yade-dev team mailing list archive

[Chiara Modenese <c.modenese@xxxxxxxxx>]

On 1 March 2011 01:24, luc scholtes <lscholtes63@xxxxxxxxx> wrote:

> Hi there,
>
> I was looking for a way to compute stress in a given subdomain and just
> found this thread :-)
>
> My purpose is to have a look at the respective distribution of normal (Sii)
> and shear (Sij) stress components in my cohesive assemblies.
>
> Has anybody already tried something? Chiara, did you manage to extend the
> bodyStressTensors function to a subdomain?
>
Hi Luc, I think the algorithm proposed by Bruno (see this thread) should
work. I am about to try as well but you are welcome to try to do it first.
;-) The only thing to compute is the volume, the function for the stress is
already in the code.

Chiara

>
> Cheers
>
>   Luc
>
> 2011/2/10 Vincent Richefeu <richefeu@xxxxxxxxxxxxxxx>
>
>
>> Le 9 févr. 2011 à 17:45, Bruno Chareyre a écrit :
>>
>> >
>> >> Oh simply cubic. Say that you divide the main cell into 8 cubic parts
>> >> and then you get the average of stress in each of them (I simply want
>> >> to compare them).
>> > Here is the algorithm :
>> >
>> > foreach sphere:
>> >    cubeStress+=bodyStress(sphere.id)*volumeInsideCube
>> > cubeStress/=cubeVolume
>> >
>> > Then if you have N cubes, sum_N(cubeStress)/N will be exactly the stress
>> > in the cell.
>> >
>> > Probably similar to what Vincent suggests. I don't think it is
>> > equivalent with weighting by branch length, since volumeInsideCube is a
>> > non linear function of position.
>> >
>> > Writing the volumeInsideCube function will be the boring part...
>> >
>> > Bruno
>>
>> I agree with you Bruno. Your 3-line algorithm is what I suggest in a more
>> readable way (less words = easier to understand)
>>
>> Chiara, I have no reference about it. Just some discussions with JJ Moreau
>> when I was in Montpellier.
>> I can scan and send you some explanations if you want, but I think Bruno's
>> mail is clear enough.
>>
>> I don't know if you use sphere bodies. If yes, computing a local mean
>> stress could be easier with a function volumeSphereInsideSphere (instead of
>> volumeInsideCube), but sum_N(sphereStress)/N will NOT be the mean stress in
>> the cell...
>>
>> Vincent
>>
>>
>>
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