Cylindrical container with a random packing of spheres

Submitted by simulguy on Fri, 06/12/2015 - 11:51

I have to write a script that generates a cylindrical container (radius 12.5 mm and height 150 mm) filled with a random packing of 500 glass spheres having the same radius (for example 1 mm).
I am interested only in obtaining the spatial coordinates (x,y,z) of the spheres after running the simulation.
How could I write this script?

Forums:

aaigner's picture

aaigner | Fri, 06/12/2015 - 13:08

Hi!

To write particle-data to a file you have (more or less) two possibilities ...

In case of the dump command you can set to save only x,y and z.
The write_data command will save also other data, but you can easily parse those files with octave/matlab or any other tool and extract the desired data.

bests
Andreas

simulguy | Fri, 06/12/2015 - 13:24

I already know this, but what commands should I put in the input file to LIGGGHTS to generate the packing?

simulguy | Mon, 06/15/2015 - 13:11

There was only a small issue when running it (an error due to a missing empty directory I just created).
It works fine now... Thanks a lot!

simulguy | Mon, 06/29/2015 - 17:19

I generated some packings with the script you suggested, but they seem all too loose.
How could I obtain a denser packing?

aaigner's picture

aaigner | Tue, 06/30/2015 - 18:12

Well... it will get tricky at some point. You will need to compress the particles somehow (servo-wall, addforce) and move the whole particle bed (wiggling plate or so).

Take into account that with mono-dispers particles you can not exceed a volumefraction of ~ 74%. Wiki article

simulguy | Fri, 07/03/2015 - 13:57

Ok, and what should I modify in the script to generate a bidisperse packed bed with 2 kind of spheres, differing for example in size and density?

simulguy | Fri, 07/17/2015 - 16:22

Thank you very much, is just what I needed!