Sound Radiation from a Plate with Embedded Active Acoustic Black Holes

Abstract

Acoustic Black Holes (ABHs) can be realised as tapered structural features that focus and absorb vibrational energy. In a plate, the damping effect of ABHs can be used to reduce the radiation efficiency, particularly above the critical frequency of the plate. However, at lower frequencies, there is still significant radiation due to the low order modes of the plate. It has previously been shown that the combination of active control and ABHs can result in an effective broadband control solution with lower computational and power requirements compared to a standalone active configuration. This paper presents an investigation into how two different active control strategies affect structural response and radiated sound power of a plate with active ABHs (AABHs). It is shown, through an active vibration control strategy and an active noise control strategy, that the AABHs can be used to successfully control either the global structural response of the plate or the radiated sound power. However, it is also shown that controlling either response can lead to an enhancement in the other.