简介：Longpilesoftheoceanoilplatformareusuallymanufacturedastheintegrationofseveralsegments,whichhavetobeassembledonebyoneduringinstallation.Duringpiledriving,excessiveporepressurewillbuildupinsuchahighlevelthathydraulicfracturinginthesoilroundthepilemaytakeplace,whichwillcausethesoiltoconsolidatemuchfasterduringpileextensionperiod.Consequently,afterpileextension,thesoilstrengthwillrecovertosomeextentandthedrivingresistancewillincreaseconsiderably,whichmakesrestartingdrivingthepileverydifficultandevencausesrefusal.Afiniteelement(FE)analysisprocedureispresentedforjudgingtheriskofrefusalbyestimatingtheblowcountsafterpileextension,inwhichtheregainofsoilstrengthisconsidered.AcaseanalysisinBohaiGulfisperformedusingtheproposedproceduretoexplainthepilerefusalphenomenon.

简介：Basedonanewdefinitionofnonlocalvariable,thispaperestablishestheLagrangianformulationforcontinuumwithinternallong-rangeinteractions.Distinguishedfromtheexistingtheories,thenonlocaltermintheLagrangianformulationautomaticallysatisfiesthezeromeanconditiondeterminedbytheactionandreactionlaw.Bythisformulation,elasticwaveinarodwiththeinternallong-rangeinteractionsisinvestigated.Thedispersionoftheelasticwaveispredicted.

简介：Aso-called“localprobabilisticParisrelationmethod”waspresentedformeasuringtherandomthresholdsoflongfatiguecrackpropagation.Acheckwasmadetotheconventionalmethod,inwhichthethresholdsweremeasuredstatisticallyanddirectlybythetestdata.Itwasrevealedthatthismethodwasnotreasonablebecausethetestdatahaveseldomaunifiedlevelofcrackgrowthrates.Differently,inthepresentedmethodtheParis-Erdoganequationwasappliedtomodelthelocaltestdataaroundthethresholds.Localprobabilisticrelationswithboththesurvivalprobabilityandtheconfidencewereestablishedonalognormaldistributionofthestressdensityfactors.Andthen,theprobabilisticthresholdswerederivedfromtheprobabilisticfactorswithagivencriticallevelofgrowthrate.AnanalysisonthetestdataofLZ50axlesteelfortheChineserailwayvehiclesverifiesthatthepresentmethodisfeasibleandavailable.

简介：Thispaperanalysesthefiveyears'monitoredstrainscollectedfromalong-termhealthmonitoringsysteminstalledonabridgewithwavelettransform.Intheanalysis,themonitoredstrainsarepre-processed,featuresofthemonitoreddataaresummarizedbriefly.Theinfluencesofthebasefunctionsontheresultsofwaveletanalysisarestudiedsimultaneously.Theresultsshowthatthedbwaveletisagoodmotherwaveletfunctionintheanalysis,andtheorderNshouldbelargerthan20,butlessthan46indeco...

简介：Thecomplexityoftheloadsactingontheoffshorewindturbines(OWTs)structuresandthesignificanceofinvestigationonstructuredynamicsareexplained.Testresultsobtainedfromascaledwindturbinemodelarealsosummarized.Themodelissupportedonmonopile,subjectedtodifferenttypesofdynamicloadingusinganinnovativeoutofbalancemasssystemtoapplycyclic/dynamicloads.Thetestresultsshowthenaturalfrequencyofthewindturbinestructureincreaseswiththenumberofcycles,butwithareducedrateofincreasewiththeaccumulationofsoilstrainlevel.Thechangeisfoundtobedependentontheshearstrainlevelinthesoilnexttothepilewhichmatcheswiththeexpectationsfromtheelementtestsofthesoil.Thetestresultswereplottedinanon-dimensionalmannerinordertobescaledtopredicttheprototypeconsequencesusingelementtestsofasoilusingresonantcolumnapparatus.

简介：Thefollowinginitial-boundaryvalueproblemforthesystemswithmultidimensionalinhomogeneousgeneralizedBenjamin-Bona-Mahony(GBBM)equationsisreviewed.Theexistenceofglobalattractorsofthisproblemwasprovedbymeansofauniformprioriestimatefortime.

简介：Inliterature,nonlineartravelingwavesinelasticcircularrodshaveonlybeenstudiedbasedonsinglepartialdifferentialequation(pde)models,andhereweconsidersuchaproblembyusingamoreaccuratecoupled-pdemodel.WederivetheHamiltonianfromthemodelequationsforthelongfinite-amplitudewaveapproximation,analyzehowthenumberofsingularpointsofthesystemchangeswiththeparameters,andstudythefeaturesofthesesingularpointsqualitatively.Variousphysicallyacceptablenonlineartravelingwavesarealsodiscussed,andcorrespondingexamplesaregiven.Inparticular,wefindthatcertainwaves,whichcannotbecourltedbythesingle-equationmodel,canarise.

简介：Tosystematicallystudythevehicle–bridgecoupleddynamicresponseanditschangerulewithdifferentparameters,avehiclemodelwithsevendegreesoffreedomwasbuiltandthetotalpotentialenergyofvehiclespacevibrationsystemwasdeduced.Consideringthestimulationofroadroughness,thedynamicresponseequationofvehicle–bridgecoupledsystemwasestablishedinaccordancewiththeelasticsystemprincipleoftotalpotentialenergywithstationaryvalueandthe‘‘set-in-right-position''rule.Onthebasisoftheself-compiledFortranprogramandbridgeengineering,thedynamicresponseoflongspancontinuousgirderbridgeundervehicleloadwasstudied.Thisstudyalsoincludedthecalculationofvehicleimpactcoefficient,evaluationofvibrationcomfort,andanalysisofdynamicresponseparameters.Resultsshowtheimpactcoefficientchangeswithlanenumberandislargerthanthevaluecalculatedbythe‘‘generalcodefordesignofhighwaybridgesandculverts(China)''.TheDieckmannindexofbridgevibrationisalsorelatedtolanenumber,andthevibrationcomfortevaluationisgoodinnormalconditions.Therelevantconclusionsfromparametricanalyseshavepracticalsignificancetodynamicdesignanddailyoperationoflong-spancontinuousgirderbridgesinexpressways.Safetyandcomfortareexpectedtoimprovesignificantlywithfurthercontrolofthevibrationofvehicle–bridgesystem.