Aeroelastic analysis of an airfoil with a hysteresis non-linearity

Hysteresis non-linearity often exists in all-moving aerodynamic surface of aircraft such as all-moving horizontal tail plane and it has a remarkable effect on its aeroelastic response characteristics. The aeroelastic model of an airfoil with hysteresis non-linearity on its pitch degree of freedom is established by a piece wise approach. Based on the Theodorsen unsteady aerodynamics and Roger's method, tune domain simulations are performed to analyze the aeroelastic response characteristics of the system. The results show that with lower air speeds, the motions of the airfoil converge at its static balance point due to the dry-friction mechanism of hysteresis non-linearity. In higher air speeds, limit cycle oscillations occur with dUTerent amplitudes. Comparisons have been made between aeroelastic responses of airfoil system with hysteresis non-linearity and free-play non-linearity. Describing function method is also implemented for flutter analysis in frequency domain. It is found that the equivalent stiffness of the system with hysteresis non-linearity is larger than that of the corresponding free-play non-linearity because of the effect of dry-friction, and the flutter boundary obtained by describing function method agrees well with that obtained by time domain simulations.