Mechanical behavior of particulate systems : experiments and modeling

221 Pages·2003·8.2 MB·English

by  Genovese, Claudia V

MECHANICALBEHAVIOROFPARTICULATESYSTEMS:
EXPERIMENTSANDMODELING
By
CLAUDIAV.GENOVESE
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT
OFTHEREQUIREMENTSFORTHEDEGREEOF
DOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
2003
Copyright2003
by
ClaudiaV.Genovese
ACKNOWLEDGMENTS
Iamprofoundlygratefultomyadvisor,Dr.RayBucklin,andmyco-advisor.Dr.
OanaCazacu,forscientificguidance,materialsupportandendlesspatience. Ialsowould
liketothankDr.NicolaieCristescuforhiscontinuoushelp. IextendmygratitudetoDr.
MuratBalabanandDr.ArthurTeixeirawhowereverykindtoadvisemeandguideme
duringthefirstyearinthiscountryandnowfortakingthetimetoreadthisdissertation
andtomakecommentsonit.
IexpressmygratitudetoDr.RalucaRoseaforherhelpandadviceinthe
numericalsimulations. Ialsothankthefollowing:theEngineeringResearchCenterfor
fundingthisproject;theERCfaculty;andtheAgriculturalandBiologicalEngineering
Departmentandstafffortheirassistance.
Iamthankfulfortheloveandsupportofmyhusband,familyandfriends.
iii
1
TABLEOFCONTENTS
1 page
ACKNOWLEDGMENTS iii
LISTOFTABLES vii
LISTOFFIGURES viii
ABSTRACT xiv
CHAPTER
INTRODUCTION 1
2 BACKGROUND 4
2.1Introduction 4
2.2LiteratureReview 5
2.3ConstitutiveModels 1
2.3.1ThevonMisesandDrucker-PragerModels 12
2.3.2Cam-clayModel 14
2.3.3CapModel 16
2.3.4LadeModel(1977) 19
2.3.5AdvantagesandShortcomingsoftheExistingModels 22
3 SHEARCELLTESTERS 25
3.1Introduction 25
3.2DirectShearTesters 25
3.2.1TheJenikeShearTester 27
3.2.2TestProtocolandDataReduction 27
3.2.3OtherTestingDevices 31
3.3IndirectShearTester 33
3.3.1UniaxialCompression 33
3.3.2BiaxialCompressionTester 39
3.3.3TriaxialCompressionTester 41
4 EXPERIMENTALSTUDYOFTHEQUASI-STATICDEFORMATIONOFDRY
SILICAPOWDER 43
4.1Introduction 43
4.2MethodologyandExperimetnalSetup 44
4.2.1Background 45
4.2.2TestingProcedure 45
4.2.3SystemunderStudy 47
4.3ResultsofMonotonicDeviatoricTestsonSilica 48
4.4ResultsonCyclicDeviatoricTests 56
4.5ModelingtheBehaviorintheElasticRegime 60
4.6ModelingtheObservedIrreversibilityinBehaviorusingElastic/Perfect
PlasticModels 65
4.7Two-SurfaceElastic/PlasticModel,Lade(1977) 67
4.7.1DeterminationofthePlasticCollapseStrainIncrement 68
4.7.2FlowRuleforHydrostaticConditions 75
4.7.3DeterminationofthePlasticExpansiveStrainIncrement 76
4.7.4FlowRuleforDeviatoricConditions 77
4.7.5WorkHardeningLaw 82
4.8SummaryoftheParametersinvolvedinLadeModel(1977)andthe
CorrespondingNumericalValuesforSilicaPowder 84
5 STUDYOFTHEQUASI-STATICDEFROMATIONOFDRYPOLYMER
PELLETS 87
5.1Introduction 87
5.2ExperimentalProgram 87
5.2.1SystemunderStudy 87
5.2.2Methodology 88
5.3ResultsofMonotonicDeviatoricTests 88
5.4ResultsofCyclicDeviatoricTests 93
5.5ModelingtheBehaviorintheElasticRegime 96
5.6ModelingtheObservedIrreversibilityinBehaviorusingElastic/PerfectPlastic
Models 98
5.7Two-SurfaceElastic/PlasticModel 100
5.7.1DeterminationofthePlasticCollapseStrainIncrement 100
5.7.2DeterminationofthePlasticExpansiveStrainIncrement 101
5.7.3FlowRuleforDeviatoricConditions 103
5.7.4WorkHardeningLaw 104
5.8SummaryoftheParametersinvolvedinLadeModel(1977)andthe
CorrespondingNumericalValuesforPEPellets 106
6 NUMERICALSIMULATION 109
6.1Introduction 109
6.2NumericalConsiderations 110
6.3TheClosestPointProjectionAlgorithmanditsApplicationtotheIntegration
ofDrucker-PragerModel 113
6.3.1DescriptionoftheClosestPointProjectionIterationforDrucker-Prager
Model 114
6.3.2IntegrationofaIterationintheLoadCycle 116
v
6.3.3CommentsontheimplementationofGeneralClosestPointProjection
AlgorithmforDrucker-Prager 117
6.3.4ComparisonbetweenDrucker-PragerPredictionsunderDeviatoricStress
ConditionsandDataonSilicaPowderandPEPellets 119
6.3.5ConclusionsConcerningthePredictiveCapabilitiesofDrucker-Prager
Model 124
6.4ClosestPointProjectionAlgorithmandConvexCuttingPlaneAlgorithm
AppliedtoIsotropicHardeningModels 125
6.4.1TheoreticalPredictionsusingLadeModelforSilicaPowdersubjectedto
HydrostaticCompression 132
6.4.2NumericalSimulationResultsofHydrostaticTestonPEPellets 138
6.4.3ConclusionsforHydrostaticTestonSilicaPowderandPEPellets 138
6.5ConvexCuttingPlaneAlgorithmappliedtoDeviatoricHardeningLade
Model 139
6.5.1NumericalSimulationResultsofDeviatoricTestsonSilicaPowder 141
6.5.2NumericalSimulationResultsofDeviatoricTestsonPEPelletsunder
DeviatoricTestConditions 147
6.5.3ConclusionsforDeviatoricTestsonSilicaPowderandPEPellets 152
6.6Conclusions 153
5 CONCLUSION 154
APPENDIX
A TRIAXIALEXPERIMENTALDATA 159
B ELASTICPARAMETERS 169
C DETERMINATIONOFPLASTICSTRAINS 171
D NUMERICALSIMULATIONDETAILS 179
E PARAMETRICSTUDYOFTHEHYDROSTATICHARDENINGLAW 182
LISTOFREFERENCES 186
BIOGRAPHICALSKETCH 196
vi
LISTOFTABLES
table gage
2.1 Classificationofparticulatesolidsdependingonsize 6
2.2 DisadvantagesandadvantagesofCam-clay,CapandLademodels 23
4.1 Strengthofthematerialanddilatancythresholdasafunctionoftheconfining
pressureobtainedinmonotonictests 56
4.2 Elasticconstantsasdeterminedfromdataobtainedinacyclictriaxialcompression
testunderaconfiningpressureof27kPa 60
4.3 Elasticconstantsasobtainedinacyclictestat70kPaofconfiningpressure 61
4.4 ParametersofLademodel(1977)forsilicapowder 85
5.1 Strengthofthematerialanddilatancythresholdasafunctionoftheconfining
pressureobtainedinmonotonictests 93
5.2 Elasticconstantsasobtainedinacyclictriaxialcompressiontestunderaconfining
pressureof35kPa 97
5.3 ParametersofLademodel(1977)forPEpellets 107
6.1 DifferencesandcommonstepsintheCPPandCCPalgorithms 127
6.2 MaterialandhardeningconstantsforLade'sparametersofsilicapowderusedin
thehydrostaticnumericalsimulations 133
6.3 PlasticandhardeningconstantsforSilicapowderandPEpelletstoimplement
Lademodelinthedeviatoricnumericalsimulations 141
vii
LISTOFFIGURES
Figure page
2.1. PowderClassificationchartbasedonsizeandparticledensity 7
2.2. Cam-clayyieldsurface 15
2.3. Ellipticcapmodel 17
2.4. Conicalyieldsurfaceandsphericalyieldcapintriaxialplane 20
3.1. Mohr-circlesandyieldlocus 26
8.
3.2. Schematicdiagramsoftheyieldlociofdifferentbulksolids 27
3.3. Jenikeshearcell 28
3.4. Jenike'sshearapparatusfordeterminationofflowpropertiesofgranularmaterial..29
3.5. Yieldlociandshearstresses 30
3.6. ShapeofshearzoneinaJeniketester 30
3.7. Schultzeshearcell 32
3.8. Peschlshearcell 32
3.5. UniaxialCompressiontest 33
3.6. Measurementsoftheunconfinedyieldstrength 34
3.7. Gerritsentester 35
3.8. ThePostecuniaxialtester 36
3. a. SchematicviewoftheBatestester 37
3.9. TheJohansonIndicizer 37
3.10. Biaxialtest 39
vm
1.
3.10a,3.10.b: Typesofbiaxialtests 40
3.1 Triaxialcompression 41
4.1. Experimentalsetup 46
4.2. Instronmachine(model5566)andthetriaxialcompressioncell 47
4.3. Silicapowdermicro-graph 48
4.4. Deviatoricstressvs.axialstrainat93kPaofconfiningpressure 50
4.5. Deviatoricstressvs.volumetricstrainat93kPaofconfiningpressure 51
4.6. Volumetricstrainprofilesatconfiningpressuresof93kPa,40kPa,and70kPa....52
4.7. Triaxialcompressioncellwithdeformedspecimen 53
4.8. Specimenafteradeviatorictest 54
4.9. Layersofparticlesdilatingastheyaresheared 55
4.10. Specimenafterahydrostatictest 55
4.11. Deviatoricstressvs.axialstrainat27kPaconfiningpressure 57
4.12. Deviatoricstressvs.volumetricstrainat27kPaconfiningpressure 58
4.13. Changeincreepdirectionatthetransitionfromcompressibilitytodilatancy
(lateralconfiningpressureof27kPa) 59
4.14. ExperimentalvariationofE(averagevalues)withconfiningpressurecompared
toDuncanandChangpowerlaw 62
4.15. ExperimentalvariationofE(averagevalues)withconfiningpressurecompared
toexponentialvariationofE(equation4.3) 63
4.16. ExperimentalvariationofK(averagevalues)withconfiningpressurecompared
toexponentialvariationofK(equation4.5) 64
4.17: Mohr-CoulombyieldSurface 65
4.18. Drucker-PrageryieldSurface 67
4.19. Pressurevs.volumetricstraincurveobtainedinhydrostatictest 70
IX
4.20. Collapsestresswork/atmosphericpressurews.f/pj,usingpowerlawvariation
forKinthecomputationoftheelasticbehavior. Fittedcurveresults:d-0.913,
U=0.0122 71
4.21. Collapsestresswork/atmosphericpressurevs.fc/pj,usingexponentiallaw
variationforKinthecomputationoftheelasticbehavior. Fittedcurveresults:
d=0.913,U=0.0122 72
4.22. Collapsestresswork/atmosphericpressurevs.fc/pj,usingexponentiallaw
variationforKinthecomputationoftheelasticbehavior. Fittedcurveresults:
d=l,U=0.0122 74
4.23. Collapsestresswork/atmosphericpressurevs.f/pj,usingexponentiallaw
variationforKinthecomputationoftheelasticbehavior. Fittedcurveresults:
d=l,U=0.0121 75
JA
4.24. Experimentallog_(\A1 7-27_vs.log/,/paatfailure 77
4.25. Variationof772withfpand05 80
4.26. Variationoftheinterceptswith03 81
4.27. VariationofWpeakwithconfiningpressure 83
4.28. Variationofzwithconfiningpressure 84
5.3.
4.29: (a)Silicayieldsurfacesinatriaxialplane;(b)representationofthesilicaconical
5.4. yieldsurfaceintheoctahedralplane 86
5.1: TriaxialtestonPEpelletsinprogress 89
5.2: PEspecimenintriaxialtestapparatus 89
Deviatoricstressvs.axialstrainat14.7kPaofconfiningpressure 90
Deviatoricstressvs.volumetricstrainat14.7kPaofconfiningpressure 91
5.5. Axialstrainprofilesatconfiningpressuresof14.7kPa,and35kPa 92
5.6. Deviatoricstressvs.axialstrainat35kPaconfiningpressure 94
5.7. Deviatoricstressvs.volumetricstrainat35kPaconfiningpressure 95
x