深层月壤采样钻具参数影响分析

A discrete element simulation analysis is carried out to analyze the influence of drilling tool parameters on the force of drilling tools and soil sampling in the deep lunar soil. A novel 3D discrete element model considering the bending and twist moment and equivalent attractive force is built firstly, and then, a triaxial simulation test is conducted to calibrate the micro-parameters. The mechanical macro-parameters of the model are calculated: the cohesion is 0.90 kPa and the internal friction angle is 42.25°, meeting with that of the real lunar soil. Key parameters of drill tool such as drill bit tooth shape, body shape, drill stem lead, tooth width, rotary speed are compared and analyzed. The simulation results show that the cylindrical vertical teeth are beneficial to soil sampling, and octagon vertical teeth are beneficial to drill force; drill force of the funnel shaped head is less than that of the cone shaped head; the increase of drill pipe lead will increase the soil sampling, but it will also increase the load; the width of drill pipe thread of 3mm is suitable for more soil sample and less load; with the rotating speed increasing rapidly, the lunar soil sample decreases seriously; with the rotating speed decreasing rapidly, the drill load increases obviously.