Integrating Rotational Degree Of Freedom in EDEM

Task

Understand - how rotational DOF are integrated inside EDEM. For this: prepare simulation which could be compared with analytics.
For this:

1. Prepare factory that creates particles
2. Prepare contact model which describes the rule of interaction
3. Prepare EDEM simulation
4. Measure something and compare it to analytic

Who we are

• Степанов Алексей (responsible for contact model)
• Дзенушко Дайнис (responsible for factory and EDEM simylation)

Factory

We create 2 particles on a distance 0.1m and rotated at an angle of 5-15 () degrees;
These particles are of 2 types "small" and a "big" one; Big particle has identity matrix as rotation matrix; Small particle is rotated using rotation matrix
Particles's velocity and angular velocity equals to zero;
Y and Z coordinates are the same (0.5,0.5); Only X is different (0.45 for "big" and 0.55 for "small");

• For small particle:
  

double OrientAngle = pi/12; // angle between particles in Radians
orientation[0] = 1.0; // Rotating particle. X axis.
orientation[4] = cos(OrientAngle);
orientation[5] = -sin(OrientAngle);
orientation[7] = sin(OrientAngle);
orientation[8] = cos(OrientAngle);

Contact Model

Alexey will soon write about it...

EDEM simulation

Globals:

Interaction: Particle to particle
Model: our contact model
No gravity
There are two materials "material" and "material_2" with different density for "material" 1000 for "material_2" 1.7e+05
Restitution: 0.5
No static and rolling friction

Particles:

We create particles of 2 types;"big" with big moment of inertia (100kgm2 X-axis) and "small"(0.000285kgm2 X-axis);Both particles are made of 2 surfaces placed along Z-axis on a distance of 2 particle radius

Measures

We measured the period of oscillation

Analytics

[math]T = 2\pi\sqrt{\frac{C}{\theta}} = 0.106[/math]

Integration

We measured period using the Graph of angular velocity and got the result
[math]T = 0.082[/math]