting process waiting.Is a lot of local wina small autocar business because of the restrictio

42、n of capital,equipment and personnel,can not carry on the search and application of comparing the system to the car bodydesign method,or only apply some one realm,applied get maximum of also just makevs.the product partial or little yellow of change.中文译文中文译文传统车身与现代车身设计方法传统车身与现代车身设计方法1、传统车身设计方法汽车车身外形

43、是汽车结构中与底盘和发动机并列的三大部分之一，其开发和生产准备周期最长，图纸及工艺准备的工作量最人，并且还经常要改型，不像底盘和发动机那样容易做到系列化、通用化。车身结构的特点在于组成车身外形的各个零部件多为尺寸大而形状复杂的空间曲面(即所谓人型覆盖件)，这些空间曲面无法用一般的机械制图方法将其完整地表现出来，因而不得不建立立体模型作为依据。为了使这些图纸和换型能够确切地表现出车身的形状和结构，需要通过一套复杂的设计程序来完成。在传统车身设计方法中，车身的设计信息和数据的传递主要是靠二维图纸和主模型，人的手工设计部分较多。传统设计方法无法克服的缺点土要体现在以下几个方面：1、人力物力消耗大。传

44、统的车身设计开发需要美工人员、工程技术人员及其工人通力合作，如二维工程图(车身曲线图的绘制)、土模型的制作和保存、模具设计、制造、研配和调试、生产准备中的工艺设计等都将耗费人量的人力和物力。2、设计精度低、周期长。精度低的主要原因在于设计和生成准备的各个环节之间信息传递是一种“移形”，例如由主图板制作主模刑，由主模型进行加工工艺补充，制造工艺模型，由凸的工艺模型翻成凹的工艺模型，再由工艺模型反靠加工冲模，原始数据经过这些环节的转换，各种人为的误差就在所难免，导致加工出的模具精度无法保证，只有靠下一步的手工研配来解决。3、车身定型过早且不能进行并行设计。传统车身设计基本上是一种单向不可逆设计状态

45、，产品一旦定型，修改或改型非常困难，通用化、系列化程度低。此外，现代汽车的车身零部件由于结构和美观的需要，空间曲面日趋复杂化，传统的设计方法己很难满足设计要求。传统的车身设计方法的流程可用图 1.1 来表示。2、现代车身设计方法随着汽车车身造型的设计与修改要求日趋增高，参数化设计更符合和贴近现代 CAD中的概念设计和并行设计思想，并可提高设计与分析的柔性，因此车身模型的参数化设计已经成为车辆制造行业发展的必然趋势。目前传统的手工造型方法已被建立在各种先进的造型建模软件基础上的计算机辅助造型方法所取代，参数化设计技术能够快速吸收国外汽车车身设计的先进技术，快速响应市场，提高我国自主设计开发汽车的

46、能力，提高汽车产品竞争能力。上世纪 70 年代以来，随着计算机辅助几何设计和计算机图形学的迅速发展，车身设计过程中部分或全程引入计算机辅助系统(CAD/CAM软件)，在计算机中构建车身三维数字化模型，以“所见即所得的”交互方式完善设计方案，是现代车身设计方法的主要特点。其基本流程：经过市场调研，形成车型的整体要求；制作手绘效果图，也可利用计算机辅助软件绘制；制作缩比例及主模型；以三坐标扫描或激光扫描的方式在计算机中构建车身数字模型；进行结构设计，构建 A 级模型；生成 NC 代码，生产样车。在绘制效果图阶段，可手工绘制也可利用计算机辅助软件绘制，具体根据设计师个人情况而定，但使用计算机绘制可更

47、快捷地构建车身数字模型并使修改工作更方便。而使用手工绘制再制作缩比例模型和1:1主模型，再以三坐标扫描或激光扫描的方式在计算机中构建车身数字模型，这是更常用的一种方法，因为以这种方式制作模型更能直观地表达出设计师的风格理念。这实际上就是一个逆向设计的过程。简单地说，逆向工程就是指将已有的产品模型转化为计算机中的数字化工程设计模型的过程，相当于是一种仿制，具有开发周期短、设计精度较高、便于进行结构设计/分析等优点，在车身设计过程中应用很广泛。著名的 C A T I A、IMAGEWARE、UG 等软件都提供了强大的逆向设计功能。车身数字模型建立后可共享，有利于各部门实现并行工作，从而大大缩短设计

48、周期，而且用于车身设计的各种 CAD/CAM系统都能够根据三维实体模型自动生成二维的车身图纸和用于数控加工的代码，同时当三维模型发生任意微小的改变时,系统都会自动地修改与之相关的图纸和数控代码。目前使用广泛的计算机辅助软件以 CATIA 最著名，它是由法国达索公司与IBM 联合开发的一套CAD/CAM/CAE 软件，功能极为强大。CATIA提供有完善的 CLASSA（A 级曲面，此名称也是由达索首先提出）构建功能。CLASS A 曲面，简单地说就是指车身外形、仪表板、内饰件等对曲面质量要求较高的一类部件的曲面，即光顺性要求较高的一类曲面，既要表面光滑、连接过渡光滑满足空气动力学原理以大幅减少空

49、气阻力，又要保留外形的美观。这里所指的 A 级曲面光顺性的概念从数学上可简单定义为:曲线二阶几何连续，没有多余拐点，曲率变化均匀，应变能较小。对曲面而言，至少是 G2 连续的（曲率连续），也即两曲面沿公共连接线处在所有方向都具有公共的法曲率。车身外形不同的曲面片在拼接时，要求光滑过渡，至少满足 G2 连续，甚至 G3 连续。CLASS A曲面是以 B 样条方法来描述，节点向量采用累加弦长参数化法；曲面在 U，V 方向上次数在 3 次到 7 次之间，最高不大于 9 次。实际设计中可从以下几个方面来评价 A 级曲面质量:曲面的设计精度、曲面的内部质量、曲面的连续性、曲面整体协调性、曲面满足车身结构

50、设计及车身制造要求。正因为在计算机中能如此方便、高效地构建 CLASS A 曲面，才让车身实体造型日益精确和迅速，设计人员能够构造出更逼近于现实、曲面质量更高的车身三维模型。在计算机中不但可以对车身外观及内饰建立数字模型，而且可以对发动机、底盘等其它零部件建立模型，并直接进行有限元分析、结构设计/分析、甚至虚拟装配、虚拟风洞试验等，使得设计人员可以在计算机中构建虚拟的电子样车并进行试验，能在实际生产前预先发现设计中存在的问题，提高了效率，降低了成本。通常各零件模型分类存放在大型数据库中，以后对车型做改进时可直接到数据库中匹配类似的零部件，修改其相关参数即可满足要求，无需重新设计，非常有利于车型