简介：Forthepurposeofachievinghigh-resolutionoptimalsolutionsthispaperproposesanodaldesignvariablebasedadaptivemethodfortopologyoptimizationofcontinuumstructures.Theanalysismesh-independentdensityfield,interpolatedbythenodaldesignvariablesatagivensetofdensitypoints,isadaptivelyrefined/coarsenedaccordingtoacriterionregardingthegray-scalemeasureoflocalregions.Newdensitypointsareaddedintothegrayregionsandredundantonesareremovedfromtheregionsoccupiedbypurelysolid/voidphasesfordecreasingthenumberofdesignvariables.Apenalizationfactoradaptivitytechniqueisemployedtopreventprematureconvergenceoftheoptimizationiterations.Suchanadaptiveschemenotonlyimprovesthestructuralboundarydescriptionquality,butalsoallowsforsufficientfurthertopologicalevolutionofthestructurallayoutinhigheradaptivitylevelsandthusessentiallyenableshigh-resolutionsolutions.Moreover,comparedwiththecasewithuniformlyandfinelydistributeddensitypoints,theproposedadaptivemethodcanachieveahighernumericalefficiencyoftheoptimizationprocess.

简介：Inthispaper,theopportunitiesandchallengeswhichfutureapplicationsbasedonnanoparticlesoffertoengineersaredescribed.Newhigh-addedvalueproductsinduceustorethinkwaystocontrolnanoparticledesignandhandling.Severalchallengesaredescribedandtypicalsolutionsaregiven:(1)findingrelevantengineeringtasksoutsidetraditionalprocessindustry;(2)theimportanceofmixingreactants;(3)obtainingmonodisperseparticles;(4)gainingefficientcontrolviaelectricforcesand(5)developingmulti-stepprocesseswhichallowmorecontroloverparticleproperties.

简介：骨胶原纤维提供成为强壮的一个好例子微--或从nanoscaletropocollagen分子通过的mesoscale纤维一蹒跚并且以一种自底向上的方式的cross-linked组织。骨胶原纤维的建筑上的特征被显示出是一条有希望的途径开发高效的碳nanotube(CNT)纤维的Mimicking。在现在的工作，一个有弹性的模型被开发在bioinspiredCNT捆以内描述负担转移和失败繁殖，并且与象CNT方面比率和纵的差距那样的很多个几何、物理的参数建立捆的机械性质的关系，接口交叉结合密度，和在CNT的导致functionalization的降级，等等。与模型一起，沿着CNTCNT接口以及在每单个CNT的压力分布是捕获的井，和沿着CNT捆的机械性质上的接口和它的效果的失败繁殖被预言。工作可以在实践为新奇CNT纤维的设计提供有用指南。

简介：Crashworthinessofcellularmetalswithalineardensitygradientwasanalyzedbyusingcell-basedfiniteelementmodelsandshockmodels.Mechanismsofenergyabsorptionanddeformationofgradedcellularmetalswereexploredbyshockwavepropagationanalysis.Resultsshowthatapositivedensitygradientisagoodchoiceforprotectingtheimpactingobjectbecauseitcanmeetthecrashworthinessrequirementsofhighenergyabsorption,stableimpactresistanceandlowpeakstress.

简介：Inthiswork,sandwichbeamsarestudiedtorevealtheunderlyingsizeeffectsoftheperiodiccorecellsforthefirsttimewithintheframeworkoffreevibrationanalysisofsuchanadvancedlightweightstructure.Theenergyequivalencemethodisformulatedasatheoreticalapproachthattakesintoaccountthecellsizeeffect.Itiscomparedwiththeasymptotichomogenizationmethodanddirectfiniteelementmethodsystematicallytoshowtheirconsistenceandapplicability.Theaccuracyoffreevibrationresponsespredictedbythedetailedfiniteelementmodelisusedasthestandardofcomparison.Itisshownthatthecellsizeisanimportantparametercharacterizingthecellularcorerigiditiesthatinfluencevibrationresponses.Thehomogenizationmodelagreesexactlywiththeasymptoticsolutionoftheanalyticalexpressionofthebeammodelonlywheneverthecellsizetendstobeinfinitelysmall.

简介：在这份报纸，为一个抑制主要系统的抑制动态颤动吸收器的一个得最高分的战略图案被调查最小化颤动大小山峰。而且，为一个two-degree-of-freedom系统减少对强迫的频率的变化的主要系统反应的敏感，主要系统应该有二座相等的回声大小山峰。满足这个要求，包括主要系统的反响的频率的分发特征的一套简化限制方程为得最高分的战略目的函数被建立。修改限制方程由另外的作者比那些有不太未知的变量，它不仅简化计算而且改进最佳的价值的精确性。建议方法的优点通过数字模拟被说明。

简介：ＩｎｔｒｏｄｕｃｔｉｏｎＴｏｐｏｌｏｇｙｏｐｔｉｍｉｚａｔｉｏｎｏｆｃｏｎｔｉｎｕｕｍｓｔｒｕｃｔｕｒｅｓｄｉｄｎｏｔｄｅｖｅｌｏｐｒａｐｉｄｌｙｕｎｔｉｌｒｅｃｅｎｔｔｅｎｙｅａｒｓｏｗｉｎｇｔｏｔｈｅｓｐｅｃｉａｌｄｉｆｆｉｃｕｌｔｉｅｓｉｎｖｏ...

简介：Theshallowcylindricalstructureissuitabletodevelopbroadbandvibrationenergyharvestersduetothepropertyoftheinherentmechanicalbistability.Inthisletter,theoptimumdesignofthebistablecylindricalshellforbroadbandenergyharvestingapplicationisinvestigatedfromthestructuralpointofview.Theoutputpowerisevaluatedbytheconceptoftheharvestablepower,whichbalancesthefrequencyofsnapthroughandthereferredoutputenergyassociatedwitheachsnapthrough.Thenondimensionalharvestablepowerisanalyticallyexpressedasthefunctionofthenon-dimensionalcurvatureparameterandoneconstructedparameter.Theuniversaldependenceoftheoptimalcurvatureparameterandtheassociatedoptimalharvestablepowerontheconstructedparameterisderived,whichcanbewellapproximatedbythelinearrelationindoublelogarithmiccoordinate.

简介：Foralineardynamicalsystem,weaddresstheproblemofdevisingaboundedfeedbackcontrol,whichbringsthesystemtotheorigininfinitetime.TheconstructionisbasedonthenotionofacommonLyapunovfunction.Itisshownthattheconstructedcontrolremainseffectiveinthepresenceofsmallperturbations.

简介：Currentproceduresformass-flowhopperdesignarebasedontheradialstresstheorydevelopedbyJenikeandinvolvethedeterminationofthecriticaloutletdimensionsforflowtobeinitiated.Theseproceduresignorethesurchargeloadsonthehopperandinvolveastudyofthepassiveorarchedstressfieldthatexistsunderflowconditions.Analternativeapproachasappliedtohopperwallloadanalysisistoemploythehorizontalslicemethod.Thearchedstressfieldandhorizontalslicemethodsofanalysisarecompared.Theinfluenceofsurchargeloadsinthedeterminationofhoppergeometryisinvestigated.

简介：Acomparativeoptimaldesignoffluid-saturatedprismaticcellularmetalhoneycombs(PCMHs)havingdifferentcellshapesispresentedforthermalmanagementapplications.BasedontheperiodictopologyofeachPCMH,aunitcell(UC)forthermaltransportanalysiswasselectedtocalculateitseffectivethermalconductivity.Withoutintroducinganyempiricalcoefficient,wemodifiedandextendedtheanalyticalmodelofparallel–seriesthermal–electricnetworktoawiderporosityrange(0.7~0.98)byconsideringtheeffectsoftwo-dimensionallocalheatconductioninsolidligamentsinsideeachUC.Goodagreementwasachievedbetweenanalyticalpredictionsandnumericalsimulationsbasedonthemethodoffinitevolume.Theconceptofligamentheatconductionefficiency(LTCE)wasproposedtophysicallyexplainthemechanismsunderlyingtheeffectsofligamentconfigurationoneffectivethermalconductivity(ETC).Basedupontheproposedtheory,aconstructstrategywasdevelopedfordesigningtheETCbyalteringtheequivalentinteractionanglewiththedirectionofheatflow:relativelysmallaverageinteractionangleforthermalconductionandrelativelylargeoneforthermalinsulation.

简介：Wepresentadesignmethodforcalculatingandoptimizingsoundabsorptioncoefficientofmulti-layeredporousfibrousmetals(PFM)inthelowfrequencyrange.PFMissimplifiedasanequivalentidealizedsheetwithallmetallicfibersalignedinonedirectionanddistributedinperiodichexagonalpatterns.Weuseaphenomenologicalmodelintheliteraturetoinvestigatetheeffectsofporegeometricalparameters(fiberdiameterandgap)onsoundabsorptionperformance.ThesoundabsorptioncoefficientofmultilayeredPFMsiscalculatedusingimpedancetranslationtheorem.Todemonstratethevalidityofthepresentmodel,wecomparethepredictedresultswiththeexperimentaldata.Withtheaveragesoundabsorption(lowfrequencyrange)astheobjectivefunctionandthefibergapsasthedesignvariables,anoptimizationmethodformulti-layeredfibrousmetalsisproposed.Anewfibrouslayoutwithgivenporosityofmulti-layeredfibrousmetalsissuggestedtoachieveoptimallowfrequencysoundabsorption.Thesoundabsorptioncoefficientoftheoptimalmulti-layeredfibrousmetalishigherthanthesinglelayeredfibrousmetal,andasignificanteffectofthefibrousmaterialonsoundabsorptionisfoundduetothesurfaceporosityofthemulti-layeredfibrous.

简介：Thelargedesignfreedomofvariable-stiffness(VS)compositematerialpresupposesitspotentialforwideengineeringapplication.PreviousresearchindicatesthatthedesignofVScylindricalstructureshelpstoincreasethebucklingloadascomparedtoquasi-isotropic(QI)cylindricalstructures.Thispaperfocusesontheanti-bucklingperformanceofVScylindricalstructuresundercombinedloadsandtheefficientoptimizationdesignmethod.Twokindsofconditions,bendingmomentandinternalpressure,andbendingmomentandtorqueareconsidered.Influencesofthegeometricaldefects,ovality,onthecylinder'sperformancesarealsoinvestigated.Toincreasethecomputationalefficiency,anadaptiveKrigingmeta-modelisproposedtoapproximatethestructuralresponseofthecylinders.InthisimprovedKrigingmodel,amixedupdatingruleisusedinconstructingthemeta-model.Ageneticalgorithm(GA)isimplementedintheoptimizationdesign.TheoptimalresultsshowthatthebucklingloadofVScylindersinallcasesisgreatlyincreasedascomparedwithaQIcylinder.

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简介：Uncertaintyisinherentandunavoidableinalmostallengineeringsystems.Itisofessentialsignificancetodealwithuncertaintiesbymeansofreliabilityapproachandtoachieveareasonablebalancebetweenreliabilityagainstuncertaintiesandsystemperformanceinthecontroldesignofuncertainsystems.Nevertheless,reliabilitymethodswhichcanbeuseddirectlyforanalysisandsynthesisofactivecontrolofstructuresinthepresenceofuncertaintiesremaintobedeveloped,especiallyinnon-probabilisticuncertaintysituations.Inthepresentpaper,theissueofvibrationcontrolofuncertainstructuresusinglinearquadraticregulator(LQR)approachisstudiedfromtheviewpointofreliability.Ane?cientnon-probabilisticrobustreliabilitymethodforLQR-basedstaticoutputfeedbackrobustcontrolofuncertainstructuresispresentedbytreatingboundeduncertainparametersasintervalvariables.Theoptimalvibrationcontrollerdesignforuncertainstructuresiscarriedoutbysolvingarobustreliability-basedoptimizationproblemwiththeobjectivetominimizethequadraticperformanceindex.Thecontrollerobtainedmaypossessoptimumperformanceundertheconditionthatthecontrolledstructureisrobustlyreliablewithrespecttoadmissibleuncertainties.Theproposedmethodprovidesanessentialbasisforachievingabalancebetweenrobustnessandperformanceincontrollerdesignofuncertainstructures.Thepresentedformulationsareintheframeworkoflinearmatrixinequalityandcanbecarriedoutconveniently.Twonumericalexamplesareprovidedtoillustratethee?ectivenessandfeasibilityofthepresentmethod.

简介：Thepulsed-sprayfluid-bedgranulation(PSFBG)processwasinvestigatedandoptimizedusingdefinitivescreeningdesign,arecentlyproposednewclassofthree-leveldesignofexperimentmethod.Suchadesignenabledquadraticmodelstobeestablishedthatdescribedtheeffectofsixinputprocessparameters-inletairtemperature,inletairhumidity,bindersprayrate,atomizationpressure,pulseperiod,andpulsewidth-onthegranulequalityinaPSFBGprocess.Mathematicalmodelsofthemeanparticlesize,relativesizedistributionwidth,productionyield,andporosityweredevelopedtoquantifytherelationshipsbetweentheinfluencingfactorsandcriticalqualityattributes.Onthebasisofconstraintsonthedesiredgranuleproperties,adesignspaceforPSFBGwasdeterminedandrangesoftheoperatingparametersweredefined.Anacceptabledegreeofpredictionwasconfirmedbyvalidationexperiments,demonstratingthereliabilityandeffectivenessofusingdefinitivescreeningdesigntostudythePSFBGprocess.Thismethodcanacceleratescreeningandoptimizationofthisprocesswithinalargemultidimensionaldesignspace.