论文部分内容阅读
针对一种基于脉冲激励的高安全性颤振边界预测方法,提出改变其原有的脉冲激励形式,采用扫频激励以改善脉冲激励激振频带较窄和信噪比较低等问题。根据采样数据和气动弹性运动方程,获得亚临界速度下的模态位移响应和模态气动力系数。采用系统辨识构建相应的非定常气动力模型,耦合状态空间的结构运动方程和气动力方程得到气动弹性稳定性分析状态方程,进而预测颤振边界。基于两种激励形式预测的颤振边界的对比结果表明,在较低的测试速度下采用扫频激励具有更高的预测精度。
Aiming at the problem of high safety flutter boundary prediction based on pulse excitation, this paper proposes to change its original pulse excitation form and to use sweep excitation to improve the narrow pulse excitation excitation frequency band and low signal-to-noise ratio. According to the sampled data and the equation of aeroelasticity, the modal displacement response and the modal aerodynamic coefficient at subcritical velocity are obtained. The corresponding unsteady aerodynamic model is constructed by using system identification, and the structural equation of motion and aerodynamic equation of coupled state space are used to obtain the equation of state of aerodynamic stability analysis to predict the flutter boundary. Comparisons of the flutter boundaries predicted based on the two types of excitation show that swept-frequency excitation at lower test speeds has higher prediction accuracy.