International Review of Mechanical Engineering (I.RE.M.E.), Vol. 8, N. 1 ISSN 1970 - 8734January 2014 Manuscript received and revised December 2013, accepted January 2014 Copyright 2014 Praise Worthy Prize S.r.l. - All rights reserved 89 Material Properties of Random Oriented Pressed Mat Coir Fibre/ Epoxy Composites Mohd Amirul Abdul Rahman, Munaim Ali Omar Baki, Azmin Shakrine Mohd Rafie, Renuganth A/L Vartharajoo AbstractThematerialmechanicalpropertiesofcoirfibre/epoxycompositewereevaluated. Highincreaseinconsumptionofcoconutfruitforfoodprocessingandotherindustrialusage nowadays lead to increaseinth productionofcoconuttrashinthe formofcoir fibre.Thesecoir fibres mostly disposed as unwanted waste since there are not much further applications toutilize thecoir fibres.Furthermore, theaerospace industries currentlyarelooking for moreto optimize the performance of the existing materials (e.g. metal and synthetic fibre composite) that would be introduced in aircraft structurewhichrelativelycutthecostinproduction, maintenance,and in-serviceaircraft,eco-friendly,andlowinweightfactor.Therefore,naturalfibrereinforce composite might be recommender answers to solve these existingproblems wherebythis solution already been introduced in the automotive and civil application. The existing raw coir fibres used are inthe form of pressed matandoriginallyin therandomoriented fibre form.They have been useddirectlyinthecompressionmouldingprocesstogetherwithdifferentfibreweightratioof 20%to50%withepoxyresinsunderroomtemperatureandcontrolledpressureforcomposite fabrication process. The fibres underwent no modification at all. Then the fabricated panels have undergonemechanical material tests;tensile,flexuralandtorsion testwith accordanceto ASTM standardtoobtainmechanicalpropertiesofthematerialincludingtensilestrength,tensile modulus and shear modulus. These properties data will be recorded and might be used for further analysissuchasaeroelasticanalysis.Theresultsshownthecompositewiththehigherfibre percentage being more flexible (higher tensile strength) and less than 50% of fibre loading, rigid composites were obtained. Copyright 2014 Praise Worthy Prize S.r.l. - All rights reserved. Keywords: CoconutCoirFibre,MaterialMechanicalProperties,NaturalFibreComposites, Epoxy Resin, Random Oriented Fibre Composite I.Introduction Theintroductionofnaturalfibreinthedesignand fabricationofcompositecouldbeaddedupasthe advantageespeciallyintermoftheutilizationofgreen technologyandlowincostmaterialinthemodern aircraft design process. Natural fibres such as coconut fibres are the fibres that extracted originally from coconut plant. The increment in consumptionsofcoconutfruitforfoodprocessingand other industrial usage in the presence day lead to increase intheproductionofnon-recyclablecoconuttrashinthe form of coconut husks. Therefore,anyrecommendedutilizationofthiswaste coirfibrethatextractedfromcoconuthusksmightbe seenasagoodrespondtomakeusethisabundantly availablerawmaterial.Untilpresenceday,theyhave beenusedforaseveralapplicationsincludingciviland mechanical structures. Nowadays,theymightregardasoneofthe significancevalueincommercialsectorsincetherapid growthinpublicawarenesstowardstheutilizationof environmental friendly materials. Thisgrowingenvironmentalconcernalsomight attracttheaerospaceindustriesinthefuturefortheir application of green technology ranging from design and manufacturingtoin-serviceaircraft.Inaddition,other criteriathatwouldaffectaircraftperformancesuchas weightandcostreductionalsowouldbetakeninto accountparticularlyinthematerialselectionprocessfor aircraft primary structure. Coir fibre is the one of natural fibresthatabundantlyavailableintropicalregions including India, Sri Lanka, Philippines, and Malaysia [1]. Brown fibre that extracted from matured coconuts are thicker,stronger,andhigherabrasionresistance comparedtowhitefibrethatextractedfromimmature coconuts. Brownfibre is mostly used inengineering and researchapplicationsandnormallyavailableinsemi-finishedproductformsnamelybristle(longfibres), mattress(relativelyshort),anddecorticated(mixed fibres) [2]. Thebenefitsofcoirfibresincludeprovideexcellent insulationagainsttemperatureandsound,noteasily combustible, flame-retardant, unaffected by moisture and dampness,toughanddurable,resilient,springbackto Mohd Amirul Abdul Rahman et al. Copyright 2014 Praise Worthy Prize S.r.l. - All rights reserved International Review of Mechanical Engineering, Vol. 8, N. 1 90 shape even after constant use, totally static free, and easy toclean[2].Epoxyresin(thermosetresingroup)isone ofthecommonlyusedmatrixmaterialsandhavethe advantages of low in densities, good corrosion resistance, lowthermalandelectricalconductivities,translucence, and aesthetis colour effects while the limitations of them arelowintransversestrengthandoperational temperature limits [3]-[4]. Inaddition,thecuringtimeofepoxyresinismuch higherthanpolyesterresinsandithasagreaterbinding property.Incaseofcoirfibrereinforcedcomposites, thereareseveralreportedworksdoneonthem.Arylmis etal.[5]workedonpreparationofcoircompositepanel forautomotiveinteriorapplications.Hefoundthe optimaluseofcompositecontentsforthatspecific purpose are 60% wt coir fibre,37% PPpowder,and 3% MAPP. Mujahidetal.[6]cameoutwiththedynamic characteristicsofthecoconutcoirfibrereinforced compositearegreatlydependentonthevolume percentage of fibre by using experimental modal analysis [EMA]onthecompositesamplebuttheincreaseof fibres will make composite tend to have low stiffness and ductility.Aireddyetal[7]studiedcoirdustreinforced epoxymatrixcompositesofdifferentcompositions.The experimentalresultsshownthat,theabrasivewear resistanceofthecompositedependsonthecoirdust concentration, sliding distance, and applied normal load.The abrasive wear resistance decreased with increased innormal load andcoir dustconcentration. Lai etal. [8] havedonetheexperimentoncoirfiber-reinforced polypropylenecompositeandhasfoundoutthe compositewithtreatedcoirfiberhaveahighertensile modulus and greater flexural strength than untreated one. Vermaet.al[4]statethatchemicalmodificationsare commonlyconsideredtooptimizetheinterfacial propertiesbetweennaturalfibreandpolymermatrix becauseofthehydrophilicnatureofnaturalfibers. However, the others research done on fiber treatment had reportedthattheusualfibertreatmentssofardidnot significantly modify the mechanical performance of coir-polyester composites as reviewed by Monteiro [9]. Razzoqiet.al[12]havestudiedtheinfluenceof compressionpressureonmechanicalpropertiesof ceramicmatrixcompositeandfoundoutthatthe mechanicalpropertiesimprovedforallcomposites generallyatincreasingofcompressingpressure.Lynda andFaycal[13]investigatedtheeffectsofshear deformationonthenaturalfrequenciesofantisymmetric cross-ply and angle-ply laminated composite plates. Thesheardeformationshowedaconsiderableeffect on the natural frequencies for composite plates. Bourouis and Mili [14] studied the effect of the fibre orientation on staticfailureofcompositesandwichbeams carbon/epoxy,kevlarepoxy,glassepoxyofstacking -3s, [0/90] 3s and [45/-45] 3s.Theyfoundoutthatthesandwichbeamswith carbon/epoxy, and glass epoxy face sheets shows the best characteristicscomparedtokevlar/epoxywhichfacing lowmechanicalresistanceinbothtensileand compressive.Thepurposesofthisresearchareto evaluateandestablishpreliminarydataformaterial mechanicalpropertiesfromstandardmechanicaltest; tensile,flexuralandtorsiontestontherandom oriented and non-modify pressed mat coir fibre/epoxy composite.Theincreaseofcostduetothetreatment of the fibres should be a point of concern. Thepreliminarydataobtainedmightbeservedin theaerospaceresearchareaincludingaeroelasticand ballisticanalysisorcanbeusedasareplacementin automotive components and construction products.Thedetailsofresearchmethodologyandresult analysis will be discussed in the next section. II.Materials and Methods Acommerciallyavailablesemi-finishedproductof rawbrowncoirfubresasshowninFig.1wereusedin theformofpressedmatandoriginallyintherandom orientedfibreform.Thefibreswereuntreated(no surface modification). Epoxyresin(ZeepoxyHL002TA)andhardener (Zeepoxy HL002 TB) that generally being used for hand lay-up that cure at room temperature were used as matrix of the composites. The low viscosity of the resins allows easyhandlingandgivesgoodwettingofreinforcement andsubstrates.Otherspecialfeaturesofthisresinare longpot-life,highheatdistortiontemperature,andgood mechanical properties. Custom made mould made from two rectangular mild steel sheets having dimensions of 600mm x 600mm with rectangularframewithuniformframewidthof40mm and thickness of 3 mm were prepared. Thefunctionsoftheseplatesandframeareto compressthefibreafterepoxyisapplied,maintain specimenthickness,andalsoasacovertoavoidthe debrisfromenteringintocompositepartsduringthe curingtime.Themouldthenwascleanedandrelease agent(wax)wasappliedonthe mouldbeforebeinglay-up with the fibre. Fig. 1. Semi-finished product of coconut coir fibre pressed mat Mohd Amirul Abdul Rahman et al. Copyright 2014 Praise Worthy Prize S.r.l. - All rights reserved International Review of Mechanical Engineering, Vol. 8, N. 1 91 Epoxy resin and epoxy hardener with weight ratio 2:1 were thoroughly mixed together before uniformly poured onthefibre.Thecurewasdonewhenfibreandepoxy mixturebeingcompressedusingcompressedmachine withappliedpressure1.64MPaforcuringtimeof48 hours at room temperature (303K). Fig.2showsthesampleoffabricatedpanel.Six categoriesofsampleswerepreparedfordifferentfibre weightratiorangingfrom20%,25%,30%,35%,40% and 50% with epoxy resins. Fig. 2. Random oriented pressed mat coir fibre/epoxy composite Thefabricatedsampleswerecutintotherequired sizes and numbers prescribed in the standard mechanical testandundergonetensile,flexuralandtorsiontestwith accordance to ASTM D 3039, ASTM D 790, and ASTM D198relativelytoobtainmechanicalpropertiesofthe materialincludingtensilestrength,tensilemodulusand shear modulus. The data have been recorded. Forthetensiletest,thesampleswhichdimensionof 250 mm 25 mm 2.5 mm were prepared and test under roomtemperatureandtestspeedof2mm/minona10 kN InstronUniversal TestingMachinetoobtainaverage YoungModulusforeachfiberweightpercentage.The threepointflexuraltestwasdonebyusing5kNInstron Universal Testing Machine test speed of 2 mm/min under room temperature. Figs. 3. Mechanical tests: (a) tensile test(b) flexural test (c) torsion test Thesampledimensionusedforthetestis100mmx 25mmx2.5mmandflexuralmodulusandflexural strengthdatawererecorded.Shearmodulus,Gdata wererecordedfromtorsiontestbyusingNorwood50 NmTorsionalTestingMachineunderroomtemperature andrateoftwistof(0.16rad/m)/min.Allthetestsare repeatedforeachfibreweightpercentagetoobtainthe averagevaluesforeachtypeofmechanicalproperties data. III.Results and Discussion TableIbelowpresentsthecalculatedaveragetensile modulusandflexuralfor20%to50%weightcoirfibre compositecompositions.Theresultshadshownthe compositeswith25%fiberloadingpercentagerecorded averagehighesttensilemodulus,Ewhichis17.42MPa while the lowest is 1.754 MPa that belongs to 40% fiber loadingpercentagesample.Oneshouldsaythereis decrementinvalueofEforincreasingamountoffiber loading and decreasing amount of epoxy resins.Therefore,thegreaterfibreloadingcomposition,the stifferthecompositeorthehighercompositeresistance to elastic deformation that results from the application of a given stress. TABLE I AVERAGE FLEXURAL MODULUS AND TENSILE MODULUS OF ELASTICITY Weight % of coir fiber Flexural Modulus of Elasticity (Mpa) Tensile Modulus of Elasticity (Mpa) 2042.89.906 2574.0217.423 3044.6615.324 3512.4511.868 407.0431.622 5013.3271.754 The similar pattern also shown in the flexural modulus and flexural strength data as depicted in Table I and Fig. 4wheretheamountofcoirfibreinfluencedthe mechanical properties recorded. Theflexuralstrengthandmodulustendstodecrease with the amount of fibre and the highest flexural modulus is74.02MPaandthehighestflexuralstrengthis58.59 MPa,both belongto25% fibreloadingwhile the lowest belongsto40%fibreloading.Asafirstcomment,the higherthan35%coirfiberloadingpanelsshownthe higherflexibilitybehaviourwhicharesoftand deformable while the less than 35% wt coir fibre loading panelsshowmorerigidbehaviourwhicharestiffand relatively hard. Therefore,upto35%fibresloadingthefabricated composite panels is structural-like materials while above thispercentage,theepoxyresinsdoesnotproperly impregnate the fibres. Lackofefficientreinforcementbycoirfibresmight attributetotheirlowmodulusofelasticityascommon behaviour for other natural fibres. Mohd Amirul Abdul Rahman et al. Copyright 2014 Praise Worthy Prize S.r.l. - All rights reserved International Review of Mechanical Engineering, Vol. 8, N. 1 92 Fig. 4. Variation of the flexural strength with the mass fraction of coir fibre The resultsthan compared to theflexural strength for pressedmatcoirfiber-polyestercompositeundertwo different fabrication compression pressures which are 2.6 MPa and 5.2 MPa that was done by Monteiro et. al [9] as showninFig.5.Thissuggeststhestrengthtendsto decreasewiththeamountoffiberandrevealsthatthe randomlyorientedcoirfibersarenotreinforcingneither epoxymatrixnorpolyestermatrixatall.Several measurementpoints(25%and35%wtfibre)hadnot beenincludedinMonteirowork.Besidesthat,the different in pressures didnot be a major influence to the value of flexural strength compared to the difference type of matrix that has been used. Fig. 5. Variation of the flexural strength with the mass fraction of coir fibre for different compression fabrication pressures TableIshowsthecomparisonbetweenflexural modulusofelasticityandtensilemodulusofelasticity. Generally,theelasticmoduliachievedfromtheflexural testaregenerallyclosetotheelasticmodulusobtained from tensile test using the same material. However,thereareseveralfactorsthatmightaffect theelasticmodulus,whichare1)elasticandplastic deformationattherollersatthesupportsortheloading pointsmightnotbesufficientlysmallincomparisonto thebeamdeflection;2)ifashortspecimenisflexural tested,deformationduetoshearstressmaytakeplace, whicharenotidealforthecalculationaccordingtothe beamtheory;3)materialsmighthavedifferentelastic modulus under flexural and tension. Therefore,theaverageelasticmodulusinflexural shouldbeidentifiedtoanyavoidconfusionsforthe interpretation of the mechanical behaviour of the material [10]-[11].Thedeterminationoftorsionalproperties, shear modulus, G was done by using torsion test. FromFig.6oftheaverageshearmodulusforeach fibreloadingpercentage,the20%fibreloading percentagerecordedhighestaverageshearmodulus while 50% fibre loading percentage recorded the lowest.The imposition of torsional stresses also evokes elastic behavioursameliketensionstresssincetherandomly orientedfibrescompositecouldbeconsideredasan isotropic materials. Therefore,theshearmodulusdataobtainedcouldbe usedforfurthersupportingthetensilemodulusand flexuralmodulusdataobtainedwhichagreedthatthe higherthan35%coirfiberloadingpanelsshownthe higherflexibilitybehaviourwhicharesoftand deformable while the less than 35% wt coir fiber loading panelsshowmorerigidbehaviourwhicharestiffand relatively hard. Fig. 6. Variation of the average shear modulus with the mass fraction of coir fibre Forthefurthercommercialandresearchinterest,the coirfibrecompositemightbefurtherusedasa alternativesreplacementmaterialfornon-critical structureforfurniture,buildingfurnished,automotive andaerospaceparts.Itmightbetailored,modified,or hybridizeintootherconventionalcompositeormaterial inordertoincreasethematerialperformanceforthe future works and use depending on the purposes. IV.Conclusion Itcanbeconcludedthattheamountofcirfibre loadingplayedanimportantroleindeterminationof stiffnesslevelofthecomposite.Tthelessthan35%wt coirfiberloadingpanelsshowmorerigidbehaviour which are stiff and relatively hard while greater than 35% coirfiberloadingpanelsshownthehigherflexibility behaviour which are soft and deformable. Thecoirfibreshowsthecommonbehavioursimilar likesothernaturalplantfibrewhichislackofefficient reinforcementthatleadtotheirlowstiffnesslevel 0204060800 20 40 60Weight of Coir Fiber (wt.%)0204060800 20 40 60Weight of Cor Fiber (wt.%)Pressure 1.3MPaPressure 2.6MPaPressure 5.2MPa00,0010,0020,0030,0040 20 40 60Fiber wt. (%) Mohd Amirul Abdul Rahman et al. Copyright 2014 Praise Worthy Prize S.r.l. - All rights reserved International Review of Mechanical Engineering, Vol. 8, N. 1 93 comparedtootherconventionalcomposites.The preliminarydataestablishedinthisresearchmightbe served as a reference for further studies. Acknowledgements Theauthoracknowledgeallthemembersofthe research for their support. References [1]Taj,S.,Munawar,A.M.,Khan.,S.(2007).Naturalfibre-reinforcedpolymercomposites.ProceedingPakistanAcademic Science, 44(2), 13-144. [2]Ali,M.(2010).Coconutfibre:aversatilematerialandits applicationsinengineering.Proceedingssecondinternational conferenceonsustainableconstructionmaterialsand technologies.[3]Gay,D.,&Hoa,S.V.(2007).Compositematerials:designand applications. New York: CRC Press. [4]Verma,D.,Gope,P.C.,Shandilya,A.,&Gupta,A.(2012).Coir fibrereinforcementandapplicationinpolymercomposites:a review. Journal Material & Environment Science., 4(2), 263-276 [5]Aryilmis,N.,Jarusombuti,S.,&Fueangvivat,V.(2011).Coir fibrereinforcedpolypropylenecompositepanelforautomotive interior applications. Fibers and Polymers, Vol. 12, 919-926 [6]Mujahid,A.Z.,NurulAliaa,M.A.,Norashida,A.,Balamurugan, A.G.,Norazman,M.N.,&Shohaimi,A.(2011).Experimental modalanalysis(EMA)oncoconutfibrereinforcedcomposite. Global Engineers and Technology Review, Vol. 1, No. 1, 15-20. [7]Aireddy,H.,&Mishra,S.C.(2011).Tribologicalbehaviourand mechanicalpropertiesofbiowastereinforcedpolymermatrix composites. Journal metal and material science, 53(2), 139-152.[8]Lai,C.Y.,Sapuan,S.M.,Ahmad,M.,Yahya,N.,&Dahlan, K.Z.H.M. (2005). Mechanical and electrical properties of coconut coirfiber-reinforcedpolypropylenecomposite.Polymer-plastics technology and Engineering, 4, 619-632. [9]Monteiro,S.N.,Terrones,L.A.H.,&DAlmeida,J.R.M.(2008). Mechanicalperformanceofcoirfibre/polyestercomposites. Polymer Testing, 27, 591-595. [10]Dowling,N.E.(1999).Mechanicalbehaviourofmaterials: Engineeringmethodsfordeformation,fractureandfatigue(2nd ed.). Singapore: Prentice Hall. [11]Hibbeler,R.C.(2005).Mechanicsofmaterial(2nded.). Singapore: Prentice Hall. [12]Razzoqi,R.N.,Mahmood,L.A.,Ahmed,M.S.,Fayyadh,S.M., Influenceofthechemicalcompositionandpressureofthe compressingonsomephysicalandmechanicalpropertiesof CeramicMatrixComposite,(2012)InternationalReviewof Mechanical Engineering (IREME), 6 (3), pp. 332-338. [13]Lynda, B., Faycal,M., A first order finite element theoryforfree vibrationofcompositeplates,(2011)InternationalReviewof Mechanical Engineering (IREME), 5 (3), pp. 459-464. [14]Bourouis,F.,Mili,F.,Theeffectofthefibreorientationonthe failureloadoffacesheetscompositesandwichbeams,(2011) International Review ofMechanical Engineering(IREME),5 (5), pp. 968-972. Authors' information MohdAmirulAbdulRahmanbornin14 November1986inMuar,Johor,Malaysia.He obtainedhisBachelorDegreeinEngineering (Aerospace)in2010fromInternationalIslamic University Malaysia.Currently studyingMaster ofScienceAerosapceEngineeringbyresearch in Universiti Putra Malaysia, Serdang, Selangor, Malaysia.Hismajorfieldofstudyis experimental aeroelasticity and natural composite. E-mail: amirulmier@gmail.com MunaimAliOmarBakiwasbornin1985. Theauthorstartedhistertiaryeducationat matriculation level in 2003 at Kolej Matrikulasi Johor,Tangkak,johor.Heobtainedhis BachelorDegreeofAircraftEngineering Technology(Mechanical)in2011atUniKL MalaysiaInstituiteofAviationTechnology (MIAT),Dengkil,Selangor.Currentlystudying MasterofScienceAerospaceEngineeringbyresearchinUniversiti PutraMalaysia,Serdang,Selangor,Malaysia.Heconcentratingin study of ballisctic impact and natural composite. E-mail: munaim1985@yahoo.com Dr.AzminShakrineMohdRafieisalecturer inAerospaceengineeringdepartmentat UniversitiPutraMalaysia.Hewasenrolledto Dip.Eng.Programin1192atUniversiti TeknologiMalaysiaforthreeyears.Thenhe continuedhisstudynbachelorprograminthe sameiuniversity.Hegraduatedin1998with B.Eng in Mechanical Engineering (Aeronautic). He joined the same university as a research assistant from 1998 to 2001 andatthesametimeenrolledthemasterprograminaeronautic engineering. In 2002 he obtained his M.Eng Degree and joint Universiti PutraMalaysiaastutor.InNovember2003,hefurtherhisstudiedin PhD program in aerospace engineering at Universiti Putra Malaysia. He thenreceivedhisPhDin2007.Hisresearchdedicatedtothe ExperimentalAerodynamicandAeroelasticity.Hehisamongthe pioneerindevelopingtheexperimentalworkonaeroelasticityfieldin Malaysia.Hiscurrentresearchinterestisprimarilyindeveloping experimentalaeroelasticityandaerodynamicespeciallyincomposite material. E-mail: shakrine@upm.edu.my RenuganthVaratharajooreceivedPh.D.In SpacecraftSysytemsfromDresdenUniversity ofTechnology(germany)in2003.Heis currentlyalecturer/reseacrcheratUniversity PutraMalaysia.Heteachessapcerealted courses.Hisresearchfocuseson1)spacecraft navifgationandcontrol;2)combinedattitude controlsystems;and3)rockettrajectory optimisation.Hehasauthorednumerouspublicationsonthesubject matter. He is also acting as a reviewer for a few aerospace journals. E-mail: renu@upm.edu.my