随动推力作用下柔性旋转飞行器稳定性分析

针对柔性旋转飞行器动力学问题，考虑了飞行器转速的作用，建立了计入陀螺力矩及随动推力影响的运动方程并分析了系统的动力稳定性问题。将柔性旋转飞行器简化为带有附加质量的非均匀转子结构，考虑陀螺力矩及随动推力的影响，采用剪切变形对轴向位移有影响的Timoshenko梁模型，基于有限元方法建立了运动方程，分析转速、剪切刚度及附加质量等因素对系统稳定性的影响，发现了转速作用下旋转飞行器刚体和弹性体模态耦合的新现象。结果表明：剪切刚度较小时，剪切变形对临界推力有较大影响；附加质量的大小及位置对临界推力和不稳定域有重要的影响；转速一般会诱发非均匀转子系统的弯曲模态与刚体模态合并为一个耦合模态，致使系统产生动态失稳。

Dynamic Stability Analysis of Flexible Spinning Flight Vehicles under Follower Thrust

Effect of spinning speed in the dynamic analysis of flexible spinning flight vehicles is emphatically considered in this paper. Taking into account gyroscopic moment and follower thrust, motion equations are formulated and then dynamic stability is analyzed. The flexible spinning flight vehicle is simplified as non-uniform rotor structure with an attached mass. Given that shear deformation influences axial displacement, Timoshenko beam model is adopted by considering the effect of gyroscopic moment and follower thrust. Finally motion equations are established based on the finite element method to analyze impacts of factors such as speed, shear stiffness and attached mass, etc. on the stability of the system. A new phenomenon of modal coupling between rigid modal and elastic modal in the system of spinning flight vehicles is discovered under the influence of spinning speed. Results show that shear deformation has great influence on the critical thrust when shear stiffness value is small; magnitude and position of attached mass has certain impacts on critical thrust and instability region; bending modal and rigid modal of the non-uniform rotor system are generally induced to merge to a coupled modal, thus resulting in dynamic instability.