yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

If you really want large and strict rigid body rotation in one step, my 
script is not exactly doing the job (you tried it yes?).
Why not rotating the loading instead? It is equivalent and needs 0 lines 
of code.

B.

_honzik@xxxxxxxxxx a écrit :
> Hi Bruno,
>
> the goal is to rotate cell and particles before the actual simulation starts and use this configuration as the initial state of the simulation..
>
> You are right, we force periodicity not aligned with packing periodicity :-) Rotating both cell and particles would solve it (but rotate particles as a poor geometrical action, not dynamic)
>
> Jan
> ______________________________________________________________
>   
> > Od: "Bruno Chareyre" <bruno.chareyre@xxxxxxxxxxx>
> > Komu: yade-dev@xxxxxxxxxxxxxxxxxxx
> > Datum: 30.06.2010 11:13
> > Předmět: Re: [Yade-dev] Bugs in Cell
> >
> > I don't really see a problem in wrapPt. It is not used directly but inside wrapShearedPoint, which is correct.
> > The apparent crazyness of your script result is because you force periodicity not aligned with packing periodicity.
> > If what you want is moving bodies with cell, you need Newton integrator.
> >
> > Try this below in your script, does it help?
> >
> > Bruno
> >
> > a=1.; r=a/4.
> > O.bodies.append(
> >    [utils.sphere(c,r) for c in [(r,r,r),(3*r,r,r),(3*r,3*r,r),(r,3*r,r),(r,r,3*r),(3*r,r,3*r),(3*r,3*r,3*r),(r,3*r,3*r)]] 
> > )
> > O.dt=10e-6
> > O.periodic=True
> > O.cell.refSize=(a,a,a)
> > zRot=-pi/100.
> > O.cell.velGrad=Matrix3(cos(zRot)-1,-sin(zRot),0,sin(zRot),cos(zRot)-1,0,0,0,0) 
> > O.engines=[NewtonIntegrator(homotheticCellResize=2)]
> > p7=O.bodies[7].state.pos
> > # run and look
> >
> >
> >
> >     
> > > The bug is in Cell.hpp in wrapPt method. If the cell in not rotated, it is ok. But if you apply rotation, periodic shifts are performed along new (local) coordinates, however, the cell is not periodic in this direction (sorry, Vaclav, I yesterday said tho opposite :-)
> > >   
> > >       
> > -- _______________
> > Bruno Chareyre
> > Associate Professor
> > Grenoble INP
> > Lab. 3SR
> > BP 53 - 38041, Grenoble cedex 9 - France
> > Tél : 33 4 56 52 86 21
> > Fax : 33 4 76 82 70 43
> > ________________
> >
> >
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> >     
>
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--
_______________
Bruno Chareyre
Associate Professor
Grenoble INP
Lab. 3SR
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 43
________________