Conference Proceedings of the Society for Experimental Mechanics Series Alex Arzoumanidis · Meredith Silberstein Alireza Amirkhizi Editors Challenges in Mechanics of Time-Dependent Materials, Volume 2 Proceedings of the 2018 Annual Conference on Experimental and Applied Mechanics Conference Proceedings of the Society for Experimental Mechanics Series SeriesEditor KristinB.Zimmerman,Ph.D. SocietyforExperimentalMechanics,Inc., Bethel,CT,USA Moreinformationaboutthisseriesathttp://www.springer.com/series/8922 (cid:129) (cid:129) Alex Arzoumanidis Meredith Silberstein Alireza Amirkhizi Editors Challenges in Mechanics of Time-Dependent Materials, Volume 2 Proceedings of the 2018 Annual Conference on Experimental and Applied Mechanics Editors AlexArzoumanidis MeredithSilberstein Psylotech DepartmentofMechanicalandAerospaceEngineering Evanston,IL,USA CornellUniversity Ithaca,NY,USA AlirezaAmirkhizi DepartmentofMechanicalEngineering UniversityofMassachusetts,Lowell Lowell,MA,USA ISSN2191-5644 ISSN2191-5652 (electronic) ConferenceProceedingsoftheSocietyforExperimentalMechanicsSeries ISBN978-3-319-95052-5 ISBN978-3-319-95053-2 (eBook) https://doi.org/10.1007/978-3-319-95053-2 LibraryofCongressControlNumber:2016949637 ©TheSocietyforExperimentalMechanics,Inc.2019 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartofthematerialisconcerned,specificallytherightsof translation,reprinting,reuseofillustrations,recitation,broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodologynowknownorhereafterdeveloped. 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ThisSpringerimprintispublishedbytheregisteredcompanySpringerNatureSwitzerlandAG Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland Preface ChallengesinMechanicsofTime-DependentMaterialsrepresentsoneofeightvolumesoftechnicalpaperspresentedatthe 2018 SEM Annual Conference & Exposition on Experimental and Applied Mechanics organized by the Society for Experimental Mechanics in Greenville, SC, June 4–7, 2018. The complete proceedings also include volumes on Dynamic BehaviorofMaterials;AdvancementofOpticalMethods&DigitalImageCorrelationinExperimentalMechanics;Mechan- ics of Biological Systems & Micro-and Nanomechanics; Mechanics of Composite, Hybrid & Multifunctional Materials; Fracture, Fatigue, Failure and Damage Evolution; Residual Stress, Thermomechanics & Infrared Imaging, Hybrid Tech- niquesandInverseProblems;andMechanicsofAdditiveandAdvancedManufacturing. Each collection presents early findings from experimental and computational investigations on an important area within ExperimentalMechanics,theMechanicsofTime-DependentMaterialsbeingoneoftheseareas. Thistrackwas organized toaddressconstitutive,time (or rate)-dependent constitutive,andfracture/failurebehaviorofa broad range of materials systems, including prominent research in progress in both experimental and applied mechanics. PapersconcentratingonbothmodelingandexperimentalaspectsofTime-DependentMaterialsareincluded. Thetrackorganizersthankthepresenters,authors,andsessionchairsfortheirparticipationandcontributiontothistrack. ThesupportandassistancefromtheSEMstaffarealsogreatlyappreciated. Evanston,IL,USA AlexArzoumanidis Ithaca,NY,USA MeredithSilberstein Lowell,MA,USA AlirezaAmirkhizi v Contents 1 ModifiedHyper-ViscoelasticConstitutiveModelforElastomericMaterials. . . . . . . . . . . . . . . . . . . . . . . . 1 KarenHarbanandMarkTuttle 2 TemperatureDependenceofStatisticalStaticStrengthsforUnidirectionalCFRPwithVarious CarbonFibers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 YasushiMiyanoandMasayukiNakada 3 Time-TemperatureMechanicalResponseofaPVADualCross-LinkSelf-HealingHydrogel. . . . . . . . . . . 23 MincongLiu,JingyiGuo,Chung-YuenHui,andAlanT.Zehnder 4 DissipativeDamageTheoryforStronglyTime-DependentCompositeMaterials. . . . . . . . . . . . . . . . . . . . 29 R.B.HallandR.A.Brockman 5 UnderstandingCreep-FatigueInteractioninFe-25Ni-20Cr(wt%)AusteniticStainlessSteel. . . . . . . . . . . 33 N.Kumar,A.Alomari,andK.L.Murty 6 TheDevelopmentofTimeDependentConstitutiveLawsofJujubeFlesh. . . . . . . . . . . . . . . . . . . . . . . . . . 39 Q.T.PhamandN.-S.Liou 7 Time-TemperatureDependentCreepandRecoveryBehaviourofMWCNTs-Polypropylene Nanocomposites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 VivekKhare,DavidKumar,G.M.Kamath,andSudhirKamle 8 ComparisonofPorcineBrainTissuewithPotentialSurrogateMaterialsUnderQuasi-static CompressionandDynamicMechanicalAnalysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 D.Singh,S.Boakye-Yiadom,andD.S.Cronin 9 ModelingofCavitationErosionResistanceinPolymericMaterialsBasedonStrainAccumulation. . . . . . 61 VahidrezaAlizadehandAlirezaAmirkhizi 10 ExperimentalInvestigationofDynamicStrainAgingin304LStainlessSteel. . . . . . . . . . . . . . . . . . . . . . . 65 BonnieR.Antoun,ColemanAlleman,andKelseyDeLaTrinidad 11 ACaseStudytoEvaluateLiveLoadDistributionsforPre-stressedRCBridge. . . . . . . . . . . . . . . . . . . . . 73 AbbasAllawi,MohannadAl-Sherrawi,MohannedAlGharawi,andAymanEl-Zohairy 12 ExperimentalInvestigationofSegmentalPost-tensionedGirders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 AbbasAllawi,MohannadAl-Sherrawi,BasimAL-Bayati,MohannedAlGharawi,andAymanEl-Zohairy 13 ExperimentalandNumericalEvaluationsofLiveLoadDistributionsofSteel-Concrete CompositeBridge. . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . . .. . . . . . . .. . 95 AbbasAllawi,AmjadAlBayati,MohannedAlGharawi,andAymanEl-Zohairy 14 StrainRateDependentFEMofLaserShockInducedResidualStress. . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 ColinC.Engebretsen,AnthonyPalazotto,andKristinaLanger vii Chapter 1 fi Modi ed Hyper-Viscoelastic Constitutive Model for Elastomeric Materials KarenHarbanandMarkTuttle Abstract Elastomers constitute an essential group of materials that are widely used in the automotive, aerospace industry, biomedical, microfluidic and signal processing applications. Elastomeric materials undergo large deformations without fracture and exhibit time dependency under a prescribed displacement or load. Characterization of elastomeric materials can be challenging, hence the use of a proper constitutive model that captures the behavior of elastomeric materials is essential.Experimentaldataobtainedfromsimpleuniaxialtensiontestsandcreeptestsperformedatvariousconstantstress levels using dog bone samples were used to approximate hyperelasticity and the time-dependent responses of the material respectively. The experimental results suggested that the instantaneous strains were largely responsible for the nonlinear behavior of the material. Thus, a rheological hyper-viscoelastic constitutive model consisting of a nonlinear spring, which wouldcapturethenonlinearinstantaneousstrains,andatwoparameterKelvin-Voightmodel,whichwouldmodelthelinear time-dependentstrainresponses,wasdeveloped.TheMooney-Rivlinmodel,aclassicphenomenologicalhyperelasticmodel, was used to represent the nonlinear spring. The resulting hyper-visco constitutive model, which obeys the Boltzmann’s superpositionprinciple,wasusedfornumericalpredictionsoftime-dependentbehaviorofthismaterialinacommercialfinite element software (Abaqus). The creep deformations predicted using this approach demonstrated good consistency with experimentalresultsovertheappliedrangeofstressesandthedurationoftimemeasurements. Keywords Elastomers·Hyperelastic·Viscoelastic·Pronyseries·Finiteelementmethod 1.1 Introduction Elastomers constitute an essential group of materials that are widely used in the automotive, aerospace industry and more recentlyinbiomedical[1–3],microfluidic[4,5],andsignalprocessing[2,6]applications.Elastomericmaterialsaretypically lightly cross-linked polymers that canundergo large deformationswithoutfractureanddisplaytime-dependent viscoelastic behavior. The nonlinear elastic behavior of elastomers under prescribed displacement or load can be modelled using the classicalGaussianstatistictheory,macromolecularnetworktheory,orcontinuummechanicsasdiscussedbythepioneersof hyperelastic constitutive models, Treolar [7], Rivlin [8], Boyce and Arruda [9]. On the other hand, the time-dependent behavior of elastomers (i.e., viscoelasticity that comprises and combines both the elastic and viscoelastic behavior) can be characterizedbymeansofcreepcomplianceorrelaxationmodulus. Hyperelastic constitutive laws, which account for the large nonlinear elastic material behavior associated large shape changes, are used to model materials that exhibit high strains without failure. Hyperelastic constitutive models are derived fromastrainenergydensityintermsofprincipalstretches[10].Thestretch(orthestretchratio),λisdefinedastheratioofthe lengthofadeformedlineelementtothelengthofthecorrespondingundeformedlineelementandtheprincipalstretchesare the associated stretches of a material that undergoes deformation in three mutually orthogonal directions. The process of findinghyperelasticparametersofamaterialrequiresrelevantexperimentaltest(s)followedbymathematicallydescribingthe physicalbehaviorofthetestresults. Viscoelasticity [11] is a mechanical behavior of polymers describes the time-dependent response to an applied stress or strain.Incontratstothebehaviorofelasticsolidssuchasmetalsandceramics,whichatlowstrainsobeystheprinciplesof K.Harban(*)·M.Tuttle DepartmentofMechanicalEngineering,UniversityofWashington,Seattle,WA,USA e-mail:[email protected] ©TheSocietyforExperimentalMechanics,Inc.2019 1 A.Arzoumanidisetal.(eds.),ChallengesinMechanicsofTime-DependentMaterials,Volume2,ConferenceProceedings oftheSocietyforExperimentalMechanicsSeries,https://doi.org/10.1007/978-3-319-95053-2_1 2 K.HarbanandM.Tuttle Hooke’sLaw[12],thestressandstrainbehaviorofpolymersmaybehighlytimedependent.Attemperatureswellbelowthe glasstransitiontemperatureandhighratesofstrain,polymersbehaveinanelasticmanner,whileathightemperaturesandlow ratesofstrain,polymersbehaveinaviscousmanner.Hence,polymersaredescribedasviscoelasticmaterials,astheyexhibit both elastic and viscous behaviors. Relevant tests (i.e. creep or relaxation) are needed to characterize the viscoelastic time- dependentbehaviorthroughformulation ofamathematicalmodel.Themostpopularmathematical form ofthisbehavioris givenbythePronySeries[13].Themathematicalbackgroundofhyperelasticityandviscoelasticityofelastomericmaterials arebrieflydiscussedinthefollowingsections. 1.2 Theoretical Background Theprocedureofderivingthehyperelasticconstitutivemodelsbeginswithfirstdefiningthestrainenergydensityasafunction of the deformation gradient tensor, specifically the Cauchy-green deformation tensor. Then, computing the invariants generally the principal stretches or strain invariants of the Left Cauchy-green deformation tensor and finally obtaining the stressesbydifferentiatingthestrainenergydensityfunctionwithrespecttotheinvariants.Notethattheconceptof“stretch” differsfromthedefinitionof“engineeringstrain”,wherethelatterisdefinedastheratioofthechangeinlengthofadeformed line element to the undeformed length. A strain energy density is a scalar valued function that represents the strain energy density of a material as a function of the deformation gradient. The strain energy density can be expressed in terms of the deformation gradient (F ), the invariants of the strain tensor (I , I , I ) or in terms of the principal stretches (λ , λ , λ ) ij 1 2 3 1 2 3 [14]. Since this research involves the study of elastomeric materials (rubbers) the assumption of incompressibility can be adaptedtosimplifythestrainenergyfunction.Ifthematerialisincompressible,itfollowsthattheJacobianofthedeformation tensorisequalto1andtheproductoftheprincipalstretchesisequalto1whichmeansthethirdprincipalstretch,λ canbe 3 representedintermsofthefirstandsecondprincipalstretches,λ ,λ .Onlyafewhyperelasticmodelsthatarebuilt-inthefinite 1 2 elementsoftwarepackageusedinthisstudyarediscussedinthissection. 1.2.1 Polynomial Model Thegeneralformofapolynomialmodelisgivenas: Xm Xn W ¼ C ðI (cid:2)3ÞiðI (cid:2)3Þj ð1:1Þ ij 1 2 i¼0 j¼0 whereC isthematerialconstants.Followingtheassumptionofincompressibility,thethirdinvariantI isassumedtobezero. ij 3 Thesecondorderpolynomialmodelisderivedfromthisstrainenergydensityexpressionfollowingm¼n¼2and1(cid:3)(i+j)(cid:3)2, expressedas: W ¼C ðI (cid:2)3ÞþC ðI (cid:2)3ÞþC ðI (cid:2)3ÞðI (cid:2)3ÞþC ðI (cid:2)3Þ2þC ðI (cid:2)3Þ2 ð1:2Þ 10 1 01 2 11 1 2 02 2 20 1 1.2.2 Mooney-Rivlin Model TheMooney-Rivlinmodelisaclassicphenomenologicalmodelwhichisbasedonstraininvariant[15].Thegeneralizedstrain energydensityoftheMooney-Rivlinmodelisexpressedas: W ¼C ðI (cid:2)3ÞþC ðI (cid:2)3Þ ð1:3Þ 10 1 01 2 whereC arematerialconstantsderivedfromthegeneralpolynomialmodelinwhichm¼n¼1and(i+j)¼1. ij 1 ModifiedHyper-ViscoelasticConstitutiveModelforElastomericMaterials 3 1.2.3 Ogden Model The Ogden model is another classic phenomenological model. Ogden [16] proposed an invariant function based model comprisingalinearcombinationofstraininvariantsandprinciplestretchessubjectedtoincompressibility.Thestrainenergy densityfunctionoftheOgdenmodelisexpressedas: XN 2μ (cid:2) (cid:3) W ¼ i λ(cid:2)αi þλ(cid:2)αi þλ(cid:2)αi (cid:2)3 ð1:4Þ α2 1 2 3 i¼1 i whereλ aredeviatoricprincipalstretchandα,μ arematerialconstants.Inthisstudy,wehaveassumedN¼2. i i i 1.2.4 Neo-Hookean Model ThismodelwasderivedfrommolecularchainstatisticsandisthesimplestformoftheMooney-Rivlinmodelbasedonlyon twomaterialparameters[17].Thestrainenergydensityisexpressedas: W ¼C ðI (cid:2)3Þ ð1:5Þ 10 1 This equation islinear in the first invariant, I which limits theability of accurately capturing large non-linear strains of 1 elastomers.Apartfromthatthestrainenergydensityexpressionisnotdependentonthesecondinvariant,I whichmayresult 2 ininaccuratestresspredictionsforabiaxialstateofstress. Theinvariantsinthestrainenergydensityfunctionsexpressedarerelatedtotheprincipalstretchesasfollows: I ¼λ 2þλ 2þλ 2 1 1 2 3 I ¼λ 2λ 2þλ 2λ 2þλ 2λ 2 ð1:6Þ 2 1 3 2 3 1 2 I ¼λ 2λ 2λ 2 3 1 2 3 wherestretch,λcanbeexpressedintermsofengineeringstrains,bytheexpressionλ¼1+e.Agoodhyper-elasticmodelis onethathasagoodcomparisonwithexperimentalresultsforanystressstatewithagivensetofmaterialpropertiesandone that gives stable results for all loadings. Uniaixal tension test were performed in this study to obtain hyperelastic material parameters. For a uniaxial tension test, the uniaxial stretch in the first principal direction can be expressed in terms of engineeringstrainsλ ¼λ ¼1+e,andtheothertwoprincipalstretchdirectionscanbeexpressedas: 1 uniaxial 1 λ ¼λ ¼pffiffiffiffiffiffiffiffiffiffiffiffiffiffi ð1:7Þ 2 3 λ uniaxial Thecorrespondingstrainenergydensityexpressioncanbeobtainedby: ð λðIÞ(cid:2)1 WðIÞ¼ σðεÞdε ð1:8Þ 0 whereεandσarethenominalstrainandstressinuniaxialtensiontest.Toaccountforlinearviscoelasticityinthismaterial,a suitablehyperelasticconstitutivemodelshouldbecoupledwiththeviscoelasticmodel. 1.2.5 Linear Viscoelasticity Theconstitutiveequationforlinearviscoelasticmaterialcanbeexpressedas: ð t _ εðtÞ¼ Jðt(cid:2)τÞε(cid:4)ðτÞdτ ð1:9Þ 0