yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

> > 2) Why do we need to continue if fn==0?
> >     
> IIRC Bruno told me that was to avoid contacts that transmit no force,
> even if they have non-zero nominal stiffness. Exact zero will be there
> for interactions that really had no force at all.
>
> I am not completely persuaded on that, since most likely contacts with
> exactly zero force will be already erased. Perhaps now it has only
> historical interest now?
>
>   
Interactions without contact (un<0 && fn==0) are not always erased. 
Think capillary law : you can have a capillary force (an interaction) 
between distant spheres, in this case the normal force is 0 (the 
capillary force is not added to fn), and there is really no stiffness to 
consider in GSTS, even if this interaction has kn!=0 and is real.

Bruno