D. Pasini, P. Radziszewski, R. Briend
Canadian Aeronautics and Space Institute
Canadian Aeronautics and Space Journal
Lunar mobility studies require a precise knowledge of the geotechnical properties of the lunar soil when it comes to design-adapted and efficient-traction systems. The remarkable progress of computers since the Apollo missions allows direct testing of the performance of new design prototypes through simulations of soil-structure interactions using the discrete-element method (DEM). Before simulating traction-system displacements on the soil, the virtual-soil parameters need to be calibrated.This study presents a systematic method for calibrating a granular soil through four steps: (1) measurement of three of the real-material properties through two experiments, (2) determination of the design variables defining the virtual soil, (3) construction of surrogate models for the virtual-material properties as a function of the design variables via simulated experiments, and (4) optimization of the design-variable values to fit the virtual-soil properties to the real-soil values. Two different experiments, a direct-shear test and an angle-of-repose measurement, were used to determine the following material properties: cohesion, internal angle of friction, and angle of repose. Optimum DEM parameters were computed to characterize two types of soil: silica sand, based on an experimental direct-shear test and angle-of-repose measurements, and lunar regolith, based on data from the literature.
Calibration, lunar soil, soil-structure interactions