着陆器足垫冲击模拟月壤的数值分析

Numerical study on impact of lunar lander footpad against simulant lunar soil

针对竖向着陆冲击过程,开展大量的模拟月壤室内单元体试验,探讨模拟月壤材料参数的确定方法和取值范围.将着陆器按月地相似比尺简化为冲击筒体,建立着陆器足垫垂直冲击模拟月壤三维动力有限元模型,模拟分析在冲击荷载作用下的足垫轴力、速度和位移的实时动力响应,与室内模型试验结果进行对比,验证了该模型的合理性.计算表明:场地塑性区域呈形状变化的椭球,影响主要分布在2.0～3.0倍最大足垫直径深度范围内,撞击变形呈盆底形,速度响应滞后于轴力,位移响应滞后于速度.

Many laboratory tests of lunar soil simulant were conducted to analyze the vertical impact during landing process. The method to determine the material parameters was discussed, and the range of materi- al constants was suggested. The space lander was simplified to be an impact column according to the simi- larity scale between earth and moon. The three-dimensional dynamic finite element model was established to simulate the process of impact against lunar soil. Comparing with the model test results, the model can rationally simulate the dynamic response of the model column＇s axial force, acceleration and penetration depth during the period of interaction. The plastic area displays ellipsoid of variational shape, the influence mainly distributes within the depth of 2.0~3.0 times of diameter and the deformation likes a basin. The response of velocity lags axial force and the displacement lags the velocity.