Control of vibration in a plate using active acoustic black holes

Acoustic Black Holes (ABHs) have been shown to provide significant vibration damping in both beams and plates. Although effective, the performance of ABHs has been shown to be limited at lower frequencies, where the local modes of the ABH dominate the structural response. Previously, integrating active control into the taper of an ABH beam termination has been explored and the resulting active ABH (AABH) has been shown to perform very well; namely it has been shown that the reflection coefficient can be controlled almost perfectly over a broad range of frequencies. In this paper, active components have been integrated into ABHs embedded in a plate and a multichannel feedforward control strategy has been presented that can be used to control the global structural response of the plate. It has been shown that active control can be used to address the low frequency performance limit of the embedded AABHs which, combined with the passive damping provided by the ABH effect, demonstrates that AABHs can be used as an effective broadband vibration control solution. It has also been shown that the AABHs provide better coupling with the secondary sources, therefore reducing the energy required to implement active control.