月壤钻取与整形过程中样品层理保持特性分析

Analysis on Stratification Retention Characteristics in Lunar Soil Drilling and Shaping Process

基于离散元方法建立了考虑颗粒间扭转、弯曲力矩及等效引力作用的三维离散元月壤模型,利用三轴仿真试验标定模型细观参数,得到满足真实月壤宏观力学特性的仿真模型。对月壤钻取和整形过程进行了仿真设计,提出了"分层概率法",以每层月壤在运动过程中向邻层错动的概率评价层理保持特性。由仿真结果可知:月壤钻进取样过程中样品层理信息会遭到钻取和整形两次破坏,二者破坏程度相当,且越靠近表层层理信息破坏越严重。分层概率法可有效描述月壤钻取与整形过程月壤样品的层理信息破坏情况,分析结果可为月壤采样机构设计提供参考。

A three-dimensional lunar soil particle contact model has been built using the discrete element method. This model includes the bending and twisting moment and equivalent gravity be- tween any two lunar soil particles. The tri-axial simulation test has been usect to calibrate the mi- croscopic parameters of the model. The macroscopic mechanical properties of the model are the same with that of the true lunar soil. Simulations for the drilling process and shaping process are designed,and ＂stratified probability method＂ is proposed to analyze the lunar soil samples~ strati- fication retention characteristics by the probability of particles in each layer to neighbored layers in the motion process. Simulation results show that in the lunar soil sampling process,the strati- fication information is destroyed twice, by drilling and shaping processes respectively, and the lev- els of the two processes are similar. The stratification information of the lunar soil sample more close to the surface is damaged more seriously. Stratified probability method can describe the sample stratification destruction of the lunar soil drilling and shaping process,and the analysis re- sults have important reference value for the lunar soil sampling mechanism design.