| Aeroelastic modal parameters of a two-degree-of-freedom pitch-plunge analytical airfoil and an experimental aircraft wing are identified from sub-critical airspeed data by experimental modal analysis. A numerical simulation of the analytical system yielded input/output data for different airspeeds, while acceleration and force data was collected from a vibration test of the experimental wing in a wind tunnel. Frequency response functions and modal parameters of the two systems are estimated from these data. For the analytical system, typical aeroelastic behavior is observed, namely converging natural frequencies and diverging damping ratios, with the damping of the second mode becoming unstable at speeds greater than the system's critical speed. For the experimental system, the natural frequencies and damping ratios are shown to change very little while the mode shapes of both systems show substantial changes over the airspeed ranges considered. |
