气囊回收系统的着陆适应性仿真分析

目的提出一种气囊着陆缓冲等效分析方法,将有限元仿真和理论分析相结合,借助理论分析的优点实现对气囊回收系统着陆缓冲冲击性能快速评估的目的。方法首先建立气囊有限元模型,通过有限元分析获得载荷-压缩量曲线,根据曲线拟合出接触载荷与气囊压缩量的关系式。同时,利用高斯函数模拟斜坡,考虑一质量块和气囊以一定初速度竖直向下撞击到该坡面上,只考虑坡度大小和表面粗糙度对气囊冲击载荷的影响。最后,利用中心差分法计算出质量块的位移、速度以及加速度。结果在撞击点的坡度为0°,20.27°和31.24°时,得到理论的水平方向和竖直方向上的最大过载,与仿真输出的结果进行对照,在误差允许的范围内,理论与仿真结果一致。分析比较不同撞击点的坡度下水平和竖直方向最大过载以及气囊离开地面时的角速度。当撞击点坡度为0°时,水平方向最大过载为0,随着撞击点坡度增大,水平方向的最大过载逐渐增大;竖直方向最大过载的值最大,为224.5 m/s2,随着撞击点坡度增大,竖直方向的最大过载逐渐减小。当撞击点坡度为0°时,角速度为0,气囊离开地面时的角速度逐渐增大,其增幅在0°到20°之间较大。结论气囊着陆缓冲等效分析方法计算得到的结果与仿真得到的结果相一致,验证了该理论计算方法的有效性,因此可以利用该方法对缓冲气囊的冲击性能进行快速评估。

Landing Adaptability Simulation Analysis of Airbag Recovery System

Objective To propose an airbag landing buffer equivalent analysis method, combine the finite element simulation and the theory analysis and have rapid assessment of the landing buffer impact performance of the airbag recovery system based on advantages of theoretical analysis. Methods Firstly, the finite element model of the airbag was established. The load-compression curve was obtained by finite element analysis. The relationship between the contact load and the airbag compression was fitted according to the curve. At the same time, the surface of a slope was simulated with a Gaussian function. A mass (simulated spacecraft) attached to an airbag impacted the slope surface with an initial velocity. Only the impact of the grade and the surface roughness on the airbag load were considered. Finally, the center difference method was used to calculate the displacement, velocity and acceleration. Results When the impact point slopes were 0°, 20.27°, and 31.24°, the theoretical maximum overload in the horizontal and vertical directions was obtained after calculation. Compared the results with the simulation outputs, within the allowable error range, the theoretical and simulation results were nearly the same. Horizontal and vertical maximum overload and the angular velocity of the airbag under the slope of different impact points were analyzed and compared. When the impact point slope was 0°, the maximum overload in the horizontal direction was 0. As the impact point slope increased, the maximum overload in the horizontal direction gradually increased. When the impact point slope was 0°, the maximum overload in the vertical direction was the maximum- 224.5 m/s2. The maximum overload in the vertical direction gradually decreased as the impact point slope increased. When the impact point slope was 0°, the angular velocity was 0, and the angular velocity of the airbag gradually increased and increased larger between 0° and 20°. Conclusion The calculated results of the air bag landing buffer equivalent analysis method are consistent with the simulation results, which verifies the validity of the theoretical calculation method. Therefore, this method can be used to quickly evaluate the impact performance of the cushion air bag.