简介:ThesufficientconditionsofHoldercontinuityoftwokindsoffractalinterpolationfunctionsdefinedbyIFS(IteratedFunctionSystem)wereobtained.Thesufficientandnecessaryconditionforitsdifferentiabilitywasproved.ItsderivativewasafractalinterpolationfunctiongeneratedbytheassociatedIFS,ifitisdifferentiable.
简介:Byusingthefundamentalequationsofaxisymmetricshallowshellsofrevolution,thenonlinearbendingofashallowcorrugatedshellwithtaperunderarbitraryloadhasbeeninvestigated.ThenonlinearboundaryvalueproblemofthecorrugatedshellwasreducedtothenonlinearintegralequationsbyusingthemethodofGreen'sfunction.Tosolvetheintegralequations,expansionmethodwasusedtoobtainGreen'sfunction.ThentheintegralequationswerereducedtotheformwithdegeneratecorebyexpandingGreen'sfunctionasseriesofcharacteristicfunction.Therefore,theintegralequationsbecomenonlinearalgebraicequations.Newton'siterativemethodwasutilizedtosolvethenonlinearalgebraicequations.Toguaranteetheconvergenceoftheiterativemethod,deflectionatcenterwastakenascontrolparameter.Correspondingloadswereobtainedbyincreasingdeflectiononebyone.Asanumericalexample,elasticcharacteristicofshallowcorrugatedshellswithsphericaltaperwasstudied.Calculationresultsshowthatcharacteristicofcorrugatedshellschangesremarkably.Thesnappinginstabilitywhichisanalogoustoshallowsphericalshellsoccurswithincreasingloadifthetaperisrelativelylarge.Thesolutionisclosetotheexperimentalresults.
简介:Anewsmoothgapfunctionfortheboxconstrainedvariationalinequalityproblem(VIP)isproposedbasedonanintegralglobaloptimalitycondition.Thesmoothgapfunctionissimpleandhassomegooddifferentiableproperties.TheboxconstrainedVIPcanbereformulatedasadifferentiableoptimizationproblembytheproposedsmoothgapfunction.Theconditions,underwhichanystationarypointoftheoptimizationproblemisthesolutiontotheboxconstrainedVIP,arediscussed.Asimplefrictionalcontactproblemisanalyzedtoshowtheapplicationsofthesmoothgapfunction.Finally,thenumericalexperimentsconfirmthegoodtheoreticalpropertiesofthemethod.
简介:Anaccuratecracksurfaceopeningdisplacementformulaforedgecracksinfinitebodieshasbeenderived,andwassubsequentlyusedtodevelopwide-rangeclosed-formweightfunctionsforedgecracks.Theanalyticalweightfunctionisgeneralandcanbeeasilyusedtodetermineaccuratestressintensityfactorsandcracksurfaceopeningdisplacementsforarbitrarilyloadededgecrackswithhighefficiency.Exampleshavebeengivenforproblemsofedgecrack(s)withanumberoftypicalloadconditionsforillustration.
简介:Aneuralnetwork(NN)isapowerfultoolforapproximatingboundedcontinuousfunctionsinmachinelearning.TheNNprovidesaframeworkfornumericallysolvingordinarydifferentialequations(ODEs)andpartialdifferentialequations(PDEs)combinedwiththeautomaticdifferentiation(AD)technique.Inthiswork,weexploretheuseofNNforthefunctionapproximationandproposeauniversalsolverforODEsandPDEs.ThesolveristestedforinitialvalueproblemsandboundaryvalueproblemsofODEs,andtheresultsexhibithighaccuracyfornotonlytheunknownfunctionsbutalsotheirderivatives.ThesamestrategycanbeusedtoconstructaPDEsolverbasedoncollocationpointsinsteadofamesh,whichistestedwiththeBurgersequationandtheheatequation(i.e.,theLaplaceequation).
简介:Structuraloptimizationforcrashworthinesscriteriaisofparticularsignificanceespeciallyatearlystageofdesign.ThecomparativestudyofKrigingandradialbasisfunctionnetwork(RBFN)wasperformedinordertoimprovethecrashworthinesseffectsofhoneycomb.ImprovingthecrashworthinesscharacteristicofhoneycombwasachievedusingLS-OPTanddomainreductionstrategy.Thisoptimizationisperformedonthebasisofvalidatednumericalsimulationtoestablishtheapproximatedmodeltoillustratetherelationshipbetweentheresponsesanddesignvariables.TheresultsshowedthatKrigingmeta-modelisexcelledinaccuracy,robustnessandefficiencycomparedtoradialbasisfunction(RBF)andcrashworthinesscharacteristicofhoneycombisimprovedby4%.
简介:Theequationofstressintensityfactors(SIF)ofinternallypressurizedthick-walledcylinderwasusedasthereferencecase.SIFequationofrotatingthick-walledcylindercontainingaradialcrackalongtheinternalborewaspresentedinweightfunctionmethod.Theweightfumctionformulaswereworkedoutandcanbeusedforallkindsofdepthofcracks,rotatingspeed,material,sizeofthick-walledcylindertocalculatethestressintensityfactors.Theresultsindicatedthevalidityandeffectivenessoftheseformulas.Meanwhile,therulesofthestressintensityfactorsinrotatingthick-walledcylinderwiththechangeofcrackdepthsandtheratioofouterradiustoinnerradiuswerestudied.Thestudiesarevaluabletoengineeringapplication.
简介:ThedissipationfunctioninturbulentplanePoiseuilleflows(PPFs)andplaneCouetteflows(PCFs)subjecttospanwiserotationsisanalyzed.Itisfoundthat,inthePCFswithoutsystemrotations,themeanpartisconstantwhilethefluctuationpartfollowsalogarithmiclaw,resultinginasimilarlogarithmicskinfrictionlawasPPFs.However,iftheflowsystemrotatesinthespanwisedirection,noobviousdependenceontherotationnumbercanbeevaluated.InthePPFswithrotations,thedissipationfunctionshowsanincreasewiththerotationnumber,whileinthePCFswithrotations,whentherotationnumberincreases,thedissipationfunctionfirstdecreasesandthenincreases.
简介:ThesolutionsofGreen'sfunctionaresignificantforsimplificationofproblemonatwo-phasesaturatedmedium.UsingtransformationofaxisymmetriccylindricalcoordinateandSommerfeld'sintegral,superpositionoftheinfluencefieldonafreesurface,authorsobtainedthesolutionsofatwo-phasesaturatedmediumsubjectedtoaconcentratedforceonthesemi-space.
简介:Anindependentmethodforpaper[10]ispresented.WeightedlatticepathsareemumeratedbycountingfunctionwhichisanaturalextensionofGaussianmultinomialcoefficientinthecaseofunrestrictedpaths.Convolutionsforpathcountsareinvestigated.whichyieldssomeVandermonde-typeidentitiesformultinomialandq-multinomialcoefficients.
简介:Inthepresentpaper,thecompatibilityequationfortheplanestressproblemsofpower-lawmaterialsistransformedintoabiharmonicequationbyintroducingtheso-calledcomplexpseudo-stressfunction,whichmakesitpossibletosolvetheelastic-plasticplanestressproblemsofstrainhardeningmaterialsdescribedbypower-lawusingthecomplexvariablefunctionmethodlikethatinthelinearelasticitytheory.Byusingthisgeneralmethod,theclose-formedanalyticalsolutionsforthestress,strainanddisplacementcomponentsoftheplanestressproblems’ofpower-lawmaterialsisdeducedinthepaper,whichcanalsobeusedtosolvetheelasto-plasticplanestressproblemsofstrain-hardeningmaterialsotherthanthatdescribedbypower-law.Asanexample,theproblemofapower-lawmaterialinfiniteplatecontainingacircularholeunderuniaxialtensionissolvedbyusingthismethod,theresultsofwhicharecomparedwiththoseofaknownasymptoticanalyticalsolutionobtainedbytheperturbationmethod.