Actively Damped Piezoelectric Composite Wing

Aerospace structures require low weight and high performances. The interaction of these structures with their environment can be of different kinds. A very important one is the aeroelastic interaction between a wing and a subsonic or supersonic stream. In this paper the aeroelastic interaction of a composite laminate swept wing in a su-personic stream will be analyzed and modeled by means of the so called 'Piston Theory'. Due to aeroelastic effects, vibrations will be induced in the wing. These vibrations are,of course, highly undesidered. Much attention has been paid, during the last decade, toactive vibration control for different kinds of structures. In this case the vibration control will be achieved by means of direct velocity feedback. The actuators and sensors needed in order to augment the control will be piezoelectricelements. This kind of materials offers a number of advantages, such as, for example, the possibility of being easily shaped, the low weight and cost. The structural dynamic problem (i.e. finding the modes of vibration and the natural frequencies of the structure) has been solved by using a modified finite element method. The equations of motion are then discretised using the same method. This method isparticulary suitable for wing structures and differs from the classical one because it takes as unknowns chordwise global quantities instead of local ones such as flexural displacements, torsional rotations, mean-line curvature, etc. Once the equations of motion for the controlled wing are found, they are solved by using the Runge-Kutta method. It will be shown how the control system contributes to give a more damped system.