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[Raphaël Maurin <question239900@xxxxxxxxxxxxxxxxxxxxx>]

New question #239900 on Yade:
https://answers.launchpad.net/yade/+question/239900

Hi all,
 
I have a question about the formulation of the equivalent damping in ViscElphys. For now, it is made such as : 
cn = ((1/cn1) + (1/cn2))^(-1) which is equivalent to cn = cn1cn2/(cn1+cn2)
However, in the case where cn2 = 0 for example, the formulation in the code is not equivalent to the expression above. In the code, it is written that in case of cn2 = 0,  1/cn2 = 0, which gives : cn =  ((1/cn1) + 0)^(-1) 
This is not equivalent to the formulation cn = cn1cn2/(cn1+cn2), because then cn would be 0. (The problem is the same if cn1 = 0)

It seems to me that the formulation of the code is false : if one damping parameter of the contact is zero, then as the two dashpot are considered in series, the equivalent damping should be zero.  
However I am not completely sure it is that simple, so I would like to have your opinion on that.

I hope my question is clear.
Thanks

Raphael

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