(462d) Irregular Soil Particle Shape Modeling

NASA is interested in simulating the descent of a spacecraft approaching the Lunar and/or Martian surface along a specified trajectory which will involve gas jet-soil particle surface interaction through the landing and engine shutdown. In order to predict the erosion of the Lunar or Martian soil (regolith), a description for the solid-phase stress for the regolith is needed. For Lunar and Martian soils, the particles are highly aspherical and irregular, and can mechanically interlock, resulting in a particle bed with very high strength. These properties of the soil, and the resulting particle-particle interactions, greatly affect the rate of crater growth, the trajectories of the liberated particles, and the resulting crater shape. This presentation will outline the development of stress closures for a particle-phase continuum treatment that incorporate features of the aspherical particle shape that are typical of actual regolith.