基于自然激励技术的颤振边界预测

为了预测紊流激励条件下机翼的颤振边界,基于自然激励技术提取紊流响应的自由衰减信号,采用矩阵束方法识别模态参数,最后通过Z-W(Zimmerman-Weissenburger)方法计算稳定性判据,拟合判据变化曲线并外推颤振边界.对平板机翼模型进行了数值仿真分析,对单独机翼模型风洞颤振试验数据进行了计算.结果表明:采用自然激励技术与矩阵束方法能够较准确地识别紊流激励响应的模态参数,频率识别误差小于6％,阻尼比识别误差小于30％,结合Z-W方法能够在较低风速较早地预测颤振边界,有助于提高试验的安全性.

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.