yade-users team mailing list archive

[Luc Sibille <luc.sibille@xxxxxxxxxxxxxx>]

Hi Nejib,

In the TriaxialCompressionEngine, I think there is a booleen that you 
can swith from 1 to 0 to stop the computation when the compaction is 
finished. I don't remember the name of the booleen, but it should be 
something like "AutoCompressionActivation".

About the stress deviator q: generally speaking, during the compaction 
phase Yade tries to reach the same stress value for the three space 
direction. During the compaction, sigma_1, sigma_2 et sigma_3 may be a 
little bit different, thus you can compute a non vanishing q value 
(negative or positive), but q value should be very small (and it is not 
really a problem).
Does it solve your problem?

  Luc


nejib hadda a écrit :
> I don't see how to seperate these two phases on yade.
> In fact what I want to do is to compact my specimen before launching the
> calculus so that I get the density I wish to have.
> But here, yade do both phases simultaniously, and the phase at which q
> takes negatives values is the phase of compaction which corresponds to
> the first ietrations.
>
>
> Le mardi 08 décembre 2009 à 17:55 +0100, Luc Sibille a écrit :
> > For which phase have you got negative q values? The compaction phase, 
> > the deviatoric phase, ... ?
> >
> > Hadda Nejib a écrit :
> > > I don’t know if it is common in YADE to have negative values for the 
> > > deviatoric stress q   in both triaxial test and triaxial test water for 
> > > the first iterations (numerical problem) until the specimen is 
> > > stabilized. I have also always had this sudden fall in the value of 
> > > sigma22 after some iterations at the beginning of my simulations.
> > >
> > > Shall I take the initial value of sigmaisocompactation near to value of 
> > > the confining pressure to avoid such problem ?
> > >
> > >  
> > >
> > >  
> > >
> > >
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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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