yade-dev team mailing list archive

[chiara modenese <c.modenese@xxxxxxxxx>]

On 31 March 2010 19:36, Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx> wrote:

> Václav Šmilauer a écrit :
>
>  You can repeat the test, is simple. The fact that the shear force
>>> changes sign from one case to the other, is not correct. The shear
>>> force is dependent on the relative shear velocity that in turn depends
>>> on the ids at contact as we define them. To me this happens because we
>>> do not define a local system.
>>> Please correct me if you see I am wrong or please explain me why the
>>> shear force changes sign (if it was really a global system as was
>>> already pointed out, it should not happen).
>>>
>>>
>>
>> Hi Chiara, if I understand right, shearForce get negated if you swap
>> ids. That is consistent. shearForce is in global coordinates, but to one
>> body (id1*), it applies positive (action), while to the other body
>> (id2*) negated (reaction).
>> Does this explain what you describe?
>>
>>
>
> Or did you force the swap in a non-symmetric case, which could really
> result in a wrong sign (not sure)?
>
I do not think so. I mean, I swapped the ids of the interaction, but if the
conventions works fine it should not be a problem. Anyway I will run again
the test and describe you better what happens (maybe I will see to store
more information to really see if I am wrong).
cheers, chia


> It would be a user defined problem, since such swap would never happen by
> default.
>
>
> B
>
>
>
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