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[janaka kumara <question172107@xxxxxxxxxxxxxxxxxxxxx>]

Question #172107 on Yade changed:
https://answers.launchpad.net/yade/+question/172107

    Status: Answered => Open

janaka kumara is still having a problem:
Hi,

Simulations were done using TriaxialTest in FileGenerator (from
Preprocessors) as given in Yade Reference Documentation, Release 1st
edition (2011), pp 76 - 85.

All eii and porosity were taken from the recorred file named,
WallStressRecordedFile. Void ratio is calculated using this porosity
i.e. void ratio = porosity/(1-porosity). Moreoevr, the above results are
related to isotropic compaction as Chareyre guessed.

@ Chareyre,
Yes, I agree that the equality I have in mind is an approximation. However, I thought the difference I experienced is very large e.g. evol = 1.10 when Db/(1+b0) = 0.65. 

I checked my data with your idea that  "If the deformation is e11, e22,
e33, then new volume is
(1+e11)(1+e22)(1+e33)=1+e11+e22+e33+e22e33+e33e11+......Hence dV/V is
NOT e11+e22+e33" (however, replacing '-' instead of '+' e.g. (1-e11)
instead of (1+e11) because this is compaction and '+' should make
difference bigger). However, results gave as DV/V = 1.00 while Db/(1+b0)
= 0.65. However, I am checking now whether initial volume of the cube
automatically  takes 1x1x1 rather than what I see during simulations
(i.e. 0.41570403939060774 x 0.41570403939060774 x 0.41570403939060774).
If the cube is 1x1x1, the difference becomes smaller but I think there
is no reason it to be 1x1x1 always.

@ Jduriez,
I think, I didnt understand well what you mea by  first order approximations (= "small transformations" hypothesis, isn't it) is a crude approximation ?. Anyway, I think you mean only first order eii is considered for DV/V determination in Yade?. 

@ Vincent,
If you mean that dV/V = Db/(1+b0)  = tr(EPS), here b is void ratio, No, that too doesnt work well. 

I am sorry if this doesnt give you my ideas well.

Any clarifications are really appreciated.

Thank you,
Janaka

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