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[Václav Šmilauer <eudoxos@xxxxxxxx>]

> in fact I am not yet dealing with cohesive laws. Actually if one wants
> to test the shear direction it is not as straightforward as for the
> normal part. I managed to do that having viscous damping at contacts
> (so that, in a sphere-sphere interaction, you first apply a force in
> the normal direction till you reach equilibrium having a damped
> solution and then you apply the shear force and look at the problem as
> it is in the normal direction, the incremental formulation eventually
> being the only difference). But if I take another law, say the Mindlin
> one, I do not know how to repeat the test not having damping for
> normal/shear direction.
Depends what you expect from pure shear test as output.

For instance, to see plasticity "surface", you could apply normal
displacement at the beginning so that maxFs>0, then turn one sphere so
that you reach maxFs; then progressively go with normal deformation to
zero. That should make shearForce follow maxFs(Fn(t)), eventually
approaching zero.

I don't really see the relationship to damping, either. Sorry.

Oh, perhaps there is misunderstanding about applying force and
displacement. In one-one.py, both spheres are non-dynamic (will not move
because of forces), and using JumpChangeSe3 (weird name, I know) will
enforce exact positions, and, by that token, also exact deformations of
the contact. Then you don't have to care about damping.

v