Kondic L, Fang X, Losert W, O'Hern C S, Behringer R P
Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2012 Jan;85(1 Pt 1):011305. doi: 10.1103/PhysRevE.85.011305. Epub 2012 Jan 18.
We study the impact of an intruder on a dense granular material. The process of impact and interaction between the intruder and the granular particles is modeled using discrete element simulations in two spatial dimensions. In the first part of the paper we discuss how the intruder's dynamics depends on (1) the intruder's properties, including its size, shape and composition, (2) the properties of the grains, including friction, polydispersity, structural order, and elasticity, and (3) the properties of the system, including its size and gravitational field. It is found that polydispersity and related structural order, and frictional properties of the granular particles, play a crucial role in determining impact dynamics. In the second part of the paper we consider the response of the granular system itself. We discuss the force networks that develop, including their topological evolution. The influence of friction and structural order on force propagation, including the transition from hyperbolic-like to elastic-like behavior is discussed, as well as the affine and nonaffine components of the grain dynamics. Several broad observations include the following: tangential forces between granular particles are found to play a crucial role in determining impact dynamics; both force networks and particle dynamics are correlated with the dynamics of the intruder itself.
我们研究了入侵者对致密颗粒材料的影响。使用二维空间中的离散元模拟对入侵者与颗粒之间的碰撞和相互作用过程进行了建模。在本文的第一部分，我们讨论了入侵者的动力学如何取决于：（1）入侵者的属性，包括其尺寸、形状和组成；（2）颗粒的属性，包括摩擦力、多分散性、结构有序性和弹性；（3）系统的属性，包括其尺寸和引力场。研究发现，多分散性及相关的结构有序性以及颗粒的摩擦特性在决定碰撞动力学方面起着至关重要的作用。在本文的第二部分，我们考虑颗粒系统本身的响应。我们讨论了形成的力网络，包括它们的拓扑演化。讨论了摩擦和结构有序性对力传播的影响，包括从类双曲线行为到类弹性行为的转变，以及颗粒动力学的仿射和非仿射分量。几个广泛的观察结果如下：发现颗粒之间的切向力在决定碰撞动力学方面起着至关重要的作用；力网络和颗粒动力学都与入侵者本身的动力学相关。
