Tutorial - 5-Bonded Particles Model Simulation

EDEM Tutorial: Bonded Particles Model Simulation

EDEM Tutorial: Bonded Particles Model

Copyrights and Trademarks ©

Copyright 2013 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. EDEM includes CGNS (CFD General Notation System) software. See the Online Help for full copyright notice. ®

®

®

®

®

EDEM EDEM Creator , EDEM Simulator , EDEM Analyst and Particle Factory are registered trademarks of DEM Solutions. All other brands or product names are the property of the respective owners.

Page 2 of 14


Introduction This intermediate tutorial is directed at users who have covered introductory exercises, as the initial set-up of simulation is abbreviated and basic functionality not explained in detail. In case of any uncertainties or problems, refer to previous tutorials or EDEM Help section. This exercise explores further options of EDEM, focusing on the use the internal bonded particle model. The main concepts are: 

Use of the Hertz-Mindlin with Bonding contact model.



Particle contact radius setup and definition.



Export of the input deck at specific time-step.



Preparation of new simulation using exported deck.



Display configuration and analysis of particles’ bonds.

1. Start EDEM. 2. Go to File > Save As… 3. Select a location on the local machine (e.g. C:\EDEM_Tutorials). 4. Enter a file name (e.g. Bonded_Particle_setup.dem) and click Save. 5. Remember to often press Save when setting up the simulation.

Page 3 of 14


EDEM Creator: Setting up the model Step 1: Set the Global Model Parameters Choose the units 1. Tools > Options… menu and select the Units tab. 2. Change the following measurement units: 

Velocity to m/s



Length to mm

Enter the model title and description 1. In the Globals tab, enter the title Bonded Particle Model in the Title field. 2. Enter a description in the Description field.

Set the gravity, define the materials and interactions 1. Check that Gravity is set to -9.81m/s2 in the z-direction. 2. Click the

button in the Materials section to create a new material.

3. Set the Name, Poisson's ratio, Shear modulus and Density as shown below:

4. Click the button in the Interaction section. This will automatically define the interaction between elements both made of new material 1, as no other material has been created. Set the coefficients as follows:

Page 4 of 14


Step 2: Define the Particles In this exercise, the bonded particles model is used. Therefore the Contact radius between the particles must be set in the Particles tab. The contact radius is important as it determines the area in which the bond can be formed. If the contact radii of two particles overlap during the bond formation time, then these two particles will be bonded together. When the particles no longer overlap the bond information is lost.

Create a new particle type and set contact radius 1. Click on the Particle tab. 2. Click the

button in Select Particle section in order to create a new particle type.

3. Click the

button and rename the particle type Bonded particle.

4. Set the Radius of the surface to 5 mm. 5. Check the Contact Radius box and set the value to 5.5 mm. 6. Set the Material to new material 1. 7. Click the Calculate Properties button and pick the Surfaces option.

Page 5 of 14


Step 3: Set the Contact Models 1. Go back to Globals tab. 2. Select Particle to Geometry from the Interaction pull-down and check that Hertz_Mindlin (no slip) model is listed. 3. Select Particle to Particle from the Interaction pull-down in the Physics section. 4. Select Hertz-Mindlin (no slip) then click the 5. Click the

button to remove it.

button and select the Hertz-Mindlin with bonding built-in model:

6. Click the configure button

to define the bond.

7. Set the parameters as follows:

Page 6 of 14


Step 4: Define the Geometry Create a standard box 1. Go to the Geometry tab. 2. In the Sections part, click the

button to create

a Box and rename it to Box by clicking on

.

3. Click on the Box tab and set the specification as follows:

Create the loading plane 1. Click the

button again, creating a Polygon this time.

2. Click the

button and rename it to a Loading plane.

3. Click on the Polygon and Dynamics tabs, set the specifications as follows:

Step 5: Create the Particle Factories 1. Click on the Factories tab. 2. Click the

button to create a new factory.

3. Set Factory Type to static. 4. Leave all other settings as default and this will fill the box with a set amount of particles. 5. Select File > Save.

Page 7 of 14


EDEM Simulator: Running the Simulation Step 1: Set the Time and Grid options Set the time step 1. Click on the Simulator button

on the toolbar.

2. Set the Fixed Time Step lower box to 5e-5 s, which would be about 29% of Rayleigh time step.

Set the simulation time and grid options 1. In Simulation Time section, set the Total Time to 1s. 2. Set the Target Save Interval to 0.01s to specify write-out frequency. 3. Set the Cell Size to 3 Rmin.

Step 2: Run the Simulation 1. Click the start Progress button

at the bottom of the simulation window.

2. Click the Refresh Viewer button at any point to update the Viewer and see how the simulation is progressing.

Page 8 of 14


EDEM Analyst: Exporting Input Deck Step 1: Check that the particles have settled Configure the geometry 1. Switch to the Analyst by selecting

button on the toolbar and click the Model tab.

2. Reduce the Opacity of the geometry to 0.8 then click Apply. 3. In Viewer Controls, select the last time-step (1s). The particles should be settled in the box as shown:

Step 2: Export Simulation Deck 1. Go to File > Export > Simulation Deck… 2. Save the 1s simulation as a new file Bonded_Particle_Run.dem in the tutorial folder. 3. In the dialog that appears, Set Start Time to 1s and click OK.

4. Close EDEM.

Page 9 of 14


EDEM Creator: Modifying the input deck The saved file is now going to be modified for the bonded particle simulation. 1. Start EDEM. 2. Go to File > Open… 3. Navigate to Bonded_Particle_Run.dem.

Step 1: Modify the Geometry 1. Go to the Geometry Tab. 2. Select Loading plane from Sections drop-down menu. 3. In the Polygon tab, redefine the size and position as follows:

5. In the Dynamics tab, modify the dynamics of the loading plane to get:

Page 10 of 14


6. Select Box from Sections pull-down. 7. In the Box tab, redefine the size and position as below. Note that ‘side 5’ is de-selected now. When this is done a warning message would appear, then select OK to remove the factory as it is no longer needed.

8. In the Domain section at the top, uncheck Auto Update from Geometry box and set the domain as follows:

The geometry should now look like the image below, with the rectangle open at one end and the loading plate above the unsupported end of the particles.

9. Select File > Save.

Page 11 of 14


EDEM Simulator: Running the Simulation Step 1: Set the Time and Grid Options Set the time step 1. Click on the Simulator button

on the toolbar.

2. Set the Fixed Time Step lower box to 2e-5 s, which would be about 12% of Rayleigh time step.

Set the simulation time and grid options 1. In Simulation Time section, set the Total Time to 2.5s. 2. Set the Target Save Interval to 0.01s to specify write-out frequency. 3. Set the Cell Size to 3 Rmin.

Step 2: Run the Simulation 1. Click the start Progress button

at the bottom of the simulation window.

2. Click the Refresh Viewer button at any point to update the Viewer and see how the simulation is progressing.

Page 12 of 14


EDEM Analyst: Analyzing the Bonds Step 1: Configuring the Display Configure the geometry 1. Switch to the Analyst by selecting

button on the toolbar and click the Model tab.

2. Set the Opacity of the geometry to 0.7 then click Apply.

Configure the particles 1. In the Particles section uncheck Display box and click Apply. The particles disappear from the viewer.

Configure the bonds 1. In the Contact/Bond section, set: 

Element to Bond



Bond State to Intact Bond

2. Check the Display box and click Apply. 3. Now set: 

Bond State to Broken Bond



Distance Threshold to 15 mm

4. Check the Display box and click Apply.

Page 13 of 14


Step 2: Coloring the bonds 1. Click on the Coloring tab to open the Coloring pane. 2. Set Element to Bond and Color by Intact Bond. 3. In the Attribute Coloring section, set Attribute to Normal Force and Component to Magnitude. 4. Set the Min Value to 0 N and Max Value to 40 N (deselect Auto Update first if it was checked). The bond disk radius was previously set to 5 mm and the bond strength to 500000 Pa. Therefore, the bonds should break at a force of approximately 40 N. Play through the simulation to analyze the bonds. At 1.01 s the intact bonds should be visible. Stepping through the model shows the forces on the bonds increasing and some bonds breaking.

Page 14 of 14

Tutorial - 5-Bonded Particles Model Simulation

Recommend Documents