Finite element modeling of vibration and sound radiation from fluid-loadeddamped shells

The vibration and noise radiation from fluid-loaded cylindrical shells are controlled by using multiple stiffeners and passive constrained layer dampi ng treatment. Dynamic and fluid finite elements are developed to study the fundamental phenomena governing the coupling between the stiffened shell, w ith and without damping, and the fluid domain surrounding it. The models ar e used to predict the response of the shell and to evaluate the effect of s tiffening rings and damping treatment on both the structural vibration and noise radiation in the fluid domain, The geometry of the shell and fluid do main allows the formulation of a harmonic-based model, which uncouples the fluid-structural response of modes corresponding to different numbers of ci rcumferential nodes. In this study, it is shown that stiffening of the shell reduces the amplitu de of the vibration and noise radiation, particularly for high-order lobar modes. The attenuation of the shell response and sound radiation can be inc reased significantly through the application of passive constrained layer d amping treatments on the inner surface of the stiffening rings. (C) 2000 El sevier Science Ltd, All rights reserved.