考虑附加力影响的弹性体远程火箭弹弹道分析

Trajectory Analysis of Aeroelastic Long-range Rockets Considering Subsidiary Load Effect

远程火箭弹具有长细比大、射程远的特点,为提高弹道分析精度,有必要充分考虑气动弹性和其它附加力的影响。以远程火箭弹非线性运动方程为基础,考虑气动弹性效应,分别采用细长体理论和气动导数法计算弹身和弹翼舵面产生的非定常气动力,并考虑地球自转和发动机燃料变化所引起的附加力以及地球曲率的影响,建立弹性体远程火箭弹六自由度运动模型。通过弹道仿真,对比分析气动弹性、附加力和结构刚度对远程火箭弹脱靶量的影响。仿真对比结果表明,气动弹性和附加力都对远程火箭弹脱靶量产生影响,且附加力与气动弹性高度耦合,在考虑气动弹性效应的前提下,附加力对远程火箭弹脱靶量的影响被显著放大,因此在全弹道仿真分析中必须同时考虑气动弹性和附加力的耦合影响;弹体结构刚度越小,远程火箭弹的脱靶量越大,在远程火箭弹初步设计中,应保证弹体结构刚度以确保命中精度。

Long-range rockets have the characteristics of large slenderness ratio and long range. To improve the accuracy of trajectory simulation, it is necessary to consider aeroelasticity and subsidiary load effect. Based on the nonlinear motion equation of the rockets, the effect of aeroelasticity is is incorporated in the trajectory simulations. The unsteady aerodynamic loads of the body, wings and rudders are calculated by slender body theory and aerodynamic derivative method, respectively. Besides, the six-degree-of-freedom flight dynamics model considering the curvature and the subsidiary loads generated by Earth rotation and fuel mass change is built. Then, the effect of aeroelasticity, subsidiary loads and structural stiffness on rocket miss distance is analyzed through the trajectory simulations. Simulation results show that aeroelasticity and subsidiary loads have a great impact on the miss distance of the rocket. In addition, the subsidiary loads are highly coupled with aeroelasticity and the effect of the subsidiary loads on miss distance of the rocket is significantly amplified with the consideration of aeroelasticity effect. Thus, it is necessary to consider the coupling effect of aeroelasticity and subsidiary loads simultaneously in whole trajectory simulation analysis. Furthermore, when the rocket structural stiffness becomes insufficient, the miss distance of the rocket increases greatly. Therefore, sufficient structural stiffness is essential for improving the hit precision in rocket preliminary design.