In order to solve the torque design problem of deep lunar soil sampling using drilling, a novel torque analysis method was presented based on discrete element model (DEM). This method includes three stages: drilling simulation of the bit and stem segment, resultant torque calculation, and predicted curve fitting. First, special drilling models were designed for a bit and stem separately. A high-density equivalent particle group, boundary vibration control, pre-drilling simulation and constant pressure surface control were designed for the bit and stem drilling modelling at different depths to ensure the rationality of the model. An example of the torque synthesis process was given, and the simulation time was analyzed. Finally, the simulation predicted torque curve was plotted and compared with the experimental curve. The experimental and simulation curves show that as the drilling depth increases, the torque increases approximately linearly first and then flattens out gradually after a depth of 1 m. The consistency between the two results indicated that the proposed method was validated. Using this method, engineers can take short time to analyze the torque and design basic parameters of the drill mechanism. The problem of high experimental cost and long simulation time in torque design is solved.

为解决深部钻探月土样品的扭矩设计问题，提出了一种基于离散元模型（DEM）的扭矩分析方法。该方法包括三个阶段：钻头和钻杆段的钻孔模拟，合成扭矩计算以及预测曲线拟合。首先，专门为钻头和钻杆设计了特殊的钻探模型。针对不同深度的钻头和钻杆钻探模型，设计了高密度当量粒子组，边界振动控制，预钻模拟和恒压表面控制，以确保模型的合理性。以扭矩合成过程为例，分析了仿真时间。最后，绘制了仿真预测扭矩曲线，并与实验曲线进行了比较。实验和仿真曲线表明，随着钻削深度的增加，扭矩首先近似线性增加，然后在1 m的深度后逐渐变平。两种结果之间的一致性表明所提出的方法是有效的。使用这种方法，工程师可以花很短的时间来分析钻削机构的扭矩和设计基本参数。解决了转矩设计中实验费用高，仿真时间长的问题。