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1、http://www.paper.edu.cnMolecular-DynamicsStudyoftheinfluencesofSi-dopinguponthestructureandthemechanicalpropertiesofcarbonnanotubeHaiyangSong(宋海洋)HemingSun(孙贺明)DepartmentofAppliedPhyscis,BeijingInstituteofTechnology,Beijing,China,100081Email:songhaiyang-110@sohu.comAbstract:inthispaper,aSi-dop
2、edarmchairedsingle-walledcarbonnanotube(SWCNT)(7,7)andaperfectSWCNT(7,7)areinvestigatedusingtheclassicalmoleculardynamics(MD)simulationsmethod.Theinter-atomicshort-rangeinteractionisrepresentedbyempiricalTersoffbondorderpotential.ThecomputationalresultsshowthatthereisradiusamplificationintheSi
3、-dopedlayerandtheYoung’smodulioftheSi-doped(7,7)SWCNTis1.015TPaandoftheperfect(7,7)SWCNTis1.096TPa,itisingoodagreementwiththeexistingexperimentalresults.Fromoursimulation,Si-dopingdecreasestheYoung’smodulusofSWCNTandwiththeincreasedstrainlevels,theeffectofSi-dopedlayerinenhancingthelocalstress
4、levelincreases.Keywords:moleculardynamicssimulation,carbonnanotube,Young’smodulus,Si-doping1.IntroductionSincethefirstreportofcarbonnanotubes(CNTs)byIijima[1],researchonCNTshasbeenattractingmuchattentiontoexploretheirunusualelectronicandmechanicalproperties.Bothexperimentalandtheoreticalstudie
5、sindicatedthatCNTsarematerialwithextraordinaryhighstiffnessandaxialstrength.Duetotheirlargeaspectratiosandsmalldiameters,CNTshaveemergedaspotentiallyattractivematerialsasreinforcingelementsinlightweightandhighstrengthstructuralcomposites.TherearesomeexperimentalstudiesoftheYoung’smodulusofCNTs
6、.Liuetal.[2]reportedtheYoung’smodulusofCNTsis1~0.1Tpawiththediameterincreasingfrom8to40nmbymeasuringresonancefrequencyofcarbonnanotubes.Krishnanetal.[3]usedTEMtoobservethevibrationofanSWCNTatroomtemperatureandreportedYoung’smodulusofSWCNTsintherangefrom0.90to1.70TPa,withanaverageof1.25TPa.Tomb
7、leretal.[4]usedAFMtobendanSWCNTandreportedtheYoung’smodulusofSWCNTsaround1.2TPa.TherearealsosometheoreticalstudiesforpredictingtheYoung’smodulusofCNTs.Lu[5]usedanempiricalforce-constantmodeltodetermineseveralelasticmoduliofSWCNTsandMWCN