简介：

简介：Byusingthewell-developedintegraltransformmethodology,thedynamicresponseofstressandelectricdisplacementaroundafinitecrackinaninfinitepiezoelectricstripareinvestigatedunderarbitrarydynamicanti-planeloads.Thedynamicstressintensityfactorsandelectricdisplacementareobtainedanalytically.Itisshownthatthedynamiccrack-tipstressandelectricfieldstillhaveasquare-rootsingularity.Numericalcomputationsforthedynamicstressintensityfactorshowthattheelectricloadhasasignificantinfluenceonthedynamicresponseofstressfield.Thehighertheratioofthecracklengthtothewidthofthestrip,thehigherthepeakvalueofthedynamicstressintensityfactoris.Ontheotherhand,thedynamicresponseoftheelectricfieldisdeterminedsolelybytheappliedelectricload.Theelectricfieldwillpromoteorretardthepropagationofthecrackdependingonthetimeelapsesincetheapplicationoftheexternalelectro-mechanicalloads.

简介：Electro-hydraulicservovalveisatypicalcomplicatedmulti-domainsystemconstitutedbymechanical,electric,hydraulicandmagneticcomponents,whichiswidelyusedinelectro-hydraulicservosystemssuchasconstructionmachinery,heavyequipment,weaponandsoforth.Thetraditionalmethodofmodelingandsimulationofservovalveisbasedonblockdiagramorsignalflow,whichcannotdescribetheservovalvesystemfromcomponentslevelnorbeusedinmodelingandsimulationofoverallservosystems.Intheprocedureoftraditionalmethod,computationalcausalitymustbeinvolvedinmodelingofservovalve,whichisinconvenienttoexecutemodificationoncomponentsorparameters.Modelicaisanobject-orientedmodelinglanguagewhichissuitedforlarge,complex,heterogeneousandmulti-domainsystems.ThekeyfeaturesofModelicaaremulti-domain,object-orientedandnon-causal,whicharesuitableformodelingofservovalveandmakethemodelreadable,reusable,andeasytomodify.Thesimulationresultsshowsimilarcurveswithtraditionalmethod.Thisnewservovalvemodelingandsimulationmethodcanprovidetheengineersamoreefficientwaytodesignandoptimizeaservovalveandanoverallservosystem.

简介：Alginatebeads,oftenusedforcontrolledreleaseofenzymesanddrugs,areusuallyproducedbysprayingsodiumalginateliquidintoagellingagentusingmechanicalvibrationnozzleorairjet.Inthisworkanalternativemethodofelectro-spraywasemployedtoformdropletswithdesiredsizefromahighlyviscoussodiumalginatesolutionusingconstantDCvoltage.Thedropletswerethencuredinacalciumchloridesolution.Themainobjectivewastoproducemono-sizedbeadsfromsuchahighlyviscousandnon-Newtonianliquid(1000-5000mPas).Theeffectsofnozzlediameter,flowrateandconcentrationofliquidonthesizeofthebeadswereinvestigated.Amongtheparametersstudied,voltagehadapronouncedeffectonthesizeofbeadsascomparedtoflowrate,nozzlediameterandconcentrationofalginateliquid.Thesizeofbeadswasreducedtoaminimumvaluewithincreasingthevoltageintherangeof0-10kV.Attheearlystagesofvoltageincrease(i.e.uptoabout4kV),therateofsizereductionwasrelativelylow,whilethedrippingmodedominated.However,inthemiddlepartoftherangeofappliedvoltage,wheretherateofsizereductionwashigh(i.e.about4-7kV),anunstabletransitionoccurredbetweendrippingandjetting.Attheendpartoftherange(i.e.7-10kV)jetmodeofspraywasobserved.Increasingtheheightoffallofthedropletswasfoundtoimprovethesphericityofthebeads,becauseoftheincreasedtimeofflightforthedroplets.Thiswasespeciallyidentifiableathigherconcentrationsofthealginateliquid(i.e.3w/v%).

简介：Remainingusefullife(RUL)estimationisatopicthathasgainedmoreandmoreattentioninthefieldoffluidpowersystems,thankstothetremendouspotentialsshownforimprovingsafetyandreducedproductionlosses.However,manychallengesrelatedtoRULestimationarenotsolvedyet,mainlyconnectedtothedefinitionofthehealthstatusofeachcomponent.Aprognosticmethodbasedonadata-drivenmethodologyforhydraulicsystemsishereproposedtoestimatethepercentageoflifealreadyspentbythemonitoredcomponents.Thepotentialsofthemethodologyareshownconsideringthecaseofatruck-mountedhydrauliccrane,forwhichasimulationmodelwasavailable.

简介：Thispaperinvestigatesthestaticbehaviorofafunctionallygradedcircularplatemadeofmagneto-electro-elastic(MEE)materialsundertensionandbending.Theanalysisisdirectlybasedonthethree-dimensionalgoverningequationsformagnetoelectro-elasticity,withtheboundaryconditionsontheupperandlowersurfacessatisfiedexactlyandthoseonthecylindricalsurfacesatisfiedapproximately(intheSaintVenantsense).Theanalyticalsolutions,derivedwithadirectdisplacementmethod,arevalidforanyfunctionallygradedmaterial(FGM)withitspropertiesvaryingindependentlyinacontinuousmanneralongthethicknessdirection.Forhomogeneousmaterials,thesesolutionsaredegeneratedtotheonesavailableintheliterature.Interestingrelationsarealsofoundbetweenthesolutionsforafunctionallygradedmagneto-electro-elastic(FGMEE)circularplateandthoseforanFGMEErectangularbeam,andeventhoseforafunctionallygradedelasticbeamwhenonlytheelasticdisplacementsareconsidered.Thebeamsolutionsarealsoderivedusingadirectdisplacementmethod.Numericalexamplesarepresentedtoverifythepresentanalyticalsolutions,showtheeffectsofmaterialheterogeneityandmulti-fieldcoupling,andindicatethecorrespondencebetweentheplatesolutionsandbeamsolutions.