Hi,

I'm trying to model a pressure vessel in Static Axisymetric Analysis, but I can't constraint Z node rotation in the center of the head to zero.

So resulting Y displacement at the top of the vessel are greater than expected. (See unconstrained configutarion in the model)

The only way I could do some similar constraint was using constraint equations to make Y displacement in the nodes on the rotation axis equal to Y displacements of the neighbour node. (See constrained configuration in the model)

Is there another way to do this?

Shouldn't node rotation constraint be possible in axisymetric analysis?

Thank you for your help.

I'm trying to model a pressure vessel in Static Axisymetric Analysis, but I can't constraint Z node rotation in the center of the head to zero.

So resulting Y displacement at the top of the vessel are greater than expected. (See unconstrained configutarion in the model)

The only way I could do some similar constraint was using constraint equations to make Y displacement in the nodes on the rotation axis equal to Y displacements of the neighbour node. (See constrained configuration in the model)

Is there another way to do this?

Shouldn't node rotation constraint be possible in axisymetric analysis?

Thank you for your help.

liml

liml

Lateral doble 24Q8.liml

103K

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## Comments

If you refine the mesh, you'll see that boundary's displacement looks more reasonable.

It would be much easier if node rotation were possible.

Actually, you don't even really need the X constraint because points on the axis can't move radially in theory. However, there tends to be a small error which vanishes with mesh refinement, so it can help a little to constrain it like you did.

CCX with coarse mesh.

CCX seems to be more precise. At least deformed profile has the correct shape.

I wanted just to confirm that with version 8 the deformed profile has a much better shape in this case.