Feedback active control using an acoustic black hole

Acoustic black holes (ABHs) are tapered structural features that can achieve high levels of structural damping within lightweight constraints. It has previously been proposed to integrate feedforward active vibration control into an ABH to enable control over a broad spectrum, however, the time advance information required in this control strategy is not always available. Therefore, this paper investigates a feedback control system, where a piezoelectric patch is used to provide the control actuation and a remote damping method is used to examine the different compensators available to control either the local taper vibration or the reflected wave component. The investigation highlights that at most frequencies minimising the taper vibration does not significantly affect the reflected wave, however minimising the reflected wave enhances the taper vibration. It is also shown that in some cases both quantities can be reduced and that it is possible to maintain the passive ABH performance whilst simultaneously limiting the taper vibration, which reduces structural fatigue.