輪軌相互作用的分析方法和輪軌外形的設計

MethodsforAnalysisofWheel/RailInteractionandDesignofWheelandRailProfiles

輪軌相互作用的分析方法和輪軌外形的設計

1Agenda

目錄ToolsfortheMeasurementofWheel/Railinteraction用于測量輪軌間相互作用的工具MethodstoAnalyzeWheel/RailInteraction輪軌相互作用的分析方法ProcessfortheDesignofWheelandRailProfiles車輪和鋼軌外形的設計過程2SimpleDiagnostics

簡單診斷VisualObservationofRCFonWheels車輪上RCF〔滾動接觸疲勞〕的目測Visualsaremoreeffectivewitharatingscaleandjobaid

目測是一種更有效的評定量表和工作輔助2345“As-ground〞RailTemplatesvs.Standards

“打磨〞鋼軌模板與標準

Templatesdesignedfor0.4mmgaugecornerrelief軌距角退讓0.4mm的模板Railsgroundtofittemplatewithin0.25mm與模板誤差小于0.25mm的打磨后的鋼軌WheelGaugesandExamplesofStandards

輪對內側距和標準的例子

22mmmin.輪緣厚度最小22mm38mmmax.輪緣高度最大38mm3mmmax.中間磨耗最大3mmManualWheelorRailProfileMeasurementwithMiniProf

手持式MiniProf的車輪或鋼軌外形的測量

StrainGaugingofRailstoMeasureLateralandVerticalForcesbyAxle

在鋼軌上用應變儀測量由車軸產(chǎn)生的垂向力和水平力

Laser-basedwheelandrailprofilemeasurementsystemsdevelopaccurateprofileandwearmeasures

基于激光的車輪和鋼軌外形測量系統(tǒng)可以精準測量外形和磨損

AutomatedRailAssessmentTools

自動化鋼軌評估工具UseofTribometertoAssessRailFrictionLevels

使用摩擦試驗機去評估鋼軌黏滑程度

11Agenda

目錄ToolsfortheMeasurementofWheel/Railinteraction輪軌相互的作用的監(jiān)測工具MethodstoAnalyzeWheel/RailInteraction輪軌相互作用的分析方法ProcessfortheDesignofWheelandRailProfiles車輪和鋼軌外形的設計過程12HertzianContact

赫茲接觸HertzianContact(1882)describesthepressures,stressesanddeformationsthatoccurwhencurvedelasticbodiesarebroughtintocontact.赫茲接觸〔1882〕描述了當彎曲彈性體接觸時發(fā)生的壓力，應力和變形?！癈ontactPatches〞tendtobeelliptical“接觸斑〞往往是橢圓形Thisyieldsparaboliccontactpressures這就產(chǎn)生拋物線型接觸壓力Undertherailsurface,thisyieldsatri-axialstressstate,lesssoascontactpatchnearstheedgeofrailandwheel.在軌面上會產(chǎn)生一個三軸向應力狀態(tài)，較小的接觸斑會靠近鋼軌和車輪的邊緣PavgPo=3/2Pavg13HertzianContact

赫茲接觸Thecontactstressesbetweentheaveragewheelandtherailprofiledesignsshouldnotexceed:磨耗車輪與設計的鋼軌外形之間接觸應力不應超過o

1500MPaforsoft(280HB)rail對于軟鋼軌〔280HB〕為1500MPao

1700MPaforintermediate(320HB)rail對于中等硬度鋼軌〔320HB〕為1700MPao

2000MPaforpremium(380HB)rail對于優(yōu)質鋼軌〔380HB〕為2000MPa14CreepForces

蠕滑力注解沒有所謂的“靜態(tài)〞和“滾動〞摩擦蠕滑的概念結合剛體力學和彈性力學在滾動的條件下，牽引輪與鋼軌接觸之間會產(chǎn)生不同的應變滑動發(fā)生在接觸斑的局部區(qū)域15Railpummellingsoftwarecalculateswherewheelswillcontactrailandatwhatcontactstresslevel

輪軌接觸軟件計算車輪與鋼軌的接觸和接觸應力水平

22個轉向架〔導向和跟隨車軸〕在圖示不同的位置匹配鋼軌時，可以顯示鋼軌損傷的位置和程度

16PummellingistheCrossProductoftheContactStresstimestheFrequencyoftheContact

匹配分析是指接觸應力次數(shù)和接觸頻率之間的乘積

17Contactstressxfrequencyofcontact=surfacefatiguepotential

外表潛在的疲勞=接觸應力*接觸頻率

RCFDevelopment:Shakedown

滾動接觸疲勞的開展：安定性ReducedStress

(e.g.wheel/railprofiles)減少應力(例如車輪/鋼軌外形)IncreasedMat’lStrength提高材料的硬度ReducedTractionCoefficient

(e.g.reducedfriction)減少切向力系數(shù)(例如：減少摩擦力)00,10,20,30,40,50,61234567tractioncoefficientT/N切向力系數(shù)T/Nloadfactor負載系數(shù)plasticShakedown塑形安定elasticshakedown彈性安定Elastic彈性Ratchetting漸變Subsurface亞外表Surface外表p0/ke19ContactStressAnalysisvs.ShakedownLimitDiagramestimatesrollingcontactfatiguedamage

接觸應力分析和安定性極限圖，可以預估出滾動接觸疲勞損傷

Wheel/RailConicityAnalysisChecksVehicleStability

輪軌等效錐度的分析，檢查車輛的穩(wěn)定性Analysisofwheelrollingradiusdifferencevs.lateralwheelsetmovement

車輪滾動圓半徑差與輪對橫移量之間關系分析RollingRadiusDifference

滾動圓半徑差Notenough(Insufficient)缺乏的時候Poorsteering導向能力缺乏Flanging輪緣貼靠Wear磨耗Noise噪聲Justenough剛剛好的時候Perfectsteering完美導向Freerolling自由滾動Toomuch(Excessive)太多〔過度〕Mildcurves輕度曲線Highlongitudinalforces大的縱向力Highconicityprofilesencouragewheel-hollowing高的輪緣錐度導致凹形車輪Agenda

目錄ToolsfortheMeasurementofWheel/Railinteraction輪軌相互的作用的監(jiān)測工具MethodstoAnalyzeWheel/RailInteraction輪軌相互作用的分析方法ProcessfortheDesignofWheelandRailProfiles車輪和鋼軌外形的設計過程24ProcessforWheelandRailProfileDesign

輪軌外形的設計過程1、Collectasampleofwornwheelprofilesthatapproximatelyrepresentsthedistributionofwornwheelshapesthatoperateovertherailwayorrouteinquestion.收集磨耗車輪外形的樣本，以近似代表有問題的路線的磨耗輪形狀分布。2、Collectasampleofwornrailprofilesthatapproximatelyrepresentsthedistributionofcurvatureontherailway/routeinquestion.收集磨耗鋼軌外形的樣本，近似代表了有問題的線路上不同曲線半徑的分布。25ProcessforWheelandRailProfileDesign

輪軌外形的設計過程3、Documentthedamageseenontherails.記錄鋼軌上的損傷。4、Pummelthesewheelsontherails(cumulativedamagesimulations),toestablishbaselineperformanceandtoverifythatanydamageseenontherailsshowsupinthepummelingplots(validatesthemodel)輪軌匹配計算〔累計損傷模擬〕，建立了基線性能，通過鋼軌上顯示的接觸點并驗證鋼軌上的任何損傷。26ProcessforWheelandRailProfileDesign

輪軌外形的設計過程5.Therailprofileswouldbemodifiedtotakeloadawayfromanylocationwhereitisconcentratedandcausingdamage,andredistributeitovertherestoftherunningsurface.Theresultsofthesemodificationsneedtobecheckedbypummelingagain…itisaniterativeprocess.

修改鋼軌的外形，使得負載遠離那些應力集中和造成損害的任何位置，并將負載重新分配在鋼軌外表的其余局部。這些修改后的外形，需要再次通過匹配檢查...這是一個迭代過程。27ProcessforWheelandRailProfileDesign

輪軌外形的設計過程6.Foramildcurvehighrail(wheelsshiftedtowardshighrailbutmostwheelsnotflanging),alterthegaugecornerandcrowntoraisetheshoulder…thisencouragessteering.Itisimportanttomanagecontactstresses,sothedesignshouldproduceconformalcontact.對于中等半徑曲線的外軌〔輪子移向外軌但是大多數(shù)的輪子不會發(fā)生輪緣貼靠〕，改變軌距角和軌冠來提高軌肩…這是促進導向。這時應重點關注接觸應力，因此設計會趨于共型接觸。28ProcessforWheelandRailProfileDesign

輪軌外形的設計過程7.

Forasharpcurvehighrail(wheelsflanging),weprovidereliefattheuppergaugecorner(andpossiblyshoulder)toproduceatwo-pointconformalcontact.IftherewasRCFattheselocationsbecausecontactstressesorsurfacetractionswerehigh,relievingthemwillreducethestresses.對于一個小半徑曲線外軌〔輪緣接觸〕，我們防止上部的軌距角〔軌肩〕產(chǎn)生兩點的共形接觸。如果這些位置已有滾動接觸疲勞，因為接觸應力和外表切向力很高，磨削軌距角將減少壓力。Ifthereliefrequiredtoreducethestressesseemsexcessive,itmaybethatthereareasignificantnumberofwheelswithanaggressiveflangeroot.Ifthetractionsaretoohigh,TOR-FMmaybeneeded.如果為減小應力所需的打磨量過大的話，可能使相當多數(shù)量的車輪在輪緣根部發(fā)生接觸，如果切向力很大時，就需要軌頂摩擦控制。29ProcessforWheelandRailProfileDesign

輪軌外形的設計過程8.

Iftherailway/routehasgoodlubrication,designofthehighrailprofilesshouldextendto60degreesgauge,toensurethatgrindingintroducesasmallamountofartificialwear如果鐵路/線路具有良好的潤滑，外軌設計外形應擴展到60度軌距角，以確保打磨時引入人為磨損。

30ProcessforWheelandRailProfileDesign

輪軌外形的設計過程

9、Fortangentrails(wetypicallydesigntwoprofiles),startwithameasuredtangentprofilethathasbeenobservedtoperformwell(noreportsofhunting,nosurfacedamage)andaltertheradiionrunningsurfacetoshiftthepummelingdistributionslightlytogaugesideofcentreandmodestlytofieldsideofcentre.Thepummelingdistributionsforthetwodesignsmustoverlapsomewhattoensurethatastressriserdoesnotdeveloponthewheeltreadbetweenthecontactbandsforthesetwodesigns.Multipletangentprofilesareusedtospreadwearacrossmoreofthewheeltread,todelaytheonsetofwheelhollowing.Iftherailway/routeinquestionhashighcurvedensity,asingletangentprofilemaybesufficient.直線鋼軌〔我們通常設計兩個外形〕，首先用一個觀察到狀態(tài)良好的測量的直線外形，改變鋼軌外表的半徑，把匹配點的分布略微移動到中心偏軌距側和中心側適度的位置。兩種設計的匹配分布點必須有一些重疊，以確保這兩種設計的車輪踏面上的接觸光帶應力的沒有更多的增加。多個直線鋼軌外形可以使車輪踏面的磨耗更均勻，以延緩凹形車輪的形成。如果鐵路/線路具有高密度的曲線路線，單一的鋼軌外形就足夠了。

31ProcessforWheelandRailProfileDesign

輪軌外形的設計過程10.Lowraildesignsgenerallyrequirealargeenoughcrownradius(250mmiscommonforharderrails)toensurelowcontactstresseswithwheels.Fieldsidereliefcanbedesigned-intoaccountforhollowwheels/falseflangesiftherailwayhaslimitedcontroloverthewheelshapes,butexcessivefield-siderelieftodealwithahollowingproblemjustworsensthefalseflangeproblem.Thegaugecorneronlyneedsenoughrelief