Adaptive broadband low-frequency vibration control using voltage-tunable acoustic black holes with polyvinyl chloride gel

Acoustic black holes (ABHs) are effective in attenuating structural vibrations over a broad frequency range, but their performance becomes sensitive and limited under low-frequency line spectrum excitations. To address this issue, this study proposes an adaptive ABH-PVC structure that integrates stacked polyvinyl chloride (PVC) gel dynamic vibration absorbers (PVC-DVAs). A coupled model was established and experimentally validated on a doubly clamped rectangular plate. Results demonstrate that the proposed structure not only retains the inherent broadband and high-damping suppression characteristics of ABHs but also leverages the tunable stiffness and high damping of PVC-DVA to significantly reduce the amplitude of additional low-frequency resonance peaks. The PVC-DVA can continuously tune its resonant frequency from 29 to 65 Hz via simple voltage control, enabling the coupled system’s anti-resonance frequency to match the varying excitation frequencies of line spectra, thereby achieving stable and effective line-spectrum control. However, the high damping also weakens the anti-resonance depth, leading to slightly inferior suppression compared to conventional ABHs when the excitation frequency coincides with the anti-resonance frequency. Overall, the proposed approach effectively addresses time-varying low-frequency line-spectrum vibrations while maintaining broadband suppression advantages, providing a feasible solution for adaptive control in complex vibration environments.