Gravity impact analysis of surface lunar soil sampling by DEM simulation

To find out the force situation of digging and shoveling bucket and make sure their differences in earth gravity and lunar gravity, a novel discrete element method considering bending and twisting movements and equivalent attraction is employed to build the lunar regolith model and simulate the interaction between soil and tool. To confirm the validity of the model, a triaxial-test is conducted to optimize the microparameters of the model. Then, the model is employed to the simulation of surface sampling process. From the computational simulation results, conclusions can be made: The change of gravity will make a big difference to the force situation of the sampling tools. The largest moment of the digging bucket will increase double from 8Nm to 16Nm while the force of the shovelling bucket will enlarge more than four times from 40N to 180N.