yade-users team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

Hi,
> 1) So, why in Yade did you choose to specify the Young’s modulus and the Poisson’s ratio? Actually I see that in this way we obtain different contact stiffnesses for each particle, but which is the advantage? Just to know..
>   
For me ("advantage" depends on your goals), the main advantage was to 
get a constant ratio between local stiffness parameters and stiffness of 
the packing. Changing particles sizes will not affect this ratio. If you 
like non-dimensional problems, you should like this.
Another advantage is, the Y. modulus of the dense packing will be of the 
same order of magnitude as the modulus you give in the beginnng. You 
have an a-priori estimate.
For Poisson, the name is only due to the fact that Poisson's ratio 
depends mostly on ks/kn. But there is no constant - not even linear - 
relation between the micro and the macro in that case.
> 2) Concerning the display of the force network between bodies.. Has anybody implemented the possibility to display also the intensity of the force network, I mean different thicknesses according to the amount of the contact forces? Probably someone else have already asked this question but I don’t remember whether he received or not any answer..
>   
It is already the case, I don't remember the exact way, but check in gui 
display options.

> 3) Again according to the display of the force network, is this visualization referred to the real contacts, is not it? Are also the virtual contacts somehow visualized?
>   
I don't know.
> 4) I have to start to implement my own engine for a new contact law.. Which release of Yade do you suggest me to start with? Putting it better, I know that the implementation of Yade is a work in progress, but for example I see you have recently changed the names of many variables.. For me it is not so simple to follow every release and if I need to add something I suppose I have to start with a specific one. I know this fact depends on the purpose I have, but is there a quite “stable” version of Yade according to the last changes?
>
>   
Last bzr snapshot is probably the best option. It will be totaly stable 
as long as you don't update it. ;)
The best is to try and update frequently however, always keep backups of 
working code before any update. In the worst case (i.e. you realize 
after a few weeks that you spent more time solving conflicts, filling 
bug reports, or negotiating changes in somebody else's code, than 
actually writing your law), you can always resume working offline.

Don't hesitate to explain here what you want to do, to avoid doing the 
same thing twice. There is an example to help people writing new law 
somewhere IIRC. Vaclav will help better than me on this part (I'm still 
using "deprecated" contact laws on my side...).

Bruno



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