yade-dev team mailing list archive

[Klaus Thoeni <klaus.thoeni@xxxxxxxxx>]

Everyone on holidays already?

Well I am still wondering why for the calculation of the stiffness of a sphere 
and a facet the radius of the facet is assumed to be twice the radius of the 
sphere. This is basically the value comming from GenericSpheresContact. In my 
opinion it doesn't make sense. The facet can be seen as a sphere with radius 
infinity. So if we take the harmonic average (as it is done in 
Ip2_FrictMat_FrictMat_FrictPhys ) considering e.g. rb->infinity the stiffnesses 
become kn = 2*Ea*ra and ks = 2*Ea*ra*Va.

You agree? If so I could commit the changed code. Please let me know.

On Sun, 11 Dec 2011 06:38:35 PM Klaus Thoeni wrote:
> Hi Guys,
> 
> what value for refR does the GenericSpheresContact return for a facet? By
> introducing TRVAR2( Ra, Rb ) e.g. in Ip2_FrictMat_FrictMat_FrictPhys::go it
> seems if a sphere is intersecting with a facet the refR value for the facet
> is just 2*refR of the sphere. Is this true? And when yes, what's the
> reason? It's fundamental for kn and ks, isn't it?
> 
> Thanks,
> 
> Klaus
> 
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