紊流激励条件下基于随机减量法的颤振边界预测研究

发展了一种紊流激励条件下的颤振边界预测方法。首先基于随机减量法从紊流激励响应中提取出系统的自由衰减响应，其次采用矩阵束法从自由衰减响应中识别出振动响应的主要模态参数，最后用识别出来的模态参数构造稳定性判据，根据稳定性判据与动压或风速的变化关系用曲线外推来预测颤振边界。数值仿真与风洞试验研究表明：利用随机减量法和矩阵束法能够较准确地识别出紊流激励响应中的主要模态参数；稳定性颤振判据下降趋势明显、规律性好，有助于在较低风速下提前预测出颤振边界，从而减小风洞试验或颤振试飞的安全隐患。

FLUTTER BOUNDARY PREDICTION OF TURBULENCE EXCITATION RESPONSE BASED ON RANDOM DECREMENT METHOD

A flutter boundary prediction technique is developed upon turbulence excitation response of wind tunnel flutter tests. Firstly the random decrement method is employed to extract the system's free decaying signal from the turbulence excitation response. Then main modal parameters, which are needed to establish the stability criterions, are identified through the matrix pencil method. Eventually, a curve fitting about variation of the criterion with dynamic pressure or velocity is plotted to extrapolate the flutter boundary. The simulated and wind tunnel test results show that: the modal parameters of turbulence excitation response can be identified precisely through the method of random decrement and matrix pencil, and the stability criterions have a clear downward trend so that it will be very helpful for advanced prediction of flutter boundary and the reduction of potential risk during flutter tests.