简介:Theplowofthesubmarineplowingtrencherisoneofthemainfunctionalmechanisms,anditsoptimizationisveryimportant.Thedesignparametersplayaverysignificantroleindeterminingtherequirementsofthetowingforceofavessel.Amulti-objectivegeneticalgorithmbasedonanalyticalmodelsoftheplowsurfacehasbeenexaminedandappliedineffortstoobtainoptimaldesignoftheplow.Foraspecificsoilcondition,thedraftforceandmoldboardsurfaceareawhicharethekeyparametersintheworkingprocessoftheplowareoptimizedbyfindingthecorrespondingoptimalvaluesoftheplowbladepenetrationangleandtwosurfaceanglesofthemaincuttingbladeoftheplow.Parameterssuchasthemoldboardsideangleofdeviation,moldboardliftangle,angularvariationofthetangentline,andthespanninglengtharealsoanalyzedwithrespecttotheforceofthemoldboardsurfacealongsoilflowdirection.Resultsshowthattheoptimizedplowhasanimprovedplowperformance.Thedraftforcesofthemaincuttingbladeandthemoldboardare10.6%and7%,respectively,lessthantheoriginaldesign.ThestandarddeviationofGaussiancurvatureofmoldboardisloweredby64.5%,whichimpliesthatthesmoothnessoftheoptimizedmoldboardsurfaceismuchgreaterthantheoriginal.
简介:Rigidblockingmassesarelocatedinthetypicalbasestructureofapowercabinbasedontheimpedancemismatchprinciple.Bycombiningtheacoustic-structuralcouplingmethodandstatisticalenergyanalysis,thefull-bandvibrationandsoundradiationreductioneffectofvibrationisolationmasseslocatedinabasestructurewasresearched.Theinfluenceoftheblockingmass’cross-sectionsizeandshapeparametersandthelayoutlocationofthebaseisolationperformancewasdiscussed.Furthermore,theeffectivenessofrigidvibrationisolationdesignofthebasestructurewasvalidated.Theresultsshowthatthemediumandhighfrequencyvibrationandsoundradiationofapowercabinareeffectivelyreducedbyablockingmass.Concerningweightincrementandsectionrequirement,suitablyincreasingtheblockingmasssizeandsectionheightandreducingsectionwidthcanresultinanefficiency-costratio.
简介:Inthisstudy,thepassageofwavesthroughpilegroupswithdifferentarrangementsisinvestigatedusingathree-dimensional(3D)numericalmodel.Forthesimulations,wavesofthreedifferentheightsof36,58,and81mm,afixedperiodof0.88s,andafixedwavelengthof1.128mwereused.Tosimulatethewavesandflowpatternthroughthepiles,Reynolds-averagedNavier–Stokes(RANS)equationsoffluidmotionweresolvedbasedonthefinitevolumemethod(FVM).Pilesweredefinedasobstaclesintherectangulardomainusingthefractionalarea/volumeobstaclerepresentation(FAVOR)method.Thevolume-of-fluid(VOF)andre-normalizationgroup(RNG)methodswereusedtosimulatethefreesurfaceandturbulencephenomenon,respectively.Byperformingdifferentnumericalsimulations,theeffectofcoastalpilearrangementsonwavepatternwasstudiedandwascomparedwithexistingexperimentaldata,andanacceptableagreementwasachieved.
简介:Inordertostudytheeffectsofgeometricparametersoftherudderonthehydrodynamicperformanceofthepropeller-ruddersystem,thesurfacepanelmethodisusedtobuildthenumericalmodelofthesteadyinteractionbetweenthepropellerandruddertoanalyzetherelevantfactors.Theinteractionbetweenthepropellerandrudderisconsideredthroughtheinducedvelocities,whicharecircumferentiallyaveraged,sotheunsteadyproblemistranslatedtosteadystate.Aniterativecalculationmethodisuseduntilthehydrodynamicperformanceconverges.Firstly,thehydrodynamicperformanceofthechosenpropeller-ruddersystemiscalculated,andthecomparisonbetweenthecalculatedresultsandtheexperimentaldataindicatesthatthecalculationprogramisreliable.Then,thevariableparametersofrudderareinvestigated,andthecalculationresultsshowthatthepropeller-rudderspacinghasanegativerelationshipwiththeefficiencyofthepropeller-ruddersystem,andtherudderspanhasanoptimalmatchrangewiththepropellerdiameter.Futhermore,therudderchordandthicknessbothhaveapositivecorrelationwiththehydrodynamicperformanceofthepropeller-ruddersystem.
简介:Inconsideringthetheoryofstructuraldynamicoptimizationdesign,adesignmethodofthestructuralstyleofshipcompositebracewithrigidvibrationisolationmasswasstudied.Twokindsofstructuraldynamicoptimizationformulationsminimizingthevibrationaccelerationofthenon-pressurehullontherestrainingconditionofthegrossweightoftheshipcabinwereestablished:1)dynamicoptimizationofthesectionaldimensionsoftherigidvibrationisolationmassinthecompositebrace;2)dynamicoptimizationofthearrangingpositionoftherigidvibrationisolationmass.Throughtheoptimizationresults,sectionaldimensionsandthearrangingpositionoftherigidvibrationisolationmasswithbetterperformanceinreducingvibrationweregained,andsomereferencewasprovidedforpracticalengineeringdesignsaswellasenrichmentofthedesignmethodofanovelshipvibration-isolationbrace.