大机动过载下不平衡转子的弯扭耦合振动分析

Analysis on Coupled Lateral and Torsional Vibration of Unbalanced Rotor under Large Maneuvering Overload

针对未来无人机承受较大机动过载的特点,基于Timoshenko梁以及圆盘单元理论建立任意机动飞行条件下不平衡转子系统的弯扭耦合振动有限元模型,分析大机动过载情况下转子的非线性响应特征。结果表明:机动飞行工况下,在弯曲自由度和扭转自由度上都产生了新的次谐振动频率成分;各频率成分幅值被放大,弯曲自由度和扭转自由度耦合增强;当转速超过1阶弯曲临界速度时,周期性明显变差。

In view of the large maneuvering overload of the rotor system in unmanned aerial vehicle,the lateral-torsional coupled vibration finite element model of unbalanced rotor system under arbitrary maneuvering conditions is established based on Timoshenko beam and disk element theories.And the nonlinear response characteristics of the rotor under the condition of large maneuver overload are analyzed.The results indicate that the new subharmonic vibrations are induced in both lateral and torsional vibrations under maneuvering flight condition.The coupling effect of lateral-torsional vibration is strengthened as the amplitude of each frequency component is amplified,and the periodicity becomes worse when the rotational speed exceeds first-order lateral critical speed.