Optimization Of Structure Parameters Of Sampling Core Drill For Deep Lunar Soil

The goal of China’s Lunar Exploration Program is to drill and sample lunar soiland return lunar soil to earth. In order to meet the strict constraints of power and theneed of maintaining lunar soil bedding information, a composite sampling core drillis put forward in this paper. Based on the constraints of the exploration program,cutting force and lunar soil disturbance is regarded as research goals. By the meansof theoretical model and DEM simulation, this paper researches and studies thestructure parameters of lunar soil sampling core drill.Firstly, the physical and mechanical properties is studied, Based on theinformation of lunar soil man has sampled from the moon and experiments of lunarsoil simulants, this paper deduces theoretical formulas of shear strength parameters.Shear strength at any depth can be known from these formulas, which laysfoundation for the rotatory cutting model in the third chapter.The third chapter puts forward a configuration of a composite sampling coredrill, introduces its structure parameters, analyzes the effect of tip angle of cuttingblade to lunar soil, and proposes a formula for designing tip angle. Then establishesthe rotatory cutting model for lunar soil, and analyzes the effects of internal frictionangle, cohesion force, cutting angle and aspect ratio of cutting blade based on thismodel.The fourth chapter discusses the simulation efficiency of EDEM based on DEMtheory. In order to reduce simulation time, layered modeling method is used forlunar soil simulant model. The particle size is determined depending on thesimulation results of different particle sizes. The effects of structure parameters tocutting force are obtained by analyzing the simulation results. Moreover, thevalidation of the rotatory cutting model is verified by the simulation results.Maintenance of lunar soil bedding information is essential in drilling process.The change of bedding information is caused by the disturbance of core drill to lunarsoil. This paper establishes an evaluation function to evaluate the disturbance oflunar soil. Based on this function, effects of cutting angle, core diameter and bladeheight and so forth on lunar soil disturbance is studied. Finally, combined with theconclus ions of the previous chapters, structure parameters of lunar soil samplingcore drill are proposed.