yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

Václav Šmilauer a écrit :
> > > But I get in trouble there is no easy way to separate scaling and
> > > (rotation+shear), right? Setting 1s on the diagonal is clearly nonsense,
> > > although that is what we (I) do now.
> > >
> > >   
> > >       
> >     
> I think I am on the right track now with this. Not as difficult as I
> tought.
>
>
>   

Cool!

I'll merge engines in the evening, so you will at least be able to 
compare r1926 and r1929. Even if stiffness works, I'd like to keep both 
controls for comparisons (one type of control or the other might be 
better in different situations, even though I prefer the stiffness 
approach to avoid instabilities).

One remark on "separate scaling and (rotation+shear)".
Actually, scaling IS shear, they are really exactly the same thing 
represented in different coordinate systems. You can only separate 
rotation. I'm sure you figured that already. ;)

The difference between pure shear and simple shear is there is a 
rotation of the material (relative to the principal axis of the strain 
rate tensor) in the second one. In this special case (simple shear), the 
rotation needs nothing special and the current code works I think (or I 
missed some details concerning bb's, collider, or interactions).

Bruno





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