← Back to team overview

yade-users team mailing list archive

Re: General questions


> 1) I would like to know why Yade performs the calculation of the contact stiffnesses using the Poisson’s ratio and the Young’s modulus, instead of just assigning ks and kn for each particle. If I say it correctly, the latter was the case in SDEC (that in practise implies having the same contact stiffness for each particle). 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..
Interaction properties are (normally) computed from bodies' material.
Materials can be shared, then the result will be always the same. If you
want and need it (although it is structurally counter-intuitive), you
can have special engine (Ip2_*_*_*) that will hardcode stiffnesses of
interaction regardless of material properties.
> 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..
Oh, yes, IIRC CwBoon asked that questions and there was no reply,
although I thought I should reply. I don't know, I think it would be
possible with Paraview and VTKRecorder. If you use the "intr" recorder
of VTKRecorder, there will be scalar field "forceN" and "absForceT". You
can add cylinder glyphs to the rendering pipeline and have their radius
scaled based on forceN/absForceT. (didn't try, but shuold work)
> 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?
Virtual contacts are implementation detail of collider and should not be
visualized. The only exception is intrAllWire option of the built-in
renderer that draws lines in green (real) and bluish (virtual) between
respective bodies; it was mainly meant for debugging collision
detection, nothing else.
> 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?
Use trunk, period. Those name changes were quite exceptional (there will
be only a few to come, no worry). There will be stable release, but not
now, since many things are half way. Don't use 0.20 in any case, or you
will get in trouble when adjusting for newer code.

Cheers, Vaclav

Follow ups