Flutter control using nonlinear tuned magnetic vibration absorbers

We will talk about the effects of nonlinear tuned magnetic vibration absorbers on the instability threshold and post-critical flutter of two-degrees-of-freedom « pitch-plunge » wing section. Two post-critical scenarios will be examined: a coupled-mode flutter scenario exhibiting limit cycle oscillations characterized by moderate amplitude in plunge and low amplitude in pitch, and a more complex flutter scenario exhibiting a second post-critical bifurcation from coupled-mode flutter to high amplitude symmetric stall flutter. Magnetic vibration absorbers have been used in plunge, in pitch or in both, and tuned as nonlinear vibration absorbers with cubic stiffness. Their efficiency will be examined in the light of wind tunnel tests and simulations. The latter have been obtained using an analytical aeroelastic model, including a nonlinear unsteady aerodynamic formulation, coupled with the vibration absorbers.