yade-dev team mailing list archive

[Vincent Richefeu <richefeu@xxxxxxxxx>]

Le 20 janv. 2011 à 13:01, Bruno Chareyre a écrit :

> Hi Vincent,
> 
> I didn't see the need to find a reference for contour integral of Cauchy stress, since it is something classical in continuum mechanics courses. The demonstration is in function's documentation.

You're right! Some people consider granular matter as a continuous media. I don't.

> I don't understand this in your paper :
> "At this scale, a Cauchy stress in the sense of continuous media cannot be defined."

The particles are rigid, i.e. 6 independent DOFs and that's all (Elasticity is introduced in force-laws).
We can always define whatever we want. The question is what is the sense of our definition.
As I said, the definition of a particle stress is ok, but the volume used in this definition is a matter of convenience.

Yade users must form their own opinions and given them a function that compute a particle stress is in my opinion a bit dangerous.
Why don't you provide a function to compute the moment tensor and then the user is free to use the volume he want in order to compute the stress?
The real aim of this proposition is to empower the user, who sometime use a function as a black box.

Vincent