Smart materials application for whirl-flutter instability control

Abstract

The whirl-flutter phenomenon is understood as aeroelastic instability which must be considered during the project of aircraft. The coupling of all structural wing's modes with the aerodynamic forces acting on the propellers and gyroscopic effect generate an instable movement that can cause damages and structural failures in the aircraft.Propellers and rotors in a nacelle's wing are susceptible to such phenomenon, especially when they have large diameters, as the vertical take-off and landing aircrafts such astilt-rotors. For certain cruise speed such instability influences the rotors, wing and pylons design. Due to the complex physical principles that compose the phenomenon,becomes important perform experiments to validate the analytical results. In order to improve the aircrafts' performance a lot of studies seek vibrational control in the rotor sand the piezoelectric application becomes an alternative, because of this type of material can be applied both passively (energy harvesting) and actuators (actively). Therefore, there is possible enhance the system stability margins and the vibration control to reduce the maintenance and operational costs, as well as improve the aircrafts performance. By the importance of the present phenomenon and the applicability of piezoelectric materials, it is proposed a numerical analysis to control the whirl-flutter in rotors applying active, passive and hybrid control using piezoelectric. At the same time an experimental apparatus will be developed, with the experimental validation possibility of the numerical results. As the results of the present proposal it is expected to obtain effective forms to control the present instability in aircraft's rotors. (AU)