On 31 March 2010 19:36, Bruno Chareyre <[email protected]> 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 > > > > _______________________________________________ > Mailing list: > https://launchpad.net/~yade-dev<https://launchpad.net/%7Eyade-dev> > Post to : [email protected] > Unsubscribe : > https://launchpad.net/~yade-dev<https://launchpad.net/%7Eyade-dev> > More help : https://help.launchpad.net/ListHelp >
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