Freevibrationsofnon-uniformcompositecylindricalshellsOriginalResearchArticle

Asemi-analyticalinvestigationofdynamicanalysisoflaminatedmulti-layeredanisotropic,openandclosedcylindricalshellshasbeendevelopedbytakingintoaccountthesheardeformationandrotaryinertiaeffects.Thestructuremaybeuniformornon-uniforminthecircumferentialdirection.Themethodusedisacombinationofhybridfiniteelementanalysisandtheshearableshelltheory.Theshellissubdividedintocylindricalpanelshaving5°offreedomsateachnodalline.Thesetofmatricesdescribingtheirrelativecontributionstoequilibriumisdeterminedbyexactanalyticalintegrationoftheequilibriumequationsinsteadoftheusuallyusedandmorearbitrarilyinterpolatingpolynomials.Thistheorygiveszerostrainsforrigid-bodymotionsinsuchawaythatthedevelopeddisplacementfunctionssatisfytheconvergencecriteriaofthefiniteelementmethod.Thistheorycanbeusedforvibrationanalysisofaxisymmetric(n=0),beam-like(n=1)andshellmode(n≥2)behaviorofcylindricalshells.Ityieldsthehighaswellastheloweigenvaluesandeigenmodeswithcomparablehighaccuracy.Reasonableagreementisfoundwithothertheoriesandexperiments.