简介:Thereisincreasingobservationalevidenceindicatingthatcrystallineinterfacialwaterlayersplayacentralroleinevolutionandbiology.Forinstanceincellularrecognitionprocesses,inparticularduringfirstcontactevents,wherecellsdecideuponsurvivalorenteringapoptosis.Understandingwaterlayersisthuscrucialinbiomedicalengineering,specificallyinthedesignofbiomaterialsinspiredbybiomimeticprinciples.Whereasthereisampleexperimentalevidenceforcrystallineinterfacialwaterlayersonsurfacesinair,theirsubaquaticpresencecouldnotbeverifieddirectly,sofar.Analysingapolaritydependentasym-metryinthesurfaceconductivityonhydrogenatednanocrystallinediamond,weshowthatcrystallineinterfacialwaterlayerspersistsubaquatically.Nanoscopicinterfacialwaterlayerswithanorderdifferentfromthatofbulkwaterhavebeenidentifiedatroomtemperatureonbothhydrophilicandhydrophobicmodelsurfaces-inairandsubaquatically.Theirgeneralizationandsystematicinclusionintothecatalogueofphysicalandchemicaldeterminantsofbiocompatibilitycompletethebiomimetictriangle.
简介:Thispaperpresentsthedesignandprototypeofasmallquadrupedrobotwhosewalkingmotionisrealizedbytwopie-zocompositeactuators.Inthedesign,biomimeticideasareemployedtoobtaintheagilityofmotionsandsustainabilityofaheavyload.Thedesignoftherobotlegsisinspiredbythelegconfigurationofinsects,twojoints(hipandknee)ofthelegenabletwobasicmotions,liftingandstepping.Therobotframeisdesignedtohaveasloperelativetothehorizontalplane,whichmakestherobotmoveforward.Inaddition,theboundinglocomotionofquadrupedanimalsisimplementedintherobot.Experimentsshowthattherobotcancarryanadditionalloadofabout100gandrunwithafairlyhighvelocity.Thequadrupedprototypecanbeanimportantsteptowardsthegoalofbuildinganautonomousmobilerobotactuatedbypiezocompositeactuators.
简介:AreviewontheresearchofMicroElectromechanicalSystems(MEMS)technologybasedbiomimeticciliaispresented.Biomimeticcilia,enabledbytheadvancementofMEMStechnology,havebeenunderdynamicdevelopmentforthepastdecade.AfterabriefdescriptionofthebackgroundofciliaandMEMStechnology,differentbiomimeticciliaapplicationsarereviewed.Biomimeticciliamicro-actuators,includingmicromachinedpolyimidebimorphbiomimeticciliamicro-actuator,electro-staticallyactuatedpolymerbiomimeticciliamicro-actuator,andmagneticallyactuatednanorodarraybiomimeticciliamicro-actuator,arepresented.Subsequentlymicromachinedunderwaterflowbiomimeticciliamicro-sensorisstudied,followedbyacousticflowmicro-sensor.ThefabricationoftheseMEMS-basedbiomimeticciliadevices,characterizationoftheirphysicalproperties,andtheresultsoftheirapplicationexperimentsarediscussed.
简介:WehavestudiedabiomimeticswimmerbasedonthemotionofbacteriasuchasEscherichiacoli(E.coli)theoreticallyandexperimentally.Theswimmerhasanellipsoidalcellbodypropelledbyahelicalfilament.Theperformanceofthisswimmerwasestimatedbymodelingthedynamicsofaswimmerinviscousfluid.WeappliedtheResistiveForceTheory(RFT)onthismodeltocalculatethelinearswimmingspeedandtheefficiencyofthemodel.Aparametricstudyonlinearvelocityandefficiencytooptimizethedesignofthisswimmerwasdemonstrated.Inordertovalidatethetheoreticalresults,abiomimeticswimmerwasfabricatedandanexperimentsetupwaspreparedtomeasuretheswimmingspeedandthrustforceinsiliconeoil.TheexperimentalresultsagreewellwiththetheoreticalvaluespredictedbyRFT.Inaddition,westudiedtheflowpatternssurroundingthefilamentwithafiniteelementsimulationwithdifferentReynoldsnumber(Re)tounderstandthemechanismofpropulsion.Thesimulationresultsprovideinformationonthenatureofflowpatternsgeneratedbyswimmingfilament.Furthermore,thethrustforcesfromthesimulationwerecomparedwiththethrustforcesfromtheory.Thesimulationresultsareingoodagreementwiththetheoreticalresults.
简介:Theunsteadyhydrodynamicsofabiomimeticfinattachedtoacylindricalbodyhasbeenstudiednumericallyusingacomputationalfluiddynamic(CFD)simulatorbasedonanin-housesolveroftheNavier-Stokesequations,combinedwitharecentlydevelopedmulti-block,oversetgridmethod.Thefin-bodyCFDmodelisbasedonamechanicalpectoralfindevice,whichconsistsofacylindricalbodyandanasymmetricfinandcanmimicflapping,rowingandfeatheringmotionsofthepectoralfinsinfishes.Firstthemulti-block,oversetgridmethodincorporatedintotheNSsolverwasverifiedthroughanextensivestudyofunsteadyflowspastasinglefinundergoingrowingandfeatheringmotion.Thenunsteadyflowspastthebiomimeticfin-bodymodelundergoingthesamemotionswerecomputedandcomparedwiththemeasurementsofforcesofthemechanicalpectoralfin,whichshowsgoodagreementinbothtime-varyingandtime-averagedhydrodynamicforces.Therelationshipbetweenforcegenerationandvortexdynamicspointstotheimportanceofthematchinfinkinematicsbetweenpowerandrecoverystrokesandimpliesthatanoptimalselectionofparametersofphaselagsbetweenandamplitudesofrowingandfeatheringmotionscanimprovetheperformanceoflabriformpropulsionintermsofeithermaximumforcegenerationorminimummechanicalpower.
简介:Whilemuchattentionhasbeengiventobio-roboticsinrecentyears,notmuchofthishasbeengiventothechallengingsubjectoflocomotioninslipperyconditions.Thisstudybeginstorectifythisbyproposingabiomimeticapproachtogeneratingthefrictionrequiredtogivesufficientpropulsiveforceonaslipperysubstrate.Wetookinspirationfromasuccessfulbiologicalsolution-thatofapplyinghair-likestructurestothepropulsiveappendages,similartothesetaefoundinnereidpolychaeteslivinginmuddyhabitats.Webeganbyexaminingthemorphologyandthemeanlocomotionparametersofoneofthemostcommonnereids:Nereisdiversicolor.Followingthisstudy,wedesignedandfabricatedaroboticsystemwithappendagesimitatingthebiologicalshapefoundintheworm.Aflexiblecontrolsystemwasdevelopedtoallowmostofthelocomotionparametersobservedintherealwormtobeappliedtotherobot.Experimentsonthreedifferentnaturalsubstratesrangingfromfinesandtogravelshowedthat,whereasaplateattachedtotheappendagegeneratedmostthrustonasmallparticlesubstrate,abundleofartificialsetaeattachedtotheappendagegeneratedmostthrustonalargeparticlesubstrate.Onalltypesofsubstratetested,anappendagewithoutanyattachmentdidsignificantlyworsethanonewith.Thissuggeststhathair-likestructurescanbeadvantageous.
简介:Wedescribethedesignoffourornithoptersranginginwingspanfrom10cmto40cm,andinweightfrom5gto45g.Thecontrollabilityandpowersupplyaretwomajorconsiderations,sowecomparetheefficiencyandcharacteristicsbetweendif-ferenttypesofsubsystemssuchasgearboxandtailshape.Ourcurrentornithopterisradio-controlledwithinbuiltvisualsensingandcapableoftakeoffandlanding.Wealsoconcentrateonitswingefficiencybasedondesigninspiredbyarealinsectwingandconsiderthataspectsofinsectflightsuchasdelayedstallandwakecaptureareessentialatsuchsmallsize.Mostimportantly,theadvanceratio,controlledeitherbyenlargingthewingbeatamplitudeorraisingthewingbeatfrequency,isthemostsignificantfactorinanornithopterwhichmimicsaninsect.
简介:Theeffectsofbiomimeticdesignsoftinefurrowopenersurfaceonequivalentpressureandpressureinthedirectionofmotiononopenersurfaceagainstsoilwerestudiedbyfiniteelementmethod(FEM)simulationandtheeffectsofthesedesignsontoolforceandpowerrequirementswereexaminedexperimentally.Geometricalstructuresofthecuticlesurfacesofdungbeetle(CoprisochusMotschulsky)wereexaminedbystereoscopy.ThestructuresofthecuticlesurfacesandUltraHighMo-lecularWeightPolyethylene(UHMWPE)materialweremodeledonsurfaceoftinefurrowopenerasbiomimeticdesigns.SevenfurrowopenerswereanalyzedinANSYSprogram(aFEMsimulationsoftware).ThebiomimeticfurrowopenersurfaceswithUHMWPEstructureswerefoundtohavelowerequivalentpressureandpressureinthedirectionofmotionascomparedtotheconventionalsurfaceandtothebiomimeticsurfaceswithtexturedsteel-35structures.ItwasfoundthatthetoolforceandpowerwereincreasedwiththecuttingdepthandoperatingspeedandthebiomimeticfurrowopenerwithUHMWPEtubularsectionridgesshowedthelowestresistanceandpowerrequirementagainstsoil..
简介:Waterstridershaveremarkablewater-repellentlegsthatenablethemtostandeffortlesslyandmovequicklyonwater.Fluidphysicsindicatesthisfeatureisduetoasurface-tensioneffectcausedbythespecialhierarchicalstructureofthelegs,whicharecoveredwithalargenumberofinclinedsetaewithfinenanogroovesinducingwaterresistance.Thisinspiresustofabricatespecialwater-repellentstructureonfunctionalsurfacesthroughthecooperationbetweenthesurfacetreatmentandthesurfacemicro-andnanostructures,whichmaybringgreatadvantagesinawidevarietyofapplications.InthispaperwepresentaprocedureforfabricatingbiomimeticwaterstriderlegscoveredwithsetaeusingPolycarbonateTrack-Etched(PCTE)membranesastemplates.Bychoosingappropriatemembranelengths,diameters,pitchesanddensitiesofthesetae,thebiomimeticlegscanbefabricatedconvenientlyandatalowcost.Furthermoreweinvestigatedtherelationshipbetweenstiffnessofthemoldingmaterials,highaspectratioanddensity,whichaffectthefidelityoffabricationandselfadhesion,tooptimizethestabilityofsetae.Theknowledgewegainedfromthisstudywillofferimportantinsightsintothebiomimeticdesignandfabricationofwaterstridersetae.
简介:Wehavecarriedoutanexperimentalstudyofliquiddropimpactonsuperhydrophobicsubstratescoveredbyacarpetofchemicallycoatednano-wires.Themicro-structureofthesurfaceissimilartosomebiologicalones(Lotusleafforexample).Inthissituationthecontactanglecanthenbeconsideredasequalto180degrees,withnohysteresis.Duetoitsinitialinertia,thedropexperiencesaflatteningphaseafterithitsthesurface,takingtheshapeofapancake.Onceitreachesitsmaximallateralextension,thedropbeginstoretractandbouncesback.Wehaveextractedthelateralextensionofthedrop,andweproposeamodelthatexplainsthetrend.Wefindalimitinitialvelocitybeyondwhichthedropprotrudesintothenano-wirecarpet.Wediscusstherelevanceofpracticalissuesintermsofself-cleaningsurfacesorspray-cooling.
简介: Thebonecompositewasproducedbybiomimeticsynthesis.Itshowssomefeaturesofnaturalboneinbothcompositionandmicrostructure.Andthecollagenmolecularsandthenano-crystalhydroxyapatiteassembleintoultrastructuresimilartonaturalbone.Itpossessesporousstructurewithporosityfrom100μmto500μmaftermixedwithPLA(polylacticacid). ……
简介:Naturalsurfaceswithsuperhydrophobicpropertiesoftenhavemicroorhierarchicalstructures.Inthispaper,thewettingbehavioursofasingledropletonbiomimeticmicrostructuredsurfaceswithdifferentroughnessparametersareinvestigated.Atheoreticalmodelisproposedtostudywettingtransitions.Theresultsoftheoreticalanalysisarecomparedwiththoseofexperimentindicatingthattheproposedmodelcaneffectivelypredictthewettingtransition.Furthermore,anumericalsimulationbasedonthemesoscaleLatticeBoltzmannMethod(LBM)isperformedtostudydynamiccontactangles,contactlines,andlocalvelocityfieldsforthecasethatadropletdisplaysonthemicrostructuredsurface.Asphericalwaterdropletwithrs=15μmfallsdowntoabiomimeticsquare-postpatternedsurfaceundertheforceofgravitywithaninitialvelocityof0.01m·s-1andaninitialverticaldistanceof20μmfromdropletcentretothetopofpots.Inspiteofahigherinitialvelocity,thedropletcanstillstayinaCassiestate;moreover,itreachesanequilibriumstateatt≈17.5ms,whencontactangleis153.16°whichisslightlylowerthanthepredictionofCassie-Baxter’sequationwhichgivesθCB=154.40°.
简介:Leukocyterollingandadhesionarecomplexphysiologicalprocessesthathavereceivedagreatdealofattentionoverthepastdecade.Significantincreasesintheknowledgebaserelatedtohowleukocytesadhereinshearflowshaveoccurredasaresultofthedevelopmentofnovelexperimentalandcomputationaltechniques.Micro-andnano-fabricationtechniqueshaveenabledthedevelopmentofnovelflowdevicesforstudyingleukocyteadhesioninsimpleandcomplexgeometries.Improve-mentsincomputertechnologyhaveenabledsimulationsofcomplexflowprocessestobedeveloped.Asaresultofthesead-vancesinknowledgerelatedtoleukocyteadhesion,numerousnoveldeviceshavebeendevelopedthatmimictheleukocyterollingandadhesionprocess.Examplesofthesedevicesincludecellseparationandenrichmentdevicesandtargetedultrasoundcontrastagents.Futureadvancesrelatedtoleukocyterollingandadhesionprocessesholdgreatpromiseforadvancingourknowledgeofdiseaseprocessesaswellasdevelopmentofnoveltherapeuticdevices.
简介:Theuseofoscillatingflexiblefinsinpropulsionhasbeenthesubjectofseveralstudiesinrecentyears,butattentionisrarelypaidtothespecificroleofstiffnessprofileinthrustproduction.Stiffnessprofileisdefinedasthevariationinlocalchordwisebendingstiffness(EI)ofafin,fromleadingtotrailingedge.Inthisstudy,flexiblefinswithastandardNACA0012shapeweretestedalongsidefinswithastiffnessprofilemimickingthatofaPumpkinseedSunfish(Lepomisgibbosus).Thefinswereoscillatedwithapitchingsinusoidalmotionoverarangeoffrequenciesandamplitudes,whiletorque,lateralforceandstaticthrustweremeasured.Overtherangeofoscillationparameterstested,itwasshownthatthefinwithabiomimeticstiffnessprofileofferedasignificantimprovementinstaticthrust,comparedtoafinofsimilardimensionswithastandardNACA0012aerofoilprofile.Thebiomimeticfinalsoproducedthrustmoreconsistentlyovereachoscillationcycle.Acomparisonoffinmaterialsofdifferentstiffnessshowedthattheimprovementwasduetothestiffnessprofileitself,andwasnotsimplyaneffectofalteringtheoverallstiffnessofthefin.Finsofthesamestiffnessprofilewereobservedtofollowthesamethrust-powercurve,independentofthestiffnessofthemouldingmaterial.Biomimeticfinswereshowntoproduceupto26%greaterthrustperwattofinputpower,withintheexperimentalrange.
简介:Manyanimalsandplantshavehighpotentialtoserveasconceptgeneratorsfordevelopingbiomimeticmaterialsandstructures.Wepresentsomeideasbasedonstructuralandfunctionalpropertiesofplantsandanimalsthatledtothedevelopmentoftwotypesofbiomimeticcableentrysystems.Thosesystemshavebeenrealizedontheleveloffunctionaldemonstrators.
简介:Thispaperpresentsthedevelopmentofamesoscaleself-containedquadrupedmobilerobotthatemploystwopiecesofpiezocompositeactuatorsfortheboundinglocomotion.Thedesignoftherobotlegisinspiredbyleggedinsectsandanimals,andthebiomimeticconceptisimplementedintherobotinasimplifiedform,suchthateachlegoftherobothasonlyonedegreeoffreedom.Thelackofdegreeoffreedomiscompensatedbyaslopeoftherobotframerelativetothehorizontalplane.Fortheimplementationoftheself-containedmobilerobot,asmallpowersupplycircuitisdesignedandinstalledontherobot.Experimentalresultsshowthattherobotcanlocomoteatabout50mm·s-1withthecircuitonboard,whichcanbeconsideredasasignificantsteptowardthegoalofbuildinganautonomousleggedrobotactuatedbypiezoelectricactuators.