Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Nonlinear energy sinks as a passive control approach to suppress airfoil flutter
Submission Author:
Adolfo Esteves Ribeiro , SP , Brazil
Co-Authors:
Adolfo Esteves Ribeiro, José Augusto Ignacio da Silva, Flavio D. Marques
Presenter: Adolfo Esteves Ribeiro
doi://10.26678/ABCM.COBEM2021.COB2021-0295
Abstract
Aeroelastic systems can be subjected to a self-excited mechanism and experience the so-called phenomenon of flutter. Under this condition, airfoils can exhibit self-sustained oscillations with exponential trends diverging to infinity, characterizing an unstable system's behavior. The high vibration levels can lead to fatigue and catastrophic failure, thereby justifying flutter suppression schemes. This work proposes an investigation about vibration absorbers known as Nonlinear Energy Sinks (NES) to suppress aeroelastic instabilities in a pitch and plunge typical section. Unsteady aerodynamic loads are modeled according to generalized Theodorsen's and Wagner's theories, represented in state space. The aeroelastic model is assumed linear. A conventional NES approach is considered, in which a pure cubic stiffness spring is adopted. A parametric study involving the physical parameters of the NES and its positioning in the airfoil is conducted to find conditions that efficiently favor the target energy transfer (TET) concept for the NES. This study assesses each NES parameter's sensitivity viewing a future investigation employing an optimization process in the NES design. An energy analysis is also carried out to evaluate the NES performance in absorbing energy from the aeroelastic system.
Keywords
Flutter, Flutter passive control, Nonlinear energy sinks, typical aeroelastic section, target energy section
