A contact dynamics code implementation for the simulation of asteroid evolution and regolith in the asteroid environment

TLDR: The Contact Dynamics method is described, a class of DEM based on non-smooth mechanics, and its implementation in the open-source software LMGC90, and a parallelized kd-tree is implemented to monitor the performance of the code as it simulates a number of granular systems.

About: This article is published in Icarus.The article was published on 2021-07-15 and is currently open access. It has received 6 citations till now.

Figures

Figure 3: Different configurations of contacts between two polyhedra leading to a different number of contact points: (a) vertex to face; (b) edge to face; (c) face to face; (d) edge to edge; See [20, 59]

Figure 13: Different simulation snapshots for the aggregate with the highest cohesion value in the (O; x, y) and (O; y, z) planes at time equal to a) 160, b) 320, c) 480 and d) 640 min.

Figure 14: Deviation of the semi-axes of the dynamically equivalent equal-volume ellipsoid during the spin-up process: (a) f0 = 1N, (b) f0 = 10 N, (c) f0 = 100 N and (d) f0 = 1 000 N.

Figure 15: Representation of the velocity field in the (O; x, y) plane at two different simulation times and for the different cohesion values: (a) 1 N, (b) 10 N, (c) 100 N and (d) 1 000 N

Figure 10: (a) Log-log representation of the evolution of the aggregate diameter, normalized by particle mean diameter d, as a function of ns in assembly of spheres (disks symbols) and polyhedra (square symbols) at µ = 0. (b) Packing fraction ν of the aggregate as a function of ns in assembly of spheres (disks symbols) and polyhedra (square symbols) at µ = 0. The inset in (b) shows the variation of both, ν and dmax as a function of the inter-particle friction µ in aggregates of spheres for ns = 3375. Different colors correspond to different particle numbers.

Figure 1: Contact frame (nα, tα, sα) defined at contact point α between two particles i and j.

Frequently asked questions

Q1. What have the authors contributed in "A contact dynamics code implementation for the simulation of asteroid evolution and regolith in the asteroid environment" ?

By providing access to the local physical mechanisms, DEM allows the exploration of microscopic based phenomena related to particles properties and interactions in various conditions and to revisit constitutive equations consequently. In this paper the authors describe the Contact Dynamics ( CD ) method, a class of DEM based on non-smooth mechanics, and its implementation in the open-source software LMGC90. In contrast to more classical approach, Hardand Soft-Sphere DEM, the CD method is based on an implicit time integration of the equations of motion and on a non-regularized formulation of mutual exclusion between particles. This numerical strategy is particularly relevant to the study of dense granular assemblies ( even of large size ) because it does not introduce numerical artefacts due to contact stiffness. So that it can be used for Small Body research, the authors implement a parallelised kd-tree and monitor the performance of the code as it simulates a number of granular systems. The authors provide examples of the simulation of the accretion of self-gravitating aggregates as well as their rotational disruption.