Flutter and Limit Cycle Oscillation Suppression Using Linear and Nonlinear Tuned Vibration Absorbers

Abstract

Aircraft are more than ever pushed to their limits for performance reasons. Consequently, they become increasingly nonlinear and they are more prone to undergo aeroelastic limit cycle oscillations. Structural nonlinearities affect aircraft such as the F-16, which can undergo store-induced limit cycle oscillations (LCOs). Furthermore, transonic buzz can lead to LCOs because of moving shock waves in transonic flight conditions on many aircraft.This study presents a numerical investigation of passive LCO suppression on a typical aeroelastic system with pitch and plunge degrees of freedom and a hardening stiffness nonlinearity. The absorber used is made of a piezoelectric patch glued to the plunge springs and connected to a resistor and an inductance forming a RLC circuit. A mechanical tuned mass damper absorber of similar configuration is also considered. The piezoelectric absorber features significant advantages in terms of size, weight and tuning convenience.The results show that both types of absorber increase the linear flutter speed of the system in a similar fashion but, when optimal, they lead to a sub-critical bifurcation while a super-critical bifurcation was observed without absorber. Finally, it is shown that the addition of a properly tuned nonlinear spring (mechanical absorber) or capacitor (piezoelectric absorber) can restore the super-criticality of the bifurcation. The tuning of the nonlinearity is carried out using numerical continuation.

Feedback control of limit cycle oscillations and transonic buzz, using the nonlinear transonic small disturbance aerodynamics

“…Considering the active feedback control of transonic buzz there have been a few attempts to systematically study the effects of feedback on transonic buzz. Verstraelen, Kerschen, Dimitriadis (2017) have attempted to suppress transonic buzz using dynamic vibration absorbers. Marzocca, Silva and Librescu (2002) have also considered the closed loop analysis of transonic buzz.…”

Smart Wing Flutter Suppression

“…In fact, they can be used as actuators and dampers to manage the aeroelastic behaviour of the wing. One effective way to avoid redesign the wing is to use piezoelectric materials to significantly delay the flutter [8]. Piezoelectric actuators have been used in active aeroelastic control of an adaptive wing [9].…”

Smart Blade Flutter Alleviation with Rotational Effect

“…They can perform as dampers and actuators to control the blade aeroelastic behavior. In fact, implementing piezoelectric materials can avoid redesigning the blade which can significantly delay flutter [8,9]. These materials have been implemented on an adaptive blade with active aeroelastic control [10].…”