Characteristics Of Wave Propagation And Power Flow In A Laminated Composite Cylindrical Shell

Laminated composite cylindrical shells are becoming increasingly used in structuressuch as spacecraft, automobiles, pressure vessels and many others because of their highspecific strengths and specific stiffnesses. In ship engineering, cylindrical shells arewidely used in submarine structures and all kinds of pipelines. It is significant for noisereduction of the composite cylindrical shell to study the characteristics of vibration andpower flow. The wave propagation characteristics and vibrational power flow of thelaminated composite cylindrical shell in vacuum, filled with fluid and submerged in adense acoustic medium are studied here.Firstly, infinite laminated composite cylindrical thin shells coupled and uncoupled areconsidered with the classical laminated plate and shell theory, ignored the sheardeformation along the direction of thickness. The pressure field in the fluid and theharmonic motion of the shell are respectively described by Helmholtz equations and Loveshell equations. The moments and forces of the laminated composite cylindrical shells areobtained by the relationship of infinitesimal stress-strain with consideration the couplingcondition on the outer surface of the laminated composite cylindrical thin shells and thenthe constitutive equation and vibration equation are presented.To a shell in vacuum, a fluid-filled shell and fluid-loaded shell, both the free and forcedvibration in the system are investigated, and the effect of velocity the contained fluid isconsidered. For the free vibration, the dispersion curves and the power flow carried bydifferent shell internal forces have been obtained. The characters of wave propagationhave been discussed in the view of displacement and energy, and the influence of all kindsof boundary conditions and shell parameters on shell frequency are studied. For the forcedvibration, the vibrational power flow input into and transmitted by the shell areinvestigated by using wave mode superposition and numerical integration methods, theresults obtained are compared with that in steel shell.The wave propagation characteristics and vibrational power flow in a laminatedcomposite cylindrical shell are also studied by using the first order shear deformationwhich abandons the Kirchhoff-Love hypotheses of straight line.