yade-dev team mailing list archive

[Václav Šmilauer <eudoxos@xxxxxxxx>]

Bruno,

in r1926, I got rid of Cell::strain and use Cell::trsf instead (current
transformation, i.e. F); this way there is no strain+Id=trsf, which you
didn't like. I also renamed a few data members to be more descriptive
(such as shearIncrt -> trsfInc and so on).

Referring to http://en.wikipedia.org/wiki/Finite_strain_theory, what
does velGrad correspond to? I am still a little at loss with this one.

I don't understand how to prescribe per-component transformation rate.
For instance I want pure shear in xy plane along +x axis, i.e. constant
rate of εyx (whatever we have as definition of εyx), without volume
changes; just pure shear. What value of velGrad will achieve that?

(For instance scripts/test/periodic-triax-velgrad.py, how to make pure
shear in the xy plane, without continuously decreasing y-size of the
cell? O.cell.trsf is Matrix3(0.944438,0.360025,0, 0,0.944438,0, 0,0,1),
but I would like it to be Matrix3(1,...,0,0,1,0,0,0,1). )

I would like to have some straightforward way, something like
trsfRate=Matrix3(0,1,0, 0,0,0, 0,0,0), which would progressively apply
just that one shear.

Cheers, Vaclav

PS read commit message for r1926 re NewtonIntegrator & getTrsfInc.