At normal scales a granular flow is made up of millions of small particles (grains of sand, for instance) each of which is subject to the laws of solid mechanics. Modeling such an assembly using traditional FEM is intractable. These systems can be made tractable, however, with some simplifying assumptions:
The particles are three dimensional rigid bodies. This saves us from calculating individual deformations.
The particles have simple shapes (usually spheres). This simplifies contact.
Each discrete element is a pseudo-particle corresponding to large numbers of particles. This reduces the number of discrete elements.
Bonding between particles is modeled using elastic beams attached to particle centers.
Taken together these assumptions are called the “Discrete Element Method.” LS-DYNA implements and couples discrete elements to solid mechanics elements. The DEM has been used to model manufacturing processes involving hoppers, explosions in mines, fractures in brittle materials, as well as for cars driving through sand. This class covers LS-DYNA’s implementation of the DEM. This class covers how to set up, run, and post-process simulations using this method. This class will also provide the theoretical background for this method including a discussion of the advantages and disadvantages of this method.
Introduction to the Discrete Element Method
Example of application of DEM
Theoretical background of the DEM
Introduction to the DES in LS-DYNA
Generating DEM Particles in LS-PrePost®
Post-Processing DEM Models using LS-PrePos
Application of DES
Interaction between DEM Particles and Structure