An Acoustic Black Hole Beam Base for Vibration Suppression and Piezoelectric Energy Harvesting in Micro-to-Small-Scale Multirotor UAVs

This study proposes an acoustic black hole (ABH) beam base for vibration suppression and piezoelectric energy harvesting in micro-to-small-scale multirotor unmanned aerial vehicles (UAVs). The long-term motivation is to reduce vibration transmitted to the battery module and supporting components mounted on the UAV base; however, the present study focuses on evaluating the vibration response of the UAV base structure itself. A conventional uniform beam base is replaced by a thickness-tapered ABH beam to guide and localize vibration energy toward the tapered region, where the energy can be dissipated or converted into electrical output through a piezoelectric patch. Theoretical modeling, ANSYS simulation, and experimental validation are conducted to compare the dynamic responses of the uniform beam base and the ABH beam base. The nonlinear uniform beam model, ABH beam model, and piezoelectric coupling equation are formulated and solved using numerical methods. ANSYS modal and forced-vibration simulations are further performed to verify the theoretical predictions. The simulation results show that the ABH beam base reduces the RMS displacement from 0.00908 m to 0.00625 m, corresponding to a reduction of 31.17%. Experimental shaker tests also confirm the vibration reduction trend, with the RMS displacement decreasing from 0.00801 m for the uniform beam base to 0.00601 m for the ABH beam base, corresponding to a reduction of 24.97%. In addition, the voltage generation performance of the ABH beam with an attached piezoelectric patch is evaluated, and the theoretical and simulated voltage outputs show reasonable agreement. These results demonstrate that the proposed ABH beam base can serve as a lightweight multifunctional structure for UAV base vibration mitigation and vibration-based energy harvesting.