Based on my test, ScGeom doesn't work in PB. It is (I think) because it
needs relative velocity, which is not defined correctly across periods.
I have a few ideas to solve that though, and some uncommited code (see
**)...
It is a pitty that we can't use the same law in periodic and finite BCs
at the moment. On one hand, there is no sphere-box, hence no
TriaxialTest, with Dem3DOF (facets and planes for boundaries is bugged
for some reasons). On the other hand, ScGeom can't be used in periodic BCs.
just a couple of quick questions about PB.
1) Are you following Cundall's algorithm?
I don't know Cundall's papers on this. Any reference?
2) I see the variable velGrad being a matrix, why?
It is the gradient of velocity. It is a tensor, just like strain tensor
and any grad(vector).
It is the matrix dH/dt in classical litterature on periodicity in
molecular dynamics.
3) I understand it is possible to set the variable
homotheticCellResize as equal to 0, 1 or 2. I was reading Cundall's
paper and I remember he was updating displacements and relative
velocities at contact according to the strain rate. Is this the same
as done in Newton Integrator?
(**) Is not done properly. We need to adjust relative velocities, which
should not be too hard using the shift2 vector in interaction dispatcher
(should be something like velGrad*shift2). It needs to consider the
ordering of the sequence contactLaw/PeriIsoCopressor/Newton carefully, too.
I plan to fix that soon, if I can find time... In the end, the case
homotheticCellResize=1
should disapear and everything will be done via velocity impulses
(homothetic=2), for now it makes things better but not perfect.
By the way, I reply to your questions because vellGrad and cellResize is
the only small part of periodic BC's that is not due uniquely to Vaclav
(they were introduced by me).
Bruno
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