Mitigating vibration and sound radiation with a digital piezoelectric meta-shell in heavy fluids

Abstract

The vibration-induced sound radiation of shell structures has a significant influence on the acoustic-stealth performance of underwater vehicles. To tackle this challenge, a programmable meta-shell featuring periodically distributed piezoelectric shuntings is investigated in this research. Its tunable local-resonance (LR) bandgap, enabled by the digital shunting circuits, is utilized to mitigate the vibration and sound radiation of underwater shells. We establish an electrical-mechanical-acoustic coupling model for the meta-shell submerged in the unbounded heavy fluid. The quadratic velocity and the radiated sound power are computed to evaluate its global vibro-acoustic behaviors. It is demonstrated that, by strategically designing LR bandgaps around the wet-mode frequencies of meta-shells, both the vibration and the sound power could be effectively reduced at target modes. The impacts of electrical damping and poles on the vibro-acoustic reduction efficiency are also identified. Lastly, the experimental set-up of a piezoelectric meta-shell equipped with 48 independently controlled cells is built. The results achieved through underwater experiments validate the meta-shell's capability to programmably suppress vibro-acoustic response peaks associated with multiple wet modes.