简介：Thispaperpresentsanewboundaryintegralequatiònfortwo-dimensionalelasticitywiththestresscomponentσijtitjasoneoftheboundaryvalues,wheretiisthedirectioncosineofthetangentontheboundary.ThisformofBEMhasanadvantageinthatthestresscomponentσijtitjontheboundarycanbecalculateddirectlyfromthenumericalsolution.Thepresentformulationforplaneproblemsusestwokernels,theoneislogarithmicallysingularandtheotheris1/rsingular.Theeffectivenessoftheapproachisalsodiscussedthroughtestexamples.

简介：Thebehavioroftwocollinearanti-planeshearcracksinapiezoelectriclayerbondedtotwohalfspacesisinvestigatedbytheSchmidtmethod.Thecracksareverticallytotheimerfacesofthepiezoelectriclayer.ByusingtheFouriertransform,theproblemcanbesolvedwithtwopairsoftripleintegralequations.TheseequationsaresolvedusingtheSchmidtmethod.Thisprocessisquitedifferentfromthatadoptedpreviously.Numericalexamplesareprovidedtoshowtheeffectofthegeometryoftheinteractingcracksandthepiezoelectricconstantsofthematerialuponthestressintensityfactorofthecracks.

简介：Inthepast,thepseudo-staticmethodusedtobethemostcommonforevaluatingthestabilityoflandslidesunderseismicloads,inwhichstaticforcesactingonthecenterofgravityofaslidingbodyareusedtoconsidertheeffectsofearthquake.However,seismicloadsofrockandsoildifferfromtimeandlocationtotimeandlocation.Obviously,itisirrationalforthepseudo-staticapproachtobeappliedtosolvingdynamicproblems.Inthispaper,adisplacementpseudo-dynamicmodelisproposedtoassessseismicstabilityoflandslides,inwhichthesinusoidalcosinusoidalwaveisappliedtosimulatingearthquakedisplacement,andan'amplificationfactor'ofpeakseismicdisplacementisreferredtoastheamplificationofseismicwavewhenitpropagatesfromthebottomtothetopofthelandslide.Theeffectsofphysico-mechanicalbehaviorsofaslidingbodyonseismicstabilityofsoilslopesaretakenintoaccountaswellasinertiaforcesanddampingforces.Thesensitivityanalysesonthepermanentdisplacementandthedynamicfactorofsafetyoflandslidesarestudiedindetail.Moreover,alarge-scaleTangjiashanlandslidethatoccurredinWenchuanearthquakeisinvestigatedtoverifytherobustnessandprecisionofthepresentmethod.Itisfoundthattheresultsfromthepresentmethodisingoodagreementwiththosefromthepreviousmethod.

简介：Thedynamicbehavioroftwoparallelsymmetriccracksinapiezoelectricstripunderharmonicanti-planeshearwavesisstudiedusingtheSchmidtmethodforpermeablecracksufaceconditions.Thecracksareparalleltotheedgeofthestrip.BymeansoftheFouriertransform,theproblemcanbesolvedwiththehelpoftwopairsofdualintegralequations.Theseequationsaresolvedusingtheschmidtmethod.Theresultsshowthatthestressandtheelectricdisplacementintensityfactorsdependonthegeometryofthecracks,thefrequencyofincidentwaves,thedistancebetweencracksandthethicknessofthestrip.Itisalsofoundthattheelectricdisplacementintensityfactorsforthepermeablecracksurfaceconditionsaremuchsmallerthanthosefortheimpermeablecracksurfaceconditions.

简介：BaseduponStrohformalismwederiveanovelandconvenientschemefordeterminingtheelasticfieldsofatwo-dimensionalanisotropicbodywithaparabolicboundarysubjecttotwokindsofboundaryconditions,whicharefreesurfaceandrigidsurface,respectively.ThecorrespondingGreen’sfunctionsarefoundbyusingtheconformalmappingmethod.Whentheparaboliccurvede-generatesintoahalf-infinitecrackorrigidinclusion,thesingularstressfieldsnearthetipofdefectsareobtained.Inparticular,thoseGreen’sfunctionsforaconcentratedmomentM0appliedatapointontheparaboliccurvearealsostudied.Itiseasilyfoundthatarbitraryparabolicboundaryvalueprob-lemscanbesolvedbyusingtheseGreen’sfunctionsandassociateintegrals.

简介：Basedonthevariationaltheory,awavelet-basednumericalmethodisdevelopedtocalculatethedefectstatesofacousticwavesintwo-dimensionalphononiccrystalswithpointandlinedefects.Thesupercelltechniqueisapplied.Byexpandingthedisplacementfieldandthematerialconstants(massdensityandelasticstiffness)inperiodicwavelets,theexplicitformula-tionsofaneigenvalueproblemfortheplaneharmonicbulkwavesinsuchaphononicstructurearederived.Thepointandlinedefectstatesinsolid-liquidandsolid-solidsystemsarecalcu-lated.Comparisonsofthepresentresultswiththosemeasuredexperimentallyorthosefromtheplanewaveexpansionmethodshowthatthepresentmethodcanyieldaccurateresultswithfasterconvergenceandlesscomputingtime.

简介：ThenanostructuredAl-basedcompositespossessthecombinationofhighyieldstrengthandgoodductility.Inthispaper,amicromechanicalmodelispresentedtosimulatethemechanicalresponseofbimodalnanostructuredAlandtheparticle-reinforcedaluminummatrixcomposite(PAMC).Theconstitutiverelationsfordifferentphasesareaddressedinthemodel,aswellasthecontributionofmicrocracks.NumericalresultsshowthatthemodelcansuccessfullydescribetheenhancedstrengthandductilityofthebimodalnanostructuredAl,andthepredictionsofthePAMCareingoodagreementwiththeexperimentaldata.ItisworthnotingthatthestrengthandductilityaresensitivetothevolumefractionofconstituentsandthedistributionofmicrocracksinbothbimodalnanostructuredAlandPAMC.Therefore,thepresenttheoreticalresultscanbeusedtooptimizethemicrostructureforimprovingthemechanicalpropertiesofnanostructuredAl-basedcomposites.

简介：基于超声的流动和精力方法的活塞理论，有在投球的方向的立方的僵硬的一个二维的翅膀的flutter运动方程被建立。气动弹性变形的系统包含结构、空气动力学的非线性。Hopf分叉理论被用来分析系统的flutter速度。flutter速度上的系统参数的效果被学习。第4顺序Runge-Kutta方法被用来计算稳定的限制周期回答和气动弹性变形的系统的混乱运动。结果证明数字和系统的平衡点的稳定性随流动速度的增加变化。除时期1的简单限制周期反应以外，也在flutter系统有加倍时期的回答和混乱运动。在这里使用的气动弹性变形的模型导致混乱的线路是加倍时期的分叉。仅仅当流动速度比线性分叉的速度和起始的条件是很小的的高时，在系统的混乱运动发生。而且，系统在表现的流动速度区域混乱是很狭窄的。

简介：Theinversionofstongscattererembeddedinthehalf-spaceisanimportantprobleminengi-neeringandaverydifficultnonlinearprolbeminmathematics,forwhichtheBorniterativemethodisofnoeffect.Inthispaperthemomentmethodisusedinthediscretizationprocedure.Anumericalapproachispr-esentedbyemployingtheregularizationtechniqueandDBI(distortedBorniterative)method.Thesimulationresultsshowthattheapproachpresentedisefficient.

简介：BasedontheLordandShulmangeneralizedthermoelasticitytheorywithonerelaxationtime,anisotropicsemi-infiniteplatesubjectedtoamovingheatsourcehasbeenstudiedbyemployingthefiniteelementmethoddirectlyintimedomain,whosedistributionsofnondimensionaltemperature,displacementandstressareillustratedgraphically.Theresultsshowthatthepresentmethodisaneffectiveandexactnumericaloneforsolvingthethermoelasticcouplingproblemandiscapableofovercomingthedefectsoftraditionalintegratedtransformationandinverseintegratedtransformationmethods.Atthesametime,thetemperaturestepofthethermalwavefrontisobtainedexactlyincontrastwithconventionalnumericaltransformationmethods.

简介：Thebandgap,animportantcharacteristicoftheperiodicstructure,isdispersionrelated,whichcanbedesignedbytailoringthelayoutofmaterialswithintheperiodicmicrostructures.Atypicalexampleofaperiodicstructureisphononiccrystals(PnCs),whicharetraditionallyfabricatedfromtwo-phasematerials.Herein,weinvestigatethetopologiesofperiodicthree-phasePnCs.Themicrostructuresofthethree-phasePnCsareoptimizedusingatwo-stagegeneticalgorithm,andthreecasestudiesareproposedtoobtainthefollowing:(1)themaximumrelativebandgapwidth,(2)themaximumabsolutebandgapwidth,and(3)themax-imumbandgapataspecifiedfrequency.Moreimportantly,thethree-phasematerialprovidessignificantadvantagescomparedtothetypicaltwo-phasematerials,suchasalow-frequencybandgap.Thisresearchisexpectedtocontributehighlytovibrationandnoiseisolation,elasticwavefilters,andacousticdevices.

简介：

简介：Inthispaper,thescatteringofharmonicantiplaneshearwavesbytwofinitecracksisstudiedusingthenon-localtheory.TheFouriertransformisappliedandamixedboundaryvalueprob-lemisformulated.Thenasetoftripleintegralequationsissolvedusinganewmethod,namelySchmidt’smethod,ThismethodismoreexactandmorereasonablethanEringen’sforsolvingthiskindofproblem.Theresultofthestressnearthecracktipwasobtained.Contrarytotheclassicalelas-ticitysolution,itisfoundthatnostresssingularityispresentatthecracktip,whichcanexplaintheproblemofmacroscopicandmicroscopicmechanics.

简介：Inthispaper,thebehavioroftwocollinearcracksinmagneto-electro-elasticcompositematerialunderanti-planeshearstressloadingisstudiedbytheSchmidtmethodforpermeableelectricboundaryconditions.ByusingtheFouriertransform,theproblemcanbesolvedwithasetoftripleintegralequationsinwhichtheunknownvariableisthejumpofdisplacementsacrossthecracksurfaces.Insolvingthetripleintegralequations,theunknownvariableisexpandedinaseriesofJacobipolynomials.Numericalsolutionsareobtained.Itisshownthatthestressfieldisindependentoftheelectricfieldandthemagneticflux.

简介：ByusingtheSomiglianarepresentationandtheconceptsoffinite-partintegrals,asetofhypersingularintegralequationsoftheinteractionbetweentwoparallelplanarcracksinathree-dimen-sionalfinitebodysubjectedtoarbitraryloadsisderived,andthenitsnumericalmethodisproposedbythefinite-partintegralmethodcombinedwiththeboundaryelementmethod.Accordingtotheanalytictheoryofhypersingularintegralequations,thesquarerootmodelsofdisplacementdiscontinuitiesintheelementsnearthecrackfrontareapplied,andthusthecomputationalprecisionisraised.Basedonthis,thestressintensityfactorscanbedirectlycalculated.Finally,thestressintensityfactorsofsever-altypicalinteractionproblemsarecalculated.