Coupling AND XSYMM

[Bas0110]

I've modelled a three point bending test for a timber beam. I used the boundary condition XSYMM to model only the half of the beam and the constraint coupling to model the load (because the load will be divided over a surface). Because the two inputconditions contain several equal nodes Abaqus gives a warning about the DOF of these nodes. In the attachement you can see the BC en constraint at which the warning occurs. I used C3D8R elements with elastic plastic material properties in a NLgeometric analysis. It looks like I can't model the XSYMM and the coupling constraint together. I have a same kind of problem with the TIE constraint and the BC at the supports.
How can I model the XSYMM and the coupling constraint of the load without the incorrect boundary conditions?

 

[johnhors]

Delete the constraint coupling and apply the load as a pressure over the surface.

http://www.Roshaz.com

 

[Bas0110]

I'm not putting the load on the model, but the deformation of the load area.
I'm using the coupling constraint because I want to know the reaction force(RF2) of the model. With the coupling constraint I can read this RF2 at the masternode.

 

[johnhors]

You haven't got too many nodes, delete the constraint coupling and apply the deformation to each node. Sum the reaction forces to get the total.

http://www.Roshaz.com

 

[Bas0110]

Isn't there any possibility to apply the coupling constraint and the symmetry BC together, so I haven't to sum the reaction force at the nodes of the load area(99 nodes!).
I'm going to model several beams, so the summarizing of the reaction forces will take a lot of time.

 

[johnhors]

Probably not.

Alter your model to stop your group of nodes making up the coupling constraint from using nodes on the symmetry plane. Reduce the coupling constraint region so that it does not extend to the symmetry plane.

http://www.Roshaz.com

 

[Bas0110]

Thanks a lot for your help!I will try to alter the model with your tips.