基于非結構化格子法的動態(tài)J積分計算.pdf

1、沈陽建筑大學碩士學位論文基于非結構化格子法的動態(tài)J積分計算姓名：陳海濱申請學位級別：碩士專業(yè)：工程力學指導教師：劉鐵林200701碩士研究生學位論文abstractIIIComputationofdynamicJintegralbytheunstructuredgridmethodAbstractSincetheearly1920sfollowingGriffith’spioneeringwkquasistaticlinearelast

2、icelasticplasticfracturemechanicsviscoelasticmaterialbehavihasbeenextensiveindepthresearch.Whenthematerialwithcrackissubjectedtoimpactingloadtheinertialfcecannotbeigned.Thecrespondingstudyofthedynamicfractureisnotenoughb

3、ecauseofthecomplexityoftheproblem.Withthedevelopmentofsciencetechnologytheimptanceofthestabilityaboutcracksunderimpactingloadbecomingincreasinglyobvioussothedynamiccrackinitiationundershtpulseloadisverynaturaltobecomeafo

4、cusintheacademicfield.DynamicJintegralnotonlypossessesthepropertyofthepathindependentintegralwhichgivesauniquevaluefanarbitraryintegralpathsurroundingthecracktipcircumventsthestresssingularityatthecracktipbutalsoavoiding

5、thesingularityofthecracktip.Soasoneofmethodsofcrackinitiationcriterionitbecomesoneofthefocusesofthestudyincreasingly.ThispapermainlystudiesthedynamicJintegralfromthenumericalcalculationusinganumericalcalculationunstructu

6、redgridmethod.ThesemethodsproveapathindependentJintegralfromnumericalmethodgivetheJintegralvalveineverymomentofdynamicnumerical.BasedontheenergyreleaseratethestaticJintegralfmulahasbeenderivedbyotherresearch.Theinertialf

7、ceisconsideredthedynamicJintegralfmulaisderivedinthispaper.AccdingtounstructuredgridmethodthealgithmofthedynamicJintegralflinearelasticityproblemispresented.ProgramisofferedinFTRANlanguage.Thenewalgithmisusedtocalculatet

8、hevaluesofdynamicJintegralthedynamicstressintensityfact.Theresultsarecomparedwiththoseofthefiniteelementmethod.TheresultsshowedthatthenewalgithmisvalidapproachwithasatisfyingaccuracyfthecalculationofthedynamicJintegral.T

9、heproblemsfdifferentcrackcasesundertheactionsofdifferentloadingareconsidered.AlltheresultsshowedthatthedynamicJintegralisofthepropertyofthepathindependentintegral.ThenewalgithmisausefultoolfcalculatingthevaluesofdynamicJ

10、integralatanytime.ThevaluesofdynamicstressintensityfactcanalsoprovidedbyusingthevaluesofdynamicJintegral.Thenewnumericalalgithmpresentedinthispaperprovidesasimplepracticaleffectivetoolfstudyingtheproblemsofthecrackinitia