yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

> 1) was it done already by someone, and I missed this?
>
>   
Membranes have been fully implemented for a while, as minkowsky sums of 
triangulated surface and sphere, in... SDEC!
The most complex part to implement in Yade is you have to track when 
interactions are going from body-facet1 to body-facet2, in order to 
guarantee the continuity of the force.
If you want to try and implement that in Yade, I'm sure colleagues will 
be glad to provide their SDEC code.

> 2) it is maybe not necessary, because periodic boundaries also allow
> to see localization due to shearing? (I doubt that, because the shift
> on one side is on different height than the shift on right side).
>
>   
Not sure.
> To detect spheres that touch the membrane I will do a Delaunay
> triangulation of whole sample, with extra four points added. Each of
> those four points is on the exterior of the sample and is a
> "membrane point". Any sphere that gets connected through Delaunay
> with this point must be lying on the boundary and is in contact with
> membrane.
>   
This is already implemented in Yade, with weighted "radical" Delaunay. 
See e.g. volumicContactLaw or TesselationWrapper::addBoundingPlanes, 
where bounding planes are spheres of very big radius far away from the 
packing (distance=radius).

> I suppose that eigen has Delaunay triangulation.
No, eigen is only for basic linear algebra, but you can use CGAL.

http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Triangulation_3/Chapter_main.html
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Triangulation_3_ref/Chapter_intro.html

Bruno


--
_______________
Bruno Chareyre
Associate Professor
Grenoble INP
Lab. 3SR
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 43
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