The effectiveness of the active constrained layer damping(ACLD) in enhancing the damping characteristics and reducing vibrations and sound radiation levels of fluid-load cylinderical shells is presented. A finite element model (FEM) is developed to describe the dynamic interaction between the shells and ACLD treatments. The model is based on Donnell's theory of shells. Eight-noded two-dimensional iso-parametric elements are used to discretize the whole continuum. The surrounding water is modeled using acoustic-fluid elements, which account for the coupling between the structural vibrations and the surrounding acoustic field. Then, the previously derived element stiffness and mass matrices for the shell/ACLD and fluid are assembled along with the coupling terms to yield the final coupled equations of motion. This model allows the investigation of effectiveness of ACLD control strategy as well as specifics to the resultant vibration mode of the submerged cylinder. The control strategies are studied and compared in order to implement the vibration and acoustic radiation control of ACLD. The obtained results suggest the potential of the ACLD treatments in controlling the vibration and acoustic radiation of fluid-loaded cylinderical shells which constitute the major building block of many critical structures such as hulls of submarines and bodies of torpedos.
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