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[Chareyre <question159394@xxxxxxxxxxxxxxxxxxxxx>]

Question #159394 on Yade changed:
https://answers.launchpad.net/yade/+question/159394

    Status: Open => Answered

Chareyre proposed the following answer:

>>> it as well? We could take the size of the cell as a reference (Radjai's
>>> suggestion).
>>>
>> So I missed it (which page?).
>>
> Page 168, hope I read well... Let me know what you think.
>

Page 168 was written by my colleagues Gaël Combe and Jean-Noël Roux
(while I was searching cell's mass in Radjai's PBC chapter) .
I got a chance to discuss the issue with them this week. Actually, when
I asked which mass should be used, the first reply was "use a value that
makes it work"... ;-)
But still, this chapter suggest a definition that is dimensionally
correct, you could try it.
There is no need to change anything in the code, since it's up to you to
give the "mass" value in your scripts. If you find that this definition
is well suited, we can maybe hardcode it in the cpp later, so that
"mass" will be totalMass/L by default (and include a mass factor to let
users modify it if needed).

Independently, I would keep the damping factor as it is now, since in
perfectly elastic situations, eq. [6.7] would oscillate forever.

In the end it would give:

strain_rate[axis] += dampFactor*dt* ( goal[axis]-stress[axis] )
*Length/(totalMass*massFactor); //massFactor=1 by default

Let us know if it works for you.

Cheers.

Bruno

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