yade-users team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

> If you generated a
> simulation where you have 1 box, filled with spheres inside, it would all
> totally explode, because spheres would behave is if they were INSIDE a
> solid box.
>
>  
But... I thought ImpactTest was generated using a box...
Ok, I see : in fact it uses 6 boxes...
There is a simpler way to represent a wall-boudary : a finite or 
infinite plane, no need to assign it mass/thickness, stiffness is 
enough. I had almost the same idea when I thought to _*one*_ box for the 
triax.
I will probably implement one of the two solutions (if not both) in the 
future.

> First (simplest
> approach) will add Stiffness without checking whether it is a sphere or
> a wall, so all spheres will also have their total contact stiffness
> summed, not only the walls.
In fact the total contact stiffness of a sphere is needed to compute 
accuretly the critical time-step (Tc).
I remember I was a bit puzzled when I looked how Tc is currentmy 
computed in Yade (but I can't remember exactly). So, perhaps it is not a 
bad thing after all to compute the total stiffness of spheres. The 
method I know to evaluate Tc is based on the matrix Mij so that dRi = 
Mij*Uj (where Ri is the resultant and Uj the displacement of the sphere).

> 3. once you have Stiffness in physicalActionContainer - you can access
> it from you DeuxEx just like you can access Force.
>
> this was a brief explanation of the idea which I have in mind. tell me
> if you understand it :) 
I understand the overall idea, but I am not sure I understand precisely 
this line (from ForceEngine.cpp) :

static_cast<Force*>( ncb->actionParameters->find( b->getId() , 
actionParameterForce->getClassIndex() ).get() )->force += force;

Could you comment a bit on this?

> I feel a small temptation to do it myself,
> because it's interesting. But I have also other work to do (lattice and
> documentation).
I must learn to do the job myself. If not, I will never take advantages 
from using Yade :).
Your help is invaluable, it should be enough :).

> it is
> easier to modify .pro files by hand (for example with F4 from mc), than
> to edit them with kdevelop3. (kdevelop3 displays scopes in a weird
> manner, so better ignore it - I hope that they will fix this in near
> future).
>  
"F4 from mc" ???!

> As a general rule - when you work with yade - it is better to add new
> classess than to modify existing ones :).
>  
Of course. When I say "modify" (previous mails), I think copy/paste in 
new file and modify.

> > "Error: Could not open /dev/nvidiactl because the permissions
> > I know how to solve it temporarily (chmod on OGL files each time I start a KDE session). 
> >    
> >
> > > > I just change
> > > > /nvidia*:root:video:0660
> > > > /
> > > > to
> > > > /nvidia*:root:video:0666/
> > > > in udev.permissions. It should fix the problem (I did not check yet).
> > > >        
> > Do you have an idea if this may be due to Yade?!
> >    
>
> your fix works,

In fact it does not apparently :-(.
I will try what you recommend. But note that the problem is still here 
after I uninstalled the last version and re-installed the "official 
release".

>

--
_______________
Chareyre Bruno
     Maître de conférence
     Institut National Polytechnique de Grenoble
     Tél : 04.56.52.86.21
     ________________________________________      
     bureau I 08
     Laboratoire 3S (Soils Solids Structures) 
     BP 53 - 38041, Grenoble cedex 9 - France 
_______________