yade-users team mailing list archive

[Václav Šmilauer <eudoxos@xxxxxxxx>]

> Suppose you have the same stress in a sample that 
> is twice higher (y-length) with the same x/z length, the sum of
> forces 
> will be multiplied by 2, you divide by the same area. YOUR stress is 
> twice bigger when it should be the same.

Very true. That explains some pathologic behavior I has with
PeriIsoCompressor when generating thin packings: the thin dimension
would get disproportionally thinner and thinner (as the stress was
always lower, as you explained). Now I just use average stress
(PeriIsoCompressor::keepProportions==true by default) and keep
proportions of the cell exactly, so it is no longer issue in the
practical sense of packings, where exact stresses don't matter that
much.

> If I change the value of, say, rb->cellMax, will it instantly
> translate 
> all particles in proportion? (you remember this old discussion?)

No (yes). But there might be new contacts of particles at the upper
boundary with the particles at the lower boundary (collider's job at
next step), as the boundary is moved.

If you want to translate in proportion instantly, you will have to write
a loop; I don't do that in PeriIsoCompressor.

Cheers, V.