关键词: 离散元方法, 数值模拟, 碎石堆, 小行星, MatDEM

Abstract: In recent years, exploration research has shown that the rubble pile structure formed by gravity and cohesion may be an important method of asteroid formation. To explore the evolution mechanism of this kind of asteroid, this paper makes secondary developments based on the discrete element software MatDEM and realizes the calculation of the element’s gravitational force. A numerical model of a “rubble mound” asteroid with a diameter of 1.2 km is established, and the rotational remodelling and failure processes of spherical aggregates under different adhesion strength and bulk densities are analysed by numerical simulation. The results show that spherical aggregates are affected by the initial increment of angular velocity to start the remodelling process of aggregates, leading to deformation or failure. With the decrease in the adhesion strength, the model will be destroyed more easily. Before destruction, the asteroid will maintain the stability of its configuration by deforming into an oblate ellipsoid. The increase in bulk density effectively increases the structural stability of the asteroid model with a certain adhesion strength, can delay the occurrence of asteroid destruction, and the number of particles falling off decreases with the increase of density. Discrete element analysis can better simulate the spin evolution process of asteroids. Combined with real asteroid data, it is beneficial to explore the mechanism of asteroid spin evolution and destruction deeply and comprehensively. 

Key words: discrete element method, numerical simulation, rubble-pile, asteroids, MatDEM