Application of Discrete Element Method in Impact Problems

Abstract

In this paper, a new numerical algorithm based on the discrete element method is presented for analyzing the dynamic problems under impact loading. Based on the basic principle of continuum mechanics, a connective model for orthotropic media is derived using disk elements. It is also extended to a bilinear hardening elastic-plastic model for calculating the plastic deformation in metals. Moreover, Mohr-Coulomb type failure criterion is used to judge the failure of concrete, and a contact discrete model is added in the algorithm. So the algorithm can calculate not only the impact problems of continuum and non-continuum, but also the transient process from continuum to non-continuum. The wave propagation in orthotropic planes under impact loading is numerically simulated. Through comparing the results with those computed by other numerical methods and examining the stability of the numerical solution, the accuracy and efficiency of the algorithm are discussed. In addition, the transient respondences of a steel warhead penetrating a concrete disc harrow is simulated, and three kinds of basic damage forms of concrete disc harrow under different penetration velocities of warhead are summarized.

Implementation of Particle-scale Rotation in the 3-D Lattice Solid Model

“…The reason is that geometrically in 3-D there is no regular tight pack for equal-sized spheres similar to the triangular pattern in 2-D case which yields macroscopic isotropic elasticity, in other words, dense packings of equal spheres are intrinsically disordered. LIU et al (2003) derived the following formulas to determine normal and shear spring stiffness from closest-packed 3-D arrangement Figure 3 Pure bending of 2-D beam, which is used to have an approximated estimation of the parameters. Vol.…”

An accurate and robust contact detection algorithm for particle‐solid interaction in combined finite‐discrete element analysis

“…The connective model has the advantage of being able to model the response of materials that are initially continuous but eventually fractured [30]. A number of DE connective models have been reported [30][31][32][33][34][35], and the model developed by Yu [34] is used in this research. The cubicarranged 27-sphere model is shown in Figure 1(a).…”

Modeling on the Effect of Coal Loads on Kinetic Energy of Balls for Ball Mills

“…The parameters with the most influence on the contact force were the stiffness, the damping, and the friction factor. The stiffness represented the stress resistance of balls to elastic deformation, the friction factor affected the power consumption of ball mills, and the damping main influenced the accumulation process and the course of energy dissipation [18]. Some properties of other parameters for the model are given in Table 2, which combines the operating characteristics of a ball mill with different performance properties of the materials.…”