Question #269063 on Yade changed:
https://answers.launchpad.net/yade/+question/269063
Status: Answered => Open
Alexander is still having a problem:
Hi, Jan.
First thanks for strains = [Matrix3(*[TW.deformation(b.id),i,j) for i in
xrange(3) for j in
xrange(3)]) for b in O.bodies] i will check it.
Now the problem, so i also messed with value of Young's module taken 2e9
instead of 2e11 :), that's why the results was so different, now they
are a little bit closer , please see pictures along the direction of
pressure F.
displacement Yade -
http://i11.pixs.ru/storage/5/9/0/pic1JPG_8725641_18032590.jpg Ansys -
http://i11.pixs.ru/storage/6/1/0/pic4JPG_2632224_18032610.jpg
stress Yade -
http://i11.pixs.ru/storage/7/6/4/pic2JPG_7240037_18032764.jpg Ansys -
http://i11.pixs.ru/storage/6/5/6/pic5JPG_6182930_18032656.jpg.
Talking about stress besides values range i also don't like
distribution because of the spheres on ABCD and KGOH has minimal values
(marked with red rectangules) . Stress distribution should be something
like in Ansys, because we checked it it with another FEM simulator
(http://i11.pixs.ru/storage/7/5/5/pic7JPG_3148063_18032755.jpg).
You already made comment: "at boundaries (=all spheres in your example
:-), the values might be approximated worse and also the physics itself
(distribution of interactions) is different than in "bulk" spheres." So
should i left this situation like that or do something? Anyway showing
stress distribution like that is not ok.
Well now about calibrating 'young' and 'poisson' arguments.
I fluently read your article (soon I'll try read it in details). As i
understand the final relation between macroscopic material properties
and microscopic model parameters described by the formulas (highlighted
in red)(http://i11.pixs.ru/storage/8/1/0/pic3JPG_6512680_18032810.jpg) .
So should i use these formulas or set 'young' and 'poisson' empirically
(by changing their values and compare with Ansys)?
If i need to use formulas the questions are:
1) where can i get k_N and K_S params in CpmMat?
2) Also how to get L_c, as i understand L_c is the distance between centers of
each 2 sphere bounded by link (so called bars length),
3) Is it applicable only for model consists of rigid spheres with uniform
radius R?
If i will try second variant (i think it's simplier :) what is the best
stategy to do it? Because i have 2 parameters and should change it
separately (may be i should fix one and change another, or for example
change both of them at one step)?
with regards, Alexander
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