The Powders Starter Pack

The Powders Starter Pack consists of nine material models with the following range of behaviors.

The Powder starter pack naming convention refers to the compressibility and flow properties from the Angle of Repose tests.

The simulation decks can be found in the following installation directory: C:\Program Files\Altair\<EDEM version>\EDEM\examples\Powder Start Pack.

To use these material models in a simulation, copy them into the Material library or modify the simulation deck provided.

Material Properties

The following table comprises nine material models indicated by the simulation range of behavior.
Material Untapped Bulk Density (kg/m3) Tapped Bulk Density (kg/m3) Angle of Repose (degrees) Compressibility Flow Character
1 678 733 27.5 Incompressible Excellent
2 675 715 29 Compressible Excellent
3 676 711 28.5 Very compressible Excellent
4 604 659 39 Incompressible Fair
5 619 662 37 Compressible Fair
6 613 650 35 Very compressible Fair/Good
7 514 593 50+ Incompressible Poor
8 523 628 50+ Compressible Poor
9 532 637 50+ Very Compressible Poor
Non-compressible Mid-compressible Highly-compressible
Non-cohesive Case 1 Case 2 Case 3
Mid-cohesive Case 4 Case 5 Case 6
Highly-cohesive Case 7 Case 8 Case 9
Case Sample height before compression (mm) Sample height after compression (mm) Amount of compression (%) Compression Ratio Carr Index (%) Hausner Ratio Flow Character
1 91 83 0.09 1.1 7.5 1.08 Excellent
2 91 66 0.28 1.4 5.59 1.06 Excellent
3 91 49 0.47 1.9 4.92 1.05 Excellent
4 102 87 0.15 1.2 8.34 1.09 Excellent
5 100 67 0.33 1.5 6.49 1.07 Excellent
6 101 50 0.5 2 5.69 1.06 Excellent
7 120 88 0.27 1.4 13.32 1.15 Good
8 118 67 0.43 1.8 16.71 1.2 Fair
9 116 49 0.58 2.4 16.48 1.19 Fair

Particle-Particle and Particle-Geometry Interactions

The following tables comprise a series of Particle-Particle and Particle-Geometry interactions to obtain the relevant material behavior.

Material-Material Interaction Parameters
Powder EEPA Surface Energy (J/m2) EEPA Constant pull-off force (N) EEPA Contact Plasticity Ratio EEPA Slope Exp EEPA Tensile Exp EEPA Tangential Stiffness Multiplier Material-Material Rolling Friction Material-Material Static Friction Material-Material Restitution
1 0 0 0.1 1.5 5 0.28571 0 0.3 0.5
2 0 0 0.5 1.5 5 0.28571 0 0.3 0.5
3 0 0 0.9 1.5 5 0.28571 0 0.3 0.5
4 0.05 -5.00E-05 0.1 1.5 5 0.28571 0.02 0.6 0.5
5 0.05 -5.00E-05 0.5 1.5 5 0.28571 0.02 0.6 0.5
6 0.05 -5.00E-05 0.9 1.5 5 0.28571 0.02 0.6 0.5
7 0.25 -0.0001 0.1 1.5 5 0.28571 0.1 0.84 0.5
8 0.25 -0.0001 0.5 1.5 5 0.28571 0.1 0.84 0.5
9 0.25 -0.0001 0.9 1.5 5 0.28571 0.1 0.84 0.5
Material-Geometry Interaction Parameters
Powder Material-Geometry Rolling Friction Material-Geometry Static Friction Material-Geometry Restitution
1 0.15 0.36 0.5
2 0.15 0.36 0.5
3 0.15 0.36 0.5
4 0.15 0.84 0.5
5 0.15 0.84 0.5
6 0.15 0.84 0.5
7 0.15 1.4 0.5
8 0.15 1.4 0.5
9 0.15 1.4 0.5

Research has shown that values of Carr Index below 15% indicate very good flow character but values above 25% indicate poor flow. Also, Hausner ratio values of around 1.00–1.25 indicate free-flowing powder, values between 1.26–1.45 indicate poor flow, and above 1.46 are related to extremely poor flow (Carr (1965), Wells (1988), Marshall (1986). The EDEM tapped density results indicate that the overall flow character of the materials is varied between excellent to fair however, the angle of repose measurements indicates that cases 4-6 have passable flow ability and cases 7-9 have very poor flow ability.

The Angle of Repose results are displayed as follows:

Compressibility test results are displayed as follows:

Each case shows the material before compression (left) and after compression (right),