Shunted piezoelectric patches are periodically placed along rods to control the longitudinal wave propagation in these rods. The resulting periodic structure is capable of filtering the propagation of waves over specified frequency bands called stop bands. The location and width of the stop bands can be tuned, using the shunting capabilities of the piezoelectric materials, in response to external excitations and to compensate for any structural uncertainty.A mathematical model is developed to predict the response of a rod with periodic shunted piezoelectric patches and to identify its stop band characteristics. The model accounts for the aperiodicity, introduced by proper tuning of the shunted electrical impedance distribution along the rod. Disorder in the periodicity typically extends the stop bands into adjacent propagation zones and, more importantly, produces the localization of the vibration energy near the excitation source. The conditions for achieving localized vibration are established and the localization factors are evaluated for different levels of disorder on the shunting parameters.The numerical predictions demonstrate the effectiveness and potentials of the proposed treatment that requires no control energy and combines the damping characteristics of shunted piezoelectric films, the attenuation potentials of periodic structures, and the localization capabilities of aperiodic structures. The theoretical investigations presented in this paper provide the guidelines for designing tunable periodic structures with high control flexibility where propagating waves can be attenuated and localized.

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.

No abstract

No abstract

No abstract