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L A B O R A T O R Y L E A R N I N G A C T I V I T Y
HoneycombStructures(GuidedInquiry)
IntroductionAcommonaimofmaterialsscientistsandengineersistocreatematerialswiththegreateststrengthandtheminimumweightandminimumamountofmaterials(minimumcost).Honeycombsandwichstructuresareoftenusedtoachievetheseoutcomesandareusedinaerospace,automotive,housing,packaging,sports-equipmentandotherindustries.Thesestructureshaveanarrangementoftubes(orchannels)sandwichedbetweentwowalls.
Glassaluminumreinforced(GLARE)honeycombcompositesandwich
structure.Photographhasbeenusedandredistributedunderaneducationalnon-
commerciallicencebypermissionofNASA.<https://commons.wikimedia.org/wiki/File:Glare_honeycomb.jpg>
Cardboardisoftenmadebysandwichingasheetofcorrugatedcardboardbetweentwosheetsofthickpaper.Incorrugatedcardboard,theopensectionsrunparalleltothewalls.
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Forcesappliedatrightanglestothehoneycombchannelswillcausethestructure
todeform.
Diagramofcorrugatedcardboard.
DiagrambyKieranFLim.
Insomeotherstructurestheopentubesarearrangedatrightanglestothewalls.Thesetubescanbedifferentshapesincrosssection.Theycouldbecircles,squares,trianglesorhexagons(likehoneycomb).
Honeycombpatternforstrengthincardboard.Imageby
sciencestockphotos.com.<http://sciencestockphotos.com/free/engineering/slides/cardboard_str
ength.html>
KeyideasForce-Aforceisapushorapull.Aforcecancausemovementinanobjectorcausecompression,tensionortorsionwithintheobject.
Impact-Impactorimpactforceisashockorlargeforceappliedforaveryshorttime.
Compressionforce–apushthatsqueezesanobjecttotrytomakeitsmallerorshorter.
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Tensionforce–apullstretchesanobjecttotrytomakeitbiggerorlonger.
Strength–Theabilityofamaterialtoresistbreakingwhenaforceisapplied.
Strengthtomassratio-Thisisameasureofthestrengthofamaterialcomparedtoitsmass.
Investigation-Ascientificprocessofansweringaquestion,exploringanideaorsolvingaproblemthatrequiresactivitiessuchasplanningacourseofaction,collectingdata,interpretingdata,reachingaconclusionandcommunicatingtheseactivities
Variable-Somethingthatcanchange.
Dependentvariable-Variablethatchangesinresponsetochangesintheindependentvariableandthatisobservedormeasured.
Independentvariable-Variablethatisdeliberatelychanged.
Controlledvariables-Variablesthatarekeptconstant.
Fairtest-Whentestingdifferentmaterialsallthevariablesexcepttheonebeingtestedneedtobekeptthesame.
Equipmentandmaterials• Kirigamihoneycombtemplate• Paper,cardboard,straws• Scissors• Craftknives• Glue• Rulers• Pencils• Weights,bricks
InvestigationInthisactivity,yourtaskistochooseaquestionaboutthestrengthofhoneycombstructuresandthenyouwillformulateahypothesisbasedonscientificknowledge.Onceyouhaveyourquestionyouneedtodesignawaytoansweritbyconstructingthedifferenthoneycomb
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structuresoutofpaper,cardboardandglueandtestingtheirstrength.Youwillensurethatyourtestswillbefairandprovidedatarelevanttoansweringyourquestion.Youwillcollect,analyseandevaluatethedatacommunicatingyourfindingsappropriately.
HazardsCuttingmaterialswithscissorsorbladesposestheriskofcuts.Careshouldbetakentokeephandsandfingersoutoftheway.Alwayscutwayfromyourself.Makesuresharpobjectsarestoredsafelywhentheyarenotbeingused.
Testingthesandwichmaterialswithloadshaspotentialforinjury.Caremustbetaken.Ensureallpeopleareatasafedistance.
KirigamihexagonalhoneycombstructureTheJapaneseartofkirigamiinvolvesbothcuttingandfoldingsheetsofpapertoobtainthree-dimensionalshapes.Recently,scientistsusedkirigamitocreateshape-shiftingmaterials,whichcouldhavelargeshapeandvolumechangesandwithextremelydirectional,tuneablemechanicalproperties[Footnote4].
Templateforkirigamihexagonalhoneycombstructure.
DiagrambyKieranFLim.
4 Neville,R.M.,Scarpa,F.,&Pirrera,A.(2016).ShapemorphingKirigamimechanicalmetamaterials.ScientificReports,6,Articlenumber31067.doi:10.1038/srep31067.Retrieved10October2017from<https://www.nature.com/articles/srep31067>.
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UsinganA3-sizedversionoftheKirigamihoneycombtemplate,constructahoneycombstructure.First,foldalongthedottedlinestomaketwofoldsup,twofoldsdown,andrepeatingthispattern.
DiagrambyKieranFLim.
Nextcutalongthesolidlines.Thenfoldinaconcertinapatternalongthelinesofthecuts.
Thekirigamihexagonalhoneycombstructure.DetailfromFigure2of
Neville,Scarpa,andPirrera(2016).FigureusedunderaCreativeCommons(CCBY4.0)licence.
<https://www.nature.com/articles/srep31067>
Finally,glue(orstaple)theflapstogethertoformahexagonalhoneycombstructure.
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Ahexagonalhoneycombstructure.Imagebysciencestockphotos.com.<http://sciencestockphotos.com/free/engineering/slides/cardboard_str
ength.html>
Makeapredictionoftheloadthatcanbesupportedbythegluedkirigamihoneycombstructure.
Weighabookorothersolidflatobjectandplacethatonthegluedkirigamihoneycombstructure.Addweightstothebookorothersolidflatobjectuntilthestructurecollapses.Whatwasthetotalmassontheload?Isthiswhatyouexpected?
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ScientificquestionTherearemanyscientificquestionsthatcouldbeaskedabouthoneycombstructures.
• Howdoesthestrengthofthehoneycombstructuredependonthenumberoftubesoropenchannels?
• Doesthestrengthofthehoneycombstructuredependonthehexagonalcross-sectionalshapeofthetubesoropenchannels?Whatifthetubesoropenchannelsweretriangular,orsquareorcircular?
• Whatwouldhappenifwehadseparatetubes,butnotconnectedorgluedtoeachother?
DiagrambyKieranFLim.
• Doesthestrengthofthehoneycombstructuredependonwhetherthetubesaregluedorjoinedtogether?
Whatloadcanbesupportedbyanumberofjoinedidentical
“tubes”?DiagrambyKieranFLim.
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Yourteacherwillleadadiscussiontodecidewhichscientificquestionswillbeinvestigated.Yourgroupwillthendecidehowtoinvestigatethatquestion.
Thescientificquestionthatmygroupwillinvestigateis:
Ahypothesisisatestable“educated-guess”answertoascientificquestion.Ahypothesisleadstooneormorepredictionsthatcanbetestedbyaninvestigation.
Ourhypothesisis:
Remembertothinkaboutvariablesthatwillneedtobecontrolledtoensurea“fairtest”.Decidewhichvariablesyouwillkeepthesame(controlledvariables)whichvariableyouwillchange(independentvariable)andwhichvariableyouwillmeasure(dependentvariable).
Ourindependentvariableis:
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Ourdependentvariableis:
Ourcontrolledvariablesare:
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Wewillusethefollowingexperimentalprocedure.(Ifappropriate,makeadrawingofyourproposal.)
Arethereanysafetyissuestoconsider?
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ResultsWhathappened?Recordyourobservationsormeasurements.(Hint:putallthedataonasinglegraph.)
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DiscussionWhattrend(s)canbeobservedinyourdata?(Hint:Useappropriatescientificlanguageandrepresentations.)
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Drawapicturerepresentingwhathappenswhenloadisplacedonasinglehoneycombtubeorchannel.
Drawapicturerepresentingwhathappenswhenloadisplacedonasetoflinkedhoneycombtubesorchannels.
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ExtensionConstructahoneycombstructureusingcoffeecups[Footnote5].Gaffertapeshouldbeusedtostickthetopsofthecupstogether(lengthwise)andcontinuearoundthebottomsofthecups(alsolengthwise).Alsousegaffertapetomakesomecrosswisebindings.
Coffeecup-honeycombsandwichstructure.
Photographbybertus52x11,andusedunderaCreativeCommonsGeneric(CCBY-NC-SA2.5)licence.
<http://www.instructables.com/id/Coffee-Cup-Honeycomb-Sandwich-Structure/>
Makeapredictionoftheloadthatcanbesupportedbythecoffeecuphoneycombstructure.
5 bertus52x11(n.d.).Coffeecup-honeycombsandwichstructure.Retrieved10October2017from<http://www.instructables.com/id/Coffee-Cup-Honeycomb-Sandwich-Structure/>.
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Testthemaximumloadthatcanbesupportedbythecoffeecuphoneycombstructure.Whatwasthetotalmassontheload?Isthiswhatyouexpected?
ConclusionWhatconclusionscanbesupportedbyyourdataandotherthoughtsandobservations?
AcknowledgementsThecontributionsofmembersofScoutsVictoriatotherefinementofthislaboratorylearningactivityaregratefullyacknowledged.
• PhotographofahoneycombpatternforstrengthincardboardhasbeenusedandredistributedunderaCreativeCommons(CCBY4.0)licence<sciencestockphotos.com/imagelicense.html>.
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• FiguresfromNeville,Scarpa,&Pirrera(2016)“ShapemorphingKirigamimechanicalmetamaterials”havebeenusedandredistributedunderaCreativeCommons(CCBY4.0)licence<https://creativecommons.org/licenses/by/4.0/>.
• PhotographofacoffeecuphoneycombsandwichstructurehasbeenusedandredistributedunderaCreativeCommons(CCBY-NC-SA2.5)licence<https://creativecommons.org/licenses/by-nc-sa/2.5/>.
• PhotographofGlassAluminumReinforced(GLARE)honeycombcompositesandwichstructurehasbeenusedandredistributedunderaneducationalnon-commerciallicencebypermissionofNASA<https://www.nasa.gov/multimedia/guidelines/index.html>.
CopyrightandCreativeCommonsExceptinglogos,trademarksorotherthird-partycontentasindicated,thisresourceisdistributedunderaCreativeCommons‘Attribution-NonCommercial-ShareAlike’4.0InternationalLicense.Themoralrightsoftheauthors,KieranLim,StuartPalmer,IanBentley,PetaWhite,JohnLong,RussellTytler,andMaryVamvakas,havebeenassertedundertheAustralianCopyrightAct1968(Cth).