Discrete Element Method

The discrete element method (DEM) is usually applied to predict the behavior of different types of granular media during mixing processes, storage and discharge or transportation on belts. Herein, the interaction of the spherical particles with themselves as well as their surrounding deformable or rigid structures can be taken into account. Friction coefficients as well as spring and damper constants can be defined in normal and tangential direction. Wet particles can be estimated with the aid of a capillary force model and a certain roughness of the spherical particles can be achieved by introducing a rolling friction.

A continuum-mechanical description can be obtained with the introduction of “bonds” between the particles. Herein, the required mechanical behavior of the bonds is automatically computed by LS-DYNA using the parameters given in the material card. With the definition of a fracture energy release rate of the bonds, fracture mechanics of brittle materials can be studied.

Attendees of this seminar will obtain an overview of the involved material cards of a successful DEM simulation. For a better understanding of the involved parameters, simple examples will be presented addressing particle-particle as well as particle-structure interaction. Finally, the associated experiments will be discussed that are needed to determine the involved parameters.

Contents

• Introduction to granular materials
• Involved keywords and their options
• Setting up DEM simulations with deformable/rigid structures
• Physical meaning of the parameters and their experimental determination
• Practice examples