Active tuning of vibration bandgap in immersed thin plates: A numerical analysis
Résumé
Active tuning of vibration bandgaps in immersed thin structures presents a significant challenge, as fluid-structure interaction (FSI) can drastically alter system dynamics and compromise control effectiveness duo to the weak inertial characteristic across the thickness direction. This study introduces a unit cell-based finite element model to design and analyze thin plates with periodic piezoelectric feedback controllers operating in a fluid environment. The model comprehensively integrates a three-parameter active control strategy with FSI effects, which are captured by a fluid added mass matrix under Bloch periodic boundary conditions. Our investigation reveals a critical finding: the fluid's added inertial mass can severely degrade the authority of feedback control, particularly for plates with low self-inertia, causing pre-designed vibration bandgaps to narrow or even vanish entirely. To counteract this adverse effect, we demonstrate that enhancing the structure's self-inertia, either by increasing its thickness or, more practically, by increasing the arrangement density of piezoelectric patches, effectively restores the tunability of the bandgaps. The predictions from the unit cell model are validated against full-scale frequency response simulations. A multi-parameter study further reveals strong coupling effects among control parameters, highlighting the importance of coordinated tuning for robust bandgap manipulation under FSI. These results underscore that considering FSI is not merely an option but a necessity for the effective design of active vibration control systems for immersed structures.