模拟月壤铺粉过程DEM数值仿真

Spaced-based Selective Laser Melting (SLM) technique in combination with In-Situ Resource Utilization (ISRU) concept can be an off-world manufacturing solution to the significant engineering challenge on the large-scale construction for extra-terrestrial bases. Powder spreading process in SLM has a major impact on the characteristics and quality of final part. The geometric shape of the lunar regolith simulant particles was modeled by means of a non-spherical particle superposition model method. The particle's dynamic model was established based on linear spring-damping contact model, Hamaker theory and Newton's laws of motion. A three-dimensional Discrete Elemeat Method (DEM) technique with soft-sphere approach was employed to investigate the rheological behavior of the lunar regolith simulant powder during spreading process under various conditions. The results show that the proposed model and method can be used to study the flowability and packing behavior of lunar regolith simulant powder system as a function of process and environmental condition parameters. Lunar reduced gravity leads to larger values of surface roughness and smaller values of packing density and averaged coordination number of powder bed; the quality of lunar regolith simulant powder bed during spreading process under lunar gravity can be improved by reducing spreading speed and geometrically optimizing blade type spreader profile, resulting in a denser and more uniform powder bed.