




已阅读5页,还剩1页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
/TextileResearchJournal/content/68/9/630Theonlineversionofthisarticlecanbefoundat:DOI:10.1177/004051759806800902199868:630TextileResearchJournalYoujiangWangandHuiSunComputerAidedAnalysisofLoomBeating-upMechanismsPublishedby:canbefoundat:TextileResearchJournalAdditionalservicesandinformationfor/cgi/alertsEmailAlerts:/subscriptionsSubscriptions:/journalsReprints.navReprints:/journalsPermissions.navPermissions:/content/68/9/630.refs.htmlCitations:WhatisThis?-Sep1,1998VersionofRDownloadedfrom630ComputerAidedAnalysisofLoomBeating-upMechanismsYOUJIANGWANGANDHUISUNSchoolofTextile&FiberEngineering,GeorgiaInstituteofTechnology,Atlanta,Georgia30332,U.S.A.ABSTRACTAnalysisanddesignofthebeating-upmechanismisofgreatimportanceforim-provingloomperformance.Computeraideddesignandanalysistoolsareusedtostudydifferentkindsofbeating-upmechanisms,includingthe4-linkand6-linksystems,andtheircharacteristicsarecomparedwiththoseoftheconjugate-cammechanism.Resultsfrommodelswithvaryinggeometricparametersarepresented,revealingthatthecom-putertoolsareeffectiveandusefulinanalyzinganddesigningbeating-upmechanismswithsmootheroperation,lowernoiseandvibration,andhigherspeeds.Thelastdecadehaswitnessedthetransformationof,thetextileindustryfromalaborintensiveoneintoahighproductivity,capitalintensiveindustry.Inmanu-facturingwovenfabrics,thereisaconstantdesireforhighperformanceloomsthatarefast,energyefficient,reliable,highlyautomated,quiet,durable,andlowmaintenance.Overthelastfewdecades,theproductionrateofloomshasincreasedtremendously,withmaxi-mumweftinsertionratesmovingfromabout200.towellover2000m/min.Suchasignificantimprovementinperformanceisaresultoftechnologicalinnovations(e.g.,shuttlelessweaving),employmentofnewtech-nologies(e.R.,computersandmaterials),andbettermachinerydesigns.Regardlessofthekindofloom,itstechnologicalstate,orthepatterntobewoven,thebasicweavingoperationsconsistsoffoursteps:shedding,picking,beating-up,andtaking-up/letting-off2J.Theshed-.dingoperationraisesandlowersspecificwarpyarnsbymeansofharnessestoformashed.Duringthepickingstep,thenewfillingyamisinsertedthroughtheshed.Beating-upoccurswhenthenewlyinsertedfillingyarnispushedfirmlyinplacebymeansofthereedmountedonthesley.Finally,thefinishedfabriciswoundonthe;clothbeam.whilemorewarpyarnisreleasedfromthe:warpbeam.Thesefouroperationsareperformedina.constantlyrepeatedsequence.Beating-upisofgreatimportancetotheweavingprocessandthequalityoftheproduct.Anormalbeat-ing-upoperationwillgiveafirm,uniformfabricstruc-ture.Inaddition,themovementofthereedcarriedbythesley,throughwhichbeating-upisachieved,hasanimportanteffectonthe.smoothnessofsheddingandpickingoperations.Inhighspeedweaving,therelativetimepercycletakenbyoperationsotherthanpickingshouldbeminimized.Itisdesirablethatthereeddwell;aslongaspossibleatthereartoleavemoretimeforweftinsertion,andthenmoveswittlytobeatupthenewfillingyarn.Thisisespeciallycrucialformodernwide-widthlooms.However,higherforcesandvibra-tionsareassociatedwithjerkymovements,anddesigncompromiseisnecessarytoachieveabalancebetweenloomspeedandsmoothoperation.Dynamicanalysisofthemotionofthesley(reed)isthereforeimportantforloomdesignersandmanufacturers.Ingeneral,therearethreebasickindsofbeating-upmechanisms:4-link.6-link,andconjugate-carn,asshowninFigure1.The4-linkmechanismisusedmostwidelyonshuttle,air-jet,andrapierlooms.sinceithasasimplestructureandiseasytomanufacture.The6-linkmechanism,whichmayprovidealongerdwellpe-riod,ismainlyusedinair-jetlooms.Theconjugate-cammechanismisbeingusedmoreandmorewidelyinshuttlelessloomsduetoitspreciseandadjustabledwellperiodofthesley.Thedesignofbeating-upmechanism;,particularlytheirmassdistributionandgeometry,hasasignificanteffectontheperformanceoftheloom.Traditionalmethodsforanalyzingthesemechanismsbasedonki-nematicanddynamicprinciplesarewellestablished,butofteninvolvelengthymathematicalderivations.Computeraideddesignandanalysistoolsprovideasimplerwayofanalyzingthedynamicresponsesofcomplexstructures.WorkingModel,asoftwareproductofKnowledgeRevolution,Ibinesadvancedmotionsim-ulationtechnologywithsophisticatededitingabilitiestoprovideausefultoolforengineeringandanimationsimulation.Amechanismcanbeconvertedintoasetofrigidbodiesandconstraintstobuildthemodelonthecomputer.ThissoftwaresimulatesthemotionofthemechanismbasedongeometricconstraintsandNewtonianmechanics.principles.QDownloadedfrom631FIGURE1.Typicalbeating-upmechanisms:(a)4-link,(b)6-J.ink.and(c)conjugate-camulatingprocessforfurtheranalysis.Thepropertiesofobjectscanbeadjustedwithitsgraphicuserinterfacetoformnewmodelswithdesirableresults.Inthisstudy,wefirstanalyzethe4-linkmechanismusingtheWorkingModelsoftware.Aparametricstudyexplorestheeffectofgeometryonthesleysmotion.Wealsobuildmodelsforthe6-linkmechanismtoiden-tifygeometricconfigurationsthatcanleadtoalonginsertionperiodinaweavingcycle.Finally,wecom-parethesleysmotionfordifferentbeating-upmech-anisms.Beating-upMechanismsFOUR-LINKMECHANISMFigure2showsthecomputermodelobtaineddafterimplementingallpartsofa4-linkmechanismwithWorkingModel,accordingtotheactualsize;mass,andconnectiontype.Quantitiesmeasuredandrecordedduringthesimulationincludethedisplacementofthesley(X),thevelocityofsley(V),theaccelerationofsley(A),andtheforce(F)actingontheswordpin.TovalidateWorkingModel,wehavecomparedtheresultsfromtheWorkingModelsimulationandkinematicsanalysisandfoundnonoticeabledifferences.Forparametricstudies,wehaveusedtheactualdi-mensionsofmachinepartsinashuttleloom(FigureIa)-crankshaftlengthr=6cm,connectingrodlengths=32cm,andsleylengthL=72.11cm.Thisgeometricconfigurationisthereferencefortheperfor-mancecomparisonwithothermodels.Wehaveas-sumedthattheloomspeedis200rpm.Toobservetheinfluenceofdifferentratiosofslronthemotionofthesley,theconnectingrodlengthvariesfrom17to102cm,whilerandLarekeptconstant.Wehaveevaluatedelevemmodelswiths/rratiosfrom2.83to17.FIGURE2.Computermodelof4-linkbeating-upmechanism.FromtheWorkingModelsimulationdata,wehaveobtainedthemaximumvaluesofsleyvelocityV,ac-celerationA,andtheforceintheconnectingrodF,foreachmodel.TheresultsareshowninFigure3,nor-malizedwithrespecttothereferencemodel.Becauses/rvariesfrom2to8,themaximumvaluesofV,A.andFdecreasesignificantly.However.thereislittlechangeinVmax,Amj,andFmaxasslrincreasesfurther.Toensuresmoothfillingyaminsertionthroughtheshed,theshedshouldbekeptlargeenoughduringthefillingtraverse.TDownloadedfrom632FIGURE3.Effectofgeometricra-tio.s/ronsleysmotioncharacter-istics.sitionofthesley.Duringaweavingcycle,thefillingyamcanonlybeinsertedwhenthesleystayscloseto.;thebackwardpositionandtheshedopeningissuffi-cient.Thus,forfastloomoperation,thesleyshouldstaybackwardmostofthetimeforfillinginsertion,andthenmoverapidlyforbeating-up.Theexactrangeofsleypositionsallowingfillinginsertiondependsontheparticulardesignofaloom.Inthisanalysis,wehaveassumedthatthefillinginsertioniscompletedduringtheperiodwhenthesleyisinthe&dquo;backzone&dquo;betweenitsoriginal(mostbackward)positionandone-halfof.itsmaximumdisplacement(Figure4).Thecorre-:.spondingperiodisreferedtoastheinsertionperiod.Fromthesimulationdataonthedisplacementofthe.sley.,weseethatthesleyreachesonehalfitsmaximum.displacementatdifferentdegreesofthecrankrotation,dependingonthegeometryofthe4-linkmechanism,.assummarizedinTableI.Withincreaseds/r,thesleystaysnearitsmostbackwardpositionforashorterFIGURE4.Effectofgeometricratiosironthedisplacementprofileofthesley.TABLE1.Insertionperiodsfordifferent4-linkmodels.amountoftime,leavinglesstimeforthefillingtobeinsertedacrosstheloom.Nomatterwhatmechanismisdiscussed,alowerAmaxindicatesasmoothermovementandahigherA,leadstoajerkyaction.Foraloominparticular,themove-mentofthesleyaffectstheefficiencyofbeating-up.Fordifferentfabrics,however,differentactionsofbeat-ing-uparedesired2.Afine,delicate
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 农业产业集群农业产业链金融产品创新与风险控制研究报告
- 2024年河北省石家庄康福外国语学校九上化学期末复习检测试题含解析
- 2024-2025学年河北省石家庄桥西区九上化学期末达标检测模拟试题含解析
- 河南省郑州市外国语中学2024-2025学年九上化学期末检测模拟试题含解析
- 浙江省绍兴市越城区五校联考2024年九年级化学第一学期期末教学质量检测试题含解析
- 2024-2025学年江苏省苏州工业园区七校联考七上数学期末经典模拟试题含解析
- 陕西中医药大学《现代发育生物学》2023-2024学年第一学期期末试卷
- 滇西应用技术大学《医学科研设计与论文写作》2023-2024学年第一学期期末试卷
- 云端漫步云端飞车创新创业项目商业计划书
- 产品细节高清拍摄服务行业深度调研及发展项目商业计划书
- JJF 1255-2010 厚度表校准规范-(高清现行)
- 2022年混凝土搅拌站建设项目可行性研究报告
- 《觉醒年代》朗诵稿
- 2022年社会学概论考试重点广东海洋
- 路基工程质量通病及防治措施
- 福建省中小学教师职务考评登记表
- 咖啡文化PPT课件:咖啡配方及制作方法步骤
- 北京市中级专业技术资格评审申报表
- 工厂供电课程设计1
- 鼠害虫害防治管理制度
- PLM_项目建议书_PTC
评论
0/150
提交评论