yade-dev team mailing list archive

[Chiara Modenese <c.modenese@xxxxxxxxx>]

On 8 February 2011 12:54, Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx> wrote:

>
> >
> >> I was thinking about the meaning of bools like reversedForces,
> >> compressivePositive and so on.
> >> Recently I was quite confused about that and my point is: say that in
> >> our contact law we decide that compressive forces are positive. Then,
> >> why not be consistent and take compressive stresses also positive? Do
> >> you agree that the bools above generate a lot of confusion? Why do we
> >> need them?
> > My opinion is that it would be nice if one script can be used with
> > different contact laws, just by changing Ig2/Ip2/Law2 functors; if
> > stress depends on the contact law, then one has to adjust also stress
> > values (goal stresses, for instance), and keep in mind which contact
> > law uses which convention etc.
> >
> Goal stresses don't have to be changed, compressive stresses are always
> negative. The only thing that needs to be changed in scripts (still too
> much, I agree) is you need PeriTriaxController.revertSign=false with
> Dem3DofGeom laws, and PeriTriaxController.revertSign=true with ScGeom
> laws (L3 laws are like Dem3Dof?).
>
Oh right, goal stresses should not be changed. I would also agree with the
idea below.
Cheers. Chiara

>
> > I added the Scene::flags thing recently, which should automatize this,
> > so that the contact law would say itself which way it stores force,
> > i.e. whether NormShearPhys.{normal,shear}Force are forces applied on
> > id1 or id2, and then functions like stress tensor would just query
> > that value.
> > It is a shame that code is not consistent in this respect, but if
> > there is no interesting to fix the cause, it can be worked around in
> > this way.
> >
> Good idea. I was thinking about a bool "signConvention" in IPhys
> (defined in laws), but it will be simpler with your solution.
>
> Cheers.
>
> Bruno
>
>
> > Cheers, v.
> >
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>
>
> --
> _______________
> Bruno Chareyre
> Associate Professor
> ENSE³ - Grenoble INP
> Lab. 3SR
> BP 53 - 38041, Grenoble cedex 9 - France
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> Fax : +33 4 76 82 70 43
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