简介:Beetlewingsareveryspecializedflightorgansconsistingoftheveinsandmembranes.Thereforeitisnecessaryfromabionicviewtoinvestigatethematerialpropertiesofabeetlewingexperimentally.Inthepresentstudy,wehaveusedaDigitalImageCorrelation(DIC)techniquetomeasuretheelasticmodulusofabeetlewingmembrane.Specimenswerepreparedbycarefullycuttingabeetlehindwinginto3.0mmby7.0mmsegments(thegagelengthwas5mm).Weusedascanningelectronmicroscopeforaprecisemeasurementofthethicknessofthebeetlewingmembrane.Thespecimenwasattachedtoadesignedfixturetoinduceauniformdisplacementbymeansofamicromanipulator.WeusedanARAMISTMsystembasedonthedigitalimagecorrelationtechniquetomeasurethecorrespondingdisplacementofaspecimen.Thethicknessofthebeetlewingvariedatdifferentpointsofthemembrane.Theelasticmodulusdifferedinrelationtothemembranearrangementshowingastructuralanisotropy;theelasticmodulusinthechordwisedirectionisapproximately2.65GPa,whichisthreetimeslargerthantheelasticmodulusinthespanwisedirectionof0.84GPa.Asaresult,thedigitalimagecorrelation-basedARAMISsystemwassuc-cessfullyusedtomeasuretheelasticmodulusofabeetlewing.Inadditiontomembrane’selasticmodulus,weconsideredthePoisson’sratioofthemembraneandmeasuredtheelasticmodulusofaveinusinganInstronuniversaltensilemachine.TheresultrevealsthePoisson’sratioisnearlyzeroandtheelasticmodulusofaveinisabout11GPa.
简介:Climbingrobotsareofpotentialuseforsurveillance,inspectionandexplorationindifferentenvironments.Inparticular,theuseofclimbingrobotsforspaceexplorationcanallowscientiststoexploreenvironmentstoochallengingfortraditionalwheeleddesigns.Toadheretosurfaces,biomimeticdryadhesivesbasedongeckofeethavebeenproposed.Thesebiomimeticdryadhesivesworkbyusingmulti-scalecompliantmechanismstomakeintimatecontactwithdifferentsurfacesandadherebyusingVanderWaalsforces.Fabricationoftheseadhesiveshasfrequentlybeenchallenginghowever,duetothedifficultyincombiningmacro,microandnanoscalecompliance.Wepresentanallpolymerfootdesignforusewithahexapodclimbingrobotandafabricationmethodtoimprovereliabilityandyield.Ahighstrength,low-modulussilicone,TC-5005,isusedtoformthefootbaseandmicroscalefibresinonepiecebyusingatwopartmold.Amacroscalefootdesignisproducedusinga3Dprintertoproduceabasemold,whilelithographicdefinitionofmicroscalefibresinathickphotoresistformsthe‘hairs’ofthepolymerfoot.Theadhesionofthesiliconefibresbythemselvesorattachedtothemacrofootisexaminedtodeterminebeststrategiesforplacementandremovaloffeettomaximizeadhesion.Resultsdemonstratethesuccessfulintegrationofmicroandmacrocompliantfeetforuseinclimbingonavarietyofsurfaces.