yade-dev team mailing list archive

[Vincent Richefeu <richefeu@xxxxxxxxx>]

Hi,

Have a look to this paper: http://www.springerlink.com/content/l133vr26m7142101/
I can send you the pdf if necessary.
The stress computation at particle level is explained in section 5. Basically, it correspond from the dimensional point of view to the moment tensor divided by a volume. The volume can be chosen so that the sum of all particle-stress equal to the global stress. In Eq. 14, I assumed a homogeneous solid fraction ('compacité' in French), but this assumption can be avoided by using the voronoi-cell volumes...

Another think: I believe we can not talk about "exact mean stress tensor" at the particle level since the local volume is not well definable.

Vincent

Le 17 janv. 2011 à 20:43, Anton Gladky a écrit :

> Thanks, Bruno!
> 
> I will have a look at this, but, please, do not delete the previous function, it is used in VTKRecorder.
> 
> Anton
> 
> 
> 
> On Mon, Jan 17, 2011 at 6:44 PM, Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx> wrote:
> XLatexIt! run report...
> *** Found expression $$\sigma_{ij}^{macro}/compacity$$
> Image was already generated
> *** Found expression $$\int_V s_{ij}dV = \int_{S_V} x_i.s_{ij}.n_j.dS = \sum_kx_i^k.f_j^k$$
> Hi,
> 
> I've been adding another definition of stress in particles (not adapted to periodic BCs yet, though not difficult).
> For those interested. The documentation is pasted below.
> _____________
> Compute the exact mean stress tensor in each sphere from the contour integral of applied load.
> After divergence theorem, at equilibrium:
> <tblatex-11.png>.
> This relation applies for arbitrary shapes but the result has to be divided by the solid's volume, computed here using the radii, hence assuming spheres. The (weighted) average of per-body stresses is exactly equal to the average stress in the solid phase, i.e. <tblatex-8.png>.
> _____________
> 
> Cheers.
> 
> Bruno
> 
> 
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-dev
> Post to     : yade-dev@xxxxxxxxxxxxxxxxxxx
> Unsubscribe : https://launchpad.net/~yade-dev
> More help   : https://help.launchpad.net/ListHelp
> 
> 
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-dev
> Post to     : yade-dev@xxxxxxxxxxxxxxxxxxx
> Unsubscribe : https://launchpad.net/~yade-dev
> More help   : https://help.launchpad.net/ListHelp