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EDEM Contact Models
A Contact Model describes how elements behave when they come into contact with each other.
Spinning Friction Contact Model
The Spinning Friction contact model is used to account for the friction that would occur if a particle face is rotating against another particle or Geometry.

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.
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.
- Base Contact Models
  Base Contact models define the physical collision between particle materials or particles and geometries.
- Rolling Friction Contact Models
  Rolling Friction is the resistive force that slows down the motion of a rolling object.
- Spinning Friction Contact Model
  The Spinning Friction contact model is used to account for the friction that would occur if a particle face is rotating against another particle or Geometry.
- Additional Contact Models
  You can also add Additional contact models to a simulation.
- Particle Body Force Contact Models
  You can define a particle body force to act on particles when a specified condition is met, when particles are in certain positions, or are traveling at a specified velocity.
- Plug-in Contact Models
  You can add Plug-in contact models to a simulation.
- Field Data Manager
  Field Data Manager allows you to import and manage field data for use in a Custom model (typically, a Particle Body Force).
- Contact Model and GPU Device Compatibility
  The Multi-Sphere solver can run on two different engines such as CPU and CUDA.
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.

Spinning Friction Contact Model

The Spinning Friction contact model is used to account for the friction that would occur if a particle face is rotating against another particle or Geometry.

Friction involves calculating the contact area and then using this value to obtain the torque on the particles as follows:

\begin{array}{l} M = \frac{2}{3} μ F_{n} R_{d i s k} \end{array}

Where F_n is the normal force, μ is the coefficient of friction, and R_disk is the effective disk radius given by approximating the contact as a disk with area equal to the normal area A_contact of the overlap region:

R_{d i s k} = \sqrt{\frac{A_{c o n t a c t}}{π}}

The torque acts in the opposite direction to the normal part of the relative angular velocity.

A Limit is applied to this torque to avoid oscillating behavior when the angular velocity is small. This is done by finding the torque which would completely eliminate the angular velocity in one Time Step and is described as:

M_{t a n g, t i m s t e p} = \frac{C_{s a f e t y} |ω_{r e l, n}| \min (I_{x, y, z})}{δ_{t}}

The ω_rel,n is the normal component of the relative angular velocity, Δt is the Time Step, and I_x,y,z is the minimum component of the moment of inertia of either of the two contacting objects excluding geometries. The extra C_safety factor is to try to avoid possible instability in cases with multiple contacts and at the moment has a value of 0.125.

The damping to damp rocking is defined as:

M_{n o r m a l d a m p i n g} = - \frac{γ_{n}}{4} R_{d i s k}^{2} ω_{r e l, t}

Where γ_n is the linear damping coefficient in the normal direction from the base model, and ω_rel,t is the tangential part of the relative angular velocity.