| The research of this paper is carried out around the vibration characteristics of infinite cylindrical shell-fluid coupled system considering the effect of high hydrostatic pressure. The input vibrational power flow and sound radiation in/from fluid-filled shell and fluid-loaded shell by using the wave propagation approach. The effect of hydrostatic pressure on input power flow and sound radiation characteristics in cylindrical shell-fluid coupled system, periodically stiffened cylindrical shell-fluid coupled system, viscoelastic cylindrical shell-fluid coupled system and viscoelastic stiffened cylindrical shell-fluid coupled system has been examined.First, free vibration in an infinite cylindrical shell-fluid coupled system subjected to hydrostatic pressure is considered. The hydrostatic pressure field is modeled using static prestress terms in the shell equation of motion, and the motion equations of shell and fluid are described as Flügge and Helmholtz equations respectively. The characteristic equation is deduced applying the coupling condition and wave propagation approach. In order to solve the characteristic equation, a Winding-number contour integral method is applied. The effect of hydrostatic pressure on natural frequency and dispersion characteristics including the complex wave numbers is investigated, and the comparison are made with the natural frequencies computed by semi analytical method and finite element method.Then, the forced vibration driven by a cosine harmonic circumferential line force of cylindrical shell-fluid coupled system is studied, and the effect of hydrostatic pressure on input power flow and sound radiation is discussed. In the analysis, Fourier transform and inverse transform are taken to derive the dynamic response, and input power flow and sound radiation can be easily obtained. Since the dispersion equation has been solved in previous paper, residue theorem can be applied to quickly calculate the input power flow.In practice, ribs are used to enhance the strength and stability of the shells. The influences of the ring are replaced by the exerting forces and moments on the shell based on discrete model. The theory of periodic structure and space-harmonic analysis are used to deduce the response of the coupled system excited by a driving force. An integrated numeric method is employed to calculate the input power flow and sound radiation in/from the ring-stiffened shell-fluid coupled system for different circumferential modes. The influence of hydrostatic pressure is examined.Due to the wide application of viscoelastic damping material, input power flow and sound radiation in/from a free damping cylindrical shell-fluid coupled system are investigated. The damping characteristics are considered by complex modulus method, and the solutions are obtained by wave propagation approach. Among the numerical results, the discussions concentrate on the influences of hydrostatic pressure.Finally, the processing method of rib and free damping layer used in previous is applied, and power flow and sound radiation in/from viscoelastic stiffened cylindrical shell-fluid coupled system are researched for different circumferential mode. The effect of hydrostatic pressure is investigated.The vibration and noise in the structure will propagate to a far location by means of waves, the essence of which is the propagation of energy, and the radiated sound power is equal to the residual of loss energy caused by damping deducted from the input power flow. In addition, the response of unbounded structure is approximately equal to the average of that of bounded structure at low frequency, and the responses of two kinds of structures drive to coincidence with the increasing of frequency. The hydrostatic pressure may exert an influence on vibration performance of deep submergence vehicles and high-pressure pipes subjected to hydrostatic pressure. So, the results presented here will be helpful to reduce vibration and noise of this kind of structures.
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