| This study was carried out as part of research contract for Structures, Materials and Propulsion Laboratory (SMPL), Institute for Aerospace Research (IAR) of National Research Council (NRC) under contract No. 31184-6-0296/001/ST: "Helicopter Individual Blade Control Strategies Using Smart Structures Technology".; The main objective of this project is to investigate the use of a "smart" spring, developed at the National Research Council of Canada, to actively control the dynamics of an individual hingeless blade. The conceptual design of the "smart" spring has been granted several patents.; A set of dynamic equations of motion of the "smart" blade, which describe the unsteady blade motion near the equilibrium operating condition, are derived based on the work done by Hodges and Dowell (Ref 11). In order to present a realistic case study, a model of a "smart" blade is developed based on a reduced scale EUROCOPTER BO105 helicopter blade.; Harmonic parametric actuation is then applied to the "smart" blade using a square wave (on-off) control law. To evaluate the stability of the periodic-coefficient equations of motion associated with the Individual Blade Control, Floquet method is used. Finally, the results are compared with those associated with the uncontrolled blade.; Significant improvements in the damping are observed. Thus, the application of the Individual Blade Control using the "smart" spring technology can be suggested to improve aeroelastic phenomena such as flutter and divergence on a hingeless helicopter blade. |
