yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

>
>> 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?).

> 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
Tél : +33 4 56 52 86 21
Fax : +33 4 76 82 70 43
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