Passive Control of the Vibration and Sound Radiation from Submerged Shells

Abstract

Vibration and noise radiation from fluid-loaded cylindrical shells are controlled using multiple stiffeners and Passive Constrained Layer Damping treatment. Dynamic and fluid finite element models are developed to study the fundamental phenomena governing the interaction between the stiffened shell, with and without damping, and the fluid domain surrounding it. The models are used to predict the response of the shell and to evaluate the effect of the stiffening rings and damping treatment on both the structural vibration and noise radiation in the fluid domain. The prediction of the models are validated experimentally and against the predictions of a commercial FE software package (ANSYS). It is shown that stiffening of the shell reduces the amplitude of the vibration and noise radiation, particularly for high order lobar modes. The attenuation of the shell response and sound radiation can be significantly increased through the application of Passive Constrained Layer Damping treatment on the inner surface of the stiffening rings. The numerical and experimental validations demonstrate the accuracy of the developed models and emphasize its potential extension to the application of smart materials for active control of vibration and noise radiation from fluid-loaded shells.

Free vibration of circular cylindrical shell with constrained layer damping

“…The effect of shear parameter and ratio of core to facing thickness on the natural frequencies and loss factors of cylindrical shells was studied. Oh et al [10] controlled vibration and noise radiation from fluid-loaded cylindrical shells by PCLD treatment. Finite element models of structure and fluid were developed to study the effect of stiffeners, damping, and the fluid loadings on the cylindrical shell.…”

Vibration suppression for laminated cylindrical panels with arbitrary edge conditions

“…Markus (1976) studied the suppression for axisymmetric vibration of thin cylindrical shells with passive damping treatments using classical thin shell theory. Other researchers (Ditaranto, 1972;Leissa and Iyer, 1981;Ramesh and Ganesan, 1993;Oh et al, 2002;Xiang et al, 2008) extended this work and developed passive constrained layer damping (PCLD) to obtain high damping characteristics for various types of cylindrical shells.…”

Acoustic radiation from the submerged circular cylindrical shell treated with active constrained layer damping

“…Moreover, the reliability of this kind of treatment was rather poor due to the control spillover or breakdown voltage of the piezoelectric layer. Ruzzene et al [2,3] treated passive constrained layer damping (i.e., PCLD) on the longitudinal ribs of a cylindrical shell to restrain the acoustic radiation, and better damping effects were achieved. Meanwhile, Saravanan et al [4] found the damping factors of the whole structures were proved to be enhanced when the PCLD treatment was applied.…”