Hi,
I am a new one to DEM in liggghts.
I am trying to model confined compression (oedometer) test in liggghts. My experimental void ratio (i.e volume of voids /volume of solids) is 0.6. my container is a cylinder of size 5cm dia and height 2cm height. I calculated number of particles for that void ratio inside the container, then inserted a 50% of actual size particles and then let them grow. when they grow they are actually more than 2cm height. So in the second try i created a horizontal wall at a height of 2 cm then let the particles get generated and grow within the confined space. Then tend to be fully packed. But when I release the wall at the top after equilibrating the particles fly off unstable.
Whats wrong with my method of generation. Between how to generate dense packings in DEM in liggghts.
regards
Monica
iluvatar | Mon, 12/03/2018 - 04:59
Are you letting tha packing relax?
Hi, first of all, are you letting your packing relax after growing the diameter? Second, what do you mean when you say that you release the wall? if I understand well and you want the particles to be compressed under certain force, maybe you should use a fix fix mesh/surface/stress/servo, you can see the docs at https://www.cfdem.com/media/DEM/docu/fix_mesh_surface_stress_servo.html . I hope this helps.