Václav Šmilauer said: (by the date of Wed, 27 Oct 2010 17:48:03 +0200)
> > For preparing the sample, it's a bit complicated now because we want > > to use sample with designated grain size distribution and porosity. > > Can Yade create a sample which has specific grain size distribution > > and porosity? What i did was, i wrote a program to put particles into > > a domain, the same size of the real sample, allowing some overlap > > between particles. Then in the simulation i set a higher viscosity > > (to prevent from 'explosion' of the particles) and zero friction so > > that the particles will move to the position. I monitor the kinetic > > energy till it's very low. If this works, then very soon I can > > calibrate the coefficient. > > Hi Jesse, welcome on board! Other people might be better able to reply > to this particular problem, but I will try at least. > > In Yade, you would generate non-overlapping sphere cloud satisfying the > desired particle size distribution (PSD); the function for that is > SpherePack.makeCloud (for piecewise-constant probability density > function, giving piecewise-linear distribution) or SpherePack.particleSD > (for probability density as union of Dirac functions, giving staircase > distribution). > > The next step is to compress the packing up to the point where the > desired porosity value is attained (this step must be currently scriped > using a few lines of python code). You can play with friction of > particles in the step; with zero friction, you will obtain dense > packing, whereas higher friction will create loose packing (friction > prevents spheres from re-arranging). > > The resulting packing will have non-zero overlaps between spheres (some > would say it is not "stress-free"). One cannot prescribe PSD, porosity > and desired overlap at the same time, since they are not orthogonal > (they are all geometrical characteristics). > > I think Chiara has some script she could perhaps send you over, to have > a look at the procesure described. If there is general interest in such > a functionality, it can be factored out into a function in yade.pack as > well. Heh, now I need it, can you share? :) My target is void ratio=0.53, so that would be porosity=0.347 -- Janek Kozicki http://janek.kozicki.pl/ | _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
