摘要
近年的探测研究表明,由引力和范德华粘附力聚合成碎石堆结构可能是小行星的一种重要形成方式。为探究这类小行星的演化机制,文章基于离散元软件MatDEM进行二次开发,实现了单元的万有引力计算。建立直径为1.2 km“碎石堆”小行星数值模型,通过数值模拟分析了不同粘附强度和体积密度下,球形聚集体的旋转重塑和破坏过程。结果表明:球形聚集体受到其角速度初始增量的影响,以启动聚集体的重塑过程,导致其发生变形或者破坏;粘附强度越小,模型越容易被破坏,破坏前小行星会通过向扁圆状椭球体变形来保持自身构型的稳定性;对于粘附强度一定的小行星模型,体积密度的增大会有效增加其结构的稳定性,可以延后小行星破坏行为发生的时间,且颗粒脱落的数量随着密度的增大而减少;采用离散元分析可以较好地模拟小行星自旋演化过程。进一步与真实小行星数据相结合,有利于深入、全面地探索小行星自旋演化破坏机理。
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.
作者
张宸玮
刘春
耿焕
刘辉
ZHANG Chenwei;LIU Chun;GENG Huan;LIU Hui(School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China)
出处
《高校地质学报》
CAS
CSCD
北大核心
2023年第5期743-755,共13页
Geological Journal of China Universities
基金
国家自然科学基金项目(41761134089,41977218)
中央高校基本科研业务费资助项目(14380103)联合资助。
作者简介
张宸玮,男,1995年生,研究生,主要从事行星科学数值模拟研究,E-mail:MG1929074@smail.nju.edu.cn;通讯作者:刘春,男,1984年生,教授,长期从事计算工程地质科研工作,E-mail:chunliu@nju.edu.cn。
