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1、MultiscalemodelingofcarbonnanotubematerialswithdistinctelementmethodADissertationSUBMITTEDTOTHEFACULTYOFUNIVERSITYOFMINNESOTABYIgorAleksandrovichOstaninINPARTIALFULFILLMENTOFTHEREQUIREMENTSFORTHEDEGREEOFDOCTOROFPHILOSOPHYAdvisers:RobertoBallarini,TraianDumitricaMay2014?IgorOstanin2014i

2、AcknowledgementsIwouldliketothankmyacademicadvisers-RobertoBallariniandTraianDumitrica-fortheirhelpandmotivatingcommentsandquestions.Iwanttothankallmyteachers,professorsandinstructorswhoguidedmethroughtheyearsofmyacademiccareer,inparticular,VladimirSynakh,VladislavDubrovsky,AlekseyTrib

3、endis,IvanKoop,DmitryBerkaev,SofiaMogilevskaya,JosephLabuz,HenrykStolarsky,RogerFosdickandElladTadmor.Ithankmyparentsandfamilyfortheirsupportandencouragement.IwanttoexpressmygratitudetoItascaConsultingGroup,whoprovidedmethefinancialandtechnicalsupport,andtheaccesstotheircommercialcodes

4、andsoftwaredevelopmenttools,withoutwhichthisworkcouldnotcometofruition.Personally,IwouldliketothankWilliamPettitt,DavidPotyondy,DavidRussel,MatthewPurvanceandSachaEmam.IwouldliketoacknowledgeErikHobbie,EvgeniyaDontsova,IliaNikiforov,TylerAnderson,LudongSun,CristianGaidauandYuezhouWangf

5、ortheireffortsthatfacilitatedsomedevelopmentspresentedinthiswork.IexpressdeepgratitudetotheNationalScienceFoundation,theUniversityofMinnesotaDoctoralDissertationFellowshipprogram,andtheJamesL.RecordChairforfundingmeduringmyPhDstudies.iiAbstractMesoscalesimulationtechniquesarebecomingin

6、creasinglyimportantduetotheinterestincomplexmechanicalproblemsinvolvingnanoscalestructuresandmaterials.Thisworkisdevotedtothedevelopmentofanovelmesoscopicmodelingtechniquebasedonanextensionofthedistinctelementmethodanditsapplicationtotheproblemofmechanicalmodelingofcarbonnanotube(CNT)m

7、aterials.Startingfromanatomisticdescription,theimportantinteractionsbetweensegmentsofthetubesareencapsulatedintotwotypesofcontactmodels.Thenanomechanicsofintratubebondsischaracterizedbytheparallelbondcontactmodel.IntertubeinteractionsareaccountedforbyananisotropicvdWcontactmodel.Ener