Lecture Notes in Applied and Computational Mechanics 56 SeriesEditors Prof.Dr.-Ing.FriedrichPfeiffer LehrstuhlBfürMechanik TechnischeUniversitätMünchen Boltzmannstraße15 85748Garching Germany E-mail:[email protected] Prof.Dr.PeterWriggers FBBauingenieur-undVermessungswesen Inst.BaumechanikundNumer.Mechanik UniversitätHannover Appelstr.9A 30167Hannover Germany E-mail:[email protected] Forfurthervolumes: http://www.springer.com/series/4623 Recent Advances in Contact Mechanics Papers Collected at the 5th Contact Mechanics International Symposium (CMIS2009), April 28–30, 2009, Chania, Greece Georgios E. Stavroulakis (Ed.) ABC Editor Prof.Dr.Inghabil.GeorgiosE.Stavroulakis DepartmentofProductionEngineering andManagement TechnicalUniversityofCrete Chania Greece ISSN1613-7736 e-ISSN1860-0816 ISBN978-3-642-33967-7 e-ISBN978-3-642-33968-4 DOI10.1007/978-3-642-33968-4 SpringerHeidelbergNewYorkDordrechtLondon LibraryofCongressControlNumber:2012948329 (cid:2)c Springer-VerlagBerlinHeidelberg2013 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation, broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology nowknownorhereafterdeveloped.Exemptedfromthislegalreservationarebriefexcerptsinconnection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. 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Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Introduction Contact mechanics is an active research area with deep theoretical and numerical roots. The links between nonsmooth analysis and optimization with contact and nonsmooth/nonconvexmechanicshavebeeninvestigatedintensivelyduringthelast decades,especiallyinEurope.Thestudyofcomplementarityproblems,variational-, quasivariational-andhemivariationalinequalitiesarisinginnonsmoothandcontact mechanicsis a hottopicfor interdisciplinaryresearchand cooperation.The needs of industryfor robust solution algorithmssuitable for large scale applicationsand theregularupdatesofthe respectiveelementsin majorcommercialcomputational mechanicscodes,demonstratethatthisinteractionisnotrestrictedtotheacademic environmentandthattheinvestigationisbynomeanscompleted. The contributions of this book have been selected from the participants of the CMIS 2009 international conference which took place in Chania, Crete and con- tinued a successful series of specialized contact mechanics conferences. A num- ber of people helped me to organize the conference and eventually prepare this book.AmongthemIwouldliketothankProfessorsMichelFre´mondandJaroslav Haslinger. During the preparation of the Conference, Professor J.A.C. Martins, Lisbon, Portugal,memberoftheInternationalScientificCommittee,passedaway.Hismem- oryandhiscontributionstothecontactmechanicscommunitywillstayalive. Finally I would like to expressmy thanksto the editorial staff of Springer,the group of Senior Editor Dr. Thomas Ditzinger, for their patience and support, as wellas to theSeriesEditors,ProfessorsFriedrichPfeifferandPeter Wriggers,for adoptingthisbookintheLectureNotesinAppliedandComputationalMechanics. Chania,Crete,Greece GeorgiosE.Stavroulakis Professor,TechnicalUniversityofCrete, DepartmentofProductionEngineeringandManagement, InstituteofComputationalMechanicsandOptimization, (www.comeco.tuc.gr),GR-73100Chania,Greece email:[email protected] Privatdozent,TechnicalUniversityofBraunschweig, DepartmentofArchitecture,CivilandEnvironmentalEngineering, InstituteforAppliedMechanics, (www.infam.tu-bs.de) Germany Contents Chapter 1: Discrete Coulomb FrictionalSystems Subjected to PeriodicLoading............................................... 1 JimR.Barber,YoungJuAhn Chapter 2: Stability in Unilateral Contact Problems with Dry Friction....................................................... 13 ElainePratt,AlainLe´ger,MichelJean Chapter 3: On a Geometrically Exact Theory for Contact Interactions ................................................... 31 AlexanderKonyukhov,KarlSchweizerhof Chapter4: ApplicationsofanExistence Result forthe Coulomb FrictionProblem............................................... 45 VincentAcary,FlorentCadoux Chapter5:Size-ScaleEffectsontheFrictionCoefficient:FromWeak FaultsatthePlanetaryScaletoSuperlubricityattheNanoscale ....... 67 MarcoPaggi,AlbertoCarpinteri Chapter6:AResidualTypeErrorEstimatefortheStaticCoulomb FrictionProblemwithUnilateralContact .......................... 85 PatrickHild,VanessaLleras Chapter7:FrictionalContactProblemsforThinElasticStructures andWeakSolutionsofSweepingProcess........................... 101 PatrickBallard Chapter 8: Scalable TFETI Algorithm for Frictionless Contact Problems:TheoryandRealWorldProblems ....................... 113 Zdeneˇk Dosta´l, Toma´sˇ Kozubek, Toma´sˇ Brzobohaty´, AlexandrosMarkopoulos,V´ıtVondra´k VIII Contents Chapter9:T-FETIBasedAlgorithmfor3DContactProblemswith OrthotropicFriction............................................ 131 JaroslavHaslinger,RadekKucˇera Chapter10:APrimal-DualActiveSetStrategyforFiniteDeformation DualMortarContact ........................................... 151 AlexanderPopp,MichaelW.Gee,WolfgangA.Wall Chapter11:NumericalAnalysisof a Bone Remodelling Contact Problem ...................................................... 173 Jose´ R.Ferna´ndez,RebecaMart´ınez Chapter 12: Postbuckling Behaviour of a Rectangular Plate SurroundedbyNonlinearElasticSupports ......................... 189 AlikiD.Muradova,GeorgiosE.Stavroulakis Chapter13:ATime-SteppingSchemeforMultibodyDynamicswith UnilateralConstraints .......................................... 205 LaetitiaPaoli Chapter14:CoupledImplicitVariationalInequalitiesandDynamic ContactInteractionsinViscoelasticity ............................. 221 MariusCocou Chapter15:ComparisonsofContactForcesduringObliqueImpact: Experimentalvs.ContinuumandFiniteElementResults ............. 239 PhilipP.Garland,RobertJ.Rogers Chapter16:DynamicResponseofMasonryWallsConnectedwitha ReinforcedConcreteFrame...................................... 257 MariaE.Stavroulaki,KaterinaPateraki Chapter17:BeamsComprisingUnilateralMaterialinFrictionless Contact:AVariationalApproachwithConstraintsinDualSpaces ..... 275 FrancoMaceri,GiuseppeVairo Chapter 18:On the SeparationZones in Aluminium Base-Plate Connections.NumericalSimulationandLaboratoryTesting .......... 293 Dimitrios N. Kaziolas, EvangelosEfthymiou, MichaelZygomalas, CharalambosC.Baniotopoulos Chapter19:CompositeSlab:AUnilateralContactProblem .......... 309 ThemistoklisS.Tsalkatidis,ArisV.Avdelas Chapter20:TheInfluenceofSlidingFrictiononOptimalTopologies ... 327 NiclasStro¨mberg Contents IX Chapter 21: Derivation of the Equation of Caustics for the ExperimentalAssessmentofDistributedContactLoadswithFriction inTwoDimensions ............................................. 337 Vasilios Spitas, Christos Spitas, George Papadopoulos, TheodoreCostopoulos Chapter22:AMathematicalMethodfortheDeterminationofthe CriticalAxialLoadsofContinuousBeamswithUnilateralConstraints forVariousInitialGeometricImperfections ........................ 351 KonstantinosA.Tzaros,EuripidesS.Mistakidis Chapter23:A NumericalApproachtothe Non-convexDynamic Problemof SteelPile-SoilInteractionunder Environmentaland Second-OrderGeometricEffects.................................. 369 AsteriosLiolios,KonstantinosLiolios,GeorgeMichaltsos Chapter 24:Effectof DifferentTypesof MaterialHardening on HystereticBehaviorofSphericalContactunderCombinedNormal andTangentialLoading ......................................... 377 YuriKligerman,VadimZolotarevsky,IzhakEtsion Chapter25:ModellingofPiezoelectricContactProblems............. 383 MikaelBarboteu,MirceaSofonea Chapter26:A MultiResolutionStudyontheBehaviorofFractal InterfaceswithUnilateralContactConditions ...................... 401 OlympiaK.Panagouli,EuripidesS.Mistakidis AuthorIndex ..................................................... 419 Chapter 1 Discrete Coulomb Frictional Systems Subjected to Periodic Loading Jim R. Barber and Young Ju Ahn Abstract. If elastic systems with frictional interfaces are subjected to pe- riodic loading, the system may shake down, meaning that frictional slip is restricted to the first few cycles, or it may settle into a steady periodic state involving cyclic slip. Furthermore, if the system posesses a rigid-body mode, the slip may also cause an increment of rigid-body motion to occur during each cycle — a phenomenon known as ratcheting. Here we investigate this behaviour for discrete systems such as finite el- ement models, for which the contact state can be described in terms of a finite set of nodal displacements and forces. If the system is ‘uncoupled — i.e. if the stiffness matrix is such that the tangentialnodal displacements are uninfluencedbythe normalnodalforces,africtionalMelan’stheoremcanbe proved showing that shakedown will occur for all initial conditions if there existsasafeshakedownstatefortheperiodicloadinginquestion.Forcoupled systems, we develop an algorithm for determining the range of periodic load amplitudes within which the long-time state might be cyclic slip or shake- down,dependingontheinitialcondition.Theproblemisinvestigatedusinga geometricrepresentationofthemotionofthefrictionalinequalityconstraints in slip displacement space. Similar techniques are used to explore ratcheting behaviour in a low-order system. 1.1 Introduction Many engineering systems comprise one or more contacting elastic bodies in nominally static contact. Examples include bolted joints between ma- chine components and the centrifugally loaded contact between aero engine Jim R. Barber · YoungJu Ahn Department of Mechanical Engineering, University of Michigan, AnnArbor, MI48109-2125, USA e-mail: {jbarber,yjahn}@umich.edu G.E.Stavroulakis(Ed.):RecentAdvances inContactMechanics,LNACM56,pp.1–11. springerlink.com (cid:2)c Springer-VerlagBerlinHeidelberg2013 2 J.R. Barber and Y.J. Ahn turbine blades and the blade disk. These systems are typically subjected to mechanical vibrations, which can cause the contact tractions to exceed the limiting frictionconditionatpartofthe interface,leadingto a state ofcyclic microslip.Thisinturnresultsinenergydissipationwhichaffectsthedynam- icsofthe systemandmayalsoleadto theinitiationoffrettingfatigue cracks emanating from the microslip region. The Coulomb friction law is still arguably the best simple approximation to the observed behaviour of unlubricated contacts and it introduces a his- tory dependence into the problem. In particular, the steady cyclic state will generally differ from that during the first cycle of loading. We would like to be able to solve for this steady state directly, and hence determine the location and magnitude of damage due to fretting fatigue and/or estimate the energy loss so as to define an equivalent (frequency-dependent) damping element.However,thesteadycyclicstateisofteninherentlynon-unique,with the state achieved depending on the initial condition or the initial transient period of loading. 1.2 Shakedown and Melan’s Theorem If the time-independent component in the compressive normal tractions is sufficiently large,the systemmayshake down, meaningthat the steadystate is one in which all points on the interface remain in a state of stick after an initial transient that may involve microslip. Shakedown is a well known phenomenon in the analogous process of elas- tic/plastic deformation, where it can be predicted using Melan’s theorem [9] whichbroadlyspeakingstatesthatifthesystemcanshakedown,itwilldoso regardlessof initial conditions. For frictional systems, anequivalent theorem might be stated as “If a set of time-independent tangential displacements at the interface can be identified such that the corresponding residual stresses when superposed on the time-varying stresses due to the applied loads cause the interface tractions to satisfy the conditions for frictional stick throughout the contact area at all times, then the system will eventually shake down to a stateinvolvingnoslip,thoughnotnecessarilytothestatesoidentified.”Tran- sient studies of cyclic frictional systems seem to confirm the validity of this theorem [7], but the proof of Melan’s theorem depends on the associativity of the plastic flow rule, whereas the Coulomb friction law is non-associative. The theorem has recently been proved in both discrete [8] and continuum [4] formulations, but only for the restricted class of systems in which there is no coupling between normal tractions and tangential displacements. This class includes the much studied case ofthe contactof two similar elastic half planes, and more generally, any system that is symmetric about the contact plane. 1 Discrete Coulomb Frictional Systems Subjected to Periodic Loading 3 The discrete theorem is established by defining a non-negative norm 1 A= (v˜−v)T κ(v˜−v) , (1.1) 2 where v is a vector of instantaneous nodal slip displacements, v˜ is a ‘safe’ shakedown vector and κ is the reduced stiffness matrix. The norm A is a measure of the deviation of the instantaneous deviation of the system from the shakedown state and the theorem is established by demonstrating that for all permissible slip motions, the time derivative A˙ < 0 and hence the shakedown state is approachedmonotonically. 1.3 Coupled Systems That the normal and tangential elastic problems be uncoupled is both a necessary and sufficient condition for Melan’s theorem to apply, except for certain very special low order discrete systems [8]. For coupled systems, it is alwayspossibletoconstructcounterexamplestothetheorem—i.e.periodic loading scenarios for which the long term state of the system may be either shakedown or cyclic slip depending only on the initial conditions. To explore this phenomenon, we consider the behaviour of a two- dimensionalN-nodediscretesystemsubjectedtoexternalloadingoftheform F(t)=F +λF (t), (1.2) 0 1 where F is a time-invariant mean load, F (t) is a periodic load, t is time 0 1 and λ is a scalar loading factor. Thediscretedescriptionoftheelasticsystemcanbecondensedsoastoin- cludeonlythecontactdegreesoffreedom,givingasystemoflinearequations q = qw+A v +B w j j ji i ij i p = pw+B v +C w , (1.3) j j ji i ji i where v ,w are respectively the tangential and normal nodal displacements, i i q ,p arethetangentialandnormal(compressive)nodalforces,qw,pw arethe i i j j nodal reactions that would be generated by the external forces F if all the nodal displacements were constrained to be zero and A,B,C are partitions of the reduced stiffness matrix κ. We note that with this terminology, the coupling between tangential displacements and normal reactions is defined by the matrix B and hence the condition for Melan’s theorem to apply is B=0. We define the Coulomb friction law for node i by the relations w ≥ 0; p ≥0 (1.4) i i w >0 ⇒p =q =0 (1.5) i i i
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