Kinematic coupling error

[ccarstensen]

Hello everyone,

I'm having an issue with one of my Abaqus models.
I have one model (circular beam), which I can change the coupling constraints from distributing to kinematic without any problems.

Then I have a second model, whose script I made on the basis of the first one. Now I get this error when I go from distributing to kinematic:

***ERROR: DEGREE OF FREEDOM 1 DOES NOT EXIST FOR NODE 2706 INSTANCE
FOILHALF-BOTTOM. IT HAS ALREADY BEEN ELIMINATED BY ANOTHER EQUATION,
MPC, RIGID BODY, KINEMATIC COUPLING CONSTRAINT, TIE CONSTRAINT OR
EMBEDDED ELEMENT CONSTRAINT. THE KINEMATIC COUPLING CONSTRAINT
CANNOT BE FORMED.

and also for the rest of the DOFs. I've attached the two scripts.

First one: circle_crack_3dmodel_master.inp (uses circle_crack_3dmodel.inp and circle_crack_fromhm.inp)

http://files.engineering.com/getfil...2af22778&file=circle_crack_3dmodel_master.inp

http://files.engineering.com/getfil...80-64f7e0308800&file=circle_crack_3dmodel.inp

http://files.engineering.com/getfil...55e-6b9076a22ea8&file=circle_crack_fromhm.inp

Second one: foil_crack_3dmodel_master.inp (uses foil_crack_3dmodel.inp and foil_crack_3dmodel_sets.inp)
The coupling constraint is located in foil_crack_3dmodel.inp

http://files.engineering.com/getfil...31a7c6244c&file=foil_crack_3dmodel_master.inp

http://files.engineering.com/getfil...8c71-c3cfcd9c4f0d&file=foil_crack_3dmodel.inp

http://files.engineering.com/getfil...b4e4b367105f&file=foil_crack_3dmodel_sets.inp

Can anybody help me?

Thanks a lot, Christian

 

[Mustaine3]

Your Coupling Reference Node is at same time also in the region that is coupled to the Ref Node, so he is master and slave at the same time. That's not possible. The easiest solution is to make a separate Ref Node.

 

[ccarstensen]

Thanks a lot!
Can I ask why it works for my first model then?

 

[Mustaine3]

Probably because you used a distributed coupling here and this does not eliminate DOFs at nodes.

 

[ccarstensen]

But I can straight away change the coupling to kinematic and it will run with no errors.
The thing is I have to run all my load cases for both distributing and kinematic coupling.

 

[IceBreakerSours]

Do what Mustaine3 has already suggested; you should not run into any similar problems.

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