Aeroelastic stability of a bearingless rotor in hover with finite-state unsteady aerodynamics

A analytical model was presented for aeroelastic stability of a bearingless rotor with finite-state unsteady aerodynamics in hover. Nonlinear strain-displacement relations were built using Green-Lagrange strain tensors. The blade was modeled as a multiple-load-path system and the finite element equations of a blade motion were obtained from Hamilton's principle. Unsteady aerodynamics effects were induced through finite-state induced flow models. The modal approaching method based on coupled rotating natural modes was used for the stability analysis. Numerical results show that the predictions using finite-state induced flow models are close to experimental values and they are better than those previously using dynamic inflow models or uniform inflow models. The calculation shows that the model is correct.