裂纹转子-轴承系统动力学特性分析

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1、万方数据东北大学硕士学位论文AbstractResearchonDynamicBehaviorsofaRotor—bearingSystemwithCrackFaultsAbstractModemturbomachineryisdesignedinhighspeed，highflexibilityandhighefficiency．Theimprovementoftheperformanceofturbomachineryhasledtoseverelystressedrotors，therefore，therotorsystemrequestsbestdesignandmanufactu

2、re．However,withseverallocationswherestresses(bothmechanicalandthermal)canincreasedespitebestdesignpractices，fatiguecracksarealwaysapossibilityinsuchrotors．Ifundetectedearly,suchcrackscanposeapotentialsourceofcatastrophicfailures．Thus，ithasgreatsignificancetostudythedynamicbehaviorsofarotor-bearing

3、systemwithcrackfaultsforconditionmonitoringandforecast．Thefiniteelementmodeloftherotorsystemwithtransverse，slantandsemi-parabolicslantcrackwerefirstsetupbasedonfiniteelementmethod．Thispapermainlystudiesthedynamicbehaviorsofasinglespanrotorsystemwithtwodiscsatdifferentcrackparametersundertwosupport

4、ingconditions：elastomericbearingandoilfilmbearing．Firstly,basedonfracturemechanicsandcastigliano’Smethod，thestiffnessmatrixofeachcrackelementwasealeulatedandthemotionequationoftherotorsystemisdeduced．Thecrackbreathingbehaviorisrepresentedbyusingstressintensityfactors．Theflexibilitycurveisverifiedb

5、ytheresultsofthepapeLwhichillustratethecorrectofthecrackdeduceinourpaper．Secondly,asimpleJeffcottrotormodalinthepaperispresented，andbasedonit，thevariationofflexibilitycoefficientsfordifferentcrackclosurelinepositionisverifiedbytheresultsofthepaper．Thelawofstiffnessvariationoftransverse，slantandsem

6、i．parabolicslantcrackunderthesameanddifferentcrackdepthiSstudied．Thelawofinherentcharacteristicsofthecrackrotorsystemisanalyzedatdifferentpositionsofcrackelementandcrackdepth．Meanwhile，dynamicbehaviorsofthethreecrackformsareresearchedattwoloadingconditions：masseccentricityandtorsionalexcitation．Fi

7、nally,thedynamicbehaviorsathorizontalandtorsionaldirectionsofatwodiscsrotorsystemwithtransverse，slantandsemi—parabolicslantcrackunderelastomericbearing，andtheinfluenceofthecrackparameters，suchasthepositionofcrack