考虑变质量效应的柔性两级火箭动力学研究

Dynamics of a Variable-Mass and Flexible Two-Stage Rocket System

研究了考虑变质量效应的柔性两级火箭的动力学建模问题.首先采用Kane方法和模态截断法建立了变质量柔性体的动力学方程,然后将火箭简化为带喷嘴的梁模型,将变质量柔性体的动力学方程应用到火箭动力学建模过程中,分别推导了针对喷嘴和梁的动力学方程,进而组集得到整个系统的动力学方程.在建模过程中,考虑了外部气动力以及两级火箭级间分离时间间隔的影响.文章最后通过数值仿真揭示了火箭柔性效应对系统特性的影响,以及单级火箭和两级火箭在动力学特性上的差异.

The dynamic modeling of a variable-mass flexible two-stage rocket system was studied. The dynamical equation of a variable-mass flexible body was derived by using the Kane＇s equation and the modal truncation method. Then the rocket system was simplified as a beam structure with a gimbaled nozzle. The dynamical equation of a variable-mass flexible body was used in the process of rocket＇s dynamic modelling. The dynamical equations of the beam structure and the gimbaled nozzle were both derivated. The dynamical equation of the whole system was obtained by assembling the dynamical equations of the beam structure and the nozzle. In the modelling for the system, the external aerodynamic force and the time interval during stage separation were considered. Finally, the effect of rocket＇s flexibility on the system characteristics and the difference between single-stage and two-stage rockets were investigated through numerical simulations.