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EDEM2.1


EDEM 2.1 User Guide

Revision 3E

EDEM User Guide

Copyrights and Trademarks
Copyright ? 2008 DEM Solutions. All rights reserved. Information in this document is subject to change without notice. The software described in this document is furnished under a license agreement or nondisclosure agreement. The software may be used or copied only in accordance with the terms of those agreements. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or any means electronic or mechanical, including photocopying and recording for any purpose other than the purchaser’s personal use without written permission. DEM Solutions 49 Queen Street Edinburgh EH2 3NH UK www.dem-solutions.com EDEM incorporates CADfix translation technology. CADfix is owned, supplied by and Copyright ? TranscenData Europe Limited, 2007. All Rights Reserved. This software is based in part on the work of the Independent JPEG Group. EDEM uses the Mersenne Twister random number generator, Copyright ? 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, All rights reserved. See the Online Help for full copyright notice. EDEM uses Lua 5.0, Copyright ? 19942008 Lua.org, PUC-Rio. See the Online Help for full copyright notice. DEM Solutions, EDEM and Particle Factory are trademarks or registered trademarks of DEM Solutions in the United Kingdom and/or other countries. FLUENT is a registered trademark of ANSYS, Inc. in the United States and/or other countries. Easy5 is a registered trademark of MSC.Software Corporation in the United States and/or other countries. Other brands and their products are trademarks or registered trademarks of their respective holders and should be noted as such.

Licensing
EDEM licensing uses Sentinel RMS. See the SafeNet website (www.safenet-inc.com) for details. Commuter Licensing With commuter licenses, you can use EDEM and its licensable features on a computer (such as a laptop) while disconnected from the Sentinel license server. A license can be "checked out" to a particular computer for a period of time up to the license's expiration date. This license is then unavailable to other users connected to the Sentinel server. Once the computer is returned to the network, the license can be checked back into the pool of free licenses where it is made available for the other network users. To check out a license, select Tools > Commuter Licenses from the Creator. Repeat to check the license back in again.

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EDEM User Guide

Contents
GETTING?STARTED?.................................................................................................................................?5? INTRODUCTION?TO?EDEM?.................................................................................................................................? 5? EDEM?USER?INTERFACE?....................................................................................................................................? 6? ARRANGING?THE?USER?INTERFACE?....................................................................................................................... ? 7? CHOOSING?UNITS?.............................................................................................................................................? 8? EDEM?CREATOR?.....................................................................................................................................?9? ABOUT?THE?EDEM?CREATOR?............................................................................................................................. ? 9? Tabs?Pane?..............................................................................................................................................? 10? Viewer?...................................................................................................................................................? 10? Viewer?Controls?(Creator)?..................................................................................................................... ? 10? Data?Browser?(Creator)?......................................................................................................................... ? 11? Creator?Toolbar?.....................................................................................................................................? 12? Creator?Menu?Bar?.................................................................................................................................? 12? GLOBAL?SETTINGS?..........................................................................................................................................? 15? THE?MATERIALS?DATABASE?.............................................................................................................................. ? 19? DEFINING?PARTICLES?.......................................................................................................................................? 21? THE?MODEL?DOMAIN?.....................................................................................................................................? 24? CREATING?GEOMETRY?SECTIONS?....................................................................................................................... ? 25? Importing?Geometry?Sections?............................................................................................................... ? 31? Merging?Geometry?Sections.................................................................................................................. ? 31? PARTICLE?FACTORIES?.......................................................................................................................................? 32? Creating?Particle?Factories?.................................................................................................................... ? 32? EDEM?SIMULATOR? ...............................................................................................................................?37? ABOUT?THE?EDEM?SIMULATOR?........................................................................................................................ ? 37? Simulator?Pane? ......................................................................................................................................? 38? Viewer?...................................................................................................................................................? 38? Viewer?Controls?(Simulator)?.................................................................................................................. ? 38? Solve?Report?(Simulator)?....................................................................................................................... ? 38? Simulator?Toolbar?.................................................................................................................................? 40? Simulator?Menu?Bar?.............................................................................................................................. ? 40? SIMULATOR?SETTINGS?.....................................................................................................................................? 41? REDUCING?SIMULATION?TIME?........................................................................................................................... ? 44? EDEM?ANALYST?...................................................................................................................................?47? ABOUT?THE?EDEM?ANALYST?............................................................................................................................ ? 47? Tabs?Pane?(Analyst)?.............................................................................................................................. ? 48? Viewer?...................................................................................................................................................? 48? Viewer?Controls?(Analyst)?..................................................................................................................... ? 48? Data?Browser?(Analyst)?......................................................................................................................... ? 48? Analyst?Toolbar?.....................................................................................................................................? 50? Analyst?Menu?Bar?.................................................................................................................................? 50? REVIEWING?YOUR?SIMULATION?......................................................................................................................... ? 52? MODEL?TAB?..................................................................................................................................................? 53? COLORING?....................................................................................................................................................? 57? BINNING? .......................................................................................................................................................? 59? Bin?Group?Queries?.................................................................................................................................? 60? Coloring?Bin?Groups?.............................................................................................................................. ? 63? CLIPPING?......................................................................................................................................................? 64?

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Contents
TOOLS?TAB?...................................................................................................................................................? 67? Selection?Groups?...................................................................................................................................? 67? Ruler?......................................................................................................................................................? 68? Protractor? ..............................................................................................................................................? 68? Scale?Grid?..............................................................................................................................................? 69? SAVING?IMAGES?.............................................................................................................................................? 70? CREATING?VIDEOS?..........................................................................................................................................? 71? EXPORTING?DATA?...........................................................................................................................................? 74? General?Settings?....................................................................................................................................? 75? Creating?a?Query?...................................................................................................................................? 76? TRUNCATING?RESULTS? .....................................................................................................................................? 80? GRAPHING?....................................................................................................................................................? 81? Creating?Graphs?....................................................................................................................................? 81? Creating?a?Histogram?(Bar?Chart)?......................................................................................................... ? 81? Drawing?a?Line?Graph?........................................................................................................................... ? 87? Drawing?a?Scatter?Plot?.......................................................................................................................... ? 88? Creating?a?Pie?Chart?.............................................................................................................................. ? 93? RUNNING?EDEM?IN?BATCH?MODE?........................................................................................................?98? EDEM’S?COMMAND?LINE?INTERFACE?(CLI)?........................................................................................................ ? 98? DYNAMICS?COUPLING?.......................................................................................................................?100? USING?THE?DYNAMICS?COUPLING?INTERFACE?WITH?EASY5?................................................................................... ? 100? Setup?Easy5?Coupling?in?EDEM?........................................................................................................... ? 100? Setup?EDEM?Coupling?in?Easy5?........................................................................................................... ? 101? Synchronize?the?Coupling?in?EDEM?..................................................................................................... ? 102? Setup?EDEM?Inputs?and?Outputs?......................................................................................................... ? 102? Choose?Integrator?............................................................................................................................... ? 103? Monitor?the?Easy5?Server?.................................................................................................................... ? 103? APPENDIX?A:?CONTACT?MODEL?THEORY?............................................................................................?104? Hertz?Mindlin?(No?Slip)?Contact?Model?............................................................................................... ? 105? Hertz?Mindlin?with?Bonding?Contact?Model? ........................................................................................ ? 106? Hertz?Mindlin?with?Heat?Conduction? ................................................................................................... ? 107? Temperature?Update?.......................................................................................................................... ? 107? Linear?Cohesion?Contact?Model?.......................................................................................................... ? 108? Moving?Plane?Contact?Model.............................................................................................................. ? 108? Linear?Spring?Contact?Model? ............................................................................................................... ? 109? Tribocharging?Contact?Model?............................................................................................................. ? 111? APPENDIX?B:?PARTICLE?BODY?FORCES?................................................................................................?112? Electrostatic?Force...............................................................................................................................? 112? APPENDIX?C:?ESTIMATING?SIMULATION?TIME?....................................................................................?115? APPENDIX?D:?ATTRIBUTE?DEFINITIONS?...............................................................................................?117? Particle?Attributes?............................................................................................................................... ? 117? Geometry?Attributes?........................................................................................................................... ? 119? Contact?Attributes?............................................................................................................................... ? 120? Collision?Attributes?.............................................................................................................................. ? 122? Bonding?Attributes?.............................................................................................................................. ? 123? APPENDIX?E:?EDEM?FILE?TYPES?...........................................................................................................?124?

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EDEM User Guide
APPENDIX?F:?MATERIALS?DATABASE?VALUES?.....................................................................................?125? REFERENCES?......................................................................................................................................?127? Core?EDEM?..........................................................................................................................................? 127? Contact?Models?...................................................................................................................................? 127? Particle?Body?Forces?............................................................................................................................ ? 128? Other?References?................................................................................................................................? 128? CONTACTING?DEM?SOLUTIONS?..........................................................................................................?129? GLOSSARY?.........................................................................................................................................?130? INDEX?................................................................................................................................................?134?

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EDEM User Guide

Getting Started
Introduction to EDEM
EDEMTM is the world's first multi-purpose Discrete Element Modeling software tool designed for the simulation and analysis of industrial particle handling and manufacturing operations. With EDEM you can quickly and easily create a parameterized model of your granular solids system. CAD models of real particles can be imported to obtain an accurate representation of their shape. Add the mechanical, material and other physical properties to form your model particles. These can be stored in a library allowing you to build a collection specific to your processes. EDEM manages information about each individual particle (mass, velocity and so on) and the forces acting on it. It can also take into account the particle’s shape, rather than assuming that all particles are spherical. For post-processing, EDEM provides data analysis tools, 3D visualizations of the particle flow, and video creation. EDEM's Particle FactoryTM technology provides a unique method for efficiently generating assemblies of particles in association with the machine geometry imported from your CAD or CAE system as a solid model or mesh. Machine components can be grouped; you can specify the kinematics of each group individually. EDEM can be coupled with leading CAE tools to simulate particle interactions with fluids, structures and electromagnetic fields. With EDEM’s powerful post-processing tools you can visualize and graph any combination of variables. Having identified important system behavior you can easily modify models to refine your simulation. You can then use the video export feature to create video files of your simulation. EDEM can even record multiple simulations in the same video.

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EDEM User Guide

EDEM User Interface
EDEM is made up of three sections: the Creator, the Simulator and the Analyst.
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Creator. Used to set-up and initialize models. Simulator. The discrete element solver. Analyst. A data analysis and visualization tool.

You can move between each section by clicking on the toolbar button indicated above. The layout of the user interface is common to each section. It consists of: the Tabs Pane, the Viewer, the Viewer Controls and the Data Browser.

The Tabs Pane
The Tabs Pane is displayed at the on the left side of the EDEM window. It is made up of a number of individual panes. The contents of each pane vary according to which section of EDEM is currently active.

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Getting Started

The Viewer
The Viewer displays 3D representations of your particles and geometry. The orientation, position and zoom factor of the Viewer are controlled using the mouse. The arrows in the bottom-left corner of the viewer indicate the current orientation: red (x), green (y) and blue (z).
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Press and hold the left mouse button then drag the pointer to alter the position. Press and hold the right mouse button to rotate. Press the Shift key and left mouse button together to rotate about the Y axis only. Press and hold the middle mouse button then move the mouse back and forth to zoom in and out. Alternatively, while holding down the Ctrl button press and hold the middle mouse button to draw a box to zoom in to. Select Options > Mouse Configuration to configure these controls.

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The Viewer Controls
The Viewer Controls are used to determine how items are displayed in the Viewer: For example, the fill-style of a particle or the opacity of a geometry. The content of the pane varies according to which section of EDEM is currently active.

The Data Browser
The Data Browser is an .html page that displays detailed information about the contents of the Viewer: For example, particle properties and interactions or the dimensions of a geometry section. The content of the page varies according to which section of EDEM is currently active.

Arranging the User Interface
Floating and Docked Panes
The Tabs pane, Viewer controls and Data browser can each be floating or docked. By default all panes are docked. To undock a pane double click on its title bar (control area) and place it anywhere in screen. Double click the title bar to re-dock it in its original position or drop it over the left or right edge or the bottom of the screen to dock it in that position.

Opening and Closing Panes
Right-click anywhere on the toolbar. Each of the panes is listed. Select or un-select a pane to open or close it. In addition each pane can be closed using the close button displayed on its title bar.

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EDEM User Guide

Choosing Units
The units of measurement used throughout EDEM can be configured. By default all quantities are measured in standard SI units (the International System of Units).

Changing Units
Select Options > Units to change the units. Changes are propagated throughout the software*. You can set units individually. Alternatively, all units can be set to CGS (centimeter-gram-second) or back to the default SI (Système International d'Unites). Property Acceleration Angle Angular acceleration Angular velocity Charge Density Energy Force Frequency Length Mass Moment of Inertia Shear Modulus Stiffness Stress Time Torque Velocity Volume Work Function Temperature Heat Flux Units available mm/s , cm/s , m/s , in/s , ft/s , fpm/s
2 2 2 2 2

SI unit m/s
2

CGS unit cm/s2 rad rad/s2 rad/s C g/cm3 erg dyn Hz cm g g/cm2 pa N/m pa s Dyne.cm cm/s cm3 J K W

rad, deg rad/s2, deg/s2 rad/s, deg/s, rpm nC, C g/cm3, kg/m3, lb/in3, lb/ft3, slug/ft3 J, erg, kwh, btu, ft-lbf, in-lbf N, dyn, kgf, lbf, ozf, pdl, gf Hz, kHz, mHz mm, cm, m, in, ft mg, g, kg, lb, oz lb/ft2, kg/m2, g/cm2, lb/in2, slug/ft2 pa, ksi N/m, lb/ft pa, Nm2, lb/in2 s, min Nm, Dyne.cm, gf-cm, kgf-m, lbf-in, lbf-ft mm/s, cm/s, m/s, in/s, ft/s, ft/min mm3, cm3, m3, in3, ft3, L J, eV K, C, F W, J/S
o o

rad rad/s2 rad/s C kg/m3 J N Hz m kg kg/m2 pa N/m pa s Nm m/s m3 J K W

* Note: Graphs are not automatically updated when units are changed. Once units have been changed, click the 'Create Graph' button to regenerate graphs.

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EDEM User Guide

EDEM Creator
About the EDEM Creator
The EDEM Creator is used to setup and initialize your model. Create or import particles and geometry and define the other model parameters.

Tabs Pane Viewer Viewer Controls Data Browser Toolbar Menu Bar

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EDEM User Guide

Tabs Pane
The Tabs Pane is displayed at the on the left side of the EDEM window. It contains the following tabs: ? Globals ? Particles ? Geometry ? Factories

Viewer
The Viewer displays 3D representations of your particles and geometry. The rotation, position and zoom factor of the Viewer are controlled using the mouse.

Viewer Controls (Creator)
The Viewer Controls are used to determine how items are displayed in the Viewer. The content of the pane varies according to which tab in the Tabs pane is currently active. Globals Current time Camera Display mode Opacity Show particles Show grids Highlight surface Show origin Show template Display lattice
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Particles

Geometry

Factories

Current time. Lists all time steps in the simulation. The selected time step is displayed in the Viewer. Camera. Choose to display the Viewer from a number of standard angles. If you change the angle manually you can return to the currently selected angle by clicking the reset button. Display mode. Used to configure the display of all the geometry in the Viewer. Choose between filled, mesh or points style display. Opacity. Used to configure the opacity level of all the geometry in the Viewer. Show particles. Choose to display particles already created by the Simulator. Show grids. Enable or disable the display of a scale grid around the particle. Highlight surface. Highlight the currently selected particle surface.

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EDEM Creator
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Show origin. Displays the origin. All multi-sphere particles must be centered on the origin. Show template. Used to display particle templates in the Viewer. Display lattice. Enable or disable the display of the particle positioning lattice. This option is only available when cubic, BCC or FCC lattice positioning is selected.

Data Browser (Creator)
The Data Browser is an .html page that displays detailed information about your model. The information displayed differs between the Creator, Simulator and Analyst. Right click anywhere within the Data Browser and choose Save to save the information in an .html file. There are five sections in the Data Browser within the Creator: Description, General, Geometry, Particles and Contacts.
Description

The description as defined in the Globals tab.
General ? ? ? ?

Dimensions. The number of dimensions in your domain. Gravity. Details of the gravity acting in your model as specified in the Globals tab. Materials. A list of all materials used in the model and their properties, as specified in the Materials Editor. Energy. The total energy in the model at the current time. It is the sum of the kinetic energy, potential energy and the energy in any contacts taking place.

Geometry ? ? ?

Domain. The dimensions of the domain as specified in the Geometry tab. Geometry Totals. Details of the number of elements that make up each section of geometry. Sections. Each section is the model and its properties are listed. Properties are as specified in the Geometry tab.

Particles ?

Particles. A list of each particle type used in the model and their properties. Details of each surface within the particle are also listed. Properties are as specified in the Particles tab. Factories. Details of each factory used in the model and their properties. Properties are as specified in the Factory tab. The total number of particles created by each factory is also listed.

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EDEM User Guide
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Particle totals. The total number of particles in the model at the current time. Totals for each particle type are also listed.

Contacts ? ?

Interactions. A list of the interaction types taking place in the model as specified in the Materials Editor. Contacts. Lists the total number of contacts in progress at the current time. The contacts are broken down into contact types: For example number of particle A particle B contacts or number of particle B - surface A contacts. The total number of collisions that have taken place during the time step are also listed.

Creator Toolbar
Icon Name Creator Simulator Analyst New Open Save Help Description Click to switch to the Creator. Click to switch to the Simulator. Click to switch to the Analyst. Click to start a new model. Click to open an existing model. Click to save your model. Click to view the online help.

Creator Menu Bar
File Menu ? ? ? ? ? ? ? ? ?

Open. Open an existing model New. Start a new model. Save. Save the current model. Save As. Save the current model with a specific name or to a specific location. Creator. Select to switch to the Creator. Simulator. Select to switch to the Simulator. Analyst. Select to switch to the Analyst. Recent Files. A list of recently opened files. Select a file to open it. Quit. Quit EDEM.

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EDEM Creator
Options Menu
Mouse Configuration

Used to configure how the mouse is used to alter the display in the 3D Viewer.
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Motions. Change the mouse button to use to translate (move), rotate, and zoom the display. Note Zoom and Zoom to Selection use the same mouse button. Modifier Keys. Assign keyboard buttons to use in conjunction with zooming, translation and rotation. Choose any unique combination of three mouse buttons and three keys for each motion. Mouse sensitivity. The mouse sensitivity can be altered independently for translation, rotation and zooming. You can also specify modifier keys for each sensitivity setting.

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File Locations

The file location options are used to determine the location of the materials database and any user-defined elements. Refer to the EDEM Programming Guide for details.
? ? ? ? ?

Materials Database. The location of the materials database, used to define any material used in a model. Contact Models. The location of custom (user-defined) contact models. See Appendix A: Contact Model Theory. Particle Body (External) Force. The location of custom (user-defined) forces. See Appendix B: Particle Body Forces. Particles. The location of particles saved independently of the model for reuse in other projects. Factories. The location of any user-defined factories.

Background

This option is used to change the fill color of the Viewer background. The background can be colored with a solid or gradient fill. The color change will affect the Creator, Simulator and Analyst.
Units

The units configuration dialog is used to set the measurement units used throughout EDEM. See Choosing Units on page 8 for more details.
Data Browser

The data browser options are used to configure the color of the data browser text and background.
Include Electrostatics Data in Simulation File

If you have purchased the Electrostatics feature, electrostatic data is included in the simulation file by default when you select the Tribocharging contact model.

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EDEM User Guide
Tools Menu
Particle Display

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Display Templates. Mesh files created in other packages can be used as particle templates. Templates can be used as a guide (outline) to help define the shape of your particle in the Creator, or as a display option in the Analyst. Files of the following type can be imported: IGES, STEP, ProE, FLUENT Mesh, STL, ACIS v1.1, Parasolid, or Catia. When a model containing a particle template is saved, an extra file (.ptf) is created alongside the usual three files (.dem, .cfg and .idx). If this file is deleted, the template information will no longer be stored within the model.

Figure 2-1: Default Particle Display

Figure 2-2: Particle Display Using a Template

Materials Database

Access the Materials Database. See The Materials Database on page 19.
Commuter Licenses

With commuter licenses, you can use EDEM and its licensable features on a computer (such as a laptop) while disconnected from the Sentinel license server. A license can be "checked out" to a particular computer for a period of time up to the license's expiration date. This license is then unavailable to other users connected to the Sentinel server. Once the computer is returned to the network, the license can be checked back into the pool of free licenses where it is made available for the other network users.

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EDEM Creator

Global Settings
Simulation
Set the simulation title and a description of the simulation.

Physics
Interaction

Select the type of physics interaction to add: ? Particle-to-Particle contact models ? Particle-to-Geometry contact models ? Particle Body Forces
Contact Models

A contact model describes how elements behave when they come into contact with each other. Using the Interaction pulldown menu and + picklist, you can build a list (stack) of contact models. The top element is applied first, then the next one down and so on. Use the up and down buttons to move the contact model up and down the list (check the sections below since some models need to be at the start or end of the list). To remove an item, click the x button. Click the preferences button to configure the selected model. Every simulation must have at least one base particle-to-particle and one particle-togeometry contact model. EDEM is supplied with several integrated contact models; you can also add your own custom plug-in contact models. Refer to Appendix A: Contact Model Theory and the EDEM Programming Guide for details.
Hertz-Mindlin (no slip)

Hertz-Mindlin (no slip) is the default contact model.
Interaction Particle to Particle, Particle to Geometry Configurable Parameters None. Position Last

Hertz-Mindlin with Heat Conduction

Hertz-Mindlin with Heat Conduction calculates the heat flux between particles in contact. Since this model includes Hertz-Mindlin, remove the default no-slip contact model from the list.
Interaction Particle to Particle Configurable Parameters Position Last Set the thermal conductivity for each type of particle. Note the unit depends on the temperature unit; for example, the unit will be W/mK when the temperature unit is Kelvins.

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EDEM User Guide
Hertz-Mindlin with Bonding

Hertz-Mindlin with Bonding bonds particles together. Since this model includes HertzMindlin, you should remove the default no-slip contact model from the list. To use, enable the bonding model for both particle-particle and particle-geometry interactions. Although particles can’t be bonded to geometry elements, the bonded model ensures that the particles contact the geometry based on the particle’s physical radius and not the contact radius.
Interaction Particle to Particle (also enable for Particle to Geometry) Configurable Parameters Position Select an active bond then set the Bond Formation Time and Last the following parameters: ? Normal Stiffness: the tensile/compressive stiffness along the bond’s principal axis ? Shear Stiffness: Shear stiffness in the orthogonal plane to the bond’s principal axis ? Critical Normal Stress: the maximum normal stress the bond can withstand before it fails ? Critical Shear Stress: The maximum tangential stress the bond can withstand before it fails ? Bonded Disk Radius: The radius of the cylindrical bond between the particles Set the bond stress and stiffness values to represent the material that is been modeled. A high stiffness value will produce high bond forces and stresses. A lower than normal timestep may be required to accurately capture these high forces. When the Bond Formation Time is reached, all defined particles in contact will be bonded together. Before this time, particles interact based on the Hertz-Mindlin contact model. The bond formation time can be updated to restart the bonding process. Existing bonds won't be affected, but any unbonded particles in contact will be bonded whenever the updated bond formation time is reached. Note that a bond between two particles will cease to exist whenever one or both of the bonded particles leaves the simulation domain. If periodic boundaries are applied when the particle leaves the domain, then the particle will exist on the opposite side of the domain; in this case the two particles will remain bonded across the periodic boundary.

Linear Cohesion

Linear Cohesion modifies Hertz-Mindlin contacts by adding a normal cohesion force.
Interaction Particle to Particle, Particle to Geometry Configurable Parameters Position Click + to add cohesion to particle-particle or particle-geometry Any interactions. Set the energy density for each interaction.

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EDEM Creator
Linear Spring

Linear Spring is a damped linear spring contact force model. Since this model includes Hertz-Mindlin, remove the default no-slip contact model from the list.
Interaction Particle to Particle, Particle to Geometry Configurable Parameters Position Set the characteristic velocity of the spring. Be sure the velocity Last is the same for both particle-to-particle and particle-togeometry.

Moving Plane

The Moving Plane model simulates a linear motion of a geometry section.
Interaction Particle to Geometry Configurable Parameters Click + to add a section to use as a moving plane. For each section, set the X, Y, and Z linear velocity. Position First

Tribocharing

Tribocharing handles the transfer of charge due to the triboelectric effect. This model is available with the Electrostatics feature.
Interaction Particle to Particle, Particle to Geometry Particle Body Forces Configurable Parameters Set the tribocharging Alpha value. This determines the rate at which charge transfers between elements. Position Any

A particle body force can be set to act on particles when a specified condition is met, for example when particles are in certain position or are traveling at a specified velocity. Refer to Appendix B: Particle Body Forces and the EDEM Programming Guide. Using the Interaction pulldown menu and + picklist, you can build a list (stack) of particle body forces. The top element is applied first, then the next one down and so on. Use the up and down buttons to move the force up and down the list. To remove an item, click the x button. Click the preferences button to configure the selected force.
Configuring Particle Body Forces

Name Electrostatics*1

Description and Parameter Values Models the forces applied to a particle due to its charge and the charge of surrounding particles and geometry. Set the electrostatic force screening distance. This is the maximum distance at which two particles (or particle and geometry) can interact. Although not strictly a force, this models a particle’s temperature over time. Set the specific heat capacity for each type of particle. Note the unit depends on the temperature unit; for example, the unit will be Jkg-1K-1 when the temperature unit is Kelvins.

Temperature Update

* Available with the Electrostatics feature

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EDEM User Guide

Gravity
Enable the gravity checkbox to set gravity in a given direction (x, y, z). The default settings are x: 0, y: 0 and z: -9.81m/s2.

Materials
Every particle or section of geometry used in a model is made of a particular material. All materials and the interactions between them must be defined in the Materials section. Materials can be created directly in the simulation or imported from the Materials Database. All materials defined in the Materials section are stored within the model.
Adding and Removing Materials

To add a material to a model:
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Click the + button then type a name for the new material in the Name field. Enter the Poisson's ratio, Shear modulus, Density and Work Function (if applicable) into the relevant fields.

You can also click Copy to create a duplicate of the currently selected material. To remove a material from a model, select the material from the drop-down list then click the x button.
Defining Interactions Between Materials

Interactions are used to define how materials act when they come into contact with each other. Interactions must be defined for all materials used in your model, including the interaction that occurs when a material comes into contact with itself: For example when two particles of the same material collide. To define an interaction between two materials:
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Select the first material from the Name drop-down list. Click the + button in the Interactions section. Select the second material from the Select Material dialog. Enter values for the Coefficient of Restitution, Coefficient of Static Friction and Coefficient of Rolling Friction into the relevant fields.

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EDEM Creator

The Materials Database
The EDEM Materials Database is a repository for material and interaction data. It stores material data in one central location. The material data can then be imported into simulations as desired. The Materials Database supplied with EDEM contains some standard materials and interactions. Refer to Appendix F: Materials Database Values on page 125 for details.
NOTE: Although the material values supplied are based on academic research, they are to be used as guidelines only and do not necessarily represent true material data.

By default, the Materials Database (MaterialsDB.ddb) is installed to the My Documents > EDEM folder. If you move the Materials Database (for example to a shared network folder for use by multiple clients), remember to update the location information in EDEM. To do this, select Options > File Locations then browse to the new location.

Adding Materials and Material Interactions to the Database
Materials and material interactions can be added to the database directly or transferred from an existing simulation. Note that materials defined in your database are not automatically added to any model. All materials used in a model must be defined directly in that model or explicitly transferred from the materials database.
Adding and Removing Materials

To add a material to the database:
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Select Tools > Materials Database from the Creator to open the Materials Database. Click the + button and type a name for the new material in the Name field. Enter values for the Poisson's ratio, Shear modulus, Density and Work Function (if applicable) into the relevant fields.

To remove a material from the database:
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Open the Materials Database. Choose the material from the drop-down list and click the x button. The material is permanently removed from the database.

Click the Copy button to create a duplicate of the currently selected material.

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EDEM User Guide
Importing Materials from other Databases

Materials can be imported from other EDEM Material databases.
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Open the Materials Database. Click the Import button and navigate to the Materials Database (.ddb) of your choice. Click Yes to import all materials and interactions. Click No to import a limited selection of the database.

Transferring Materials to and from the Materials Database

Any material or interaction defined in a model can be transferred to the materials database for use in other simulations. Similarly, materials and interactions can be imported from the database into your model. To transfer a material to or from the database:
? ? ?

Click the Transfer button. The Transfer dialog box appears. Click on the material to transfer. The material's properties are displayed at the bottom of the dialog. Click the appropriate arrow to transfer the material to or from the database.

Conflicts

If a material in the model and one in the database have the same name but different properties they are highlighted in red to indicate the conflict. If you continue with the transfer, one material will overwrite the other. If two materials have the same name and the same properties they are both highlighted in green.

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EDEM Creator

Defining Particles
All types of particle used in a model are defined in the Particles pane. These are the base or prototype particles. A model can contain any number of different particle types.

Select Particle
Creating or Removing Particle ? ? ?

To create a particle click the + button and type a name in the Name field. A single spherical surface is automatically created. To copy an existing particle, select it from the drop-down list and click the button. To remove a particle, select it from the drop-down list and click the x button.

Importing a Particle

Any particle created in EDEM can be exported for use in other models. To import a particle click the Import button and navigate to your chosen file.
Using a Particle Template

Mesh files created in other packages can be used as particle templates. A template can be used as a guide to create your particle and its properties automatically calculated from it. Any of the following file types can be used: IGES, STEP, ProE, EDEM geometry, FLUENT Mesh, STL, ACIS v1.1, Parasolid, or Catia. We recommend using a template if your model uses multi-sphere particles. To use a template:
? ? ? ?

Go to the Tools > Particle Display menu. Click the Import button and navigate to the file of your choice. Any templates used in your model must first be imported here. Select the Show Template option in the Viewer controls pane at the right of the screen and choose your template from the drop-down list. Create surfaces to match the template outline.

When a model containing a particle template is saved, an extra file (.ptf) is created alongside the usual three files (.dem, .cfg and .idx). If this file is deleted, the template information will no longer be stored within the model.

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EDEM User Guide

Surfaces
A particle is defined using one or more spherical surfaces. Multiple surfaces can be overlapped to create multi-sphere particles.
? ? ?

Click the + button then type a name for the surface in the Name field. Type the surface Radius. Select Contact Radius when the particle has a different contact radius due to another (long-range) force acting upon it. This option should only be used with a relevant user-defined contact model. When two contact radii overlap the contact force calculation is entered into, however internally the physical radius of the spheres is used to calculate the magnitude of the contact force. For multiple surfaces, use the Position X, Y and Z options to define their relative positions. Note that multi-sphere particles should be centered on the origin along the principle axes to ensure that the moments of inertia are calculated correctly.

?

Properties
Particle properties refer to the whole particle, not just to individual surfaces. Particle properties can be inserted manually or calculated automatically.
Automatically

? ? ?

Click Calculate Properties then select whether to calculate using the spherical surfaces that make up your particle, or (preferably) from an imported template. Check whether you want to automatically center the particle when calculating the moments of inertia. Unchecking this option may result in unphysical results. Click OK. EDEM calculates the mass, volume, and moments of inertia.

Since random sampling is used to calculate particle properties, re-calculating for particles with multiple surfaces may result in slightly different values.
Manually

Type values for each property into the relevant field. If a value turns red it is not recommended. Property Material Mass Volume Moment of Inertia X/Y/Z Description Choose a particle material. The drop-down list is populated with any material defined in the Globals pane Mass of the particle. Volume of the particle measured. The moment of inertia is a measure of a body's resistance to angular acceleration. A particle consists of a number of spheres, i, each with mass mi and radius ri. If each sphere is a distance di from a particular axis of rotation, then the moment of inertia of the particle about that axis is given by:

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EDEM Creator

Particle Limits
Under certain simulation conditions the velocity of a particle can become too large and cause surrounding particles to behave erratically: For example, when the simulation time step is too large. There are two ways to help combat this. Particle velocities can be capped at a specified limit or particles exceeding that limit can be removed from the simulation. Particle velocity and angular velocity can be treated separately.

Particle Export
Once a particle has been defined it can be exported for use in other EDEM simulations. Click the Export button and save the file to your Particles folder (as specified using Options > File Locations). Files are exported in the .dem format.

Custom Particle Properties
With Custom Particle Properties you can dynamically define custom particle attributes to use in your simulation. Custom particle properties can be graphed and exported just like any other particle attribute. When loaded, contact models, particle body forces, and coupled applications can all use and share data about these new custom particle properties on a per-particle basis.
Creating a Custom Particle Property

Click Custom Properties to open the Property Manager window. The Property Manager window is in two halves: the bottom half is where you set-up and modify new custom particle properties. When simulation starts, these tentative properties move to the top half which lists all finalized properties. Once a property is finalized, you cannot modify or delete it. Click New User Property to add a new tentative particle attribute. Attribute Name # Elements Units Initial Value Description Double-click to enter a unique name for the particle property, for example Temperature. Set the number of elements. Usually a particle property has one element. A property with a position in 3D space would have three elements (X, Y, and Z). Select the property’s units from the menu. If the property has no unit, select None. Specify the property’s initial value.

Note: You must have an EDEM Extended API license to use custom particle properties with user-defined contact models and particle body forces. Refer to the EDEM Programming Guide for details.

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EDEM User Guide

The Model Domain
The model domain is the area where simulation takes place. It is defined in the Geometry tab and indicated by the red box in the Viewer:

Particles that move out of the domain during the course of the simulation are permanently removed by the Simulator (unless a periodic boundary option has been selected). Geometry can move in and out of the domain during a simulation.

Defining the Model Domain
Domain size has an effect on simulation time - the larger the domain, the longer the simulation will take to run. Use the auto-update option to automatically fit the domain around any sections of geometry defined, thus creating the smallest domain possible. Note: Sections of geometry should not be placed totally coincident with the edge of the domain. Particles are removed as soon as they reach the domain edge, so cannot interact with any geometry placed there.

Periodic Boundaries
Periodic boundaries enable you to set what happens to a particle once it leaves the domain. If the option is turned on for a particular direction, any particle leaving the domain in that direction will instantly re-enter it on the opposite side.

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EDEM Creator

Creating Geometry Sections
Geometry sections are used to create the environment in which your particles act: For example, a pipe or a mixing drum. Sections can be defined in EDEM or imported from a CAD (or similar) package. Particle factories are also created using sections. A model can have any number of sections allowing complex machinery to be created. A section can be defined as a box, a cylinder or as an n-sided polygon. Each section comprises a number of triangular elements: For example a square surface is made up of two elements and a ten-sided polygon of ten elements. Information on these elements can be examined at a later point: For example, contacts with a particular element. The individual elements can be seen by choosing the mesh display mode.

Create a New Geometry Section
To create a new section: 1. Go to the Geometry tab. 2. Click the + button then choose the shape. Select box, cylinder or polygon. 3. Type a name for the section in the Name field. The section should now appear in the Viewer. Note the default size of some sections is quite small and may not be immediately visible in your domain. Set the basic properties in the Details tab: Property Volume Description A section is described as a volume or a surface. Completely closed boxes and cylinders are volumes; polygons and open boxes or cylinders are surfaces. This field is completed automatically. Volumes or virtual surfaces can later be turned into particle factories. Select a section material from the drop-down list. The materials listed are defined using the Materials Section in the Globals pane. A section is either virtual or physical. A physical section is an actual surface or volume that particles can interact with. A virtual section (used to create particle factories) is a surface or volume of interest that does not actually exist and does not interact with anything in a simulation. For every closed-volume geometry (such as a box or closed cylinder), EDEM automatically calculates the center of mass when you first import or create the geometry. If required, set the center of mass parameters for X, Y, and Z components (for imported geometries) or click the auto-adjust checkbox for geometry sections defined in EDEM. If you have purchased the Electrostatics feature, set the geometry’s starting surface charge or tick the Exclude checkbox to ignore charge for this geometry. Excluding from electrostatics calculations speeds up simulation time.

Material Type

Center of Mass

Electrostatics

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EDEM User Guide

Specify the Section Properties
Once a section has been created a third tab (Box, Cylinder or Surface) will appear. Click on the tab and define size, shape and position of your section. Note geometry sections outside of or directly coincident with the domain boundary do not take part in the simulation, and will hence be 'invisible' to particles. Section Box Parameters
? ? ? ?

Center. Set the position of the center of the box. Dimensions. Set the box height, width and length. Rotation. Set the box rotation about the x, y or z axes. Enable Sides. Any of the six sides of the box can be removed. Radius Start. Set the radius of one end of the cylinder. The end can be open or closed. Radius End. Sets the radius of one end of the cylinder. The end can be open or closed. Start Point (x), End Point (x). Set the x-position of each end of the cylinder. Start Point (y), End Point (y). Set the x-position of each end of the cylinder. Start Point (z), End Point (z). Set the x-position of each end of the cylinder.

Cylinder

? ? ? ? ?

Polygon

All polygons except a 4-sided polygon are defined as follows:
? ? ? ?

Edges. Set the number of edges. The minimum number is three. Center. Set the position of the center of the polygon. Rotation. Set the angle of rotation about the surface normal. Surface normal. Define the surface normal to determine the orientation of the polygon.

A 4-sided polygon is specified as follows:
? ? ? ?

Edges. Set the number of edges to four. Center. Set the position of the center of the polygon. Dimensions. Set the length and the width. Rotation. Set the angle of rotation about the x, y or z axes.

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EDEM Creator

Example Geometry Sections
Box Section Examples

A closed cube Center (m) 0.5 0.5 0.5 Dimensions (m) 0.2 0.2 0.2 Rotation (rad) 0 0 0

An open, tilted cuboid. Center (m) 0.5 0.5 0.5 Dimensions (m) 0.5 0.2 0.1 Rotation (rad) -0.5 0 0

X Y Z

X Y Z

Cylinder Section Examples

A vertical cylinder Radius Start: Radius End: Start Point (x): Start Point (y): Start Point (z): 0.1 0.1 0.5 0.5 0.2 End Point (x): End Point (y): End Point (z): 0.5 0.5 0.8

A cylinder tilted in the y-direction Radius Start: Radius End: Start Point (x): Start Point (y): Start Point (z): 0.1 0.1 0.5 0.5 0.2 End Point (x): End Point (y): End Point (z): 0.5 1.0 0.8

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EDEM User Guide

A cylinder tilted in the x-direction Radius Start: Radius End: Start Point (x): Start Point (y): Start Point (z): 0.1 0.1 0.5 0.5 0.2 End Point (x): End Point (y): End Point (z): 1.0 0.5 0.8

A funnel tilted in the x-direction Radius Start: Radius End: Start Point (x): Start Point (y): Start Point (z): 0.1 0.3 0.5 0.5 0.2 End Point (x): End Point (y): End Point (z): 1.0 0.5 0.8

Polygon Section Examples

A 6-sided polygon. Center (m) 0.5 0.5 0.5 Surface normal 0 0 1

An 4-sided, tilted polygon. Center (m) 0.5 0.5 0.5 Rotation (rad) 0 0 0.5

An 3-sided, tilted polygon. Center (m) 0.5 0.5 0.5 Surface normal 0 0.5 1

X Y Z

X Y Z

X Y Z

Radius = 0.4m, Rotation = 0 rad

Side 1 = 0.5m, Side 2 = 0.3m

Radius = 0.3m, Rotation = 0 rad

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EDEM Creator

Specify the Section Dynamics
Sections of geometry can be static or dynamic. Static sections remain in a fixed position during the course of a simulation whereas static sections move. Sections can move under translation or rotation. Sections are strain limited, that is, they will not move when a force provided by another element is applied to it: For example a section will not move when another section comes into contact with it or when a particle bounces off it. Sections pass through each other when they come into contact. Specifying a Translation
? ? ? ?

Select the section from the Sections drop-down list. Go to the Dynamics tab. Click the + button then type a name for the dynamic in the Name field. Set the dynamic type to Linear or Sinusoidal Translation (used to model oscillating motion). Translation Linear Set-up
? ?

Set the Start time and End time. This determines the points in the simulation at which the motion will begin and end. Set the Initial velocity of the section in each direction. This determines the speed and direction the section will start moving in the specified start time. Specify the Acceleration of the section. Acceleration can be set to 0. Set the Start time and End time. This determines the points in the simulation at which the motion will begin and end. Set the distance (also known as the amplitude) of the oscillation in each direction. Specify the frequency of the oscillation. Specify the oscillation offset: For example, two sections with identical oscillations offset by 180° will travel in opposite directions.

?

Sinusoidal

? ? ? ?

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EDEM User Guide Specifying a Rotation
? ? ? ?

Select the section from the Sections drop-down list. Go to the Dynamics tab. Click the + button then type a name for the dynamic in the Name field. Set the dynamic type to Linear or Sinusoidal Rotation (used to model oscillating motion). Rotation Linear Set-up
? ?

Set the Start time and End time. This determines the points in the simulation at which the rotation will begin and end. Set the Initial velocity of the section in each direction. This determines how fast and in what direction the section will start rotating at the specified start time. Specify the Acceleration of the section. Acceleration can be set to 0. Specify the point of action (the center of the rotation). If the geometry section is also moving under a translation, select the Moves With Body option to update center as the section moves. This will ensure that the center of the rotation remains in the same relative position to the geometry section. Set the Start time and End time. This determines the points in the simulation at which the motion will begin and end. Set the angle of the oscillation in each direction. Specify the frequency of the oscillation. Specify the oscillation offset. Specify the center of the rotation. If the geometry section is also moving under a translation, select the Moves with body option to update center as the section moves. This will ensure that the center of the rotation remains in the same relative position to the geometry section.

? ?

Sinusoidal

? ? ? ? ?

Turning a Section into a Particle Factory
Particle factories are used to define where, when and how particles appear in a simulation. Any virtual surface or volume (physical or virtual) can be turned into a particle factory. See Particle Factories on page 32 for more details.

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EDEM Creator

Importing Geometry Sections
Rather than defining sections using EDEM, geometry can be imported from a range of other packages. Files of the following types can be imported: IGES, STEP, ProE, EDEM geometry, FLUENT Mesh (Note .msh files are always imported as surfaces), STL, ACIS, Parasolid. 1. Click the Import button in the Sections area of the Geometry tab. 2. Navigate to the file to import then click Open. If applicable, the Geometry Import Parameters dialog is displayed. a) Choose to import as a quality or curvature mesh. ? ? A quality mesh is usually made up of equilateral facets. It often contains more facets compared with a curvature mesh. A curvature mesh usually matches the contours of a body well, but is often made of non-equilateral facets.

b) Set the facet options, depending on the method you selected. Set facet sag and facet length to a percentage of the model diameter, or use the default values. Click OK. 3. The Import Options dialog is displayed. a) Select the unit of measurement the geometry is measured in. b) Tick the Merge Sections checkbox to merge separate geometry sections into one single section. See also Merging Geometry Sections below. 4. Click OK. Once imported, the geometry is displayed in the Viewer. Each section is listed in the section drop-down list. 5. Complete the Details and Dynamic sections as before. There is no box/cylinder/polygon tab available for any imported section.

Merging Geometry Sections
Geometry sections can be merged at any time. 1. Select the section to merge into. The merged sections inherit this section name. 2. Click the Merge button in the Sections area of the Geometry tab. 3. Select the geometry sections to merge then click OK.

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EDEM User Guide

Particle Factories
Creating Particle Factories
Particle factories are used to define where, when and how particles appear in a simulation. Any virtual surface or volume (physical or virtual) can be turned into a particle factory. Particles, based on the prototype particles previously defined, are then created on or in the specified section. A model can have an unlimited number of particle factories. Click on the + button to create a new factory. Click the copy button to create a copy of the currently selected factory. Click the Import button to import your own custom particle factory (for details on custom particle factories, refer to the EDEM Programming Guide). There are two types of particle factory: static and dynamic.
Static Factories

Static factories produce particles at a specified time. Simulation is paused during particle creation. Parameter Number of particles Details A static factory can either:
? ?

Produce a specified number of particles or

Start time Max attempts to place particle

Create as many particles as will fit on or in the chosen geometry section. If the random particle position option is chosen you must also specify the Packing Fraction. Set the time at which particle creation will take place. If the random particle position option is selected, the maximum number of attempts to place the particle must also be defined. During simulation, EDEM will attempt to place particles in a random position in or on the specified section. If placing the particle in that position would cause an overlap with any other physical element in the model, the simulator will abandon the position and try to find another. It will attempt this for the specified number of times for each particle.

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EDEM Creator
Dynamic Factories

Dynamic factories produce particles over the course of a simulation. Simulation continues as the particles are created. Parameter Number of particles Details Set the total number of particles to be created by the factory. If the Unlimited option is selected, the factory will attempt to create particles continuously from the specified start time until the end of the simulation. Note that the Simulator will continue to create particles even after a section surface or volume is full. This will cause the rest of the simulation to slow down. Define the number of particles the simulator will attempt to place in or on the section every second. Set the time at which particle creation will start. During simulation, EDEM will attempt to place particles in a random position in or on the specified section. If placing the particle in that position would cause an overlap with any other physical element in the model, the simulator will abandon the position and try to find another. It will attempt this for the specified number of times for each particle.

Creation rate Start time Max attempts to place particle

Initial Conditions

The initial conditions area is used to specify the section to use as a factory, and to define the starting conditions of the particles it creates. Parameter Section Options Select the section that will become a particle factory. Only suitable sections are listed. Any virtual surface or volume (physical or virtual) can be turned into a factory. A factory can produce one or two different types of particle. Particle types must first be defined in the Particles pane. The options are as follows:
? ?

Type

Fixed. One fixed particle type. Binary. Two types of particle can be used. This option is useful when creating binary lattices.

Size

The standard size of any particle type is defined in the Particles pane; however factories can produce particles with a distribution of sizes based upon this standard size. All sizes are defined as factors of the originally specified size. The options are as follows:
? ?

Fixed. All particles are of an equal size: For example, if the size ratio is set to two, all particles will be twice the standard size. Random. Particles are randomly sized within a set size range: For example if the minimum size is set to 0.5 and the maximum to 1.5, particles no smaller than half and no bigger than one a

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EDEM User Guide

Parameter

Options half times the size the standard size will be produced.
?

Normal distribution. The particle sizes have a normal distribution. The average (mean) particle radius or volume and the standard deviation must be defined. The mean and standard deviation should both be normalized, that is, the mean is the ratio of the mean to the input particle radius or volume and similarly for the standard deviation. Use the capping options to cap the maximum and minimum particle sizes. Log-normal distribution. The particle sizes have a log-normal distribution. The average (mean) particle radius or volume and the standard deviation must be defined. The mean and standard deviation can be defined using the logarithmic scale or linear scale. With a logarithmic scale, the input values are exponential functions. For example, a mean value of 1 in the logarithmic scale denotes an actual scaling of 2.718 in the linear scale. Note that the mean and standard deviation should both be normalized i.e. the mean is the ratio of the mean to the input particle radius or volume and similarly for the standard deviation.

?

Position

When particles are created they are placed on or in the specified section. Particles are never created on top of one another. When a factory tries to create a particle it will repeatedly attempt to find free space in which to place it. During simulation the Simulator will display a red-lattice version of your particles at each potential position (if the auto-update option has been selected). If the position is valid the particle will be drawn in full. The position of the particles can be defined as follows:
?

Random. Particles are positioned randomly or through a random walk. If the factory is static the Packing Fraction must also be defined.
? ?

Random. Particles are positioned randomly. Random Walk. Particles are positioned using a random walk. Particles are placed one after another along a path in discrete steps of a defined length. This length is a factor of the maximum extent of the particle. The maximum angle that can be turned at each step is also defined.

?

Cubic. Particles are created in a simple cubic lattice. Select the Display Lattice option in the Viewer controls pane to show the lattice in the Viewer. BCC lattice. Particles are created in a body-centered cubic lattice. It is defined in the same way as a cubic lattice. FCC lattice. Particles are created in a face-centered cubic lattice. It is defined in the same way as a cubic lattice.

? ?

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EDEM Creator

Parameter Velocity

Options Particles can be given a velocity at the time of creation. The options are as follows:
? ? ?

Fixed. All particles have the same fixed velocity. The velocity must be defined as a vector. Random. Each particle is given a velocity at random within a defined range. Normal distribution. The particle velocities have a normal distribution. The particle direction, mean velocity and the standard deviation must be defined. Linear distribution. The particles are given velocities that fall on an arbitrary arc drawn between two defined velocity vectors.

?

Orientation

Spray. The particles are formed in a conical spray. The spray direction is defined as a velocity vector. The angle is the angle of maximum deviation from the normal. The mean velocity and standard deviation must also be defined. Particles can be given an orientation at the time of creation. This is useful for non-spherical particles. The options are as follows:
? ?

Fixed. All particles have the same fixed orientation. The orientation is defined in an orientation matrix. EDEM automatically adjusts the values you enter to maintain an orthogonal orientation matrix.

Angular velocity

? Random. Each particle is given a random orientation. Particles can be given an angular velocity at the time of creation i.e. they will be spinning when placed on or in the specified section. The options are as follows: ? ? ?

Fixed. All particles have the same fixed angular velocity. The velocity must be defined as a vector. Random. Each particle is given an angular velocity at random within a defined range. Normal distribution. The particle angular velocities have a normal distribution. The particle direction, average angular velocity and the standard deviation must be defined. Linear distribution. Particles are given angular velocities that fall on an arbitrary arc drawn between two velocity vectors.

?

35

EDEM User Guide Charge If you have purchased the Electrostatics feature, particles can be given a charge at the time of creation. The options are:
? ? ?

Fixed. All particles have the same positive or negative charge. By default, particles start with zero charge. Random. Each particle is given a random charge within a defined range.

Custom Particle Property

Normal distribution. The particle charges have a normal distribution. The particle mean charge and standard deviation must be defined. If you have defined any custom properties, particles can be given a custom property value at the time of creation. Options are:
? ? ?

Fixed. All particles have the same fixed value. Random. Each particle is given a value at random within a defined range. Normal distribution. Custom property values have a normal distribution. The mean and standard deviation must be defined.

Table 2-1: Table of particle parameters

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EDEM User Guide

EDEM Simulator
About the EDEM Simulator
The EDEM Simulator is the discrete element solver used to carry out your simulation. Select the contact model and watch as your model is processed.

Simulator Pane Viewer Viewer Controls Solve Report Toolbar Menu Bar

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EDEM User Guide

Simulator Pane
The Simulator Pane is where you set the time step, simulation time, and grid options.

Viewer
The Viewer displays 3D representations of your particles and geometry. The rotation, position and zoom factor of the Viewer are controlled using the mouse. The simulation start/stop button and simulation progress bar are just below the viewer. See Starting and Stopping a Simulation on page 43 for more details.

Viewer Controls (Simulator)
The Viewer Controls are used to determine how items are displayed in the Viewer.
?

Current time. The current simulation time is displayed. Simulation can be stopped and any previous time step viewed. Simulation can be restarted from any previous time step. Display grid. Enable or disable the display of the domain grid. Auto update. If this option is selected the Viewer will update for every iteration. Simulation will be slower if this option is selected, however the slow down can be minimized by lowering the particle detail. Refresh Viewer. When the auto update option is off click the Refresh Viewer button to refresh the Viewer display. Camera. Choose to display the Viewer from a number of standard angles. A custom view can be created by positioning your model as desired and then pressing the + button. This new view is then stored in the list. If you change the angle manually you can return to the currently selected angle by clicking the reset button. Display mode. Used to configure the display of all the geometry in the Viewer. Choose between filled, mesh or points style display. Opacity. Used to configure the opacity level of all the geometry in the Viewer.

? ?

? ?

? ?

Solve Report (Simulator)
The Solve Report is an .html page that displays detailed information about your model. The information displayed differs between the Creator, Simulator and Analyst. Right click anywhere within the Solve Report and choose Save to save the information in an .html file.

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EDEM Simulator There are six sections in the Simulator’s Solve Report:
Simulation ? ? ? ? ?

Status. Whether the simulation is processing or stopped. Current time. Time into processing. Time step. The time step used by the model as detailed in the Simulator. Estimated total computation time. The estimated total time to complete the simulation. Elapsed computation time. Time elapsed since the simulation started (excluding pauses).

Grid cells ? ? ? ?

Status. Whether the simulation is allocating grid cells or grid cells have been initialized. Total number. The total number of grid cells in the model. Side length. The dimensions of grid cells as specified in the Simulator. Created. The number of grid cells created.

Particles ? ? ? ?

Total number. The total number of particles in the model. Total removed. The total number of particles removed from the model: For example, particles that move beyond the domain boundaries. Minimum speed. The speed of the slowest particle in the model. Maximum speed. The speed of the fastest particle in the model.

Geometry Section ? ?

Speed. The speed of the geometry section. Number of particles in contact. The total number of particles in contact with the geometry section at the current time step.

Energy ?

? ? ? ? ?

System Energy. The total energy in the model at the current time. It is the sum of the kinetic energy, potential energy and the energy in any contacts taking place. It should be equal to the total energy gained by creating particles plus the total energy gained by geometry movement minus the energy lost through contacts minus the energy lost by removing particles. Kinetic & Potential Energy. The total kinetic and potential energy in the system. Total lost by removing particles. Total energy lost by removing particles from the domain. Total lost through contacts. Total energy lost by contacts between elements. Total gained by creating particles. Total energy gained. Total gained by geometry movement. The total energy gained through the movement of sections of geometry.

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Factory ? ? ? ? ? ?

Status. The current factory status. Total particles created. The number of particles accepted and currently being generated. Creation rate. The particle creation rate as specified in the Factories pane. Total particles regenerated. The number of particle creation attempts. Total particles failed. The number of particles that could not be placed once the Max attempts to place particle is reached. Total particles accepted. The number of particles accepted in the grid.

Simulator Toolbar
Icon Name Creator Simulator Analyst New Open Save Help Description Click to switch to the Creator. Click to switch to the Simulator. Click to switch to the Analyst. Click to start a new model. Click to open an existing model. Click to save any changes made to Simulator settings. Click to view the online help.

Simulator Menu Bar
File Menu ? ? ? ? ?

Save. Save any changes made to Simulator settings. Creator. Select to switch to the Creator. Simulator. Select to switch to the Simulator. Analyst. Select to switch to the Analyst. Quit. Quit EDEM.

Options Menu

The Simulator’s Options Menu is the same as for the Creator.
Tools Menu

The Simulator’s Tools Menu is the same as for the Creator.

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EDEM Simulator

Simulator Settings
Rayleigh Time Step
The time step is the amount of time between iterations (calculations) in the Simulator. It is a fixed time step that remains constant throughout the course of a simulation. The value is presented as both the actual time step (s) and as a percentage of the Rayleigh time step. The smaller the time step, the more data points are produced. A large number of data points produce results with a very fine level of detail; however the simulation time will be larger due to the increased number of calculations that take place. Refer to Appendix C: Estimating Simulation Time for more information on time steps.
Choosing a Time Step

If the time step is too small, the simulation will take a long time to run. If the time step is too large, particles can behave erratically. For example, the figure below shows two particles moving towards each other. At time step 1 they are some distance apart. The particles are moving towards each other at some speed, and when their positions are recalculated at time step 2 they are apparently over-lapping. The particle forces and energies are recalculated at this point, however these values are very large due to the apparent overlap; this supplies each particle with a very large and incorrect velocity, and they move off erratically at time step 3. Subsequently, these particles can come into contact with other elements in the system, often causing an 'explosion' of incorrectly moving elements. To recover from such an event, setting particle limits from the Creator’s Particles tab.

Time step 1

Time step 2

Time step 3

Simulation Time
The simulation time is the amount of real time your simulation represents. The number of iterations required to complete a simulation of a defined time using the defined time step is displayed at the bottom of the Simulation Time section. For example, 5e+05 iterations are required to produce one second of simulation with a time step of 2e-06.
Writing out Data Points

Data points are the points at which data is collected from the simulation for analysis. It is not usually necessary to write a data point for every iteration in a simulation. Doing this will usually result in a slow simulation and a very large amount of data being collected: For example, a 1s simulation with a time step of 2e-06 that wrote out data for each iteration would result in 500,000 data points.

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EDEM User Guide

Grid
Select the Display Grid option to display the grid in the Viewer. The main computational challenge in DEM simulation is the detection of contacts. By dividing the domain into grid cells, the simulator can check each cell and analyze only those that contain two or more elements (and therefore a possible contact), thus reducing processing time. The results achieved by a simulation are not affected by the number of grid cells, only the time taken to reach them. In simple terms, the simulator works as follows: 1. The grid is drawn, dividing the domain into cells of a specified size. 2. Active cells (those containing two or more elements) are identified and are checked for contacts. 3. Forces on elements are calculated. 4. Elements are repositioned as a result of any force acting upon them. 5. Active cells are again identified and the process repeats. As the grid length decreases, fewer elements are assigned to each grid cell and contacts become easier to resolve. The fewer particles per grid cell, the more efficient the simulator. If there is no more than one particle in each grid cell then no contact detection needs to take place so the simulation will progress faster. The idealized length of a grid cell is 2Rmin where Rmin is the minimum particle radius in the simulation. If this results in more memory allocation than available, reduce the number of grid cells to avoid the time-consuming swapping of memory to the hard disk.

Collision Detection
EDEM uses the grid to detect collisions. The domain is split into grid cells whose dimensions are approximately that of the particle diameter. Each particle and geometry element is then assigned to one or more grid cell based on its position. Once this is complete for all particles and elements, each grid cell is investigated to see whether it contains more than one object. Any grid cell containing more than one object is analyzed further to check for objects in contact with each other. To do this, EDEM compares the distance between the center of the spheres and the known radii of the spheres.

Storing Collision Data
During a simulation data can be recorded about both contacts and collisions.
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Contacts are the impacts occurring between elements at data write-out points. In other words, the contact is in progress when the write-out takes place. The contact has an associated force, position and so on - these are discrete values. If two elements stay in contact with each other for some time e.g. over 4 write-out points, four contacts will be stored and each of these may have a different force, position and so on. Collisions are complete impacts. When two elements collide it will register as one collision, regardless of how long the elements stay in contact for. Data is collected for the duration of the collision e.g. total energy loss, min/max/average

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EDEM Simulator normal force data and so on. Collisions may occur in-between write-outs and never register as contacts. EDEM records all contact data as standard. To record collision data, enable Track Collisions. Storing collision data will significantly increase memory usage. Collision data is stored in memory until it is written out at the rate specified in the Simulator. If a large number of collisions are occurring and the write out frequency is too low, the amount of data being stored in memory will become very large and use up all memory resources. To minimize this, be sure data is written out frequently.

Processors
The number of processors available to the Simulator depends on: ? ? ? The number of physical processor cores in your system The number of processor keys you have purchased The number of processor keys in the pool of available licenses

Select the required number of processors from the Number of Processors pulldown. When you start a simulation, EDEM reserves the requested number of keys from the license pool (if available). Note: If your BIOS has hyper-threading enabled, EDEM may report the number of processors incorrectly. Be sure to take into account the number of physical cores in your system.

Starting and Stopping a Simulation
The start/stop button is used to start and stop the simulation:

The current simulation time is shown in the top left corner of the Viewer Controls pane. All previous time steps are also listed. You can stop and start the simulation from any time step (current or previous) using the start/stop button. Simulation can also be stopped using the keyboard shortcut Ctrl + Shift + K. Starting a simulation finalizes any tentative custom particle properties. Starting a simulation also reserves processor keys from the license pool. If there are not enough keys currently available, EDEM prompts you to decide whether to stop or continue with fewer processors (depending on how many processor keys are available). Stopping a simulation saves simulation data (this may take a while, depending on the size of the simulation) and returns reserved processor keys to the pool of total keys available to all users.

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Reducing Simulation Time
The following can help to reduce processing time.
? ? ?

Close the Data Browser. Turn off the auto-update option. If this option is selected, processing time can still be reduced by lowering the particle detail. Reduce the grid size.

Simulation Parameters
The time taken by the software to perform a single iteration, titeration, is affected quite significantly by the simulation parameters. An obvious parameter is the number of elements (particle surfaces and geometry elements) to be simulated. EDEM has a nearlinear dependence on the number of elements up to 20,000 (at which point memory considerations can affect the simulation speed). Contact detection is the most significant overhead to an EDEM simulation and extra parameters such as geometry dynamics and contact models typically have a secondary effect. However, it is worth noting that Particle Factories use contact detection to place their particles so a high number of factories, or factories within regions of space with medium to high particle volume fractions will significantly affect the simulation speed.

The Data Browser
The data browser (solve report) at the bottom of the EDEM window is constantly updated with particle details. To speed up the simulation, close the data browser or turn off the display of factory information. You can re-open the browser by right-clicking anywhere on the EDEM toolbar and selecting Data Browser from the pop-up menu. The display of factory information in the Data browser can be turned on and off using the controls in the Simulator's Tools > Solve Report menu.

The Auto-update option
When the auto-update option is selected (from the Viewer controls pane in the Simulator), the Viewer is updated for every iteration (time step). Potential particle positions are also drawn. Consequently simulation will be slower, however the slow down can be minimized by lowering the particle detail. The particle detail controls are used to determine the number of polygons used to create each particle. The greater the number of polygons, the better the appearance of the particle. However, if the polygon number is high it will slow down the following:
? ? ?

Simulation (if the auto-update option is selected) Animation playback in the Analyst Altering the view in the Viewer (position, rotation or zoom factor).

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EDEM Simulator

Grid size
The fewer particles per grid cell, the more efficient the simulator. If there is no more than one particle in each grid cell then no contact detection needs to take place so the simulation will progress faster. The idealized length of a grid cell is 2Rmin where Rmin is the minimum particle radius in the simulation. If this results in more memory allocation than available, reduce the number of grid cells to avoid the hugely time-consuming swapping of memory. The grid options are in the Simulator.

Domain size
The domain is the area in which simulation takes place and is illustrated by the red box in the Viewer. The size of the domain size has an effect on simulation time - the larger the domain, the longer the simulation will take to run. Use the auto-update option to automatically fit the domain around any sections of geometry defined, thus creating the smallest domain possible. Similarly if you are only interested in the activity in a particular part of your geometry, reduce the domain to fit around that area. Please note that sections of geometry should not be placed totally coincident with the edge of the domain. Particles are removed as soon as they reach the domain edge, so cannot interact with any geometry placed there. The domain options are in the Geometry pane in the Creator.

Hardware and Drivers
Earlier it is shown how titeration is affected by the amount of memory available to the software. Of equal importance is the type of memory, the processor(s) and the communication between the two. A faster processor is capable of carrying out more calculations per second and adding extra processors allows for the total computational load to be divided. DEM Solutions has good links with hardware vendors and tests are continuously under way on possible speed improvements through hardware. In addition to the hardware, maintaining up-to-date drivers can also help.

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EDEM User Guide

EDEM Analyst
About the EDEM Analyst
The EDEM Analyst is the post-processor used to examine the results of your simulation. Play back your simulation as an animation, graph your results, create a video or export data for examination elsewhere.

Tabs Pane Viewer Viewer Controls Data Browser Toolbar Menu Bar

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EDEM User Guide

Tabs Pane (Analyst)
The Tabs Pane is displayed on the left side of the EDEM window. It has five tabs: ? Model ? Coloring ? Binning ? Clipping ? Tools

Viewer
The Viewer displays 3D representations of your particles and geometry. The rotation, position and zoom factor of the Viewer are controlled using the mouse. A number of animation controls appear just below the Viewer. See Reviewing Your Simulation on page 52 for details.

Viewer Controls (Analyst)
The Viewer Controls are used to determine how items are displayed in the Viewer.
? ?

Current Time. Choose the time step displayed in the Viewer. Camera. Choose to display the Viewer from a number of standard angles. A custom view can be created by positioning your model as desired and then pressing the + button. This new view is then stored in the list. If you change the angle manually you can return to the currently selected angle by clicking the reset button. Step Factor. The step factor determines the amount of time or number of time steps the animation controls step through. For example, setting the factor to 5 (time steps) will increase the speed of the movie playback as only every fifth time step is displayed. Text. Add descriptive text to the Viewer. Click the + button and enter the text in the text field. Choose the text color using the color drop-down list. To position the text select the Position Text option and click a location anywhere within the Viewer window.

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Data Browser (Analyst)
The Data Browser is an .html page that displays detailed information about your model. The information displayed differs between the Creator, Simulator and Analyst. Right click anywhere within the Data Browser and choose Save to save the information in an .html file. There are up to six sections in the Data Browser within the Analyst: Description, General, Geometry, Particles, Contacts and Groups.

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Description

The description as defined in the Globals pane.
General ? ? ? ?

Dimensions. The number of dimensions in your domain. Gravity. Details of the gravity acting in your model as specified in the Globals pane. Materials. A list of all materials used in the model and their properties, as specified in the Materials Editor. Energy. The total energy in the model at the current time. It is the sum of the kinetic energy, potential energy and the energy in any contacts taking place.

Geometry ? ? ?

Domain. The dimensions of the domain as specified in the Geometry pane. Geometry Totals. Details of the number of elements that make up each section of geometry. Sections. Each section in the model and its properties are listed. Properties are as specified in the Geometry pane.

Particles ?

Particles. A list of each particle type used in the model and their properties. Details of each surface within the particle are also listed. Properties are as specified in the Particles pane. Factories. Details of each factory used in the model and their properties. Properties are as specified in the Factory pane. The total number of particles created by each factory is also listed. Particle totals. The total number of particles in the model at the current time. Totals for each particle type are also listed.

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Contacts ? ?

Interactions. A list of the interaction types taking place in the model as specified in the Materials Editor. Contacts. Lists the total number of contacts in progress at the current time. The contacts are broken down into contact types: For example, the number of particle A - particle B contacts or particle B - surface A contacts. The total number of collisions that have taken place during the time step are also listed.

Groups ?

Bin groups. A table of information describing the contents of each bin in a bin group. The content of the bin is specified in the Binning pane. All bin groups in your model are listed. Selection groups. All selection groups are listed. Details of all particles, geometry and contacts within each group are shown. 49

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EDEM User Guide

Analyst Toolbar
Icon Name Creator Simulator Analyst Open 3D Viewer Create Graph Help Description Click to switch to the Creator. Click to switch to the Simulator. Click to switch to the Analyst. Click to open an existing model. Click to switch to the 3D Viewer. Click to switch to the Graph Creator. Click to view the online help.

Analyst Menu Bar
File Menu ? ?

Open. Open an existing model. Export Input Deck. Export the current time step of your input deck as a .dem file. A single time step from your simulation can be exported as a .dem. Use the animation or time controls to first pick a time step. Exporting a deck in the .dem format allows it to be transferred to another location and run again using identical simulation parameters. Export Data. Export specified data for analysis. See Exporting Data on page 74 for details. Truncate Results. Remove sections of data from your model. See Truncating Data on page 80 for details. Save Image. Save a copy of the image currently displayed in the Viewer. See Working with Images on page 70 for details. Print Image. Print a copy of the image currently displayed in the Viewer. Creator. Select to switch to the Creator. Simulator. Select to switch to the Simulator. Analyst. Select to switch to the Analyst. Recent Files. A list of recently opened files. Select a file to open it. Quit. Quit EDEM.

? ? ? ? ? ? ? ? ?

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EDEM User Guide
Options Menu
Mouse Configuration

See the Creator Options menu on page 13 for details.
File Locations

See the Creator Options menu on page 13 for details.
Background

See the Creator Options menu on page 13 for details.
Units

See the Creator Options menu on page 13 for details.
Data Browser Configuration

See the Creator Options menu on page 13 for details.
Initial Timestep

Models can be loaded into the Analyst with the first or last time step appearing first.
Axis Key

Turn the display of the axis key in the Viewer on or off.
Bounding Box

Turn the display of the boundary box (marking the domain edges) in the Viewer on or off.
Show Timestamp

Turn the display of the time stamp in the Viewer on or off.
Tools Menu

The Analyst’s Tools Menu is the same as for the Creator. See the Creator Tools menu on page 14 for details.

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Reviewing Your Simulation
The Analyst is used to review and examine your simulation. A number of animation controls appear just below the Viewer. These are used to examine every iteration of your simulation. The buttons are: Jump to start Play backwards Step backward Stop Step forward Play forwards Jump to end Record animation (video)

Viewer Control Options
Camera

The camera controls are used to set the angle at which your model is displayed in the Viewer. Six angles are available by default: +X, +Y, +Z, -X, -Y and -Z. Additional custom views can also be created.
? ? ?

Position your model as desired using the position, zoom and rotation controls. Click the + button and type a name into the drop down list. The new view is stored.

Custom views can be deleted using the x button. If you alter the view click the reset button to restore the it to the select view.
Step Factor

The step factor determines the number of iterations or the amount of time the animation controls step through. For example, setting the factor to 5 iterations will increase the speed of the animation playback as only every fifth iteration is displayed. Setting the time factor to every iteration will result in a smoother but slower playback.
Time

The time control is used to jump to a particular point in your simulation.
Text

Text can be added to the Viewer.
? ? ?

Click the + button and type your message into the drop-down list. By default the text reads 'Message 1'. Set the text color using the color drop-down list. Select the Position Text option and click anywhere in the Viewer to position it.

Text can be deleted using the x button. Note: Close the Data Browser to speed up playback.

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EDEM User Guide

Model Tab
Options in the Model tab are used to configure the display of your model in the Viewer. You can enable or disable the display of geometries, particles, contacts, bonds, or selection groups (as defined in the Selection Groups section in the Analyst’s Tools tab). Note: If there are any display conflicts, the relevant control is highlighted.

Geometry
Display options can be applied to all the geometry in your model, to individual sections, or to selection groups. The options apply to the geometry or selection group selected in the drop-down lists. Once you have set the geometry options, click the Apply button.
Display by

Select Type for geometry sections or Selection Group for geometry in a selection group.
Type/Selection Group

Depending on the Display-by drop-down list, select either a geometry section, all geometry sections, or a selection group.
Properties by selection group

For selection groups, enable or disable geometry type display options for the selected selection group.
Display checkbox

Enable or disable the display of the selected section or selection group.
Display Mode

Choose between filled, mesh or point style display. The mesh option is used to display the triangular elements the section is made up of. The points option shows the vertex of each element.

Figure 4-5: Filled Geometry

Figure 4-6: Mesh Geometry

Figure 4-7: Points Geometry

Opacity

Set the opacity level from 0 (fully transparent) to 1 (opaque).

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EDEM User Guide

Particles
Display options can be applied to all particles, particles of a particular type, or particles in a selection group. The options apply to the particle type or selection group selected in the drop-down lists. Once you have set the particle options, click the Apply button.
Display by

Select Type for types of particles or Selection Group for particles in a selection group.
Type/Selection Group

Depending on the Display-by drop-down list, select either a type of particle, all particles, or a selection group containing particles.
Properties by selection group

For display by selection groups, enable or disable particle type display options for the selected selection group.
Display

Enable or disable the display of the selected particles or selection group.
Representation

Choose how to represent particles: either default, cone, vector, stream, or template. Click the Options button to set further display attributes. Option Default Description By default, particles are displayed as they were defined in the Creator.

Cone

Particles are displayed as cones. The direction, length and base width of the cone can be set to represent a variety of particle attributes.
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Direction. Represents velocity, torque, total force, angular velocity, or custom property (consisting of exactly three values) Length. Represents: velocity, total force, moment of inertia, kinetic energy, mass, rotational kinetic energy, compressive force,

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EDEM User Guide

Option

Description torque, volume, angular velocity, charge, electrostatic force, or a custom particle property.
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Base width. Can represent: velocity, total force, compressive force, torque, mass, kinetic energy, rotational kinetic energy, volume, moment of inertia, angular velocity, charge, electrostatic force, or a custom particle property.

Vector

Particle display reverts to standard spheres when EDEM cannot show particles as cones (for example, if the selected attribute has no values). Particles are displayed as vectors. The direction and length of the vector can be set to represent a variety of particle attributes.
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Direction. Can represent: velocity, torque, total force or angular velocity, or custom property (consisting of exactly three values) Length. Can represent: velocity, total force, moment of inertia, kinetic energy, mass, rotational kinetic energy, compressive force, torque, volume, angular velocity, charge, electrostatic force, or a custom particle property.

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Stream

The path of the particle is displayed as a stream with variable coloring.
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Number of Steps. Define the number of time steps the particles should be streamed for. The number indicates that the streams will be drawn for the previous n time steps up to and including the current time step. Stream All Steps. Streams are drawn across all time steps. Stream Fade. Fades the color intensity of the streams.

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Template

Particles are displayed using one of the currently imported templates.

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EDEM User Guide

Contacts and Bonds
Contacts

Contacts between different types of particle and between particles and individual sections of geometry can all be examined independently. Select Contact from the Element pulldown then use the Type 1 and Type 2 controls to choose a pair of elements. Enable the Display option to show the contacts in the Viewer. The display can represent the following attributes: ? Contact Vector ? Normal Force ? Normal Overlap ? Tangential Force Refer to Appendix D: Attribute Definitions for more information on attributes.
Bonds

Bonding between different types of particle can be examined independently. Select Bond from the Element pulldown then select the Bond State (either Intact Bond or Broken Bond). Use the Type 1 and Type 2 controls to choose a pair of elements. Enable the Display option to show the bonds in the Viewer. For broken bonds, set the distance threshold to define the distance between particles before broken bonds are no longer displayed. The display can represent the following attributes: ? Normal Force ? Normal Moment ? Tangential Force ? Tangential Moment Refer to Appendix D: Attribute Definitions for more information on attributes.

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Coloring
Use the Coloring tab to color different elements of your model in a variety of ways. Any section of geometry, particle, contact type, bond, or selection group can be colored independently.

Static Coloring Static coloring is used to set the standard color for any element: For example, a particular particle type or geometry in a selection group.
The color applies to whatever element and type or group is selected in the Select Element section. The figure on the right shows particles in three separate selection groups each colored differently.

Attribute Coloring
Attribute coloring is used to color any element of the model by a particular attribute: For example, the figure on the right shows all particles colored by velocity. The particles with the greatest velocity are colored red; those with the lowest colored blue. Choose the element to color from the Select Element section, then select the attribute to color by. The attributes and their components available for each element are listed in the table below. Refer to Appendix D: Attribute Definitions for more information. Element Particle Attributes Angular Velocity Charge Compressive force Electrostatic force Moment of Inertia Kinetic energy Mass Potential energy Rotational kinetic energy Torque Total energy Total force Components Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z

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EDEM User Guide

Element Particle

Geometry

Contact

Bond

Attributes Velocity Volume Custom property Charge Compressive force Total force Torque Velocity Contact vector 1 Contact vector 2 Normal force Normal overlap Tangential force Tangential overlap Normal force Normal moment Tangential force Tangential moment

Components Magnitude, X, Y, Z n/a Depends on number of elements n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z

Table 4-1: Attributes for Coloring Elements

A color should also be assigned for the minimum, median and maximum values. Elements will be colored depending on whereabouts in the range they fall. The value range is determined by setting the minimum and maximum attribute values. The values can be entered directly or can be read from the model by clicking the update buttons. This takes the current maximum and minimum values of the selected attribute from the model. If the auto-update options are selected these values will update according to which time step is being viewed.
Attribute Legend

Enable the Show Legend option to display a color legend in the Viewer. Select the Position Legend option then click anywhere in the Viewer to position it. The following options can be set: ? Width ? Height ? Value interval ? Alignment (horizontal or vertical) ? Title

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Binning
Binning splits the model domain into a grid. Each grid is known as a bin group and each cell is known as a bin. Binning allows data to be extracted from a particular area (bin) of your model and analyzed. Anything in or moving through each bin can be monitored. A model can contain any number of bin groups.

Figure 4-10: A Bin Group with a Highlighted Bin at the Center

Bin groups are created in the Edit Binning section. Click the + button to create a new group. Click the Apply button to apply settings and display the group in the Viewer. If you define several groups, use the Display checkbox to control which groups are shown in the Viewer.
Bin Elements

The Bin Elements section is used to determine which elements in your model are included in the bin group. By default all elements are included in the group and hence are colored green. The elements are categorized by type - particles, geometry, contacts, and bonds. Double click on any element to remove it from the group. Its listing in the Bin Elements section will turn black indicating its exclusion. The element will remain visible in the Viewer but no data regarding it will be available when the bin group is analyzed. An element can be added by into the group by double clicking on it a second time.
Bin Group Area

The Group Area section is used to define the size and number of cells in the bin group. By default the bin group covers the entire domain, however it can be limited to a specific area. The number of bins in the group is determined by the number of bins along each axis. Empty bins (those containing no elements) can also be removed. This can help reduce the amount of time it takes to extract data, as less cells have to be analyzed. If the bin becomes non-empty at a different time step it is automatically added back into the group.

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Bin Group Queries
A query is used to define a single element attribute: For example, particle velocity, total force on a geometry section or number of collisions. The query information can then be displayed in the Viewer and in the Groups section in the Data Browser. Bin cells can also be colored according to the results of the query. To define a query click the Edit Group Queries button. The Binning Data dialog will appear.

Figure 4-11: Binning Data Dialog

Select an element and attribute from the list. The elements are categorized by type: particle, geometry, bond and contact. Refer to Appendix D: Attribute Definitions. Contacts Affects all contacts or any combinations of specific particle-particle or particle-geometry contacts. Attribute Contact vector 1 Contact vector 2 Normal force Normal overlap Number of contacts Tangential force Tangential overlap Query type Average, maximum, Average, maximum, Average, maximum, Average, maximum, n/a Average, maximum, Average, maximum, Component Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z n/a

minimum or total minimum or total minimum or total minimum or total minimum or total minimum or total

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EDEM User Guide Bonds Affects all bonds or any combinations of specific particle-particle bonds. Attribute Normal force Normal moment No. of broken bonds No. of intact bonds Tangential force Tangential moment Geometry Affects all geometry or a particular section (as specified in the Creator). Attribute Charge Compressive force Number of geometry elements Total force Torque Velocity Particles Affects all particles or a particular particle type (as specified in the Creator). To cumulatively sum the number of particles over a period of time, select the 'Total over time' option. As you step forward through the simulation the total number of particles will be recorded. Cumulative particle totals for bin groups only works when stepping forward through your simulation: if you jump back, the totals may not be accurate. Note that particles leaving then re-entering a bin group are only counted once. Consequently, binning may not provide accurate particle counts for decks with recirculating particles. Attribute Angular Velocity Charge Compressive force Electrostatic force Moment of Inertia Kinetic energy Mass Number of particles Potential energy Query type Average, maximum, minimum or total Average, maximum, minimum or total Average, maximum, minimum or total Average, maximum, minimum or total Average, maximum, minimum or total Average, maximum, minimum or total Average, maximum, minimum or total Total-over-time checkbox Average, maximum, minimum or total Component Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a n/a n/a Query type Average, maximum, minimum or total Average, maximum, minimum or total n/a Average, maximum, minimum or total Average, maximum, minimum or total Average, maximum, minimum or total Component n/a n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Query type Average, maximum, Average, maximum, n/a n/a Average, maximum, Average, maximum, Component Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z

minimum or total minimum or total

minimum or total minimum or total

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Attribute Rotational kinetic energy Torque Total energy Total force Velocity Voidage Volume Custom property

Query type Average, maximum, minimum or total Average, maximum, n/a Average, maximum, Average, maximum, n/a Average, maximum, minimum or total minimum or total minimum or total minimum or total

Component n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a Depends on number of elements

Average, maximum, minimum or total

Use the Type/Section control to choose the section (for geometry elements) or type of element the information will be displayed for: For example, an attribute relating to particles of type A, a particular section of geometry or a contact between two specific particle types. The Query type option is used to determine the type of data displayed. Choose from average, maximum, minimum or total: For example the average velocity or the maximum force. This option is only available for certain element attributes (see the tables above for details). Next select the component of the attribute you are interested in. Choose from Magnitude, X, Y, Z component: For example, the X component of the particle velocity or the magnitude of the normal force in a surface-surface contact. This option is only available for certain element attributes. If applicable, select the Specify range option to constrain the data collected to a particular value range: For example, particle velocities between 1m/s and 10m/s. Click the Add button once the query has been fully defined. Multiple queries can be created and added to the list. All queries are automatically added to a table in the Groups section of the Data browser. Click on a query and select the Display On-screen button to show the results of the query next to each bin in the Viewer. Once you have created the bin group and defined its queries, click the Apply button to display the query results.

Figure 4-12: A Bin Group with query results (number of particles) displayed on-screen.

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Coloring Bin Groups
Bins can be colored in one of two ways: Highlighting individual bins, or coloring all bins by a specific query.
Highlighting a bin ? ? ?

Click the Group Coloring button. Select the Highlight Bin option. Choose a bin to highlight from the drop-down list. Only one bin can be highlighted at a time.

Coloring by query

Bin groups can be colored according to any pre-defined query: For example, bins could be colored by the number of collisions taking place in them, or by the average speed of the particles they contain.
? ? ? ?

Click the Group Coloring button. Select the Bin Coloring option. Choose a query from the drop-down list. Set the value range. This is determined by setting the minimum and maximum query values. The values can be entered directly or can be read from the model by clicking the update buttons. This takes the current maximum and minimum values of the selected query. If the auto-update options are selected, these values will automatically update according to the time step being viewed. Bins will then be colored depending on whereabouts in the range they fall. The colored used are fixed: From blue (minimum) through green to red (maximum). Select the Legend option to display a color legend in the Viewer. Use the opacity option to vary the opacity of the bin coloring.

? ?

Figure 4-13: A bin group colored by average particle velocity. Bin cells have an opacity of 0.2.

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Clipping
Clipping is used to remove ('clip') areas of the model that are not currently of interest. A model can be clipped in three ways - using planes, slices or the domain boundaries. A clip group is a collection of one or more planes, slices or domain boundaries (though it can only contain clips of one type). A model may have any number of clip groups: For example, the model of a pipe may have two clip groups, one containing different slices of the pipe and another containing an area of pipe constrained by a number of planes. Create a clip group by clicking the + button, then choose the clipping type from the Active Sets drop-down list. The planes, slices or boundaries can then be defined in the lower half of the Clipping Elements section. The top half of this section contains the list used to determine which elements within your model are affected by the clipping group: For example, you may wish to only clip the geometry and leave the particles intact. By default all elements are included in the group and hence are colored green. The elements are categorized by type - particles, geometry, contacts, and bonds. Double click on any element to remove it from the group. Its listing will turn black indicating its exclusion. An element can be added into the group by double clicking on it a second time. The figure below shows a model of a pipe where geometry has been included in a slice and particles have been excluded.

Figure 4-14: Sliced pipe

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Planes
A planes clipping group can contain up to six individual planes. Choose a plane from the Elements drop-down list in the Clipping Elements section. The plane is then defined by its orientation and its distance from the center of the model. The section of the model that falls on one side of the plane will be clipped from the model. Simply negate the orientation of the plane to switch which side of the model is removed. The Visual Representation option can be used to display a preview of the plane in the Viewer. Select the Enable Plane option to activate the plane and clip a section from the model.

Figure 4-15: A Model Before Clipping

Figure 4-16: A Model After Plane Clipping

Slices
A slices clipping group can contain up to three individual slices. Choose a slice from the Elements drop-down list in the Clipping Elements section. The slice is then defined by its orientation, distance from the center of the model and depth. The section of the model that falls outside the slice will be clipped from the model. The Visual Representation option can be used to display a preview of the slice in the Viewer. Select the Enable Slice option to activate the slice and clip an area of the model.

Figure 4-17: A Model Before Clipping

Figure 4-18: A Model After Slice Clipping

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Domain Boundaries
Each side of your domain can be used to clip your model in a Domain Boundaries clipping group. Choose a side from the Elements drop-down list in the Clipping Elements section and the select the Enable Slice option to clip the area of the model outside of the domain on that side.

Figure 4-19: A Model Before Clipping

Figure 4-20: A Model After Clipping

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Tools Tab
Selection Groups
Selection groups are similar to bin groups. However, instead of allowing you to monitor any element passing through a particular area (bin), selection groups are used to select and track particular elements wherever they move within the domain. You can then display, color, graph or export data based on these groups. Selection groups are created in the Tools tab.
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Click the + button to create a new group. Select the Enable Selection option. This activates the selection group functionality. Move the pointer into the Viewer. Press the Ctrl key and drag the pointer to draw a selection box.

All elements captured by the box will be part of the selection group. If an element is not displayed in the Viewer (after being turned off using the controls in the Models tab) it will not be captured by the selection box. All selected elements are highlighted in orange. Additional selection boxes can be drawn to add further elements to the group. All captured elements are listed in the Selected IDs list. Double-click on any element in the list to remove it from the group. It will no longer be highlighted in the Viewer. Additional individual elements can be added by double-clicking on them within the Viewer window. Select the Display in data browser checkbox to add information on elements in the selection group to the Groups section within the Data browser.

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Ruler
The ruler is used to measure the distance between elements in the Viewer. The ruler is created in the Ruler tab in the Tools tab. Select the Enable option to activate the ruler and the Display coordinate option to display the coordinate of the end of each ruler.
Points

The radio button in the Points section are used to determine which end of the ruler is being defined in the Define Point section.
Define Point

The coordinates of each end of the ruler are defined in this section. The distance between the defined points is shown at the bottom of the pane and alongside the ruler in the Viewer. The points can each be defined manually or automatically. To measure between particular elements in your model, select an element from the Selected IDs list in the Selection Groups section. Elements are added to this group using selection groups. If that element is geometry the Use Selected Item control can be used to set the ruler to its center or one of the three nodes. If a particle is selected, the ruler can be set to its center. Repeat the process to determine the other end point of the ruler.

Protractor
The protractor is used to measure the angle between elements in the Viewer. The protractor is created in the Protractor tab in the Tools tab. Select the Enable option to activate the protractor and the Display coordinate option to display the coordinate of the end of each ruler.
Points

The radio buttons in the Points section are used to determine which of the protractor points is being defined in the Define Points section.
Define Point

The coordinates of the protractor start point, end point and axis (center) are defined here. The angle defined by the protractor is shown at the bottom of the pane and in the Viewer.

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EDEM User Guide The points can each be defined manually or automatically. To measure between particular elements in your model, select an element from the Selected IDs list in the Selection Group section. Elements are added to this group using selection groups. If that element is geometry the Use Selected Item control can be used to set the protractor point to its center or one of the three nodes. If a particle is selected, the point can be set to its center. Repeat the process to determine the other points of the protractor.

Scale Grid
The scale grid is a visual aid used to indicate the scale of your model. A grid can be added to each side of the domain (+X, +Y, +Z, -X, -Y and -Z). The number of intervals in each grid is also specified. The coordinates of each vertex and the length of each edge are shown. The figure below shows a model with 10 interval +X and +Y grids displayed:

Figure 4-21: Example Model with Scale Grid

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Saving Images
Full-color images can be exported at any time. You can export the image of a single time step or of a range of time steps.

Saving a Single Image
The image displayed in the Viewer can be exported and saved as a .png (table network graphic) or .bmp (bitmap). 1. Use the animation controls to choose the image you wish to export. 2. Use the camera controls to set the angle. 3. Use the controls in the Options menu to turn on or off the display of the axis key, bounding box or timestamp. Increase the particle detail to improve the appearance of particles. 4. Select Save Image from the File menu. The Save Image dialog will appear.
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Select Filename. Set the file name and save location. Screen Grab. If this option is selected, the image exported will be the same dimensions as the Viewer. Width. Set the image width if the screen grab option is not selected. Height. Set the image height if the screen grab option is not selected.

Saving Multiple Images
To save a range of time steps: 1. Use the animation controls to choose the first image in the range and display it in the Viewer. Images will be exported from this point onward. 2. Set the step factor in the Viewer controls pane. This determines how often an image is exported: for example every fifth time step or every 0.0001s. 3. Use the controls in the Options menu to set the axis key, boundary box and time stamp. Increase the particle detail to improve the appearance of particles. 4. Click the blue record animation button in the viewer. The Export Images/Video dialog is displayed.
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Export Format. Set the export format to Images. Filename. Set the base file name and save location. Each image will be given the base name plus a numeric suffix. Frame Width. Set the width of each image. For example, 640 pixels. Frame Height. Set the height of each image. For example, 480 pixels. Set to Screen Size. Click the screen grab button to set the width and height to match the screen size. The image exported will be the same dimensions as the Viewer.

5. Click OK. The record animation button turns red: 6. Use the animation controls to play or step through the simulation. 7. When finished, click the record animation button again to stop recording.

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Creating Videos
EDEM can export videos as AVI, WMV (Windows Media Video), or EnSight Video files. You can specify encoding quality, frame rates and which compressor (codec) to use. A video can contain multiple display modes (for example, change the camera angle and particle representation halfway through the video) and even contain different simulations in the same video.

Prepare to Record a Video
1. Use the animation controls to select a start point. The video will be exported from this point onward. 2. If necessary, set the step factor in the Viewer controls pane. 3. Use the controls in the Options menu to set display of the axis key, boundary box and time stamp. Increase the particle detail to improve the appearance of particles. 4. Click the blue record animation button in the viewer. The Export Images/Video dialog is displayed:

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Video Configuration
Export Format

Set the export format to either EnSight Video, AVI Video, or Windows Media Video. ? Select EnSight Video to save the video as a .evo file. The video can then be viewed using CEI’s EnVideo, or edited using EnVe. ? Select AVI Video to save the video as a .avi file. Save your video as an AVI when you want to use a particular codec or when you need a high degree of video configuration. You can use any video compressor (codec) installed on your system (for example, Cinepak, DivX, Xvid, or H.264). ? Select Windows Media Video (WMV) to use Microsoft’s video compressors. A WMV file is better suited for sharing, since it should play on any PC without the need to install video codecs. You can also set a constant bitrate, useful for streaming the video from a website.
Select Compressor

Select the compressor (codec) to use or select uncompressed to not use any compressor. The list of compressors available depends on the compressors installed on your system and on which operating system you are running EDEM. Be sure the system on which you intend to playback the video also has same compressor installed. ? For AVI Video, select a compressor then (if available) click the configure button to set any additional compressor options. ? For EnSight Video, select Motion-RLE for lossless video files or select MotionJPEG for compressed video. NOTE: DEM Solutions does not provide support for external compressors developed by third-parties. Refer to the codec’s documentation or developer’s website for assistance.
Video Options

Set the frame options and encoding quality as necessary.
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Frame Width. Set the width of the video. For example, 640 pixels. Frame Height. Set the height of the video. For example, 480 pixels. Frame Rate. Set the frame rate. For example, 25 fps. A lower frame rate decreases the size of the video. Set to Screen Size. Click the screen grab button to set the width and height to match the screen size. The video exported will be the same dimensions as the Viewer. Compression Quality. Use the slider to set the encoding quality (where available). The higher the quality, the larger the size of the video. Use Target Data Rate. Tick this checkbox to specify a Constant Bitrate (CBR). You would typically use this when you want to stream the video from a website. Force Keyframes. Tick this checkbox then set how often to write a keyframe to the video. Because video compression only stores incremental changes between frames, forcing keyframes can result in a video that is easier to fast-forward or rewind.

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Record the Video
1. Click OK. The record animation button turns red: 2. Use the animation controls to play or step through the simulation. While recording, you can change whatever is displayed in the viewer. Any changes are recorded in the video. For example, you can: ? Change the camera or move, rotate and zoom the display ? Change the display mode, opacity, and particle representation ? Modify attribute coloring and legends ? Add different labels at different timesteps ? Load a completely different simulation 3. When finished, click the record animation button again to stop recording. Use a media player (such as Windows Media Player or VLC media player) to view the saved video.

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Exporting Data
Data collected during your simulation can be exported for analysis. Data can be exported from a single time step, a range of time steps, from all elements in your model or just from a selection or bin group. Exporting data is carried out using queries. A query is used to define a single element attribute: For example, a query could be set up to extract the x-position of particles of type A in your model. Multiple queries can be grouped together under one Configuration ID and exported to a single file.

Creating a Configuration
Export data using the Export Data Dialog (File > Export Data).

1. Click on the + button to create a new Configuration ID. Multiple queries can be created within a single Configuration. In addition, multiple configurations can be created for any model: For example, one configuration may contain a number of queries relating to particles whilst another might have queries solely relating to contacts. Configurations can be edited at any point: For example, new queries added or redundant ones removed. 2. Select the output file format: Ensight (.case) or Text (.csv). For Ensight files, be sure the total number of characters (filename and directory) is not more than 72. 3. Give the configuration a title and enter a file name and location.

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General Settings
Options

Output Averages, Maximums, Minimums and Totals in Columns. This determines how data is laid out in the exported file. If this option is selected, data will be separated and extracted in unlabelled columns. The figures below both show a sample of some exported data. The data is the same in each case. In the first figure, the data is presented with this option not selected. The second figure shows it with the option selected.

Figure 4-23: Column Option Not Selected

Figure 4-24: Column Option Selected

Output Domain This option is only available when exporting data to an EnSight file. If selected, information on the domain will be exported with the data. If it is not, a new domain will be created automatically when the file is loaded in EnSight. Delimiter and Line Break If you are exporting to a text file, optionally change the delimiter to use and set whether to start a new line after X columns. By default, EDEM inserts a line break at 256 columns (the maximum allowable by Microsoft Excel).
Part Selection

This section is only active when exporting data to an EnSight file. Choose to export data on all elements in your model or just from specified ones. The elements are categorized by geometry sections and particle types. Information on contacts cannot be exported. Double click on any element to remove it from the group. Its listing will turn black indicating its exclusion. An element can be added into the list by double clicking on it a second time.
Time Steps

Data can be extracted from all time steps in your simulation or from a defined range.

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Creating a Query
Queries define what information is exported. A configuration can contain multiple queries, each of which defines one data attribute.

Figure 4-25: The Query Tab

Click on the Queries tab and click the + button to create a new query. The attributes that can be exported are listed under the element they relate to (collisions, contacts, particles or geometry). Click on any attribute to select it and then select the component of that attribute you are in interested in: For example the magnitude of a contact vector. All available attributes and their components are listed in the tables below. Next choose the geometry section or type of particle or contact you want to export data for: For example choose only collisions between certain particle types, or the force on a particular geometry section. Data can be extracted on all elements of the selected type (or geometry section) or it can be limited to just those contained within a particular bin group or selection group. This can be selected using the Selection drop-down list where all bin and selection groups that have been created are listed. Enable the Multiple Selection Query checkbox to export a separate query for each bin in a group (if defined), rather than one combined query for the entire group. The Query Type option is used to determine which data values will be exported for a particular attribute: For example, if the query has been set up to export the velocity of particles of type A you could choose to export the maximum, minimum or average velocity per time step. The following data is exported for each query type:
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Standard. The value of the attribute for every element of the selected type for each time step in the defined range: For example, the velocity of every particle at each time step. Total. The sum of the values of the attribute for every element of the selected type: For example, the total velocity of all particles per time step. The total can be calculated per time step or over the range specified in the General settings section.

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Maximum. The maximum value of the attribute across all elements of the selected type for each time step in the defined range: For example, the maximum particle velocity per time step. The maximum can be calculated and exported per time step or over the range specified in the General settings section. Minimum. The minimum value of the attribute across all elements of the selected type for each time step in the defined range: For example, the minimum particle velocity per time step. The minimum can be calculated and exported per time step or over a specified range. Average. The average value of the attribute across all elements of the selected type for each time step in the defined range: For example, the average particle velocity per time step. The average can be calculated per time step or over a specified range.

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The final option is Specify Range. This is used to specify a value range for the data exported. In other words, limiting the export to data that falls between two specified values. For example, only exporting particle velocity data for particles traveling between 3m/s and 5m/s. Further queries can be created in the same way. Once all queries have been set up, click the Export button to export your data to your specified file. Refer to Appendix D: Attribute Definitions for more information on attributes. Collision Elements Affects all or any combination of specific particles types or geometry sections. Attribute Average normal force Average tangential force Duration End time ID ID Element n Maximum normal force Maximum tangential force Normal energy loss Number of collisions Position Relative velocity Relative velocity normal Relative velocity tangential Start time Tangential energy loss Velocity of element A Velocity of element B Components n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a X, Y, Z n/a n/a n/a n/a n/a n/a n/a Query Type Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. n/a n/a n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. n/a n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max.

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EDEM User Guide Contacts Elements Affects all or any combination of specific particles types or geometry sections. Attribute Contact vector 1 Contact vector 2 Normal force Normal overlap Number of contacts Position Tangential force Tangential overlap Bond Elements Affects all or any combination of specific particles types. Attribute End time Normal force Normal moment No. of broken bonds No. of intact bonds Start time Tangential force Tangential moment Geometry Elements Affects all or any individual section (as specified in the Creator). Attribute Charge Compressive force ID Node n Position Torque Total force Velocity Components n/a n/a n/a X, Y, Z X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Query Type Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. n/a n/a n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Components n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Query Type n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. n/a n/a n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Components Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a X, Y or Z Magnitude, X, Y, Z n/a Query Type Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max.

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EDEM User Guide Particle Elements Affects all or any individual particle type (as specified in the Creator). Attribute Angular velocity Charge Compressive force Electrostatic force ID Moment of Inertia Kinetic energy Mass Number of particles Orientation Position Potential energy Rotational kinetic energy Torque Total energy Total force Velocity Volume Custom property Components Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z n/a n/a n/a n/a X, Y or Z n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a Depends on number of elements Query Type Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Avg., Total, Total over time, Min. or Max. n/a n/a n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. n/a Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max. Standard, Avg., Total, Min. or Max.

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Truncating Results
The Truncate Results option is located in the File menu and used to remove results data (time steps) from your simulation. Data can be removed entirely, or simply 'thinned out' by removing every nth result. Select File > Truncate Results. The Truncate results file dialog is displayed:

Set the Start and End Times. This defines the times steps between which you would like to remove data. Set the Step Factor. A factor can be selected from the list or a new value entered directly. This determines how often a time step in the range is removed. If the step factor is set to one, every time step will be removed thus removing all data in the specified range. If it is set to greater than one, the data in the range will effectively be 'thinned out'. The greater the step factor, the less data is removed. By default the selected data will be truncated from the current input deck. However, if the Create New File option is selected, a copy of the file is created and the data is deleted from it, leaving the current file intact. If this option is selected a new input deck is created.

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Graphing
Creating Graphs
Data collected during your simulation can be graphed in a number of ways. Select the Analyst then switch between 3D Viewer and graph mode using the toolbar buttons:

Figure 4-26: The 3D Viewer and Graph Buttons

When you select graph mode, the Graph tab replaces the standard Tabs pane and the graph is displayed in the Viewer. The Graph pane has four individual tabs, one for each type of graph:
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Histogram Line Graph Scatter Plot Pie Chart

Note: Only one graph of each type can be created at any one time.

Creating a Histogram (Bar Chart)
A histogram is a graphical display of tabulated frequencies. For example, the figure below is a histogram which shows the number of particles traveling in particular velocity ranges. A tabular version of the data is also included.

Figure 4-27: Data Showing the Distribution of Particle Velocities

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Selecting the Elements to Graph
The Select Element section is used to determine which elements to collect data from. Choose the group or type of elements you are interested in. Group Particle Geometry Contact Collision Bond Type All or any individual particle type (as specified in the Creator) All or any individual section (as specified in the Creator) All or any combination of specific particle types or geometry sections All or any combination of specific particle types or geometry sections All or any combination of specific particle types

Configuring the X-Axis
Click on the X-axis tab then select the attribute and component to plot on the x-axis. The attributes available in the list will depend on the elements previously selected. The table below shows the attributes and components available for each element. Refer to Appendix D: Attribute Definitions for more information on attributes. Element Particle Attribute Angular velocity Charge Compressive force Distance Electrostatic force Kinetic energy Mass Potential energy Rotational kinetic energy Time Torque Total energy Total force Velocity Volume Custom property Time Components Magnitude, X, Y, Z n/a n/a Define reference object* Magnitude, X, Y, Z n/a n/a n/a n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a Depends on number of elements n/a

Geometry

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Element Contact

Collision

Bond

Attribute Contact vector 1 Contact vector 2 Distance Normal overlap Normal force Tangential force Tangential overlap Time Average normal force Average tangential force Distance Duration Maximum normal force Maximum tangential force Normal energy loss Number of collisions Relative velocity Relative velocity normal Relative velocity tangential Tangential energy loss Time Total energy loss Velocity element A** Velocity element B Normal force Normal moment Tangential force Tangential moment Time

Components Magnitude, X, Y, Z Magnitude, X, Y, Z Define reference object* n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a

* If the attribute is set to Distance you must define a point or plane from which the distance is measured. When distance is selected the Define Reference Object section of the pane will be activated. Choose Point or Plane and define its position and, for a plane, its distance from the origin. ** The velocity of the first element in the collisions. Similarly for Velocity element B.

The x and y axes are related. The attribute you choose to measure on the x-axis will limit those available to measure on the y-axis. Similarly if the y-axis is configured first the attributes available on the x-axis will be limited.

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Configuring the Y-Axis
Click on the Y-axis tab and select the element attribute and component to be plotted on the y-axis. The attributes available in the list will depend on the elements previously selected and the attribute being measured on the x-axis. A component type can also be selected for certain attributes. This is used to determine which value will be graphed for a particular attribute component: For example, maximum, minimum or average particle velocity. The table below shows the range of attributes, components and component types available for each element. Refer to Appendix D: Attribute Definitions for more information on attributes. Element Contact Attribute Contact vector 1 Contact vector 2 Distance Normal force Normal overlap Number of contacts Tangential force Tangential overlap Average normal force Average tangential force Distance Duration Maximum normal force Maximum tangential force Normal energy loss Number of collisions Relative velocity Relative velocity normal Relative velocity tangential Tangential energy loss Total energy loss Velocity of element A Velocity of element B Components Magnitude, X, Y, Z Magnitude, X, Y, Z Define ref. object* Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Define ref. object* n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Type Average, Max or Min Average, Max or Min Average, Max or Min Average, Max, Min, or Total Average, Max or Min Total or Total in Range** Average, Max, Min, or Total Average, Max or Min Average, Max, Min, or Total Average, Max, Min, or Total Average, Max or Min Average, Max or Min Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Total or Total in Range** Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total

Collision

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Element Geometry

Particle

Attribute Charge Compressive force Distance Torque Total force Velocity Angular velocity Charge Compressive force Distance Electrostatic force Kinetic energy Mass Number of particles Potential energy Rotational kinetic energy Torque Total energy Total force Velocity Volume Custom property Normal force Normal moment No. of broken bonds No. of intact bonds Tangential force Tangential moment

Components n/a n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Define ref. object* Magnitude, X, Y, Z n/a n/a n/a n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a Depends on no. of elements Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z

Type Average, Max, Min, or Total Average, Max, Min, or Total Average, Max or Min Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max or Min Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Total or Total in Range** Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Average, Max, Min, or Total Total, Total in range Total, Total in range Average, Max, Min, or Total Average, Max, Min, or Total

Bond

* If the attribute is set to Distance you must define a point or plane from which the distance is measured. When distance is selected the Define Reference Object section of the pane will be activated. Choose the point or plane from which the distance should be measured. A point is defined by its xyz position and a plane by its orientation and distance from the origin. ** When the axis is set to measure the number of particles or number of contacts, it is possible to graph either the total number of particles/contacts or the total number in a defined range: For example, counting only those particles with a mass between 0.1kg and 0.2kg or velocity between 2m/s and 5m/s. When the Total in Range option is selected the Secondary Attribute section of the pane is activated. Choose the attribute and component you wish to restrict the range by and enter the maximum and minimum values of that range.

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Settings
Time Step

Graphs can be created for elements in a particular time step or over a range of time steps. By default the Current Time step option is selected. The current time step can be changed using the Current Time control in the Viewer control pane at the right of the screen. For example, the figure below shows two histograms each showing the number of particles traveling in particular velocity ranges. The graph on the left is for one time step, so each particle is only counted once. The graph on the right is for a range of ten time steps. The velocity of the particles may change between time steps and therefore be counted more than once: For example, a particle traveling at 4.92 m/s in the first time step and 5.0 m/s for all subsequent time steps will be counted once in the 4.91-4.93 column and nine times in the 4.99-5.01 column.

Figure 4-28: Histograms Showing the Distribution of Particle Velocities. Axis Range

The x and y axis ranges can be determined automatically (from the values of the attributes selected) or entered manually. The number of intervals on each axis should also be defined. A greater number of intervals increases the accuracy of the chart.
Display Options

Click the Display Options button to open the dialog.
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Title. Set the graph title. X-label, Y-label. The axes labels can be determined automatically or entered manually. Show grid. Turn the interval grid on and off. Show average value. Turn the display of a horizontal line showing the average value on and off. Show minimum value. Turn the display of a horizontal line showing the minimum value on and off. Show maximum value. Turn the display of a horizontal line showing the maximum value on and off.

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Create the Graph
Create the graph once the axes have been configured and the time step and display options set. Click on the Create Graph button to draw the graph. Use the Clear Graph button to clear it. If any setting is altered (including changing the units) click the Create Graph button to view the graph with the changes. To save the graph data, right-click on the graph then select Export as Text.

Drawing a Line Graph
A line graph is used to measure any variable over time. That is, how the value of a particular variable changes over a specified time. For example, the figure below is a line graph which shows the number of particles present in the model over a particular time. It clearly shows a large number of particles created in the first 0.0334s followed by a small increase over the next 0.0666s and finally a second large increase in the final 0.034s.

Figure 4-29: Line Graph Showing the Number of Particle in a Model

Selecting the Elements to Graph
The Select Element section is used to determine which elements in your model to collect data from. Choose the group of elements, the type of elements within that group and which selection of those elements you are interested in.

Configuring the X-Axis
Click on the X-axis tab. In a line graph the x-axis always measures the variable Time. Use the Start and End controls to set the range of time over which to plot your data. The number of intervals on the axis should also be defined. A greater number of intervals increases the accuracy of the chart.

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Configuring the Y-Axis
Click on the Y-axis tab and select the element attribute and component to be plotted on the y-axis. The attributes available in the list will depend on the elements previously selected. A component type can also be selected for certain attributes. This is used to determine which value will be graphed for a particular attribute component: For example, maximum, minimum or average particle velocity. Note that if you are graphing the number of elements (i.e. number of particles, contacts or collisions) then any interpolated data points (those constructed from the discrete set of known data points) are rounded down to the nearest whole number. Refer to Appendix D: Attribute Definitions for more information on attributes. Element attribute options are the same as for a Histogram (with the exception of collisions). See Configuring the Y-Axis on page 84 for details.

Settings
See Settings on page 86.

Drawing a Scatter Plot
A scatter plot is a way of displaying the distribution of two variables in relation to each other. The value of one variable is measured on the X axis and the values of the other on the Y axis. A wide scatter of the plots denotes poor correlation between the two variables. If the two variables are perfectly correlated, then all the plots will fall on the diagonal (regression line). For example, the figure below is a scatter plot which shows the velocity of a set of particles as they travel away from a specified point. The plots are clearly scattered around the regression line indicating that the two variables are well correlated. The further a particle travels from the specified point, the greater its velocity.

Figure 4-30: Scatter Plot Showing Two Well Correlated Variables

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Selecting the Elements to Graph
The Select Element section is used to determine which elements in your model to collect data from. Choose the group of elements, the type of elements within that group and which selection of those elements you are interested in.

Configuring the X-Axis
Click on the X-axis tab and select the element attribute and component to be plotted on the x-axis. The attributes available in the list will depend on the elements previously selected. Refer to Appendix D: Attribute Definitions for more information on attributes. Element Contacts Attribute Contact vector 1 Contact vector 2 Distance Normal force Normal overlap Position Tangential force Tangential overlap Average normal force Average tangential force Distance Duration Maximum normal force Maximum tangential force Normal energy loss Position Relative velocity Relative velocity normal Relative velocity tangential Tangential energy loss Total energy loss Velocity element A** Velocity element B Compressive force Charge Distance Position Torque Total force Velocity Components Magnitude, X, Y, Z Magnitude, X, Y, Z Define reference object* Magnitude, X, Y, Z n/a X, Y, Z Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a n/a X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z

Collisions

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Element Particle

Bond

Attribute Angular velocity Charge Compressive force Distance Electrostatic force Kinetic energy Mass Position Potential energy Rotational kinetic energy Torque Total energy Total force Velocity Volume Custom property Normal force Normal moment Tangential force Tangential moment

Components Magnitude, X, Y, Z n/a n/a Define reference object* Magnitude, X, Y, Z n/a n/a X, Y, Z n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a Depends on number of elements Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z

* If the attribute is set to Distance you must define a point or plane from which the distance is measured. When distance is selected the Define Reference Object section of the pane will be activated. Choose Point or Plane and define its position and, for a plane, its distance from the origin.

The x and y axes are related. The attribute you select to measure on the x-axis will limit those available to measure on the y-axis. Similarly if the y-axis is configured first the attributes available on the x-axis will be limited.

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Configuring the Y-Axis
Click the Y-axis tab then select the element attribute and component to be plotted on the y-axis. The attributes available in the list depend on the elements previously selected and the attribute to be measured on the x-axis. A component type can also be selected for certain attributes to determine which value will be graphed for a particular attribute component: For example, maximum, minimum or average particle velocity. Refer to Appendix D: Attribute Definitions for more information on attributes. Element Contacts Attribute Contact vector 1 Contact vector 2 Distance Normal force Normal overlap Position Tangential force Tangential overlap Average normal force Average tangential force Distance Duration Maximum normal force Maximum tangential force Normal energy loss Position Relative velocity Relative velocity normal Relative velocity tangential Tangential energy loss Total energy loss Velocity element A** Velocity element B Charge Compressive force Distance Position Torque Total force Velocity Components Magnitude, X, Y, Z Magnitude, X, Y, Z Define reference object* Magnitude, X, Y, Z n/a X, Y, Z Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a n/a X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z

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Element Particle

Bond

Attribute Angular velocity Compressive force Distance Kinetic energy Mass Position Potential energy Rotational kinetic energy Torque Total energy Total force Velocity Volume Custom property Normal force Normal moment Tangential force Tangential moment

Components Magnitude, X, Y, Z n/a Define reference object* n/a n/a X, Y, Z n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a Depends on number of elements Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z

* If the attribute is set to Distance you must define a point or plane from which the distance is measured. When distance is selected the Define Reference Object section of the pane will be activated. Choose Point or Plane and define its position and, for a plane, its distance from the origin. ** When the axis is measuring the number of particles or number of contacts it is possible to graph either the total number of particles/contacts or the total number in a defined range: For example, counting only those particles with a mass between 0.1kg and 0.2kg or velocity between 2m/s and 5m/s. When the Total in Range option is selected the Secondary Attribute section of the pane is activated. Choose the attribute and component you wish to restrict the range by and enter the maximum and minimum values of that range.

Settings
See Settings on page 86.

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Creating a Pie Chart
A pie chart is a circular diagram divided into segments, each representing a category or subset of data (part of the whole). The amount for each category is proportional to the area of the sector. The total area of the circle is 100% and it represents the total population that is being shown. For example, the figure below is a pie chart which shows the number of collisions, broken down by collision type. The largest slice is for particle X - particle Y collisions, which account for over 40% of the total.

Selecting the Elements to Graph
The Select Element section is used to determine which elements in your model to collect data from. Choose the group of elements you are interested in. For each element type, you can choose either to split the data by type or selection/bin group and these will form the segments (categories) of the pie chart. When Type or Selection Group is selected, the categories within that selection are listed: For example if Contacts > Type are selected, all specific contacts are the categories listed: For example, particle x - particle x, particle x - particle y and particle y - particle y. Similarly if Contacts > Selection groups is selected, all selection and bin groups in your model are the categories listed. All categories within a type or group are included in the chart by default. A category can be removed by double clicking on it and added back by double clicking on it a second time. Categories colored green are currently included in the pie chart, those colored black are not. When the Selection group option is chosen, all selection and bin groups in your model are listed. Both the whole group and each individual bin are listed: For example 'bin group' (the group name) and 'bin group0', 'bin group1', 'bin group2' (the individual bins). When creating a pie chart, exclude the group name to compare the contents of individual bins (the bin group encompasses all of the individual bins and therefore accounts for 100% of the pie chart). For example, the figure below graphs the number of particles in a model. It is clear that all particles are contained within the bin group. However, if you want to compare how many are in each bin, exclude the whole bin group and just examine the individual bins.

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Figure 4-32: Alternative pie charts

Define Attribute
Click on the Select Attribute tab and select the element attribute and component you want to examine using the pie chart. The attributes available in the list will depend on the elements previously selected. The component type available for most attributes is Total as this is the only type that can be displayed using a pie chart: For example, the total mass of particles of Type A compared to particles of Type B. Refer to Appendix D: Attribute Definitions for more information on attributes. Element Contacts Attribute Contact vector 1, 2 Normal force Normal overlap Number of contacts** Tangential force Tangential overlap Average normal force Average tangential force Maximum normal force Maximum tangential force Normal energy loss Number of collisions** Relative velocity Relative velocity normal Relative velocity tangential Tangential energy loss Total energy loss Velocity of element A Velocity of element B Components Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z

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Element Geometry

Particle

Bond

Attribute Charge Compressive force Distance Torque Total force Velocity Angular velocity Charge Compressive force Distance Electrostatic force Kinetic energy Mass Number of particles** Potential energy Rotational kinetic energy Torque Total energy Total force Velocity Volume Custom property Normal force Normal moment Number of broken bonds Number of intact bonds Tangential force Tangential moment

Components n/a n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Define reference object* Magnitude, X, Y, Z n/a n/a n/a n/a n/a Magnitude, X, Y, Z n/a Magnitude, X, Y, Z Magnitude, X, Y, Z n/a Depends on number of elements Magnitude, X, Y, Z Magnitude, X, Y, Z n/a n/a Magnitude, X, Y, Z Magnitude, X, Y, Z

* If the attribute is set to Distance you must define a point or plane from which the distance is measured. When distance is selected the Define Reference Object section of the pane will be activated. Choose the point or plane from which the distance should be measured. A point is defined by its xyz position and a plane by its orientation and distance from the origin.

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Settings
Two options are set in the Setting tab.
Time Step

Pie charts can be created for elements in a particular time step or over a range of time steps. By default the Current Time step option is selected. The current time step can be changed using the Current Time control in the Viewer control pane at the right of the screen. For example, you could chart the total number of particles in each bin in a bin group at a particular time or the total number that have been in the bins over the course of the entire simulation. Comparing the charts we can see that at t=0.0021s most particles are in bins 09 and 04, however this is not indicative of their location over the course of the whole simulation.

Graph Text

Set the pie chart title.

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Example Pie Chart of Bin Groups
A model contains a bin group dividing the model domain into 10 bins. You want to show the number of contacts that are occurring in each bin at a given time. 1. Select the element Contact > Selection Groups.

2. Choose the attribute Number of Contacts (Total).

3. Go to the Settings tab and give the chart a title. 4. Go to the Viewer Controls pane and choose the time step at which you want to examine the contacts. Ensure the Current time step option in the Settings tab is selected. 5. Click the Create Graph button. 6. The pie chart and the percentage breakdown of the number of contacts occurring in each bin will be displayed in the Viewer. For example:

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Running EDEM in Batch Mode
EDEM’s Command Line Interface (CLI)
With EDEM’s command line interface, you can run EDEM in batch mode without using the GUI. You may want to do this when:
? ? ?

You have a cluster with limited display capability and want to do grid processing You need to create batch jobs to run EDEM simulations You want to develop advanced scripting for parametric optimization.

The Command Line can also export data to a .csv file once simulation completes.

Using the Command Line
The EDEM Command Line has the same flags for both Windows and Linux:
edem.exe –console –i “input.dem” [processing flags][post-processing flags][-h]

For full details, use the –h flag to display the EDEM command line help.
Processing Flags

The processing flags set the simulator options such as simulation time, time step, and number of processors. If you do not specify any processing flags, default values are used.
Post-Processing Flags

Use the post-processing flags to specify data export parameters. You can either specify the type of data to export (all, particle, geometry, etc.) or specify your simulation’s configuration file. If you want to export data from the command line, first select File > Export Data from the Analyst to set the path and filename to export to.

Command Line Processing Output
While processing, the EDEM Command Line outputs a row of numbers at regular intervals. From left to right, the columns indicate: ? ? ? ? ? ? Number of time steps Simulation time (s) Processing time (s) Expected time to process one second of simulation time (s) Total linear kinetic energy (J) Total rotational kinetic energy (J)

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Examples
Example 1: default processing options

1. Create and save an input deck using the EDEM Creator. 2. Open a console (cmd) window then change directory to the EDEM bin directory. 3. Type the following:
edem.exe -console -i "c:\My Documents\EDEM\mysim.dem" -rewind

The input deck is rewound to the start then each time step is processed. A message is displayed once complete. You can then open the deck and use the EDEM Analyst to perform any post-processing.
Example 2: specifying processing options

1. Create and save an input deck using the EDEM Creator. 2. Open a console (cmd) window then change directory to the EDEM bin directory. 3. Type the following:
edem.exe -console -i "c:\My Documents\EDEM\mysim.dem" –p 4 –r 10

This command runs the simulation using 4 processors for 10 seconds total run time.
Example 3: run simulation and export data

1. Create and save an input deck using the EDEM Creator. 2. Open a console (cmd) window then change directory to the EDEM bin directory. 3. Type the following:
edem.exe -console -i "c:\My Documents\EDEM\mysim.dem" –rewind –ePC “c:\My Documents\EDEM\mysimdata.csv”

This command rewinds then runs the simulation using default processing flags. It then exports particle and contact data to a .csv file.
Example 4: run simulation and export data based on deck configuration

1. 2. 3. 4.

Create and save an input deck using the EDEM Creator. Switch to the Analyst then select File > Export Data. Define the export queries then set the filename. Click Close. Switch back to the Creator then save your deck. The configuration file is updated with details of the export queries. 5. Open a console (cmd) window then change directory to the EDEM bin directory. 6. Type the following:
edem.exe -console -i "c:\My Documents\EDEM\mysim.dem" –rewind –e “c:\My Documents\EDEM\mysim.dem.cfg”

This command rewinds then runs the simulation using default processing flags. It then exports data based on the queries defined in the deck’s configuration file.

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Dynamics Coupling
EDEM Dynamics Coupling is an interface to enable EDEM’s geometry motion to be controlled by any suitable 3rd-party dynamics application. For example, it can be used to couple EDEM with MSC Software’s engineering analysis software Easy5 and Adams.

Using the Dynamics Coupling Interface with Easy5
To incorporate a DC block into your MSC.EASY5 schematic, do the following:

Setup Easy5 Coupling in EDEM
1. Start EDEM. 2. Open the EDEM model you want to couple with Easy5. 3. Click the Geometry tab. 4. Tick the checkbox to enable coupling:

5. For each piece of geometry to be controlled by Easy5: a. Be sure the geometry section does not have a space in its name. b. Click the Dynamics tab. c. Enable the dynamics control checkbox:

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Setup EDEM Coupling in Easy5
1. Start Easy5. 2. In the EASY5 schematic, add an extension component for EDEM:

3. Open the component editor. To configure the EDEM component, click Select / Configure EDEM model. This adds connectivity information to the EDEM model by adding variables for inputs and outputs:

EDEM and Easy5 are now both ready to be synchronized to send and receive data to each other.

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Synchronize the Coupling in EDEM
1. Switch to EDEM. Be sure not to close Easy5. 2. Click the Geometry tab then click the Synchronize button once only:

Setup EDEM Inputs and Outputs
Each piece of geometry in EDEM has a corresponding array created in the Easy5 block for input and output. These arrays need to be expanded to extract the inputs to translations and rotations, and to get the forces and moments. 1. Switch back to Easy5. 2. Add an EDEM input- and output-block for each piece of geometry from EDEM to the schematic. This encodes and decodes the arrays into easy-to-use variables. For example:

Below are the example inputs and outputs:

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NOTE: both the velocity and the displacement must be returned for each direction of interest. Failure to do so will result in either an unphysical or failed simulation.

Choose Integrator
A number of integrators can be used to solve the Easy5 side of the coupled model. If you need to use the BCS Gear integrator, be sure to set small time-steps on both the Easy5 and the EDEM sides of the simulation. This will maximize stability and reduce the likelihood of unrepeatable results.

Monitor the Easy5 Server
To monitor the Easy5 server: 1. Select Tools > Dynamics Coupling Server. A popup is displayed:

2. Click the Reset button when the status is inactive or when you want to resynchronize the calculations. The Easy5 server is stopped and restarted.

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Appendix A: Contact Model Theory
A contact model describes how elements behave when they come into contact with each other. EDEM includes the following integrated contact models:
? ? ? ? ? ? ?

Hertz-Mindlin (no slip) – this is the default contact model Hertz-Mindlin with Bonding Hertz-Mindlin with Heat Conduction Linear Cohesion Linear Spring Moving Plane (Conveyor) Tribocharging (with the Electrostatics feature)

Example simulations that use these contact models are in the examples folder. You can also create your own user-defined models: EDEM is supplied with sample source files you can modify and compile to create additional plug-in contact models. Refer to the EDEM Programming Guide for more details.

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Hertz Mindlin (No Slip) Contact Model
This contact model is the default model used in EDEM due to its accurate and efficient force calculation. The model is based on the work of Mindlin (Journal Applied Mechanics, Volume 71, 1949). The normal force, , is given by

Where Y* is the equivalent Young’s Modulus,

the equivalent radius and , given by

the

normal overlap. Additionally there is a damping force,

Fnd = ?2
where and and
rel

5 rel β S n m * vn 6

is the equivalent mass, vn is the normal component of the relative velocity (the normal stiffness) are given by

β=

ln e ln 2 e + π 2

Sn = 2Y * R*δ n
with the coefficient of restitution. The tangential force, overlap and the tangential stiffness . , depends on the tangential

Ft = ?Stδ t
with

St = 8G* R*δ n
Additionally, tangential damping is given by:

Ft d = ?2
where vt friction
rel

5 β St m* vtrel 6

is the relative tangential velocity. The tangential force is limited by Coulomb

μs Fn where μs is the coefficient of static friction. τ i = ?μ r Fn Riωi

For simulations in which rolling friction is important, this is accounted for by applying a torque to the contacting surfaces.

with μr the coefficient of rolling friction, Ri the distance of the contact point from the center of mass and ωi the unit angular velocity vector of the object at the contact point.

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Hertz Mindlin with Bonding Contact Model
The Hertz Mindlin with Bonding contact model can be used when you want to bond particles with a finite-sized “glue” bond. This bond can resist tangential and normal movement up to a maximum normal and tangential shear stress, at which point the bond breaks. Thereafter the particles interact as hard spheres. This model is particularly useful in modeling concrete and rock structures. Particles are bonded at the bond formation time tBOND. Before this time, the particles interact through the standard Hertz-Mindlin contact model. After bonding, the forces (Fn,t)/torques (Tn,t) on the particle are set to zero and are adjusted incrementally every timestep according to:

δFn = ?v n S n Aδt δFt = ?vt S t Aδt δM n = ?ω n S t Jδt δM t = ?ω t S n
where:

J δt 2
2

A = πRB

1 4 J = πRB 2

R

is the radius of the “glue”, Sn,t are the normal and shear stiffness respectively and δt is the timestep. vn,t are the normal and tangential velocities of the particles and ωn,t the normal and tangential angular velocities.
B

The bond is broken when the normal and tangential shear stresses exceed some predefined value:

σ max < τ max

? Fn 2 M t + RB A J ? Ft M n RB < + A J

These bond forces/torques are in addition to the standard Hertz-Mindlin forces. Since the bonds involved in this model can act when the particles are no longer physically in contact, the contact radius should be set to higher than the actual radius of the spheres. This model may only be used between particles.

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Hertz Mindlin with Heat Conduction
For dilute phase simulations, convective heat transfer is dominant and conductions between the particles or wall can be neglected. However, for dense phase, contacts between particles are significant such that conductive heat transfer must be taken into account. A single phase DEM simulation on heat transfer in granular flow in rotating vessels provides a simple approach in modelling inter-particle heat transfer. The heat flux between the particles is written as:

Q p1 p 2 = hc ΔT p1 p 2
where the contact area is incorporated in the heat transfer coefficient hc and is given by:

4k p1 k p 2 ? 3FN r * ? hc = ? ? k p1 + k p 2 ? 4 E * ?

1/ 3

where FN is the normal force, r* the geometric mean of the particles radii from the Hertz’s elastic contact theory and E* is the effective Young’s modulus for the two particles. The bracketed term on the RHS of the equation models the contact area between particles.

Temperature Update
After all the heat fluxes have been calculated, the temperature change over time of each particle is updated explicitly using:

m pCP

dT = ∑ Qheat dt

where mp, CP and T are the mass, specific heat capacity and temperature of the particle material type. The RHS denotes the sum of convective and conductive heat fluxes.
Use

1. Select Particle-to-Particle from the Interaction pulldown in the Physics section of the Creator. 2. Click the + drop-down list then select Hertz-Mindlin with Heat Conduction. 3. Click the configuration button to define the thermal conductivity for each particle type. 4. Select Particle Body Force from the Interaction pulldown. 5. Click the + drop-down list then select Temperature Update. 6. Click the configuration button to define the specific heat capacity for each particle type.

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Linear Cohesion Contact Model
This cohesion model modifies Hertz-Mindlin contact by adding a normal cohesion force. This force takes the form:

F = kA
where A is the contact area and k is a cohesion energy density with units Jm-3. This force is added to the traditional Hertz-Mindlin normal force. No additional tangential force is added in this model, however the magnitude of the noncohesive normal force is increased beyond Hertz-Mindlin and therefore a stronger frictional force can be withstood before slippage.
Use

1. Select the required category from the Interaction pulldown in the Physics section of the Creator. 2. Be sure a model for contact forces is listed in the Model section. If not, click the + drop-down list then select (for example) Hertz-Mindlin (no-slip). 3. Click the + drop-down list then select Linear Cohesion. 4. Click the configuration button Contact Models on page 15. to define contact model parameters. See

Moving Plane Contact Model
The moving plane model simulates a linear motion of a geometry section (for example, to simulate a conveyor). The whole section moves at the same velocity. The contact model adds this linear velocity to the velocity of the geometry section only within the contact model (so the geometry section does not actually move). Note that the contact model also increments the tangential overlap for the contact by (v_t(with moving plane )v_t(without moving plane )).dt This model should only be used for particle-geometry contacts.
Use

7. Select Particle-to-Geometry from the Interaction pulldown in the Physics section of the Creator. 8. Be sure a model for contact forces is listed in the Model section. If not, click the + drop-down list then select (for example) Hertz-Mindlin (no-slip). 9. Click the + drop-down list then select Moving Plane. 10. Click the configuration button to define the sections to use as moving planes. For each section, set the X, Y, and Z linear velocity. See Contact Models on page 15.

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Linear Spring Contact Model
The damped linear spring contact force model is based on the work by Cundall and Strack (1979). A linear spring with stiffness k is in parallel with a dashpot with coefficient, c. The magnitude of the normal force between two particles, FN, is:
FN = k δ + c δ&

where k is the linear spring stiffness, c is the dashpot coefficient, δ is the overlap, and δ& is the overlap velocity. Similar force can be applied to the tangential direction. The spring stiffness and the dashpot coefficient are the parameters in this model and it is a common practice to estimate the spring stiffness and calculate the dashpot coefficient based on this stiffness. The simulation timestep is then estimated based on the spring stiffness. The spring constant and dashpot coefficient can be calculated based on a combination of material properties and kinematic constraints. One common method is obtained by equating the maximum strain energy in a purely Hertzian contact (Ehertzian) with the maximum strain energy of the existing contact (Emax). This gives:
* 2 ?5 ? 16 * ? 15m V ? k= R E 1 ? ? 15 *2 * ? 16 R E ? 1 *2 1

where v is Poisson’s ratio, m* = (1/m1+ 1/m2)-1 is the effective mass, R* = (1/R1+ 1/R2) -1 is the effective radius, and 1/E* = (1-v12)/E1 + (1-v22)/E2 is the effective Young’s modulus of the contact. For two identical spherical particles with masses of 7.63e-03 kg, radius of 9 mm and Young’s modulus of 2.6e+08, colliding at a velocity of 3 m/s, k ≈ 2.0e+05 N/m2. The impact velocity in an EDEM simulation can usually be taken as a characteristic velocity in the simulation. You can base this velocity as the maximum velocity in the simulation, for example, for a blending operation with the blender operating at ? rad/s, the characteristic velocity is equal to r ? m/s, where r is the radius of the blender. The dashpot coefficient is related to the coefficient of restitution as:

c=

4m* k
? π ? 1+ ? ? ? ln e ?
2

where ?β = π/(ln ε?); ε ?is the coefficient of restitution. Note that ε remains constant with the impact speed (assuming other model parameters are constant). The tangential stiffness is usually estimated as a ratio of the normal spring stiffness (Cundall, 1979). EDEM has the tangential stiffness equal to the normal stiffness.

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EDEM User Guide The dashpot coefficient is calculated using the tangential stiffness in the equation above. The tangential force is computed via: min ,

where kt and ct are the tangential spring and dashpot coefficient, μ is the coefficient of friction. The simulation timestep is usually a small percent of the contact duration of the particles. The contact duration for a linear spring model is obtained using the normal stiffness as:

where ?β = π/(ln ε?); ε ?is the coefficient of restitution. For ε = 0.5 we have a contact time of 0.00043 sec. The simulation time step must be less than this value for better integration of the particle states. We recommend you have a value of about 5-10 % of this contact time for accurate results. The details of the softparticle contact model are relatively unimportant due to the fact that a lumped parameter approach which neglects the details of the contact force (e.g. a coefficient of restitution) is sufficient to describe the collision dynamics. Note that you can increase the simulation timestep and then try to fix a stiffness that will not allow for excessive overlap. However, since the stiffness and timestep are not based on physical laws, the accuracy of the results is not guaranteed: you might obtain a qualitative similarity but not a qualitative one. We recommend to calculate the stiffness based on the material properties and fix the timestep in EDEM. There is no general consensus on what is the best contact model. The linear spring model is simpler than Hertz-Mindlin due to less computational overhead. However, in both the models the contact force is discontinuous at the first and last point of contact, and energy dissipation is poor in systems with small relative velocities. For the same stiffness, we obtain a larger force for the same time step in a Hertz-Mindlin model in comparison with the linear spring. Hence a larger time step can be used with a linear spring contact model.
Use

1. Select the required particle interaction from the Interaction pulldown in the Physics section of the Creator. 2. Click the + drop-down list then select Linear Spring. 3. Click the configuration button Contact Models on page 15. to define contact model parameters. See

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Tribocharging Contact Model
Tribocharging takes place when two objects of different material come into contact with one another. Charge is passed between contacting objects resulting in each element having a different charge once the contact has finished. Note: Since this model is for triboelectric effects only, use it in conjunction with a model that handles forces for contacts (such as the Hertz-Mindlin no-slip model). The tribocharging equation used in the Tribocharging contact model is based on the work by Greason (2000). Greason describes a tribocharging situation where a metal sphere is rolling through a dielectric tube. The equation used is:

where q is charge on the sphere at time t, qs is the saturation charge, and α and β are the time constants of the charge generation and dissipation respectively. Integration of this equation gives:

dq = α (qs ? q ) ? βq dt

q(t ) = q s

1 1 ? e ?(α + β ) t β 1+ α

[

]

Charge dissipation will be mostly through atmospheric ion impingement, which is a relatively slow process. Therefore the charge dissipation is assumed to be negligible (β ≈ 0) which gives:

q (t ) = q s 1 ? e ?α t

(

)

Saturation charge, qs, is when the surface charge density is sufficient to cause atmospheric breakdown or ionization that limits the charge buildup. For air at standard temperature and pressure, this breakdown field is ~ 30,000 V/cm or 3,000,000 V/m. This translates to a surface charge density of 2.66 × 10-5 C/m2. To get qs, we multiply this charge density by the surface area of a sphere. Assuming 2-axis rolling of spheres, the resulting surface charge should be fairly uniform over the surface of the sphere.
Usage

If you have purchased the Electrostatics option: 1. Select the required category from the Interaction pulldown in the Physics section. 2. Be sure a model for contact forces is listed in the Model section. If not, click the + drop-down list then select (for example) Hertz-Mindlin (no-slip). 3. Click the + drop-down list then select Tribocharging. 4. For each material where charging is required, set the material’s Work Function from the Creator’s Materials section. 5. Click the configuration button to define an Alpha Value. This determines the rate at which charge transfers between elements. See Contact Models on page 15.

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Appendix B: Particle Body Forces
A particle body force can be set to act upon particles when a specified condition is met; for example, when they are in certain position, or are traveling at a specified velocity. EDEM includes the following integrated particle body forces:
? ?

Electrostatics (with the Electrostatics feature) Temperature Update (see page 107)

Example simulations that use these particle body forces are in the examples folder. You can also create your own user-defined forces: EDEM is supplied with sample source files you can modify and compile to create additional plug-in forces. Refer to the EDEM Programming Guide for more details.

Electrostatic Force
An integrated, screened electrostatic force is available when you have purchased the EDEM Electrostatics option. EDEM’s screened electrostatic force is a long-range model that works with the existing Hertz-Mindlin calculations. This model is based on Coulomb’s law, where the electrostatic force, F, is given by:

F=

q1q 2 ? r 4πε 0 r 2 1

where q1 and q2 are the charges of two particles, r is the distance between their centers and ε0 is the permittivity of free space. This model alone does not take into account the effects of other charged particles within the local vicinity of a target particle. To introduce these effects, a screening term must be used in the electrostatic potential:

Ue =

q1 q 2 ?κ r e 4πε 0 r

where Ue is the electrostatic potential and:

κ = qe ? ?

?

? 1 ni zi2 ? ∑ ? ? εε 0 K BT i ?

In this screening term, κ is the inverse of the Debye length, λD, and is based on the local charge concentration (where n is the number of particles of charge z) around a target particle, qe is the charge of an electron (1.602 × 10-19 C), ε is the relative permittivity of the medium, ε0 is the permittivity of free space (8.854 × 10-12 F?m-1), KB is Boltzmann’s constant (1.38 × 10-23 J?K-1), and T is the temperature in Kelvin.

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EDEM User Guide The screened Coulomb Force, Fs, is given by:

FS = ?

dU e q1 q 2 = dr 4πε 0

?κ 1 ? + 2 ?r r

? ?κ r ?e ?

Screening Distance

To optimize the calculation process, EDEM lets you define a maximum screening distance, D. This reduces the number of particles included in the charge concentration calculation and decreases processing time. The figure below shows a schematic outlining this defined screening distance:

To allow access to the charge and location parameters of the particles within this screening distance, the contact algorithm uses a Cartesian grid to produce a sub-grid of dimensions D3. The algorithm then constructs an internal list of particles that lie within the sub-grid. Since use of the grid cells produces a cubed sub-grid, further filtering is required to remove particles that are located beyond the spherical screening distance. The figure below shows a charge concentration using the EDEM sub-grid:

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Using the Force

1. From the Creator, select the Globals tab. 2. Select Particle Body Force from the Interaction pulldown menu. 3. Click the + drop-down list then select Electrostatics. 4. Click the configuration button to define the screening distance. This is defined either as a direct distance or as a function of the smallest particle radius. Note that a higher screening distance will result in a slower simulation time, since more grid cells need to be screened.

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Appendix C: Estimating Simulation Time
Exact estimation of the real time required for a DEM simulation is almost impossible, as each simulation and each computer is different. However, see below for some general advice on estimating simulation time.

Time Step
One of the key numbers in DEM simulation is the Rayleigh time step. This is the time taken for a shear wave to propagate through a solid particle. It is therefore a theoretical maximum time step for a DEM simulation of a quasi-static particulate collection in which the coordination number (total number of contacts per particle) for each particle remains above 1. It is given by: 0.1631 0.8766

where R is the particle’s radius, ρ its density, G the shear modulus and v the Poisson’s ratio. In practice some fraction of this maximum value is used, and for high coordination numbers (4 and above) a typical time step of 0.2TR (20%) has been shown to be appropriate. For lower coordination numbers, 0.4TR (40%) is more suitable.

Hertzian Contact
Whilst the Rayleigh time step is a suitable starting point for quasi-static simulations, for systems undergoing flow it may be that a shorter time step is required. Consider two elements approaching each other at a speed v. In one time step, t, the maximum possible overlap is: In DEM, particles undergoing elastic (Hertzian) contact are treated as overlapping and this overlap is equated to a surface compression. t in the above equation must be such that the maximum overlap is lower than the theoretical maximum overlap for Hertzian contact. In practice, to get a good numerical integral to the contact graph at least six time points should occur (though then is more desirable) - three during approach and three during separation.

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Elastic Impact
From Hertz theory of elastic collision the total time of contact is given by:

2.87 Where: 1 1 1

Where

and

are the mass of the two elements. 1 1 1

Where

and

are the radii of the two elements. 1 1 1

where

and

are the poisons ratio of the two materials.

Where

is the relative velocity and

and

are the velocity of the two elements.

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Appendix D: Attribute Definitions
Particle Attributes
Attribute Angular velocity Description Angular velocity is defined as the speed at which an object rotates. For a particle of radius r (m) rotating at

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