generation of non-spherical particles in LIGGGHTS

Submitted by keepfit on Fri, 12/30/2011 - 19:22

Hi Christoph,

I was wondering, how do you generate non-spherical particles in LIGGGHTS according to the mesh scanned from Laser Scanner?

1) Simply fill in single particle inside the mesh manually with minimum number of particles?

2) or fill in automatically by means of certain algorithm according to the points or surfaces?

I think method 1) is not difficult but can not apply to large-scale case, for example thousands of rock with different shapes. So is it possible to generated rocks with random shapes based on basic types of rock (e.g. flat, compact and elongated) which are already scanned into mesh model?

Thanks in advance.

Best regards,

David Long

Forums:

keepfit | Tue, 01/03/2012 - 13:17

thanks Christoph.

Now I am using some other algorithm to generate stones with random , simple shapes (less than 10 spheres), which can be used to simulate large-scale project comprising many discrete stones efficiently.

http://www.springerlink.com/content/g1307987l7u18412/
http://www.tandfonline.com/doi/abs/10.1080/17486020802253992?journalCode...
http://www.icevirtuallibrary.com/docserver/fulltext/geot59-779.pdf?expir...

Cheers,

David Long

Bajo87 | Sun, 01/29/2012 - 00:26

Hi Christoph,

can you explain how you are doing the "Multisphere from CAD model". I think it is just possible with the developer version of liggghts, but what functions do you use to realise it?

Is it also possible to generate e.g. a defined mass of multisphere particles?

thanks, best regards
Alex

ckloss's picture

ckloss | Mon, 01/30/2012 - 13:13

We have a paper in the pipeline about this:

"Approximation of objects by spheres for multisphere simulations in DEM", ECCOMAS 2012 Congress, MS202: Modelling of medium to dense gas-particle flows - Discrete element methods; Authors: S. Amberger, M. Friedl, C. Goniva, S. Pirker, C. Kloss, all Johannes Kepler University/AT

As available we will probably post the paper here

Christoph

Bajo87 | Thu, 03/15/2012 - 22:15

Hello Christoph,

in the update 1.5.2 there is a new command "particletemplate/multisphere". I tried to test it put I didn't get it working, there is also no reference in the documentation. Can you explain me the code for a multisphere template with eg. 2 particles?

fix pts1 all particletemplate/multisphere ....

I think I will need the following commands "nr of spheres", "coordinates" , "radius", "density" but I don't know the right order and style for the multisphere template.

regards
Alex

ckloss's picture

ckloss | Fri, 03/16/2012 - 09:11

Hi Alex,

do you mean fix particletemplate/multiplespheres ? this was new in 1.5.1 to enable the breakage functionality, but I did not have time to add a doc, but have a look at the 'breakage' example.

Cheers, Christoph

Bajo87 | Fri, 03/16/2012 - 14:46

Hi Christoph,

that's right, I mean the particletemplate/multiplespheres command.
Thanks, I will test it with the breakage example.

regards, Alex

andybond13 | Wed, 06/12/2013 - 16:03

Has there been any progress on the documentation of this multi-sphere feature? The breakage example uses single-spheres of multiple sizes to eventually break a particle into a number of smaller ones, but doesn't provide a good example of bonded spheres that overlap (i.e. multi-sphere method).

The following video on the features page of the website does show what I'm interested in: complex particle shapes resulting from clumped/bonded spheres: http://cfdem.dcs-computing.com/media/DEM/nonspherical/multisphere.avi

Could you share the input file for this simulation?

Thanks - Andy

ckloss's picture

ckloss | Thu, 06/13/2013 - 17:56

Hi Andi,
this is not in the public release. In the next few months, we will make a major update of the website, denoting clearly which features are in the public version

Cheers
Christoph

nateanderson | Thu, 08/22/2013 - 19:23

Christoph,

I am in the process of evaluating software to determine which code my company should invest in. The website update would be helpful, but it appears that it has not be completed yet. Can you list which features are included in the public version?

Thanks

ckloss's picture

ckloss | Fri, 08/30/2013 - 15:36

Hi Nate,

thanks for your interest. We'll post the list here along with the website re-launch but not earlier.
If you need more information, feel free to mail me directly!

Cheers
Christoph