轮轨相互作用的分析方法和轮轨外形的设计PPT课件

MethodsforAnalysisofWheel/RailInteractionandDesignofWheelandRailProfiles轮轨相互作用的分析方法和轮轨外形的设计,MichaelRoneyConsultantandretiredChiefEngineer,CanadianPacificWiththeassistanceofRobCaldwell,NationalResearchCouncilofCanada加拿大太平洋铁路公司的顾问和退休总工程师，加拿大国家研究委员会对罗布考德威尔援助,ChinaRailwayCorporationTECHNICALWORKSHOP中国铁路技术研讨会16October,2015,Agenda目录,ToolsfortheMeasurementofWheel/Railinteraction用于测量轮轨间相互作用的工具MethodstoAnalyzeWheel/RailInteraction轮轨相互作用的分析方法ProcessfortheDesignofWheelandRailProfiles车轮和钢轨外形的设计过程,SimpleDiagnostics简单诊断,VisualObservationofRCFonWheels车轮上RCF（滚动接触疲劳）的目测,Visualsaremoreeffectivewitharatingscaleandjobaid目测是一种更有效的评定量表和工作辅助,2,3,4,5,“As-ground”RailTemplatesvs.Standards“打磨”钢轨模板与标准,Templatesdesignedfor0.4mmgaugecornerrelief轨距角退让0.4mm的模板,Railsgroundtofittemplatewithin0.25mm与模板误差小于0.25mm的打磨后的钢轨,WheelGaugesandExamplesofStandards轮对内侧距和标准的例子,22mmmin.轮缘厚度最小22mm,38mmmax.轮缘高度最大38mm,3mmmax.中间磨耗最大3mm,ManualWheelorRailProfileMeasurementwithMiniProf手持式MiniProf的车轮或钢轨外形的测量,StrainGaugingofRailstoMeasureLateralandVerticalForcesbyAxle在钢轨上用应变仪测量由车轴产生的垂向力和水平力,Laser-basedwheelandrailprofilemeasurementsystemsdevelopaccurateprofileandwearmeasures基于激光的车轮和钢轨外形测量系统可以精准测量外形和磨损,AutomatedRailAssessmentTools自动化钢轨评估工具,UseofTribometertoAssessRailFrictionLevels使用摩擦试验机去评估钢轨黏滑程度,Agenda目录,ToolsfortheMeasurementofWheel/Railinteraction轮轨相互的作用的监测工具MethodstoAnalyzeWheel/RailInteraction轮轨相互作用的分析方法ProcessfortheDesignofWheelandRailProfiles车轮和钢轨外形的设计过程,HertzianContact赫兹接触,HertzianContact(1882)describesthepressures,stressesanddeformationsthatoccurwhencurvedelasticbodiesarebroughtintocontact.赫兹接触（1882）描述了当弯曲弹性体接触时发生的压力，应力和变形。“ContactPatches”tendtobeelliptical“接触斑”往往是椭圆形Thisyieldsparaboliccontactpressures这就产生抛物线型接触压力Undertherailsurface,thisyieldsatri-axialstressstate,lesssoascontactpatchnearstheedgeofrailandwheel.在轨面上会产生一个三轴向应力状态，较小的接触斑会靠近钢轨和车轮的边缘,HertzianContact赫兹接触,Thecontactstressesbetweentheaveragewheelandtherailprofiledesignsshouldnotexceed:磨耗车轮与设计的钢轨外形之间接触应力不应超过o1500MPaforsoft(280HB)rail对于软钢轨（280HB）为1500MPao1700MPaforintermediate(320HB)rail对于中等硬度钢轨（320HB）为1700MPao2000MPaforpremium(380HB)rail对于优质钢轨（380HB）为2000MPa,CreepForces蠕滑力,注解没有所谓的“静态”和“滚动”摩擦,15,蠕滑的概念结合刚体力学和弹性力学在滚动的条件下，牵引轮与钢轨接触之间会产生不同的应变滑动发生在接触斑的部分区域,Railpummellingsoftwarecalculateswherewheelswillcontactrailandatwhatcontactstresslevel轮轨接触软件计算车轮与钢轨的接触和接触应力水平,16,22个转向架（导向和跟随车轴）在图示不同的位置匹配钢轨时，可以显示钢轨损伤的位置和程度,PummellingistheCrossProductoftheContactStresstimestheFrequencyoftheContact匹配分析是指接触应力次数和接触频率之间的乘积,17,Contactstressxfrequencyofcontact=surfacefatiguepotential表面潜在的疲劳=接触应力*接触频率,RCFDevelopment:Shakedown滚动接触疲劳的发展：安定性,ReducedStress(e.g.wheel/railprofiles)减少应力(例如车轮/钢轨外形),IncreasedMatlStrength提高材料的硬度,ReducedTractionCoefficient(e.g.reducedfriction)减少切向力系数(例如：减少摩擦力),0,0,1,0,2,0,3,0,4,0,5,0,6,1,2,3,4,5,6,7,tractioncoefficientT/N切向力系数T/N,loadfactor负载系数,plasticShakedown塑形安定,elasticshakedown弹性安定,Elastic弹性,Ratchetting渐变,Subsurface亚表面,Surface表面,p0/ke,ContactStressAnalysisvs.ShakedownLimitDiagramestimatesrollingcontactfatiguedamage接触应力分析和安定性极限图，可以预估出滚动接触疲劳损伤,Wheel/RailConicityAnalysisChecksVehicleStability轮轨等效锥度的分析，检查车辆的稳定性,Analysisofwheelrollingradiusdifferencevs.lateralwheelsetmovement车轮滚动圆半径差与轮对横移量之间关系分析,RollingRadiusDifference滚动圆半径差,Notenough(Insufficient)不足的时候Poorsteering导向能力不足Flanging轮缘贴靠Wear磨耗Noise噪声Justenough刚刚好的时候Perfectsteering完美导向Freerolling自由滚动Toomuch(Excessive)太多（过度）Mildcurves轻度曲线Highlongitudinalforces大的纵向力Highconicityprofilesencouragewheel-hollowing高的轮缘锥度导致凹形车轮,Agenda目录,ToolsfortheMeasurementofWheel/Railinteraction轮轨相互的作用的监测工具MethodstoAnalyzeWheel/RailInteraction轮轨相互作用的分析方法ProcessfortheDesignofWheelandRailProfiles车轮和钢轨外形的设计过程,ProcessforWheelandRailProfileDesign轮轨外形的设计过程,1、Collectasampleofwornwheelprofilesthatapproximatelyrepresentsthedistributionofwornwheelshapesthatoperateovertherailwayorrouteinquestion.收集磨耗车轮外形的样本，以近似代表有问题的路线的磨耗轮形状分布。2、Collectasampleofwornrailprofilesthatapproximatelyrepresentsthedistributionofcurvatureontherailway/routeinquestion.收集磨耗钢轨外形的样本，近似代表了有问题的线路上不同曲线半径的分布。,25,ProcessforWheelandRailProfileDesign轮轨外形的设计过程,3、Documentthedamageseenontherails.记录钢轨上的损伤。4、Pummelthesewheelsontherails(cumulativedamagesimulations),toestablishbaselineperformanceandtoverifythatanydamageseenontherailsshowsupinthepummelingplots(validatesthemodel)轮轨匹配计算（累计损伤模拟），建立了基线性能，通过钢轨上显示的接触点并验证钢轨上的任何损伤。,26,ProcessforWheelandRailProfileDesign轮轨外形的设计过程,5.Therailprofileswouldbemodifiedtotakeloadawayfromanylocationwhereitisconcentratedandcausingdamage,andredistributeitovertherestoftherunningsurface.Theresultsofthesemodificationsneedtobecheckedbypummelingagainitisaniterativeprocess.修改钢轨的外形，使得负载远离那些应力集中和造成损害的任何位置，并将负载重新分配在钢轨表面的其余部分。这些修改后的外形，需要再次通过匹配检查.这是一个迭代过程。,27,ProcessforWheelandRailProfileDesign轮轨外形的设计过程,6.Foramildcurvehighrail(wheelsshiftedtowardshighrailbutmostwheelsnotflanging),alterthegaugecornerandcrowntoraisetheshoulderthisencouragessteering.Itisimportanttomanagecontactstresses,sothedesignshouldproduceconformalcontact.对于中等半径曲线的外轨（轮子移向外轨但是大多数的轮子不会发生轮缘贴靠），改变轨距角和轨冠来提高轨肩这是促进导向。这时应重点关注接触应力，因此设计会趋于共型接触。,28,ProcessforWheelandRailProfileDesign轮轨外形的设计过程,7.Forasharpcurvehighrail(wheelsflanging),weprovidereliefattheuppergaugecorner(andpossiblyshoulder)toproduceatwo-pointconformalcontact.IftherewasRCFattheselocationsbecausecontactstressesorsurfacetractionswerehigh,relievingthemwillreducethestresses.对于一个小半径曲线外轨（轮缘接触），我们避免上部的轨距角（轨肩）产生两点的共形接触。如果这些位置已有滚动接触疲劳，因为接触应力和表面切向力很高，磨削轨距角将减少压力。Ifthereliefrequiredtoreducethestressesseemsexcessive,itmaybethatthereareasignificantnumberofwheelswithanaggressiveflangeroot.Ifthetractionsaretoohigh,TOR-FMmaybeneeded.如果为减小应力所需的打磨量过大的话，可能使相当多数量的车轮在轮缘根部发生接触，如果切向力很大时，就需要轨顶摩擦控制。,29,ProcessforWheelandRailProfileDesign轮轨外形的设计过程,8.Iftherailway/routehasgoodlubrication,designofthehighrailprofilesshouldextendto60degreesgauge,toensurethatgrindingintroducesasmallamountofartificialwear如果铁路/线路具有良好的润滑，外轨设计外形应扩展到60度轨距角，以确保打磨时引入人为磨损。,30,ProcessforWheelandRailProfileDesign轮轨外形的设计过程,9、Fortangentrails(wetypicallydesigntwoprofiles),startwithameasuredtangentprofilethathasbeenobservedtoperformwell(noreportsofhunting,nosurfacedamage)andaltertheradiionrunningsurfacetoshiftthepummelingdistributionslightlytogaugesideofcentreandmodestlytofieldsideofcentre.Thepummelingdistributionsforthetwodesignsmustoverlapsomewhattoensurethatastressriserdoesnotdeveloponthewheeltreadbetweenthecontactbandsforthesetwodesigns.Multipletangentprofilesareusedtospreadwearacrossmoreofthewheeltread,todelaytheonsetofwheelhollowing.Iftherailway/routeinquestionhashighcurvedensity,asingletangentprofilemaybesufficient.直线钢轨（我们通常设计两个外形），首先用一个观察到状态良好的测量的直线外形，改变钢轨表面的半径，把匹配点的分布略微移动到中心偏轨距侧和中心侧适度的位置。两种设计的匹配分布点必须有一些重叠，以确保这两种设计的车轮踏面上的接触光带应力的没有更多的增加。多个直线钢轨外形可以使车轮踏面的磨耗更均匀，以延缓凹形车轮的形成。如果铁路/线路具有高密度的曲线路线，单一的钢轨外形就足够了。,31,ProcessforWheelandRailProfileDesign轮轨外形的设计过程,10.Lowraildesignsgenerallyrequirealargeenoughcrownradius(250mmiscommonforharderrails)toensurelowcontactstresseswithwheels.Fieldsidereliefcanbedesigned-intoaccountforhollowwheels/falseflangesiftherailwayhaslimitedcontroloverthewheelshapes,butexcessivefield-siderelieftodealwithahollowingproblemjustworsensthefalseflangeproblem.Thegaugecorneronlyneedsenoughrelieftoavoidcontactw