DISCRETE ELEMENT METHOD

What is DEM?  
DEM simulation DEM is a mathematical modeling technique that applied to communition uses Newton's second law - kinematics - to calculate the position of each elements  - balls and ore particles of all sizes  - as they are affected by each other and in contact with liners, lifters and grates. The first DEM models for milling were 2D and viewed the charge motion as a cross sectional slice of the cylindrical mill. The models improved into 3 space which included the effects of the cone shaped mill ends on particle motion. Recent improvements, a visual example displayed to the right, have incorporated other modeling methods such as computational fluid dynamics and discrete grain
breakage.

High Fidelity Simulation is the term now used to describe the combined modeling techniques.

DEM continued...

DEM is well suited for computer programming since the computations involve solving the position formula
simultaneously for huge number of particles and one instance in time. These vector based motion equations
use fixed parameters for particle shape, density, stiffness, friction. Linear and rotational velocities of each                    photo from Conveyor-Dynamics.com
 sphere are calculated via numerical integration of  Newton's second law. The displacement of each sphere is calculated by a second integration.
The particles start at rest and then set in motion. The calculation is performed for an initial t, then t +1, t+2, t+n.

                                                                                                                                                                   

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