Uncertainty analysis of piezoelectric nonlinear energy sink for energy harvesting of an aeroelastic system in flutter condition

A nonlinear energy sink (NES) is a nonlinear absorber, typically implemented as a secondary mechanical system designed as a passive absorber. As defined herein, the Piezoelctric Nonlinear Energy Sink (PNES) is an NES that integrates a piezoelectric component, thereby enabling it to also function as an energy harvester capable of converting mechanical vibrational into electrical energy, useful for powering autonomous systems. This paper investigates the robustness of a PNES integrated into an aeroelastic typical section, comparing its performance to a linear harvester. The primary objective is to assess the robustness of the PNES via uncertainty analysis. A low-order model is employed, validated against Computational Fluids Dynamics (CFD) simulations. A comprehensive uncertainty analysis is conducted to assess the impact of parametric variability on the harvested electrical power. The results indicates the superior robustness of the PNES-equipped system, particularly at higher levels of input uncertainty, where it exhibited lower output coefficient of variation compared to the linear system. The electromechanical coupling and plunge stiffness were identified as the most influential parameters on power output. Furthermore, the statistical distribution of the power harvested by the PNES was found to be highly asymmetrical, characterized by a small number of high-power events. In conclusion, this work demonstrates that the inclusion of a PNES facilitates energy harvesting from flutter, and also enhances the system's robustness against parametric uncertainty.