简介:Moleculardynamics(MD)simulationswereperformedtostretchtherectangulargraphenesheetsdopedwithsilicon,nitrogenorboronatoms.Young’smodulus,ultimatestress(strain)andenergyabsorptionweremeasuredforthegraphenesheetswiththedopingconcentration(DC)rangingfrom0to5%.Theemphasiswasplacedonthedistincteffectsofeachindividualdopantonthefundamentalmechanicalpropertiesofgraphene.TheresultsindicatedthatincorporatingthedopantsintographeneledtoanalmostlineardecreaseinYoung’smodulus.Monotonicreductionsinultimatestrength,ultimatestrainandenergyabsorptionwerealsoobserved.Suchdopingeffectswerefoundtobemostsignificantforsilicon,lesspronouncedforboron,andsmallornegligiblefornitrogen.Theoutputsprovideanimportantguidanceforthedevelopmentandoptimizationofnovelnanoscaledevices,andfacilitatethedevelopmentofgraphene-basedM/NEMS.
简介:Basedonthethermodynamictheory,anorthotropicdamageconstitutivemodelwasdevelopedtodescribethenonlinearmechanicalbehaviorofC/SiCcomposites.Thediferentnonlinearkinematicandisotropichardeningfunctionswereadoptedtodescribeaccuratelythedamageevolutionprocesses.Thedamagevariablesweredefinedwiththedamagedmodulusandtheinitialundamagedmodulusonenergyequivalenceprinciple.Theinitialorthotropyanddamagecouplingwerepresentedinthedamageyieldfunction.Tensileandin-planeshearloadingandunloadingtestswereperformed,andagoodagreementbetweenthemodelandtheexperimentalresultswasachieved.