yade-users team mailing list archive

[Václav Šmilauer <eudoxos@xxxxxxxx>]

Hi Chia, nice synchronicity, we 've been just discussing this about 5
minutes ago with Bruno and Jan. Greetings to Oxford :-)

useShear does not use the total formulation, it updates (incrementally)
the current value of shear displacement (rather than updating shear
force directly), which you use to compute shear force then (in
Law2_ScGeom_FrictPhys_Basic with useShear, as you say). The shear force
is computed at every step from the current value of shear displacement.

For the total shear displacement, we don't currently have that value
stored anywhere. What you could do is to have elastic+plastic and
elastic displacements and track both of them using ScGeom::rotate; the
latter would be changed during plasticity activation, while the former
one would not.

HTH,

Vaclav (& Bruno & Jan)


> Hi,
> 
> just a confirmation about the way we could compute the contact shear
> force using the total shear displacement. For example, in
> Law2_ScGeom_FrictPhys_Basic if we set useShear to True we use the
> total shear displacement formulation. Then, if we slide, we reduce
> both total shear displacement and shear force. This is correct, right?
> So if I wanted to know how much is the total shear displacement
> (elastic+plastic), I guess I should add a new variable which instead
> would not be updated. Is it?
> 
> Thanks for confirmation.