desne granular packing

Submitted by amrita on Mon, 08/22/2011 - 16:06

Hi,
What is the best technique of making dense granular packings in liggghts?
Thanks in advance
Amrita K

Forums:

cgoniva's picture

cgoniva | Mon, 08/22/2011 - 16:35

hi,

please have a look at the liggghts example cases "packing" and "region_tetMesh".

both generate an initial packing.

Chris

amrita | Mon, 08/22/2011 - 16:53

Hi Chris,
I came across one command in "region_tetMesh" file which I can not find in the doc pages of liggghts. Can you give me its detail and function? The command is:
region mesh mesh/tet
Thanks in advance,
AK

ckloss_ | Wed, 08/24/2011 - 00:40

hi, currently there is no doc yet, but there is a tutorial associated with it. Doc will follow shortly (within the next few weeks)
Cheers, Christoph

amrita | Sat, 08/27/2011 - 06:02

Hi,
Thanks for helping me. I have another problem.
I have created dense packing by growing particle diameter method. The final packing fraction is 0.65; this packing is inside big simulation domain and bound with frictional wall. But when I change the value of upper friction wall to new higher value then particles fill the whole new region and packing fraction drops to low value. How can I keep the packing fixed while changing upper wall to new higher value for inserting new particles? For example, zplane of my simulation was this during packing:
fix zwalls all wall/gran/hertz/history 1 0 zplane -0.05 0.05 1

When I restart the simulation and change the value to :
fix zwalls all wall/gran/hertz/history 1 0 zplane -0.05 0.055 1
Then particles fill the new box till 0.55 (upper zwall).
Thanks in advance
AK

raguelmoon's picture

raguelmoon | Sun, 08/28/2011 - 04:59

Hi,
You can use fix wall/region command to bound the particle but I dont know these bound particles will interact with new particles you want to put in simulation box later...
Cheers
Ram

Ram

ckloss's picture

ckloss | Mon, 08/29/2011 - 11:03

what do you mean by "packing fraction drops to low value" - a value like 0.6? maybe the 0.65 was chosen too high?

Christoph

amrita | Mon, 08/29/2011 - 11:25

Hi,
I want to pack particles of particle density 0.65. But when I increase the box size by changing top wall to new value then packed particles suddenly moves to new volume till upper wall limit. It means that now packing faction must be less than 0.65.

ckloss's picture

ckloss | Tue, 08/30/2011 - 08:59

yes but maybe 0.65 is simply to high - either for the geometric configuration or the simulation model?
Christoph