高速飞行器热结构工作时变模态参数辨识

高速飞行器由于其很高的飞行速度而无可避免地受到气动加热作用的影响,进而引起结构特性的时变。采用理论或有限元方法(FEM)进行数值分析,难以获取反映结构在飞行(工作)状态下的真实模态参数。通过辨识获取高速飞行器热环境下的时变结构模态参数是一项十分具有挑战性的任务。针对此问题,引入参数化时频域的最大似然方法,对气动加热作用下的高速飞行器升力面结构的时变模态参数进行了辨识。通过模拟真实飞行状态的数值算例研究,说明参数化时频域的最大似然方法能够很好地辨识出低信噪比(SNR)情况下的模态频率和模态振型,验证了参数化时频域最大似然方法适用于具有显著时变特征的高速飞行器热结构的时变结构模态参数辨识,可为将来相关的工程研究和应用提供良好的理论支持。

Operational identification of time-varying modal parameters for thermal structures of high-speed aerial vehicles

The high-speed aerial vehicles are unavoidably impacted by the aerodynamic heating effect due to their high speed, which may further result in the time-varying characteristics of their structures. The theoretical and finite element method (FEM)-based numerical approaches hardly acquire the real modal parameters of the in-flight (operational) aerial vehicles. Focusing on this problem, the parametric time-frequency-domain maximum likelihood method is introduced into the application of the high-speed aerial vehicles and the time-varying modal parameters are estimated by this parametric time-frequency-domain maximum likelihood method. Based on a high-fidelity simulation example, it is proved that the introduced method can identify the modal frequency and mode shapes even in the low signal noise ratio (SNR) cases and the method is suitable for the modal parameter estimation of thermal structures of high-speed aerial vehicles with notable time-varying natures, which can theoretically support the relative engineering studies and applications.