简介:
简介:Theconstitutiveequationunderthelow-cyclefatigue(LCF)wasdiscussed,andatwo-dimensional(2-D)modelforsimulatingfatiguecrackextensionwasputforwardinordertoproposeanewcyclicJ-integral.Thedefinition,primarycharacteristics,physicalinterpretationsandnumericalevaluationofthenewparameterwereinvestigatedindetail.Moreover,thenewcyclicJ-integralforLCFbehaviorswasvalidatedbythecompacttension(CT)specimens.ResultsshowthatthecalculatedvaluesofthenewparametercancorrelatewellwithLCFcrackgrowthrate,duringconstant-amplitudeloading.Inaddition,thephenomenonoffatigueretardationwasexplainedthroughtheviewpointofenergybasedontheconceptofthenewparameter.
简介:Dispersionofmulti-walledcarbonnanotubesinpoly(p-phenylene)compositeexposedtotoluenewasexperimentallyinvestigated.3mgofmulti-walledcarbonnanotubeswithnominalsizeof20nmwascompoundedwith30mgofpoly(p-phenylene)withthepresenceofterpineolasbindinginitiator.Toinvestigateanoptimalconditionforhomogenizingallconstituents,ultrasonicationwithanoutputpowerof750Wwasemployedwithcompoundingtimeof3,10,20and30min.WithFTIRanalyses,itcouldbeconfirmedthathomogeneouscompositeofmulti-walledcarbonnanotubesandpoly(p-phenylene)couldbeprepared.SEManalyseswerealsoconductedtoexaminethedispersionofmulti-walledcarbonnanotubesinthepolymermatrix.Thenintrinsicelectricalresistanceofthecompositesafterbeingexposedtotoluenewasalsoinvestigated.Itwasfoundthatthecompositefilmpreparedwithultrasonicationfor20mincouldprovidesufficientlysensitiveresponsewithrespecttovariedconcentrationoftoluene.