Attenuation of wave propagation in fluid-loaded shells with periodic shunted piezoelectric rings

The vibration and the sound radiation of cylindrical shells are analyzed and controlled. Shunted piezoelectric rings are placed periodically along the shell length to act as sources of impedance mismatch. The resulting periodic structure features a behavior which is characterized by frequency bands,,stop bands', where the vibrations are attenuated and wave propagation is impeded. The location and the width of the stop bands are controlled by the impedance mismatch introduced along the structure. In the considered configuration, the stop bands can be tuned by proper selection of the shunting circuit. A finite element model is developed to predict the structural response and the acoustic radiation of the considered class of shells. The model accounts for the presence of the rings and for the effect of the shunting parameters on the behavior of the structure. The developed model is used to estimate the frequency response function of the shell and to formulate the transfer matrix for the considered periodic structure. The transfer matrix determines the nature of wave propagation and in particular can be used to estimate the stop bands. The presented results show the effectiveness of the proposed concept when the rings are shunted through a resistive-inductive circuit. The considered shunting strategy is able to generate an additional stop band at the tuning frequency. The location of the stop band is unaffected by the presence of the fluid loading, which demonstrates the robustness of the considered vibration control treatment with respect to significant structural modifications.