模拟月壤钻进取样量影响因素分析及试验研究

在月球钻取采样器的设计中,软袋取心方式可获得细长的连续钻取样心,具有较高的取心率,并能够保证次表层月壤样品的层理信息.由于取心过程中月壤颗粒运动复杂,尚无系统的方法对软袋取心的取样量影响因素进行分析.剖析了软袋取心中月壤颗粒的流动情况,基于极限平衡理论构建了软袋取心力学模型.该模型以月壤和取心钻具之间以及各部分月壤之间的相互作用为力学边界条件,描述了月壤从取心钻具外进入取心软袋内的动力学过程.基于该模型提出了预测取心率数值计算方法,分析了钻进规程、月壤特性和钻具构型等因素对取心率的影响.利用HIT-LS1#模拟月壤和HIT-2型试验钻具开展了钻进取样试验,取心率的理论预测值与试验结果的平均误差小于5%.

Analysis and test research on influencing factors of drilling and coring quantity of lunar soil simulant

During the design of drilling and coring mechanism for lunar exploration, a coring method based on a flexible tube can obtain slim continuous sample core, which enables high coring rate and preserves the stratification information of the subsurface samples. Since the complex movement of lunar soil particles during the flexible tube coring, there is no systemic method to analyze the factors that determine the coring quantity. The flowage of the lunar soil particles in flexible tube was analyzed and the coring model of the flexible tube based on the theory of limit equilibrium was established. The mechanical boundary conditions of the model were interactions between lunar soil and coring drill tools and among each part of lunar soil. The coring model described the dynamic process of lunar soil flowing from the outside of coring drill tools into the flexible tube. A numerical prediction method for coring rate was proposed based on the coring model. Drilling parameters, lunar soil properties and drill tool structure were analyzed as key influencing factors of coring rate. A verifying test with simulant of lunar soil HIT-LS1# and drill tools HIT-2 was implemented on a simulated drilling test-bed. The average error between the test results and the predicted results is less than 5%.