Problem with DOF constraint

[barney75]

Hi guys,
I have some difficulties to constraint the displacement DOF of nodes 1 and 2 (see the attached file) to the correspondent nodes 3 e 4 (in the figure the rigid body RB3D2 is shifted in order to make the nodes to be visible, actually the nodes are superimposed i.e. have the same coordinates). Moreover the rigid body RB3D2 shall be free to rotate about the Axis A.
I use the kinematic coupling between each couple of nodes but it raise me this error message:

***ERROR: OVERCONSTRAINT CHECKS: NODE 4 INSTANCE ARS-1 IS USED MORE THAN
ONCE AS A SLAVE NODE IN THE *TIE KEYWORD. REMOVE MULTIPLE USAGE OF
THIS NODE AS A SLAVE NODE OR COMBINE THE MASTER SURFACES TOGETHER
AND USE THIS SURFACE INSTEAD.
***NOTE: DUE TO AN INPUT ERROR THE ANALYSIS PRE-PROCESSOR HAS BEEN UNABLE TO
INTERPRET SOME DATA. SUBSEQUENT ERRORS MAY BE CAUSED BY THIS OMISSION

***ERROR: OVERCONSTRAINT CHECKS: NODE 3 INSTANCE ARS-1 IS USED MORE THAN
ONCE AS A SLAVE NODE IN THE *TIE KEYWORD. REMOVE MULTIPLE USAGE OF
THIS NODE AS A SLAVE NODE OR COMBINE THE MASTER SURFACES TOGETHER
AND USE THIS SURFACE INSTEAD.
***NOTE: DUE TO AN INPUT ERROR THE ANALYSIS PRE-PROCESSOR HAS BEEN UNABLE TO
INTERPRET SOME DATA. SUBSEQUENT ERRORS MAY BE CAUSED BY THIS OMISSION

I don’t understand the error message because actually I never use TIE command!
Where am I wrong?
What can I use for this purpose?


Thank u

Bye

 

[rstupplebeen]

Please post your CAE or INP file.

Rob Stupplebeen

 

[barney75]

I got around it.
I fix the problem using suitable connectors element to link the nodes of one rigid body to the corrispondent of the the second rigid body in order to achive the system configuration given in attached files. Reading the documentation I figured out that the error with overconstraint is due to the fact that is not possible to use kinematic coupling to link the displacement/rotaion of nodes belonging to two different rigid body. It is mandatory to use connectors to constraint the desidered DOF. That's it. Now with connectors the model works properly.

Bye bye