Flutter boundary prediction based on natural excitation technique

In order to predict the flutter boundary of the wing under the turbulence excitation, the natural excitation technique was used to obtain the free decaying signal from the turbulence response, and the matrix pencil method was adopted to identify the modal parameters, then the flutter margin was calculated by the Z-W(Zimmerman-Weissenburger) method, and finally the flutter boundary was extrapolated by the fitting margin curve. Plate wing numerical simulation model was analyzed and responses of alone wing model wind-tunnel flutter test were calculated. Results show that the natural excitation technique and the matrix pencil method can identify the modal parameters more accurately with the error of identified frequency less than 6% and identified damping ratio error less than 30%,and the flutter boundary can be predicted early at a low airspeed before the flutter point when combined with the Z-W method thus be helpful to protect the modal and improve the test safety. © 2016, Editorial Department of Journal of Aerospace Power. All right reserved.