yade-dev team mailing list archive

[Chiara Modenese <c.modenese@xxxxxxxxx>]

On 8 December 2010 12:26, Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx> wrote:

>
> > - Alphas&Co are not really physical parameters;
>
> Why not?
> Do you include alpha=Ks/Kn in Alphas&Co?
> If so, why?
> If not, why would alpha be an acceptable constitutive parameter, but not
> alpha_rolling?
>
For completeness I should have included also Ks/Kn. They are all parameters
of the interaction, however do they have a specific physical-basis? I am not
saying that it is wrong to employ them, that is indeed a common assumption
in a dem model. As we all know, those parameters are generally quantified to
obtain realistic behaviour at the macro-scale. This is the reason why for me
I would define them directly in the Ip2 (no need to average them, what is
the reason here if they are numbers not physically based?), in such a case.
It is only a thought, I will not change the code.



>
> I would define rolling strength a bit differently, consistently with
> previous discussion
> on using min strength :
>
> Now :
>                Real EtaRoll =
> 2.0*sdec1->etaRoll*sdec2->etaRoll/(sdec1->etaRoll+sdec2->etaRoll);
>                contactPhysics->maxRollPl = EtaRoll*min(Da,Db);
>
> Suggestion :
>                contactPhysics->maxRollPl =
> min(sdec1->etaRoll*Da,sdec2->etaRoll*Db);
>
r2597. Thanks for suggestion :-)
Chiara

>
> Cheers.
>
> B.
>
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