yade-users team mailing list archive

[chiara modenese <c.modenese@xxxxxxxxx>]

On 19 April 2010 09:11, Jerome Duriez <jerome.duriez@xxxxxxxxxxxxxxx> wrote:

>
>
> chiara modenese a écrit :
>
>  Actually if one wants to test the shear direction it is not as
>> straightforward as for the normal part. I managed to do that having viscous
>> damping at contacts (so that, in a sphere-sphere interaction, you first
>> apply a force in the normal direction till you reach equilibrium having a
>> damped solution
>>
> Did you apply gravity ? Or any, say vertical, force (if normal of the
> interaction is vertical) applied by hand or with ForceEngine maybe. That is
> what I would advice you in order to have a normal force non equal to zero at
> the interaction. But I do not see the link with damping ?

Hi Jerome,
say that you want a constant normal force at the interaction and meanwhile
you apply a shear force. If you do not apply damping (hereby in the normal
direction) your bodies would bounce and the normal force would not be
constant.. Every time you apply damping at contacts you end up dissipating
energy and, as a consequence, you reach the equilibrium so that you do not
oscillate anymore around that.. It is like dealing with a 1-dof
spring-(dashpot) system..

>
>
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