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1、循环对称结构的模态分析简介SymmetrieloadsymmetryofaxisymmetricstructureThemodalanalysisofcyclicsymmetricstructuresismainly-usedinthemodalanalysisofcyclicsymmetricobjectssuchasgear,turbineandimpeller・Itextendstotheentiremodelbyanalyzingthissectorthroughasectorofthesimulationstructure・Therea
2、resixmainsteps・1,createabasicsectormodel,whichisamodelof1/n,atoothandaleaf・Identifycyclicsymmetry(whichcanbeautomaticallydeterminedormanuallyselected)・Youapplytheboundaryconditions・4,makeanalysisandanalysisoptions・5,specifytheloopsolutionoptionthroughthecycopcommandandsolveit
3、withsolve・6,through/cyexpandtoextendthevibrationtothefull360degreerange,observethewholeresult・Becauseoftherelationshipbetweentheselectedharmonicexponentials,thenaturalfrequencyisalittiemessyinthepermutations.Thepreviousversionofansyscalledtheconceptofharmonicexponents,whichar
4、enowcalledharmonicexponentials.Accordingtotheoverallstructureanalysis,thesystemwillbearrangedinasmallsize・Withharmonicindexcalculatedfrequency,soheisinthearrangementaccordingtotheincreaseofharmonicindex,therefore,thecorrespondingnaturalfrequencyhavegreatlysmall,irregular(butv
5、alues,istoarrangedifferent)・Thesolutionistoextracttheresultsandarrangetheminasmallorder・Andthere，salittlebitofattentiontothisprocess・Aisgoingtobeinthecolumnframewhenbuildingthebasicsector,youputthecsys1,Balso,thesectorAngleoptioncanbedivisibleby360.Cchoosesthenodesinthesymmet
6、ricfaceofthecycle,asifothercharacteristicsarenotgood(forthereasonotherpeoplehavetoldme,forget)・Acismoreimportant,bisalittlebitcareful.Andthenthere'sthesolutionTocalculatevibrationalmodeinaxisymmetricunits,notallaxisymmetricunitscanbeused,refertothefollowingintheANSYShelp:Axis
7、ymmetricElementswithNonaxisyminetricLoads-indicateswhichAxisymmetricunitscanperformnon-axisymmetricanalysisandhowtodoit;Modecommand-definestheaxialharmonicnumberofanaxiallysymmetricunitfornon-axisymmetricanalysisShell61-theaxisymmetricsimpleharmonicshellunit(actuallyalineunit
8、)fornon-axisymmetricanalysisVM151-acalculationofthenon-axisymmetricv
