Flutter suppression of an airfoil using a nonlinear energy sink combined with a piezoelectric energy harvester

We propose an absorber combined with a nonlinear energy sink and piezoelectric energy harvester (NES-PEH) for suppressing the flutter of a two-degree-of-freedom (2-DOF) airfoil. The NES-PEH is a cascade device comprising of a magnetic nonlinear energy sink (NES) and a tuned piezoelectric beam for broadening the vibration absorption frequency band. It is installed inside a 2-DOF airfoil, supported by four spring cantilever beams and a spring steel wire, for suppressing the flutter response and harvesting mechanical energy. A flutter model of the airfoil connected to the NES-PEH is established using unsteady aerodynamic theory. The influence of the dimensionless parameters of the NESPEH on the flutter response and output voltage is explored. Furthermore, experiments are designed and tested for verifying the effectiveness of airfoil flutter suppression by the NES-PEH. The results indicate a significant influence of the installation position of the NES-PEH on the flutter response. The NES-PEH installed behind an elastic axis can increase the flutter speed by 20.4%, whereas that installed in front of the elastic axis can effectively suppress the pitch amplitude of the limit cycle oscillation (LCO) by 24.2%. Moreover, at d = -35 mm, the NES-PEH exhibits the best performance compared with the nonlinear energy sink and its fixed counterpart, suppresses flutter and the LCO, and outputs 10 & mu;W power. Overall, this study presents a novel method for suppressing flutter and harvesting energy simultaneously.& COPY; 2023 Elsevier B.V. All rights reserved.