固体火箭发动机随动推力作用下细长体亚临界试车及动力学失稳临界推力预示

Subcritical trial and critical dynamic instability thrust prediction of slender body under solid rocket motor based follower thrust

设计了随动推力作用下细长体模拟件试车试验系统,开展固体火箭发动机试车;理论推导了耦合模态频率差-推力关系的多项式,结合亚临界试车数据外推预示失稳临界推力。研究结果表明:理论分析与地面试验结果吻合,只需开展少数几次安全可控的亚临界试车试验,获取系统的振动响应数据,即可准确预测临界推力;亚临界试验验证了随动推力横向分量引起模态间的刚度耦合,对于弯曲振动明显的细长体飞行器,推力对结构的影响应视为随动载荷。

A trial system for follower thrust acted on slender body test piece was designed and applied to solid rocket motor trial.The relational expression between coupled mode frequencies difference and thrust was theoretically derived.It was shown that theo⁃retical results agree with test data,and critical thrust can be predicted based on vibration data from a few of safe and controllable subcritical trials;stiffness coupling caused by transverse component of follower thrust is verified by subcritical trials;thrust should be considered as follower load for the slender vehicle with obvious bending vibration.