yade-dev team mailing list archive

[Václav Šmilauer <eudoxos@xxxxxxxx>]

> I am not as confident as you. Imagine spheres that do not overlap on a regular grid.
> If you impose a shear rate at constant volume (without gravity) by making the displacement of each sphere proportional to their height (the total height of the cell remain constant), I think that the spheres will never interact (!) By imposing velocity proportional to the height, the displacement of each sphere will be different due to the different inertia. So, it seems not exactly equivalent in my opinion.

I think there is some misunderstanding, read the code in doubts.

The cell size changes, that's why it makes sense to displace sphere in
such way that those at the boundary move the same as the boundary and
the ones in-between interpolate this displacement. This effectively
avoids the boundary effect, since it disperses the change everywhere
exactly the same. (The velocity increment adds velocities corresponding
the cell resizing rather than changing positions directly).

> Even if periodic boundary condition works fine for triaxial loadings, it seems to me that the framework offered by yade deserves more than "tinkering". Otherwise I do not understand the interest! For this reason, I think it would be interesting to look in more detail what Gael and I say about H, r and s...
> This is not something complicated and it is well-tested.

I would prefer reference to some paper rather than writing formulas in
e-mails. (I appreciate your efforts on trying to make this generally
usable, of course, don't take it wrong!)

v