Learning Forum

[saeedms]

I am running a thermomechanical simulation and I have an issue regarding imposing a special boundary condition. I require to apply a constraint on nodes of a plane to allow them only to move together in certain direction (e.g. all nodes should be free to move in z-direction but all the nodes should have the same displacement in that direction). In other words, I require that plane to remain flat and keep the normal constant all the time, although the entire plane can still move . I do not want to fix the plane in that particular direction, but only to constrain the nodes to move together in certain direction. I haven't find a solution to this so far. Any idea how to do it?

[Chandra Sekaran]

That sounds like using 'Coupling' in either MAPDL or Mechanical. In MAPDL you would use the CP command. In Mechanical Static Structural - Right mouse click- insert - coupling should do it. If the plane is not parallel to the global coordinate system then you can rotate the nodes on that plane to a rotated coordinate system and then couple the Z axis as you want in that coordinate system.

[saeedms]

Thanks for your comment. I used coupling of nodes on the top surface as you can see in the attached file. But it conflicts with other BCs. I have no idea why it should conflict. I have fixed two side planes in the normal direction as they are symmetry planes. They are free to move in z-direction. Do you have any idea why it does conflict with this BCs. Thanks.

[peteroznewman]