Realization of an autonomous virtual acoustic black hole with piezoelectric patches

Acoustic black holes (ABHs) offer new opportunities for designing mechanical devices that can trap and reduce the vibrational energy of a system. This paper proposes the digital realization of the ABH effect, also called virtual ABH (VABH), through piezoelectric patches. A self-contained and autonomous reduction vibration device is thus developed. However, piezoelectric VABHs raise theoretical and experimental difficulties which are discussed herein. An improved pseudo-collocated approach is proposed, and the synthetic impedance is theoretically derived. Experiments are conducted using a cantilever beam where the VABH is implemented with few piezoelectric patches. It is shown to provide excellent vibration reduction over a large frequency range. The herein presented original concept solves the two long-lasting challenges of mechanical ABHs, i.e, its manufacturing and inability to operate at low frequencies, making it highly attractive for applications on real-life structures.