yade-users team mailing list archive

[Luc Sibille <luc.sibille@xxxxxxxxxxxxxx>]

Hi Nejib

nejib hadda a écrit :
> Hello Bruno,
>
> I am not Talking about changing the wall thickness in the xml file which
> by increasing the wall thickness gave me an extension in the compression
> direction 'axis2' and the lowest value of stress was S22, but actually
> I'm talking about incresing the wall thickness when generating the
> packing!
>
> Here I join a figure with 2 curves showing the difference in the results
> using the same values for all the parametrers  but  the wall thickness.

Are the two samples exactly the same (same spheres, with the same radius 
at the same place) or are samples statistically similar (same parameters 
 for the generation process, but not for the wall thickness, and 
different initial random cloud of particles)? I understand you are in 
the second case, so you cannot say that there is a difference between 
the curves. In my opinion you don't find exactly the same curves because 
of randomness of the samples, so wall thickness has no influence. Try to 
perform two real triaxial tests with two samples made with the same sand 
at the same density: you will find also such a difference between the 
two curves.


Luc


> Relying on  what you're saying down here, the influence of changing the
> repatition of the same spheres  in a pack is not neglectible.
>
> I think spheres are approximately the same if we keep the same other
> parameters when generation a new pack, just positions changes (since the
> Granular curves of different generation tests keep well superposed)
>
>
>
>
>
> Le mardi 26 janvier 2010 à 18:16 +0100, Bruno Chareyre a écrit :
> > > I confirm that changing the wall thickness (by default on yade about 1%
> > > of the box edge dimension) has influence on these values, but I don't
> > > know if  changing the wall thickness can keep the problem well
> > > positioned.
> > >   
> > This is strange. Box thickness should not change anything, it should not 
> > even be a parameter of the simulation actually...
> > Or you changed it in the middle of the simulation perhaps?
> >
> > Bruno
> >
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--
Luc Sibille

Université de Nantes - Laboratoire GeM UMR CNRS

IUT de Saint Nazaire
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44606 Saint-Nazaire Cedex, France

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