不同重力场下颗粒冲击过程的离散元分析

开展不同重力场下颗粒材料冲击动力学研究有助于加深对颗粒运动机制的理解和深空探测任务的实施。本文采用离散元模拟对颗粒介质受球形冲击物的冲击过程进行了数值模拟，并与地球重力下冲击的试验结果进行对比验证。在此基础上，进一步研究了重力加速度对冲击物动力学的影响规律。计算结果表明，在所有重力加速度下，冲击物的穿透深度d与冲击速度v₀的关系可以用Poncelet模型表达；d与冲击物下落的总高度H表现为d～Hⁿ的幂律关系，当H<10 m时，d与H的幂率标度为0.322,而H>10 m时，d与H的幂率标度下降到0.211。此外，穿透深度小于冲击物半径时，重力加速度对冲击物减速过程无影响。在所有的重力加速度下，当冲击速度大于5 m/s时，冲击物的持续碰撞时间t_c是恒定的，且与重力的-1/2次方呈正比。

Numerical analysis of particle impact under different gravity conditions by discrete element method

The study of the impact dynamics of granular materials in different gravity environments contributes to the understanding of particle motion mechanisms and the implementation of deep space exploration missions.In this paper,the discrete element method (DEM) is used to simulate the dynamic behaviors of granular materials subjected to spherical impactors,which is verified by the experimental results under Earth gravity.Then the effect of gravitational accelerations on dynamic properties of the impactor is further investigated.The DEM results show that the relationship between penetration depth d and impact velocity v₀ can be expressed by the Poncelet model at all gravitational accelerations;d and total drop distances H exhibit a power law relationship of d~ Hⁿ,where n is 0.32 when the total fall distance H is less than 10 m,While n drops to 0.211 when H is greater than 10 m.In addition,the acceleration of gravity has no effect on the deceleration process of the impactor when the penetration depth is smaller than the radius of the impactor.At all gravitational accelerations,the collision duration of the impactor is constant and proportional to the -1/2 power of gravity when the impact velocity is greater than 5 m/s.