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Re: Modification in Cundall damping - IMPORTANT


Damn! I'm sorry to tell that but I just double-checked the equation of 
damping in PFC3D, and unless there is a typo in the PFC documentation, 
PFC3D uses the same form of damping as the one that was in Yade before I 
change it (i.e. independent damping of each component of forces and 

This is very strange as i'm sure that such damping can result in 
oscillations around positions that are not equilibrium positions!
I've had a look in the litterature and I've found both forms of damping 
depending on the authors.
I've even found some authors using the same form of damping as me... and 
considering it as the usual Cundall non-viscous damping...

So I don't really know what to do now... Personnaly, I'll stick with the 
equations of damping in the current (modified) form, even if it's not 
the "true" Cundall damping. But it is correct to let people download 
Yade and use classes named "CundallNonViscous..." if the equations 
inside are perhaps not exactly the Cundall ones (I'm still trying to 
find the early papers of Cundall to check this though...)?


Janek Kozicki a écrit :

>Bruno Chareyre said:     (by the date of Mon, 20 Nov 2006 12:36:54 +0100)
>>The new equations of damping have been commited to Berlios repository.
>>If you checkout repository, be aware that you will now have the 
>>CundallNonViscousForceDamping.cpp and 
>>CundallNonViscousMomentumDamping.cpp as modified by me...
>>It should not be a problem for anyone as the new equations are supposed 
>>to be better ;), so in fact I recommend that you update your source now :).
>Great, thanks!

Chareyre Bruno
Maître de conférence

Institut National Polytechnique de Grenoble
Laboratoire 3S (Soils Solids Structures) - bureau I08
BP 53 - 38041, Grenoble cedex 9 - France     
Tél :

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