工科研究生毕业答辩-英文版ppt课件

.,CharacterizationofRoadTopographyandEffectsofSolidParticlesonWetAdhesionPropertiesofTread,Reporter:Tutor:Professor,路面形貌表征及固体颗粒对轮胎湿附着性能的影响,汇报人:导师:教授,TheSourceofProject,TheNationalNaturalScienceFunds“Thestudyoftheeffectsofsolidparticlesonhydroplaningpropertiesoftireonwetroad(Grantnumber:50908222),Content,Chapter1:IntroductionChapter2:Thestudyofthree-dimensionalcharacterizationofroadtopographyChapter3:Thestudyofhydroplaningmodeloftire/roadChapter4:TheeffectsofsolidparticlesonwetadhesionpropertiesofthetireChapter5:Summaryandoutlook,Introduction,Whenacarrunningontheroughroad,thefrictionbetweenthetireandtheroadtransfersavarietyofinteractionforcesbetweenthevehicleandtheroad.Oncetheroadsurfaceiscoveredbywaterfilmwhichgeneratesdynamicallubricationonthecarrunningatahighspeed,thewetadhesionpropertiesoftirewilldecrease,andfinallyhydroplaningphenomenonwillhappen,whichgreatlyreducethestabilityandsafetyofthecar.Therefore,theresearchabouttheskidresistanceoftire/roadisofgreatpracticalsignification.,Hydroplaning,Rainwaterflow,Waterfilmgeneratesdynamicallubricationonthecarrunningatahighspeed,thetireflowedup,contactareareduced,thewetadhesionpropertiesoftiredecreased.,Introduction,Microandmacrotextureofasphaltpavement,Roadistheexternalconditionsofvehicles,directlyaffectsthetrafficsafety,comfortandeconomy.Roadmorphologyisgenerallyexpressedasthetextureofthepavementinthefieldofhighwayresearch.Themicroandmacrotexturesofroadsurfacesignificantlyaffectthetire/roadskidresistance.,Introduction,Adoptappropriatesurfacemorphologyoftestingmethodsandequipment,accuratelygettheroadmorphologyinformation,andusesurfacemorphologyparameterstofullycharacterizetheroadsurfacemorphologywhichisnotonlybeneficialtothefunctionaldesignoftheroad,butalsoprovideanimportanttheoreticalbasistothedesignoftire/roadskidresistance.,Thecharacterizationofroadsurfacetopographyandtheeffectsofsolidparticlesonwetadhesionpropertiesoftreadwerestudiedinthispaper.,Researchstatus,Theearlyresearchonhydroplaningandskidresistanceoftirewasmostlybasedontest,toaboutthe1960s,analyticalmethodsappeared.Representatives:Daughaday、Browne、Zmindar、Ongandsoon.,Roadmorphologyplaysanimportantroleinroadskidresistance.Itsessentialtoselectappropriatesurfacemorphologycharacterizationparametersandmethods.Commonmethods:benchmarkparametermethod,fractalmethod,motifsmethodandwaveletanalysismethod.Newmethods:ISO25178parameters,volumeparametersandconnectivityparameter.,Workofthispaper,Inthestudyofthree-dimensionalcharacterizationofroadsurfacetopography,theATOSopticalscannerwasusedtoscantheroadsurfacetopographyinordertoobtaintheoriginalinformationandthenrelatedprocessingwascarriedout.ThecharacterizationparametersofsurfacetopographywhichincludeISO25178parametersandconnectivityparameterswereusedtocharacterizethethree-dimensionaltopographyofroad.Bycontrollingtheroadsurfaceroughnessequallyaseriesofsimulatedroadsurfaceswhichincludehorizontalslot,doubleslot,chute,doublechuteandisotropicslotwereconstructedtoanalyzetheeffectsofgroovetypeandsamplingintervalonthecharacterizationparametersofroadsurfacequantitatively.Theperformanceoftheslidingandwearoftheroadwasalsoanalyzedindepth.,Inthestudyoftheeffectsofsolidparticlesonwetadhesionpropertiesoftread,theeffectsofvolumeconcentrationofsolidparticlesinrainwaterwerefullyconsidered,ahydroplaningmodelbasedonaverageflowequationwasdevelopedtosimulateviscoushydroplaningoftire/tread,andtheaffectsofhydrodynamicactionandsqueezeactionwerealsotakenintoaccount.Thismodelcouldbeusedtoanalyzetheeffectsofsolidparticles,externalloads,initialheightandslidingspeedonwetadhesionperformanceoftirewithnumericaliterativesolutionsofFiniteDifferenceMethod.Meanwhile,verticaldeformationandpressuredistributionofthetreadunitalsowereanalyzedindepth.,Workofthispaper,Thestudyofthree-dimensionalcharacterizationofroadtopography,1,Collectionandprocessingofroadtopographyinformation,Flowchartofcollectionandprocessingofroadtopographyinformation,Restorediagramofroadmorphology,Modulusdiagramofroadblock,ATOSopticalscanner,Collectionandprocessingofroadtopographyinformation,2，Simulationconstructofgroovedpavement,Horizontalslot,Doubleslot,Thestudyofthree-dimensionalcharacterizationofroadtopography,Chute,Doublechute,Isotropicslot,Simulationconstructofgroovedpavement,3，CharacterizationofroadtopographybyISO25178parameters,ISO25178parameterforthecharacterizationofsurfacemorphologyisthelateststandarddevelopedbytheInternationalOrganizationforStandardization(ISO):ISO/TSCD25178-2-2006.,Heightparameters：Sa、Sq、Sp、Sv、Sz、Sku、Sskandsoon；Spatialparameters：Sds、Str、Std、Salandsoon；Volumeparameters：Vmp、Vvv、Vmc、Vvcandsoon；Comprehensiveparameters：Sdr、Sdqandsoon.,Thethree-dimensionalcharacterizationofparametervaluesofroadmorphologycanbeobtainedAccordingtothedefinitionofISO25178parametersandrelatedmatlabprogram.,Thestudyofthree-dimensionalcharacterizationofroadtopography,Theactualroad,CharacterizationofroadtopographybyISO25178parameters,Theroughnessofordinarycementroadisabout1.8mm.,ISO25178parameterstableofgroovedroad,Diagramofheightparameters-samplinginterval,CharacterizationofroadtopographybyISO25178parameters,Diagramofvolumeparameters-samplinginterval,Diagramofheightparameters-roadroughness,DiagramofVmp-roadroughness,CharacterizationofroadtopographybyISO25178parameters,DiagramofVmc-roadroughness,CharacterizationofroadtopographybyISO25178parameters,DiagramofVvv-roadroughness,DiagramofVvc-roadroughness,4，Characterizationofroadtopographybyconnectivity,Theroadconnectivitytablewhensamplingintervalof0.5mm,DiagramofE-samplinginterval,Thestudyofthree-dimensionalcharacterizationofroadtopography,TheroadconnectivitytablewhenSa=1.8mm,DiagramofE-roadroughness,Characterizationofroadtopographybyconnectivity,Horizontalslot,Doubleslot,Chute,Doublechute,Isotropicslot,Actualroad,Thestudyofhydroplaningmodeloftire/road,Physicalmodeloftire/road,Accordingtothehydrodynamiclubricationtheory,ahydroplaningmodeloftire/roadbasedontheaverageflowequationwasdevelopedtosimulateviscoushydroplaningoftiretread,takingintoaccounttheaffectsofhydrodynamicactionandsqueezeaction.Themodelprovidedatheoreticalbasisforthenextstepofthenumericalsolutionandsimulationanalysis.,Theaverageflowequationis,Combinethefollowingformula,Verticaldeformationformula：,Loadbalanceequation：,Asperitiesbearingequation：,Acompletemathematicalmodeloftire/loadhydroplaningcouldbeconstructed,andthusthenumericalanalysisofvariousfactorsonthewetadhesionpropertiesoftirewereconductedaswellasstressanddeformationdistribution.,Thestudyofhydroplaningmodeloftire/road,Theeffectsofsolidparticlesonwetadhesionpropertiesofthetire,Duetothepresenceofabrasive,sand,dustandotherimpurities,thewaterfilmontheroadwillinevitablycontainalargenumberofsolidparticles,whichchangetheviscosity,temperatureoftheliquidandotherphysicalcharacteristics.,AssumingthatthewaterviscosityisaffectedonlybysolidparticlesinthemodelEstablished,andtheEinsteinformulaisexpressedas,Where0isthebasicviscosityoftheliquidandcisthevolumeconcentrationofsolidparticles.,1,IntroductionofSolidparticles,2，Numericalcalculationprocess,Flowchartofcalculatingprogram,Theeffectsofsolidparticlesonwetadhesionpropertiesofthetire,3，Analysisofwetadhesionpropertiesoftread,Variationoffilmthicknessatdifferentconcentrationofsolidparticles,Theeffectsofsolidparticlesonwetadhesionpropertiesofthetire,（a）F=5N,（b）F=15N,Variationoffilmthicknessatdifferentconcentrationofsolidparticlesanddifferentload,Analysisofwetadhesionpropertiesoftread,Variationoffilmthicknessatdifferentwedgeangle,Variationoffilmthicknessatdifferentroughness,Analysisofwetadhesionpropertiesoftread,Variationoffilmthicknessatdifferentslidingvelocity,Variationoffilmthicknessatdifferentinitialheight,Analysisofwetadhesionpropertiesoftread,4，Analysisofverticaldeformationoftread,（a）t=0.001ms,(b)t=0.4ms,Verticaldeformationcurveoftreadatdifferenttimes,Theeffectsofsolidparticlesonwetadhesionpropertiesofthetire,Verticaldeformationcurveoftreadatdifferentconcentrationofsolidparticles,Verticaldeformationcurveoftreadatdifferentloads,Analysisofverticaldeformationoftread,5，Analysisofpressureoftread,（a）t=0.001ms,(b)t=0.4ms,Liquidpressureatdifferenttimes,Theeffectsofsolidparticlesonwetadhesionpropertiesofthetire,Liquidpressureatdifferentconcentrationofsolidparticles,Analysisofpressureoftread,Liquidpressureatdifferentloads,Summaryandoutlook,ThecharacterizationparametersofsurfacetopographywhichincludeISO25178parametersandconnectivityparameterswereusedtocharacterizethethree-dimensionaltopographyofroad.A