Dynamic vibration absorbers for ground resonance control in hinged rotor helicopters
Résumé
This paper provides a numerical analysis on the influence of dynamic vibration absorbers (DVA) on the ground resonance phenomenon in an undamped articulated rotor helicopter. A torsional lead/lag absorber to be installed on the blade lag hinges is proposed. A simplified linearized four bladed helicopter model taking into account only the planar motion of the fuselage and the lead/lag motion of the blades is considered for the simulations. The instability zones for this model are known beforehand. The use of Coleman variables allows an eigenvalue analysis to be performed in the full system (helicopter + DVAs) within a typical range of rotor speed. By verifying the influence of each DVA parameter, namely, the inertia ratio, the natural frequency and the damping coefficient, on the stabilization, an optimality condition can be met.