Welcome
What's New
New features and enhancements available in EDEM.
About EDEM
EDEM is a high-performance simulation software for bulk and granular materials.
Release Notes
This section contains information about the EDEM release, such as key features, enhancements, bug fixes, and known issues.
Tutorials
Start using EDEM with our interactive tutorials.
Get Started with EDEM
The EDEM user interface comprises three icons for each simulation component - Creator, Simulator, and Analyst.
EDEM Creator
EDEM Creator is the pre-processor for creating an EDEM simulation model, including setting up equipment and defining the generation of bulk materials.
EDEM Simulator
EDEM Simulator is a powerful solver used for fast and efficient simulations.
- Set Simulator Parameters
  You can set simulation parameters such as the Time Step, simulation time, grid options, and Simulator Engine for the CPU mode, along with the GPU parameters.
  - Time Steps
    A Time Step is the amount of time between iterations (calculations) in EDEM Simulator.
  - Set Data Save
    You can configure settings that determine the simulation data saved, the type of data to be saved, save interval, and data compression.
  - Export Simulation Results
    While running simulations, you can export simulation results to assess the behavior of the simulation during processing without the need for stopping and post-processing in EDEM Analyst.
  - Simulator Grid (CPU Engine only)
    The main computational challenge in DEM simulations is the detection of contacts. EDEM Simulator can examine each cell and analyze only those that contain two or more elements (and hence a possible contact) by dividing the domain into grid cells, saving processing time.
  - Track Collision Data
    During a simulation, EDEM can record data about both contacts and collisions.
  - Preserve Contact Between Triangles
    You can preserve the contact history for a particle passing from one element to another.
- Start and Stop a Simulation
  The current simulation time along with all the previous time steps are displayed in the Viewer Controls pane.
- Dynamic Domain
  When you define a Geometry object as a Dynamic Domain, all material inside the object will be active, and EDEM excludes any stationary material outside the object from any calculations, therefore, improving simulation speed. Dynamic Domain is based on the method outlined in Mio et al., 2009.
- Select the EDEM Simulator Engine
  You can run a simulation in CPU or GPU engine mode. However, the GPU mode requires supported GPU hardware.
- Run EDEM in Batch Mode
  EDEM's Command Line Interface allows you to run EDEM in batch mode without using the GUI.
- Reduce Simulation Time
  The time taken by the Simulator to perform a single iteration, t_iteration, is affected quite significantly by the simulation parameters.
EDEM Analyst
EDEM Analyst is the post-processor used to analyze and visualize the results of your simulation.
EDEM Contact Models
A Contact Model describes how elements behave when they come into contact with each other.
EDEM Cal Utility
EDEM Cal is a utility which works with EDEM and is designed to assist in performing calibration.
EDEM Calibration Kits
The EDEM Calibration kits are a collection of EDEM models of standard bulk solids characterization tests commonly used for EDEM material model calibration.
GPU CUDA Guide
The EDEM CUDA GPU module uses the latest General Purpose Computing on Graphical Processing Units (GPU) technology.
Programming Guide
The EDEM Programming Guide describes the EDEM API.
Coupling Interface Programming Guide
The Coupling Interface Programming Guide provides an overview of how to use the EDEM Coupling Interface to couple with a generic CFD code and/or Multi Body dynamics codes.
EDEMpy
EDEMpy is a Python library for accessing EDEM data from .h5 files (the underlying EDEM file format). EDEMpy does not require prior knowledge of advanced programming.
EDEM Solver Capabilities
EDEM contains four solver engines.
Appendix
This section provides additional information about how to estimate simulation time, supported EDEM File types, attribute definitions, and so on.
EDEM Terminology
Definitions of terms used in EDEM.
References and Bibliography
This section cites the contributions made by various authors and sources that have been used as reference material for EDEM, and the specifics of how they have been applied can be found in the individual contact model sections.

Track Collision Data

During a simulation, EDEM can record data about both contacts and collisions.

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 such as over four 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 is registered as one collision, regardless of how long the elements stay in contact. Data is collected for the duration of the collision. For example, total energy loss, min/max/average normal force data, and so on. Collisions may occur in-between write-outs and never register as contacts.

The following example shows a force-time graph for a single particle-geometry collision where each point is a contact.

EDEM records all contact data as standard. To record collision data, you must enable Track Collisions. Storing collision data will significantly increase memory usage and reduce the speed of the simulation. Collision data is stored in the 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 exhaust all memory resources. To minimize this, ensure that the data is written out routinely.

Note: As of EDEM 2020.1, the forces for collisions are undamped.

Energy Loss

Energy loss in a collision between two elements (particle-particle or particle-geometry) lasting n contacts over time is calculated by:

E_{d} = t_{c o n t a c t} \int 0 (F_{n}^{d} d δ_{n} + F_{t}^{d} d δ_{t})

$E_{d} = \int_{0}^{t_{c o n t a c t}} (F_{n}^{d} d δ_{n} + F_{t}^{d} d δ_{t})$

Where


Expression	Description
F	Contact force [N]
V_i	Relative velocity after contact [ms^-1]
V_i-1	Relative velocity before contact [ms^-1]
d_t	Time step [s]