Lunar regolith simulations with discrete element method based on Chang'E-5 mission's lunar soil particle morphology

To align with the current strategic planning of "survey, mining, and development" in China's lunar exploration mission, and to obtain more accurate physical and mechanical properties of lunar regolith, this study focuses on the influences of lunar regolith particle shape based on particle images from the lunar regolith of the Chang'E-5 mission. A discrete element numerical simulation method that considers lunar regolith particle morphology is proposed by linking particle shape characteristics with gradation. Initially, the shape characteristics and size information of the particles are extracted from the lunar regolith images. The particles are subsequently categorized into six groups based on their sphericity, establishing the corresponding relationships. Secondly, the study utilizes a three-dimensional (3D) lunar regolith contact model and calculates rolling and twisting resistances at inter-particle contact by incorporating shape parameters to account for lunar particle shape effects. Subsequently, the model considers particle size characteristics within the discrete element analysis. Ultimately, a discrete element numerical model that incorporates the particle shape characteristics of the China's lunar regolith is developed. Comparison with the results of Apollo lunar regolith laboratory tests reveals that the variability of grain shape in lunar particles can be directly incorporated into the discrete model. Additionally, the benefits of considering the grain shape characteristics of lunar regolith are discussed in comparison to numerical samples that neglect the characteristics. The results show that the proposed method can effectively capture the main characteristics of the mechanical behavior of lunar regolith, and provide a basis for the lunar resource exploration and exploitation methods.