Understanding the Discrete Element Method

The aim of this book is to advance the field of granular and multi-body studies while giving readers a more thorough understanding of the discrete element method (DEM). By working through this volume, researchers will be better equipped for independent work and will develop an ability to judge methods related to the simulation of polygonal particles. When materials are not handled as fluids, they are dealt with mostly in granular form (e.g. cement, sand, grains, powders). Granular materials are characterized by abrupt transitions from loose to dense, from flowing to static states, and vice versa. Many problems in natural disasters (earthquakes, landslides, etc.) are also of a granular nature. Continuum methods have been applied in these fields, but lack any intrinsic mechanism to account for the transitions, behavior that is inherently discontinuous. The natural approach is to use particle simulation methods, often called the discrete element method, where bodies in the physical system and the simulation match one to one. The field of discrete element simulation has changed little since the early 1990s, when simulations predominantly used spherical particles. The aim of this book is to show the practicability and usefulness of non-spherical discrete element simulations. Phenomena from related fields (mechanics, solid state physics, etc.) are discussed, which as test cases are sometimes not applicable due to intriguing reasons. Understanding both the pitfalls and applications will help one to predict the outcome of simulations and use the predictions for the design of future experiments. Introduces the discrete element method (DEM) starting from the fundamental concepts (theoretical mechanics and solid state physics), with 2D and 3D simulation methods for polygonal and polyhedral particles Explains the basics of coding DEM, requiring little previous knowledge of granular matter or numerical simulation Highlights numerical tricks and pitfalls that are usually only recognized after years of experience, using relevant simple experiments to illustrate applications Presents a logical approach starting with the mechanical and physical bases, followed by a description of the techniques and their applications Written by key authors presenting ideas on how to model the dynamics of angular particles using polygons and polyhedrals Accompanying website includes MATLAB programs providing the simulation code for two-dimensionalconvex polygons This book is ideal for researchers and graduate students who deal with particle models in areas such as fluid dynamics, multi-body engineering, finite element methods, virtual reality, the geosciences, and multi-scale physics. Computer scientists involved with solid modeling and game programming will also find this book a useful reference for the design of physics engines.