Whirl-flutter control through direct piezoelectric effect

Abstract

The aeroelastic instability known as whirl-flutter must be considered during the design of a propeller-driven aircraft. Usually, aircraft with single or multiple rotors may suffer with such phenomenon, especially when large rotor diameter is applied, such as vertical take-off and landing aircrafts (VTOL) with or without tilt rotors. Depending on the cruise speed, the whirl-flutter influences the project of rotors, wings and pylons. With the advent of modern air mobility, a better understanding of such phenomenon, as well as the development of vibrational control techniques to increase the stability margins becomes important. Although smart materials, such as piezoceramics, are commonly applied to control aeroelastic phenomena, the application to whirl-flutter control remains uninvestigated. Thus, the present research proposes passive control technique based on the direct piezoelectric effect, in a unimorph and bimorph harvester configurations, observing its effect on the aeroelastic system’s behavior. As main result of the piezoelectric material presence, an increased the flutter speed is observed, improving the system’s stability. Additionally, the bimorph configuration is more efficient to postpone the critical speed.