电厂锅炉汽包低周疲劳寿命评估技术及压力管道结构分析研究

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1、浙江大学博士学位论文电厂锅炉汽包低周疲劳寿命评估技术及压力管道结构分析研究姓名：王勇申请学位级别：博士专业：化工过程机械指导教师：蒋家羚2002.3.1AbstractFatiguefailureinthepowerplantboilerdrumandpressurepipingisthecommonfailurewhichcausedbyfatigueloadingandothers．Onthebasisoftheexperimentalstudiesoflow．cyclefatigue，perf

2、ormedontheBHW-35powerplantboilerdrumand12CrMoVpressurepipingrespectively,thefatiguelifeevaluationmethodsareestablishedinthispaper．Allstudiescanbeconcludedasfollows．P．S．NcurvesofBHW．35steelandofitsweldmetalareobtainedwiththetotalstaincontrolledlow．cycle

3、fatiguetestandtheprobabilityandstatisticmethod．TherelationsbetweenthedummystressamplitudeandfatiguelifecanbeeasilydevelopedAndthen，theBHW-35steelfatiguedesigncurvecanbeobtainedaccordingwithASMEcriterionandBS5500criterion．Comparedwiththedesigncurvesprov

4、idedbytheASMEandBS5500criterion，thecurvegotinthispaperprovidesreliabledirectionforthefatiguedesignofboilerdrum，whichusedonthealteringgeneratingpowerplantset．Stressconcentrationmeasureonthemodelofboilerdrumwithtwonozzleswasexecutedandthetestingresultswe

5、recomparedwiththeASMEcriterion，experientialvalueandthevalueoffiniteelementmethodrespectively．Thismeasurementresultprovidesdirectionforevaluationofstressamplitude．WiththeexperimentofsurfacecrackgrowthofBHW-35weldmetal．thelawofthesurfacecrackshapevariati

6、onwhenitgrowswasobtained．andthe1awofsurfacecrackgrowthratewasalsogotten．Thesedirecttheevaluationofthesurfacecrackfatiguegrowthlireandthecriticalvalueofitslength．Onthebasisofalltheseresearch．themethodoflow．cyclefatiguelifeanalysisandestimationfor41OT／Hb

7、oilerdrumwassetuD．Withthesuperimposemodel．theformulaofthestresscalculationoftheelbowswithellipticsectionandnonuniformthicknesswasproposedinthispaper．Theformulaisversifiedbytheexperimentoftwoelbows．Thefatiguetestofthe12CrMoVsteelprovedthemethodofevaluat

8、ionthefatiguegrowthlifeoftheelbowssufieringinternalpressure．Themodelofexhaustionpotentialisreviewedandanewexhaustionpotentiaimodelissuggested．Yang’selasticmodulusdropisusedtodescribedamagevariable．Theproposedmodelisfoundtoaccordwithexpe