轮胎有限元分析之材料测试.docx

轮胎有限元分析之材料测试.docx

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轮胎有限元分析之材料测试

MaterialTestforFEA

Content

1、Elastomer（hyperelastic）Characterization2

1.1TypicalDenseElastomerExperiments2

1.2SpecimenPreparation6

1.3ElastomerTestingServices6

2PlasticCharacterization7

2.1TypicalPlasticExperiments:

8

2.2PlasticSpecimenPreparation12

3ElastomericSponge（foam）Characterization13

3.1Introduction13

3.2TypicalFoamElastomerExperiments:

13

4FabricTesting16

4.1Introduction16

4.2TypicalPlasticExperiments:

16

5WireTesting17

6DurabilityandCrackGrowthTesting18

6.1Introduction18

6.2TearandCrackGrowthExperiments:

18

7FrictionMeasurements20

7.1Introduction20

7.2TypicalPlasticExperiments:

20

8HighStrainRateExperiments21

8.1Introduction22

8.2TypicalHighStrainRateExperiments:

22

9LongTermCreepandStressRelaxationTests24

9.2Experiments:

25

10ThermalPropertiesMeasurements26

10.1Introduction26

10.2Thissectionisdividedintosectionsasfollows:

26

11VibrationandViscoelasticExperiments27

11.1Introduction27

11.2Thissectionisdividedintosectionsasfollows:

27

基于有限元分析的关于高分子材料的基础实验情况全简介

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1、Elastomer（hyperelastic）Characterization

Introduction:

Theanalysisofelastomersinfiniteelementanalysisoftenrequiretheuseofhyperelasticmaterialmodels.Thesemodelsrequirethatmaterialspecimensofthesubjectmaterialbestretchedandstress-straindatacollected.Mosthyperelasticmodelsperformbetterifmultiplestatesofstrainarerepresented.Elastomersshouldbecharacterizedatthetemperatureoftheapplication.

MultipleStrainStates

Thereare3strainstateswhichareparticularlyusefulincharacterizingdenseelastomers.Theyaresimpletension,pureshearandequalbiaxialextension.Iftheelastomerisconfinedinitsapplicationandthecompressiblenatureoftheelastomerisaconcern,avolumetriccompressionexperiment（bulkmodulus）mayalsobeadvisable.Thissectionisdividedintoexperimentalsectionsasfollows:

1.1TypicalDenseElastomerExperiments

◆SimpleTension

◆PureShear

◆EqualBiaxialExtension

◆VolumetricCompression

◆SimpleCompression

◆ElastomerSpecimenPreparation

1.1.1SimpleTension

Simpletensionexperimentsareverypopularforelastomers.Thereareseveralstandardsforthetestingofelastomersintension.However,theexperimentalrequirementsforanalysisaresomewhatdifferentthanmoststandardizedtestmethods.Themostsignificantrequirementisthatinordertoachieveastateofpuretensilestrain,thespecimenmustbemuchlongerinthedirectionofstretchingthaninthewidthandthicknessdimensions.Theobjectiveistocreateanexperimentwherethereisnolateralconstrainttospecimenthinning.

SimpleTensionTestSpecimenOutline

SimpleTensionTestinanEnvironmentalChamberFittedwithOpticalGlassforusewithaLaserExtensometer

1.1.2PlanarTension（PureShear）

Thepureshearexperimentusedforanalysisisnotwhatmostofuswouldexpect.Theexperimentappearsatfirstglancetobenothingmorethanaverywidetensiletest.However,becausethematerialisnearlyincompressible,astateofpureshearexistsinthespecimenata45degreeangletothestretchingdirection.Themostsignificantaspectofthespecimenisthatitismuchshorterinthedirectionofstretchingthanthewidth.Theobjectiveistocreateanexperimentwherethespecimenisperfectlyconstrainedinthelateraldirectionsuchthatallspecimenthinningoccursinthethicknessdirection.

PlanarTensionTestSpecimenOutline

PlanarTension（PureShear）withLaserExtensometer

1.1.3EqualBiaxialExtension

Forincompressibleornearlyincompressiblematerials,equalbiaxialextensionofaspecimencreatesastateofstrainequivalenttopurecompression.thoughtheactualexperimentismorecomplexthanthesimplecompressionexperiment,apurestateofstraincanbeachievedwhichwillresultinamoreaccuratematerialmodel.

EqualBiaxialTestSpecimen

EqualBiaxialExtensionExperiment

1.1.4VolumetricCompression（BulkModulus）

Volumetriccompressionisanexperimentwherethecompressibilityofthematerialisexamined.Inthisexperiment,acylindricalspecimenisconstrainedinafixtureandcompressed.Theactualdisplacementduringcompressionisverysmallandgreatcaremustbetakentomeasureonlythespecimencomplianceandnotthestiffnessoftheinstrumentitself.Theinitialslopeoftheresultingstress-strainfunctionisthebulkmodulus.Thisvalueistypically2-3ordersofmagnitudegreaterthantheshearmodulusfordenseelastomers.

VolumetricCompressionExperiment

1.1.5SimpleCompression

Thecompressionexperimentisalsoapopulartestforelastomers.Whentestingforanalysis,purestatesofstrainaredesiredandthisisespeciallydifficulttoachieveexperimentallyincompressionfordensematerials.However,forfoammaterials,theerrorduetofrictionbetweenthespecimenandplatenisnotassignificant.

SimpleCompressionTest

1.2SpecimenPreparation

Materialtestingexperimentsonelastomerstypicallyrequiresheetsofelastomerfromwhichtestspecimensarediecut.Ifelastomersheetsaren'tavailable,sometimessheetscanbeskivedfromthickerslabsoractualparts.

SpecimenShapesStampedfromSheets

BandknifeSlicingSystemtoCreateRubberSheetsFromBulkPieces

1.3ElastomerTestingServices

Theobjectiveofthetestingservicesistodefinethebasicmaterialpropertiesofelastomericmaterials.

1.3.1.BasicHyperelasticProperties

3simpletensionspecimens,3planartensionspecimensand3equalbiaxialspecimensarecutfromtheprovidedslabs.Orforfoammaterials,3simpletensionspecimens,3simpleshearspecimensand3simplecompressionspecimensarecutfromprovidedslabs.Thespecimensareloadedslowlybetweenzeroforceandauserdefinedstretchlevelfor5loadingsandunloadingsatupto4maximumstrainlevelssoastoexaminetheinitialstressstrainbehaviorandthe“stabilized”stressstrainbehaviorateachofthemaximumstrainconditions.（5slabs,150mmby150mmby1.0to2.0mmthickarerequiredforeachtemperaturecondition）

1.3.2ShortTermStressRelaxationProperties

Stressandtimedataiscollectedcontinuouslyatasinglesetstrainlevelfor2000seconds.3specimensaretested.Simpletension,planartension,compressionorequalbiaxialspecimensmaybeused.Thistestcanbeexpandedtoincludemultiplestrainlevels,andmultipletypesofspecimen.Assuch,itmayreplacethebasichyperelasticpropertiesplusstandardshort-termrelaxationpropertiestestsinsomematerialmodels.（Twostandard150mmby150mmby1.0to2.0mmthicktestslabsofthematerialisrequiredforeachtemperatureorstraincondition,ineitherastandardoranexpandedshort-termstressrelaxationtest）.

1.3.3.VolumetricCompression

AspecimenisfullyconstrainedandcompressedforthepurposeofdeterminingtheBulkModulusofthematerial.6.35mmdiameterdisksarecutfromstandardslabsandstacked.TheinitialslopeofthiscurveistheBulkModulus.

1.3.3.Friction

Tomeasuretheaforementionedproportionallyfactororcoefficientoffriction,a50mmby100mmsledwithonematerialisdraggedagainstalargersecondmaterial.Rubberandplasticmaterialsmaybesensitivetothenormalpressurebetweenthesurfaces.Thenormalpressureismodifiedbyrestingweightsonthesled.

RequiredMaterials:

◆Materialsheetsorplaquesgreaterthan50mmx150mmforthesled.

◆Materialsgreaterthan100mmx500mmforthebase.

1.3.4.StaticTearing

Thestatictearingexperimentisameaningfulwaytoexaminethefailureofanelastomerintearing.Asharpcutisintroducedintoaplanartensionspecimenandthespecimenisstretcheduntilfailure.Failurestress,failurestrainandtotaltearingenergyarereported.

1.3.5.ThermalProperties

Thermalconductivity,thermaldiffusivityandspecificheataredeterminedusingthetransientplanesourcemethod（HotDisk™）.Onestandard150mmby150mmtestslab（morethan1mmthick）ofthematerialisrequiredforeachtemperaturecondition.

ThermalexpansionisdeterminedbyexaminingthedimensionalchangeinamaterialspecimenastemperaturechangesusingaPerkin-ElmerDiamondTMAinstrument.

2PlasticCharacterization

Introduction

Thephysicaltestingofplasticmaterialsforthepurposeofdefiningmaterialconstitutivemodelsinfiniteelementanalysiscanbeverysimpleorincrediblycomplexdependingontheobjectiveoftheanalysis.Linearanalysisofstructuralpartsisroutinelyperformedusingonlyacouplesimpleparameters.Morecomplexanalysismayinvolveelevatedtemperatures,severeplasticdeformationandstrainratesensitivityrequiringcustomizedmaterialmodeldevelopmentandrigorousexperimentation.

PlasticTensileTestData

Thereareafewexperimentsthatareparticularlyusefulincharacterizingplasticsforanalysis.TheyaresimpletensionwithtransversestrainmeasurementforelasticityandPoisson'sratiodetermination,simpleloadandunloadexperimenttoseparatetheplasticandelasticstraincomponentsandthermalexpansionasafunctionoftemperature.Severaloftheseexperimentsareoutlinedbelow.

2.1TypicalPlasticExperiments:

◆TensileTest

◆TensileTestwithTransverseStrainMeasurement

◆LoadingandUnloadingExperiments

◆ShortTermCreepExperiment

◆ShearTest

◆PlasticFilmExperiment

◆Compression

⏹PlasticSpecimenPreparation

2.1.1TensileTest

Thetensiletestisperformedbystrainingaplasticspecimeninonedirectionsuchthatthesidesifthespecimenarefreetocontract.Theregionofinterestisthenarrowedsectionwherethedesiredstateofstrainisachieved.Basicparametersderivedfromatensile