Enhancement of piezoelectric energy harvesting using ABH structural tailoring

The acoustic black hole (ABH) in thin-walled structures allows the reduction of phase velocity of flexural waves, producing high energy density within structural areas which offers excellent potential for vibration based energy harvesting. The broadband characteristic of the ABH effect is beneficial to increase the operational frequency range of vibration energy harvesters. In this paper, finite element models of a beam with embedded ABHs and its full coupling with piezo-transducers bonded on its surface are analyzed. The size of piezoelectric patches is designed to be relatively smaller than the wavelengths of ABH features in order to make sure that the positive and negative electric charge generated on the surface of harvesters won't be neutralized. The performances of energy harvesters in the ABH structure are investigated and compared with those of the uniform beam under steady state in numerical simulations. The results show that the ABH features are much more effective for vibration energy harvesting than conventional uniform structures.