PI-SiO-,2-雜化薄膜疲勞特性的研究.pdf

1、北京交通大學碩士學位論文PISiO雜化薄膜疲勞特性的研究姓名：趙欣欣申請學位級別：碩士專業(yè)：工程力學指導教師：王正道20061201ABSTRACTPolyimides(PIs)andtheirhybridfilmsareonekindofpolymericfilmsowningmanyexcellentproperties，eggoodtoughnessandflexibilityInthepastfortyyears，theyhav

2、ebeendevelopedrapidlyandalsoappliedinvariousfieldsHoweverduetothermaldisturbanceoraffectedbyotherfactors，theyusuallyundertakealternateloadingintheapplicationTherefore，thefatiguepropertyiscriticalindecidingtheirworkinglif

3、eHoweveruntilnowtheresearchonthemechanicalpropertyofthiskindofhybridfilmsismainlyfocusedonquasistaticloadingandfewreportswereeverinvolvedinthefatiguepropertiesInexperiment，someavailablereportsaboutthefatiguepropertyoffil

4、msareconcentratedonmetallicfilm，singlecrystalorpolycrystalofsiliconfilmandferro—electricityfilmAsconsideringtheirhighviscoelasticityandplasticdeformationcapabilitypolymersandtheirhybridfilmsmustshowquitedifferentfatiguep

5、ropertyfromthatofthematerialsmentionedaboveAboutthetheoryresearchoffatiguelifeprediction，althoughvadousmodels，egmodelsoffatiguestrength，fatiguestiffnessandenergymethod，havebeenproposed，mostofthemsuitableformetalmaterials

6、，andfewareespeciallyforpolymersandtheircompositematerialsBasedonstress—lifecyclicexperimentusingtensiontensionfatigueloading，thefatiguepropertyofthiskindofcompositefilmsWastakeninthisstudyThedevelopmentofhysteresiscurves

7、，strainamplitudeandhysteresisenergywithincreasingofthefatiguecyclesweregivenforPIhybridfilmwithdifferentsilicacontents(Owe／，1wW，3wt％，8wt％)Meanwhile，thepaperalsoshowsthechangeofthedampingangle，storagemodulus，lossmodulusan

8、denergydissipationduringthefatigueexperimentbasedonviscoelastictheoryInordertoevaluatethecreepandplasticdeformationofthiskindofmaterials，afourelementviscoelasticmodelWasusedTheSEMmethodWasappliedtoanalyzethefailuremodelf

9、orPI／Si02filmunderhigh／lowcyclesFinallybyusingthefatiguemodulusconcept，alogarithmicmodeloffatiguelifewasproposedInthismodel，somefactorshavebeenconsidered，egthecharacteristicsnonlinearrelationofstressstrainresponseforpoly

10、mersandmatrixcontrolledpolymericcomposites，theexponentrelationbetweenthedecreasingrateoffatiguemoduleandthecyclicnumberMoreovertheeffectofthefatiguemodeWasalsoconsideredbyusingadimensionlessparameter礦teplacethestressleve