# 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).

Gives readers a more thorough understanding of DEM and equips researchers for independent work and an ability to judge methods related to simulation of polygonal particles Introduces DEM from the fundamental concepts (theoretical mechanics and solidstate physics), with 2D and 3D simulation methods for polygonal particles Provides the fundamentals of coding discrete element method (DEM) requiring little advance knowledge of granular matter or numerical simulation Highlights the numerical tricks and pitfalls that are usually only realized after years of experience, with relevant simple experiments as applications Presents a logical approach starting withthe mechanical and physical bases,followed by a description of the techniques and finally their applications Written by a key author presenting ideas on how to model the dynamics of angular particles using polygons and polyhedral Accompanying website includes MATLAB-Programs providing the simulation code for two-dimensional polygons Recommended for researchers and graduate students who deal with particle models in areas such as fluid dynamics, multi-body engineering, finite-element methods, the geosciences, and multi-scale physics.

# Handbook of Discrete Element Method for Dense Granular Solids

To help new users, the book carefully follows important steps, from conceptual model, to the numerical simulation of dense granular materials. This includes contact models, numerical schemes, simulation setup and post-processing.

Handbook of Discrete Element Method for Dense Granular Solids provides scientists and engineers with the solutions to the basic problems of DEM modeling of granular solids, both conceptual and practical. In order to help new users, this book follows the main steps, from conceptual model to numerical simulation of dense granular materials. This includes contact models, numerical schemes, simulation setup, and post-processing. The authors present many examples, including the complete code which assists the reader in reproducing the simulations with open-source code—Yade-DEM—that was developed by the author and his colleagues at the University of Grenoble. Presents the basics, along with effective usage of DEM code Details state-of-the-art, practical implementation for research and numerical methods Provides examples with scripts, linking the book to online content and freely available software (yade-dem.org)

# Discrete Element Methods

Proceedings of the Third International Conference on Discrete Element Methods, held in Santa Fe, New Mexico on September 23-25, 2002.

Proceedings of the Third International Conference on Discrete Element Methods, held in Santa Fe, New Mexico on September 23-25, 2002. This Geotechnical Special Publication contains 72 technical papers on discrete element methods (DEM), a suite of numerical techniques developed to model granular materials, rock, and other discontinua at the grain scale. Topics include: DEM formulation and implementation approaches, coupled methods, experimental validation, and techniques, including three-dimensional particle representations, efficient contact detection algorithms, particle packing schemes, and code design. Coupled methods include approaches to linking solid continuum and fluid models with DEM to simulate multiscale and multiphase phenomena. Applications include fundamental investigations of granular mechanics; micromechanical studies of powder, soil, and rock behavior; and large-scale modeling of geotechnical, material processing, mining, and petroleum engineering problems.

# Discrete Element Method to Model 3D Continuous Materials

Complex behavior models (plasticity, cracks, visco elascticity) face some theoretical difficulties for the determination of the behavior law at the continuous scale.

Complex behavior models (plasticity, cracks, visco elascticity) face some theoretical difficulties for the determination of the behavior law at the continuous scale. When homogenization fails to give the right behavior law, a solution is to simulate the material at a meso scale in order to simulate directly a set of discrete properties that are responsible of the macroscopic behavior. The discrete element model has been developed for granular material. The proposed set shows how this method is capable to solve the problem of complex behavior that are linked to discrete meso scale effects.

# The Discrete Element Method for Granular Solids

To help new users, the book carefully follows important steps, from conceptual model, to the numerical simulation of dense granular materials. This includes contact models, numerical schemes, simulation setup and post-processing.

The Discrete Element Method for Granular Solids provides scientists and engineers with solutions to the basic problems of DEM modeling of granular solids, both conceptual and practical. To help new users, the book carefully follows important steps, from conceptual model, to the numerical simulation of dense granular materials. This includes contact models, numerical schemes, simulation setup and post-processing. The authors present many examples, including the complete code which assists the reader in reproducing the simulations with open-source code—Yade-DEM—that was developed by the author and his colleagues at the University of Grenoble. Presents the basics, along with effective usage of DEM code Details state-of-the-art, practical implementation for research and numerical methods Provides examples with scripts, linking the book to online content and freely available software (yade-dem.org)

# Proceedings of the 7th International Conference on Discrete Element Methods

Cagnoli, B., Piersanti, A.: Grain size and flow volume effects on granular flow mobility in numerical simulations: 3-D discrete element modeling of flows of angular rock fragments. J. Geophy. Res. Solid Earth 120(4), 2350–2366 (2015) 3.

This book presents the latest advances in Discrete Element Methods (DEM) and technology. It is the proceeding of 7th International Conference on DEM which was held at Dalian University of Technology on August 1 - 4, 2016. The subject of this book are the DEM and related computational techniques such as DDA, FEM/DEM, molecular dynamics, SPH, Meshless methods, etc., which are the main computational methods for modeling discontinua. In comparison to continua which have been already studied for a long time, the research of discontinua is relatively new, but increases dramatically in recent years and has already become an important field. This book will benefit researchers and scientists from the academic fields of physics, engineering and applied mathematics, as well as from industry and national laboratories who are interested in the DEM.

# Discrete Element Modelling of Particulate Media

Produced in celebration of the 70th Birthday of Colin Thornton, this book contains a selection of papers concerning advances in discrete element modelling which were presented at the International Symposium on Discrete Element Modelling of ...

This title showcases the wide application of discrete element modelling in gas-solid fluidisation, particulate flows, liquid-solid systems and quasi-static behaviour.

# Investigation of Micro and Macro phenomena in Densely Packed Granular Media Using the Discrete Element Method

Granular materials are in abundance in nature and are estimated to constitute over 75% of all raw materials passing through the industry.

Granular materials are in abundance in nature and are estimated to constitute over 75% of all raw materials passing through the industry. Granular or particulate solids are thus of considerable interest to many industrial sectors and research communities, where many unsolved challenges still remain. This thesis investigates the micro- and macro-phenomena in densely packed particulate systems by means of the Discrete Element Method (DEM), which is a numerical tool for analysing the internal complexities of granular material as the mechanical interactions are considered at the grain scale. It presents an alternative approach to phenomenological continuum approaches when studying localisation problems and finite deformation problems in granular materials. In order to develop a comprehensive theoretical understanding of particulate matter and to form a sound base to improve industrial processes, it is desirable to study the mechanical behaviour of granular solids subject to a variety of loading conditions. In this thesis, three loading actions were explored in detail, which are biaxial compression, rigid object penetration and progressive formation of granular piles. The roles of particle shape and contact friction in each of these loading scenarios were investigated. The resulting packing structures were compared and studied to provide a micromechanical insight into the development of contact force network which governs the collective response. The interparticle contact forces and displacements were then used to evaluate the equivalent continuum stress and strain components thus providing the link between micro- and macroscopic descriptions. The information collected from the evolution of strong contact network illustrates the underlying mechanism of force transmission and propagation. DEM simulations presented in this thesis demonstrate strong capability in predicting the bulk behaviour as well as capturing local phenomenon occurring in the system. The research first simulates a testing environment of biaxial compression in DEM, in which the phenomenon of strain localisation was investigated, with special attention given to the interpretation of underlying failure mechanism. Several key micromechanical quantities of interest were extracted to understand the bifurcation instability, such as force chains, contact orientation, particle rotation and void ratio. In the simulation of progressive formation of granular piles, a counterintuitive pressure profile with a significant pressure dip under the apex was predicted for three models under certain conditions. Both particle shape and preparation history were shown to be important in the resulting pressure distribution. During the rigid body penetration into a granular sample, the contact forces were used to evaluate the equivalent continuum stress components. Significant stress concentration was developed around the punch base which further led to successive collapse and reformation of force chains. Taking the advantage of micromechanical analysis at particle scale, two distinct bearing failure mechanisms were identified as the penetration proceeded. To further quantify the nature of strain mobilisation leading to failure, Particle Image Velocimetry (PIV) was employed to measure the deformation over small strain interval in association with shear band propagation in the biaxial test and deformation pattern in the footing test. The captured images from DEM simulation and laboratory experiments were evaluated through PIV correlation. This optical measuring technique is able to yield a significant improvement in the accuracy and spatial resolution of the displacement field over highly strained and localised regions. Finally, a series of equivalent DEM simulations were also conducted and compared with the physical footing experiments, with the objective of evaluating the capability of DEM in producing satisfactory predictions.

# The Combined Finite Discrete Element Method

Tillemann, H.J. and Herrmann, H.J. (1995) Simulating deformations of granular solids under shear. Physica A, 217, 261–288. Ting, J.M. and Corkum, B.T. (1988) Strength behavior of granular materials using discrete numerical modeling.

The combined finite discrete element method is a relatively new computational tool aimed at problems involving static and / or dynamic behaviour of systems involving a large number of solid deformable bodies. Such problems include fragmentation using explosives (e.g rock blasting), impacts, demolition (collapsing buildings), blast loads, digging and loading processes, and powder technology. The combined finite-discrete element method - a natural extension of both discrete and finite element methods - allows researchers to model problems involving the deformability of either one solid body, a large number of bodies, or a solid body which fragments (e.g. in rock blasting applications a more or less intact rock mass is transformed into a pile of solid rock fragments of different sizes, which interact with each other). The topic is gaining in importance, and is at the forefront of some of the current efforts in computational modeling of the failure of solids. * Accompanying source codes plus input and output files available on the Internet * Important applications such as mining engineering, rock blasting and petroleum engineering * Includes practical examples of applications areas Essential reading for postgraduates, researchers and software engineers working in mechanical engineering.

# Handbook of Conveying and Handling of Particulate Solids

466–8555, Japan "Graduate student, Nagoya Institute of Technology The dynamic response of granular materials to impact of a spherical projectile was investigated experimentally and also numerically using discrete element method.

This handbook presents comprehensive coverage of the technology for conveying and handling particulate solids. Each chapter covers a different topic and contains both fundamentals and applications. Usually, each chapter, or a topic within a chapter, starts with one of the review papers. Chapter 1 covers the characterization of the particulate materials. Chapter 2 covers the behaviour of particulate materials during storage, and presents recent developments in storage and feeders design and performance. Chapter 3 presents fundamental studies of particulate flow, while Chapters 4 and 5 present transport solutions, and the pitfalls of pneumatic, slurry, and capsule conveying. Chapters 6, 7 and 8 cover both the fundamentals and development of processes for particulate solids, starting from fluidisation and drying, segregation and mixing, and size-reduction and enlargement. Chapter 9 presents environmental aspects and the classification of the particulate materials after they have been handled by one of the above-mentioned processes. Finally, Chapter 10 covers applications and developments of measurement techniques that are the heart of the analysis of any conveying or handling system.

# Fundamentals of Discrete Element Methods for Rock Engineering Theory and Applications

Chang, C. S. and Ma, L., Elastic material constants for isotropic granular solids with particle rotation. International Journal of Solids ... Cundall, P. A., BALL – a program to model granular media using the distinct element method.

This book presents some fundamental concepts behind the basic theories and tools of discrete element methods (DEM), its historical development, and its wide scope of applications in geology, geophysics and rock engineering. Unlike almost all books available on the general subject of DEM, this book includes coverage of both explicit and implicit DEM approaches, namely the Distinct Element Methods and Discontinuous Deformation Analysis (DDA) for both rigid and deformable blocks and particle systems, and also the Discrete Fracture Network (DFN) approach for fluid flow and solute transport simulations. The latter is actually also a discrete approach of importance for rock mechanics and rock engineering. In addition, brief introductions to some alternative approaches are also provided, such as percolation theory and Cosserat micromechanics equivalence to particle systems, which often appear hand-in-hand with the DEM in the literature. Fundamentals of the particle mechanics approach using DEM for granular media is also presented. · Presents the fundamental concepts of the discrete models for fractured rocks, including constitutive models of rock fractures and rock masses for stress, deformation and fluid flow · Provides a comprehensive presentation on discrete element methods, including distinct elements, discontinuous deformation analysis, discrete fracture networks, particle mechanics and Cosserat representation of granular media · Features constitutive models of rock fractures and fracture system characterization methods detaiing their significant impacts on the performance and uncertainty of the DEM models

# Computational Granular Mechanics and Its Engineering Applications

Finally, for the DEM-FEM coupling method for the interaction between continuum and granular material, ... of a granular solid and its contacting deformable structure under uni-axial compression–Part1: joint DEM-FEM modelling and ...

This book systematically introduces readers to computational granular mechanics and its relative engineering applications. Part I describes the fundamentals, such as the generation of irregular particle shapes, contact models, macro-micro theory, DEM-FEM coupling, and solid-fluid coupling of granular materials. It also discusses the theory behind various numerical methods developed in recent years. Further, it provides the GPU-based parallel algorithm to guide the programming of DEM and examines commercial and open-source codes and software for the analysis of granular materials. Part II focuses on engineering applications, including the latest advances in sea-ice engineering, railway ballast dynamics, and lunar landers. It also presents a rational method of parameter calibration and thorough analyses of DEM simulations, which illustrate the capabilities of DEM. The computational mechanics method for granular materials can be applied widely in various engineering fields, such as rock and soil mechanics, ocean engineering and chemical process engineering.

# The Finite Element Method for Solid and Structural Mechanics

A robust algorithm for ellipse based discrete element modelling of granular materials. Computers and Geotechnics, 13:175–186, 1992. L. Vu-Quoc, X. Zhang and O.R. Walton. A 3-discrete-element method for dry granular flows of ellipsoidal ...

This is the key text and reference for engineers, researchers and senior students dealing with the analysis and modelling of structures – from large civil engineering projects such as dams, to aircraft structures, through to small engineered components. Covering small and large deformation behaviour of solids and structures, it is an essential book for engineers and mathematicians. The new edition is a complete solids and structures text and reference in its own right and forms part of the world-renowned Finite Element Method series by Zienkiewicz and Taylor. New material in this edition includes separate coverage of solid continua and structural theories of rods, plates and shells; extended coverage of plasticity (isotropic and anisotropic); node-to-surface and 'mortar' method treatments; problems involving solids and rigid and pseudo-rigid bodies; and multi-scale modelling. Dedicated coverage of solid and structural mechanics by world-renowned authors, Zienkiewicz and Taylor New material including separate coverage of solid continua and structural theories of rods, plates and shells; extended coverage for small and finite deformation; elastic and inelastic material constitution; contact modelling; problems involving solids, rigid and discrete elements; and multi-scale modelling

# Matrix Discrete Element Analysis of Geological and Geotechnical Engineering

YADE-OPEN DEM: an opensource software using a discrete element method to simulate granular material. ... The lattice solid model to simulate the physics of rocks and earthquakes: incorporation of friction.

This book introduces the basic structure, modeling methods, numerical calculation processes, post-processing, and system functions of MatDEM, which applies the basic principles and algorithm of the discrete element method. The discrete element method can effectively simulate the discontinuity, inhomogeneity, and large deformation damage of rock and soil. It is widely used in both research and industry. Based on the innovative matrix discrete element computing method, the author developed the high-performance discrete element software MatDEM from scratch, which can handle millions of elements in discrete element numerical simulations. This book also presents several examples of applications in geological and geotechnical engineering, including basic geotechnical engineering problems, discrete element tests, three dimensional landslides, and dynamic and multi-field coupling functions. Teaching videos and the relevant software can be accessed on the MATDEM website (http://matdem.com). The book serves as a useful reference for research and engineering staff, undergraduates, and postgraduates who work in the fields of geology, geotechnical, water conservancy, civil engineering, mining, and physics.

# Predictive Modeling of Pharmaceutical Unit Operations

Powder Technol. 130, 41À48. Harthong, B., Jerier, J.F., Doremus, P., Imbault, D., Donze, F.V., 2009. Modeling of highdensity compaction of granular materials by the discrete element method. Int. J. Solids Struct. 46, 3357À3364.

The use of modeling and simulation tools is rapidly gaining prominence in the pharmaceutical industry covering a wide range of applications. This book focuses on modeling and simulation tools as they pertain to drug product manufacturing processes, although similar principles and tools may apply to many other areas. Modeling tools can improve fundamental process understanding and provide valuable insights into the manufacturing processes, which can result in significant process improvements and cost savings. With FDA mandating the use of Quality by Design (QbD) principles during manufacturing, reliable modeling techniques can help to alleviate the costs associated with such efforts, and be used to create in silico formulation and process design space. This book is geared toward detailing modeling techniques that are utilized for the various unit operations during drug product manufacturing. By way of examples that include case studies, various modeling principles are explained for the nonexpert end users. A discussion on the role of modeling in quality risk management for manufacturing and application of modeling for continuous manufacturing and biologics is also included. Explains the commonly used modeling and simulation tools Details the modeling of various unit operations commonly utilized in solid dosage drug product manufacturing Practical examples of the application of modeling tools through case studies Discussion of modeling techniques used for a risk-based approach to regulatory filings Explores the usage of modeling in upcoming areas such as continuous manufacturing and biologics manufacturingBullet points

# Dynamic Flowsheet Simulation of Solids Processes

Adv. Coll. Interface. Sci. 227, 53–62 (2016) Gladkyy, A., Schwarze, R.: Comparison of different capillary bridge models for application in the discrete element method. Granular Matter 16(6), 911–920 (2014) Mikami, T., Kamiya, H., Horio, ...

This book presents the latest advances in flowsheet simulation of solids processes, focusing on the dynamic behaviour of systems with interconnected solids processing units, but also covering stationary simulation. The book includes the modelling of solids processing units, for example for comminution, sifting and particle formulation and also for reaction systems. Furthermore, it examines new approaches for the description of solids and their property distributions and for the mathematical treatment of flowsheets with multivariate population balances.

# Coupled CFD DEM Modeling

... of particle shape on the mechanical interactions of granular media in a hopper using the Discrete Element Method. ... [50] Beverloo, W.A., Leniger, H.A., and van de Velde, J. (1961) The flow of granular solids through orifices.

Discusses the CFD-DEM method of modeling which combines both the Discrete Element Method and Computational Fluid Dynamics to simulate fluid-particle interactions. Deals with both theoretical and practical concepts of CFD-DEM, its numerical implementation accompanied by a hands-on numerical code in FORTRAN Gives examples of industrial applications

# Modern Trends in Geomechanics

In recent years, the discrete element method (DEM) [3] has been used extensively to investigate the behaviour of granular solids subjected to a variety of loading conditions. However, the majority of the numerical computations were ...

This book is loaded with rich and stimulating articles by a roster of brilliant scholars, reflecting some recent trends in the frontier research of geomechanics. This collection of 32 contributions stems from an international workshop on "Modern Trends of Geomechanics" held in Vienna. The contributions span a wide range of topics and an enormous range of physical scales, from micromechanics at grain scale to engineering problems at large scale; from laboratory and field testing over constitutive modelling to numerical analysis. The key features of this book are: thermodynamics, multiphase continua and transport phenomena; constitutive modelling, localized bifurcation, micropolar theory, unsaturated soil, viscous and cyclic behaviour; numerical and analytical methods; discrete element method, micromechanics, grain crushing and damage; laboratory and field testing, foundation and mining engineering. This book will be rewarding for anyone interested in the frontier research in geomechanics and geotechnical engineering, appealing to graduate students, researchers and engineers alike.

# Multifield Problems in Solid and Fluid Mechanics

The discrete element method (DEM) was originally brought up in [4], which used the method for granular media consisting of spherical bodies. The modeled systems consist of many distinct particles which displace independently from one ...

This book gives an overview of the research projects within the SFB 404 "Mehrfeldprobleme in der Kontinuumsmechanik". The book is for researchers and graduate students in applied mechanics and civil engineering.

# Engineering Applications of Discrete Element Method

Operation Analysis and Optimization Design of Coal and Agricultural Machinery Xuewen Wang, Bo Li, Rui Xia, Haozhou Ma ... of DEM, the contact model is essentially an elastoplastic analysis of the contact mechanics of granular solids ...

This book introduces the engineering application of the discrete element method (DEM), especially the simulation analysis of the typical equipment (scraper conveyor, coal silos, subsoiler) in the coal and agricultural machinery. In this book, the DEM is applied to build rigid and loose coupling model, and the kinematic effect of the bulk materials, the mechanical effect of the interaction between the bulk materials, and the mechanical equipment in the operation process of the relevant equipment are studied. On this basis, the optimization design strategy of the relevant structure is proposed. This book effectively promotes the application of DEM in engineering, analyzes the operation state, failure mechanism, and operation effect of related equipment in operation, and provides theoretical basis for the optimal design of equipment. The book is intended for undergraduate and graduate students who are interested in mechanical engineering, researchers investigating coal and agricultural machinery, and engineers working on designing related equipments.