Energy harvesting efficiency of unimorph piezoelectric acoustic black hole cantilever shunted by resistive and inductive circuits

A unimorph piezoelectric cantilever equipped with an Acoustic Black Hole (ABH) termination is designed for broadband energy harvesting. The ABH termination, its tapered region, induces a focusing of the flexural vibrations which can be used to increase efficiency harvesting device. modal-based analytical model presented, providing explicit form electro-mechanical coupling each beam eigenmode. Closed-form expressions coupled mechanical response and electrical outputs are obtained, allowing one draw out complete parametric study optimize optimization procedure conducted following two steps: first, optimal location dimensions single patch achieved by maximizing modal factor (MEMCF) structural mode. Thanks proposed approach, it clearly shown that putting at maximum strain field in adjusting length accordance focalization created effect, produces much higher MEMCFs over wide frequency range thus outperforms those uniform beam. Second, shunted circuit comprehensively performed only resistance, or both resistance inductance, series parallel. Analytical results show key design rule resides matching time scale forcing frequency. Addition inductance allows enhancing performance, but on narrow band. Finally, advantages further obtained considering multiple patches, optimum when tuned targeting eigenmode