yade-users team mailing list archive

[Václav Šmilauer <eudoxos@xxxxxxxx>]

> Simple question about the sign convention used in contact laws. 
> For the total shear force we use the sign minus for the incremental
> way, why not plus? Is this related to the shear direction?
https://bugs.launchpad.net/yade/+bug/493102 It is a bug that we should
solve at some point. I think it is better do define interaction force as
it applies on id2 (since then normal*force=positive for tension).
> Second I am looking at the ViscoelasticPM contact law and I see that
> the total shear force is given by:
> shearForce -= (phys.ks*dt+phys.cs)*shearVelocity;
> Why do we account the viscous force with the same sign of the shear
> one? Should not always oppose the motion?
I am not sure if this is not actually related to the first question.
Sega will give you the anwer, since he wrote that code and he never
commits code that is not perfect.

Cheers, Vaclav