简介：

简介：

简介：Thevibrationandsoundradiationofasubmergedsphericalshellarestudiedinthetime-domainbyLaplacetransformmethod,whereaCWpulseforceactsattheapexoftheshell.Thenumericalresultsforthecaseoflongpulseshowthatthedifferentvibrationalmodesandtheresonantorbeatradiatedsoundareexcitedfordifferentcarrier-frequencies,butlitlesoundisra-diatedforsomevibrationalmodes.Forthecaseofshortpulsethewaveformsofthepulsebecomewidenedanddeformed,whenthepulsepropagatesbetweenapexesoftheshell.Then,theDoublyAsymptoticApproximations(DAA2)andKirchhoff‘sRetardedPotentialFormulate(KRPF)areusedtosolvethesameproblem.ItisshownthattheresultsofDAA2andKRPFmethodhaveagoodagreementwiththeresultsofLaplacetransformmethod.

简介：Afiniteelement/boundaryelement—modifiedmodaldecompositionmethod(FBMMD)ispresentedforpredictingthevibrationandsoundradiationfromsubmergedshellofrevolution.Im-provementhasbeenmadetoacceleratetheconvergencetoFBMDmethodbymeansofintroducingtheresidualmodeswhichtakeintoaccountthequasi-statecontributionofallneglectedmodes.Asanexample,thevibrationandsoundradiationofasubmergedsphericalshellexcitedbyaxisymmetricforcearestudiedincasesofka=1,2,3and4.FromthecalculatedresultsweseethattheFBMMDmethodshowsasignificantimprovementtotheaccuracyofsurfacesoundpressure,normaldisplace-mentanddirectivitypatternsofradiatingsound,especiallytothedirectivitypatterns.