Ejection Separation Characteristic Analysis of Parachute Container Cover from Return Capsule for Lunar Exploration

The parachute container cover ejection separation is the first and foremost motion for the return capsule recovery system, which is related to the success of a recovery system. Adopting the computational fluid dynamics （CFD） simulation and flight dynamics coupling method, the parachute container cover ejection separation is simu lated. The rationality of the ejection separation speed and dynamic characteristics of the separation process is ana- lyzed. Meanwhile, the influences of angle of attack, Mach number and ejection separation speed on the parachute container cover ejection are also investigated. Results show that the ejection separation speed design is reasonable. It has a certain design margin for parachute container cover to escape from the wake region, and to pull out the drag parachute completely. The results may provide a theoretical basis for recovery system engineering design of the lunar exploration project.     

基于代理模型技术的返回舱外形优化

针对返回舱再入过程中需要满足的复杂气动力热务件,在典型高超声速条件下以升阻比和阻力系数为目标,以驻点热流和容积率为约束条件进行返回舱外形多目标优化设计。气动特性分析采用基于三维Navier-Stokes方程和结构网格的计算流体力学数值仿真（CFD）方法,采用Fay-Riddell经验公式计算驻点热流,采用NSGA－II优化算法进行全局寻优,为了增强多目标优化设计的计算效率,利用Kriging代理模型替代CFD计算,并引入改进的EI函数加点策略,大大减少了构建代理模型时所需的样本点数目。优化计算结果表明,代理模型计算结果与CFD计算结果误差可以控制在7％以内,基于代理模型技术的优化过程可以节省95％以上的计算开销。因此,该方法能够较好地满足初步设计的要求,为返回舱外形优化提供有益的借峪。     

可折叠铍青铜弹性豆荚杆焊接成型工艺

可折叠铍青铜豆荚杆的焊接成型是该类豆荚杆研制的难点之一,本文对铍青铜豆荚杆的储能点焊工艺进行了研究,分析了工艺参数及热处理对焊接接头名义剪切强度的影响,给出了优选的工艺参数为焊接电压180 V、保压7 s。在最佳工艺条件下成型并经过340℃/2 h时效处理后,焊接接头的名义剪切强度由52 MPa提高到68 MPa。铍青铜焊接接头的名义剪切断口随着焊接电压的增大,从焊接接头区域向热影响区转移。