In detail, the contacts between the lander and the small body are processed by utilizing the Polygonal Contact Model (PCM). This paper proposes a method to simulate six degrees of freedom motion of arbitrary-shaped landers in the neighborhood of a small body with multi-contact. However, such surface dynamics problem is so difficult that the high-fidelity simulation of a lander on and above the surface of a small body is still a big challenge. It is also very meaningful for the research of morphologic evolution of small bodies. The surface dynamics of small bodies is a key problem for landing and sample return missions. Additionally, the softening feasibility is also discussed by decreasing the Young’s modulus of the material, mainly analyzing the outgoing results and the calculation efficiency. The multiple-collision case is studied under the Brazil nut effect with ellipsoidal granules. Specifically, the restitution coefficient, the angular velocity, the rebound angle, and the kinetic energy are applied as indicators for the single collision. By considering the macroscopical results and calculation efficiency, the single-collision and multiple-collision cases are analyzed by comparing the four contact models. The four contact force models include one linear model and three nonlinear models derived from the complete Mindlin–Deresiewicz equations. This paper applies four different contact force models in the newly-proposed DEM algorithm to analyze their difference and implication. In order to manage the contact between the non-spherical granules, the Polygonal Contact Model (PCM) has been introduced into the DEM method. The discrete element method (DEM) is usually applied in analyzing the scientifical origin/evolution of the asteroids and the landing/sampling of the regolith.

Freecadweb review