| This study investigates the aeroelastic stability of the elastic lead-lag and flap bending, torsion of a uniform, untwisted hingeless "smart" rotor blade in hover flight. As a first attempt, no offsets are considered between the elastic, aerodynamic and tension axes and the pre-cone angle is taken to be zero. In order to perform a realistic stability analysis, configuration parameters of a reduced scale model of an actual blade of a Eurocopter BO105 helicopter are used in the present work.; The nonlinear partial differential equations of motion for such a blade are derived. First, by applying Galerkin's method, the equilibrium deflections are defined. This is followed by the development of the perturbation equations, which describe the unsteady blade motion near the equilibrium operating condition. The stability is then determined using standard techniques.; The equations of motion are also modified to incorporate sinusoidal "smart" spring actuation. Actuating the spring, one can change the cross-sectional parameters of the blade, thus affecting the dynamic behaviour of the rotor. The effects of these changes are investigated in this study. The time-dependent linear differential perturbation equations of motion are solved for the eigenvalues using the Floquet method. The obtained results are compared with those found using a constantly actuated or non-actuated "smart" spring.; Results are obtained for a variety of blade configurations in order to provide "smart" rotor blade stability characteristics. It is shown that the "smart" spring technology could be used to eliminate instabilities, such as divergence and flutter, by sinusoidally actuating the spring. |
