考虑颗粒形状的模拟月壤力学特性离散元研究

Discrete element study on mechanical properties of lunar regolith simulant considering particle shape

为深入研究IRSM-1模拟月壤复杂颗粒形状对力学特性的影响,基于图像处理技术与离散单元法构建了五种不同颗粒形态特征的模拟月壤离散元试样,并开展数值试验,研究了双轴压缩条件下试样的宏细观力学特性,包括应力-应变关系、剪胀特性、摩擦角、力学配位数和法向接触力的演化规律,讨论了整体规则度对模拟月壤力学行为的影响规律.结果表明:考虑模拟月壤真实颗粒形状的试样具有更高的抗剪强度、临界和峰值摩擦角及更显著的剪胀性.试样整体规则度越低,平均力学配位数越高,等向压缩时内部孔隙越大,剪切过程中法向接触力的各向异性越不明显.此外,忽略月壤及模拟月壤复杂颗粒形状、基于理想圆或球颗粒开展的离散元模拟研究可能会低估其工程力学性能.

To thoroughly investigate the influence of the intricate particle shape of IRSM-1 lunar regolith simulant on its mechanical properties,based on image processing technology and the discrete element method(DEM),five discrete element samples of simulated lunar soil with different particle morphology characteristics were constructed,and numerical experiments were carried out.The macroscopic and microscopic mechanical properties of specimens under biaxial compression conditions were studied,including stress-strain relationship,shear dilation characteristic,friction angle,mechanical coordination number,and the evolution of normal contact force.The impact of overall regularity on the mechanical behavior of lunar regolith simulant was discussed.The results indicate that specimens considering the realistic particle shape of lunar regolith simulant exhibit higher shear strength,critical and peak friction angles,and more pronounced shear dilation.As the overall regularity of specimens decreases,the average mechanical coordination number increases,internal porosity enlarges under isotropic compression,and the anisotropy of normal contact forces during the shearing process becomes less evident.Furthermore,neglecting the complex particle shape of lunar soil and its simulants in DEM simulation based on idealized circular or spherical particles may lead to an underestimation of their engineering mechanical performance.