运载器准三维着陆动力学与极限工况缓冲性能研究

Analysis of Quasi-three-dimensional Landing Dynamics and Attenuation Performance under Extreme Conditions for Launch Vehicle

为满足垂直降落重复使用运载器多工况着陆分析时模型精度与求解效率相兼顾的需求,搭建了对称着陆模式下的准三维动力学模型,模型中考虑了运载器主体平面运动、足垫空间运动及支柱侧向载荷,同时基于集中参数法建立了油液缓冲力模型,并引入了含Stribeck效应的滑移-粘滞摩擦力及非线性接触力来构建地面作用力模型。在此基础上,开发出运载器着陆动力学分析程序,结合径向基函数代理模型与模拟退火优化方法给出了以着陆倾角、结构过载、缓冲行程、支柱载荷及反弹高度为指标的七种极限着陆工况,分析了各工况下的缓冲性能及着陆稳定性能,得到了不同冲击条件对运载器着陆动力学行为的影响规律。研究表明:在四腿同时触地时运载器过载峰值大,在2-2着陆模式下运载器姿态易倾斜,在1-2-1着陆模式下先触地支腿受载恶劣且主体易反弹。

In order to improve both the accuracy and efficiency of landing dynamic analysis under multiple conditions for vertical landing reusable launch vehicle,a quasi-three-dimensional model under symmetric landing modes is established considering main-body in-plane motion,footpad space motion and strut side load simultaneously.The model also incorporates the hydraulic attenuation force based on lumped parameter method,the slip-static friction force with Stribeck effect,and the nonlinear normal contact force.Based on above model,a landing dynamic analysis program for launch vehicle is developed,and seven extreme landing conditions regarding tilt angle,structural overload,attenuation stroke,strut force and rebound height are obtained by employing both the radial-basis-function surrogate model and the simulated annealing optimization method.The dynamic responses under these conditions are then analyzed,and the influencing rules by landing conditions on dynamic responses are attained.The results show that the structural overload reaches maximum when all struts touchdown simultaneously.Besides,the tilt angle gets maximum under 2-2 landing mode,while the strut load and rebound height reach maximum under 1-2-1 landing mode.