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Symmetri condition on 2D mesh

Builder
Builder

Dear world,

I am having the following problem:

I wand to make use of the symmetry. My model is formed by a half slice of a pipe, meshed with solid elements (CHEXA20) and two regions (thinshell), meshed with CQUAD8 2D elements.

In the attched image a part of the model is presented. It is easy to apply the symetric constraint on face A, but I cannot apply symmetry on the edge of the thin shell.

Could you please help me?

Many thanks

Ionut

4 REPLIES

Re: Symmetri condition on 2D mesh

Phenom
Phenom

Why can't you put constraint on that edge?

disp normal to the plane of sym = 0

moment in the plane = 0

Production: NX9.0.3.4, NX10.0.2.6
Development: VB.NET (amateur level !)

Re: Symmetri condition on 2D mesh

Builder
Builder
I cannot select the edge. It selects the whole sheet.
Thank you

Re: Symmetri condition on 2D mesh

Builder
Builder

Thank you for your answer. I managed to do what you suggested. See the attached images. After prescribing all the conditions, I get the following message:

 

"***ALERT: Node 5902 cannot be a rigidlink slave
               since it has one of its displacement degrees of freedom fixed.
     ***ALERT: Node 5903 cannot be a rigidlink slave
               since it has one of its displacement degrees of freedom fixed.
     ***ALERT: Node 5904 cannot be a rigidlink slave
               since it has one of its displacement degrees of freedom fixed."

 

I do not know how to eliminate this conflict.

Many thanks

Ionut

Re: Symmetri condition on 2D mesh

Siemens Phenom Siemens Phenom
Siemens Phenom

The nodes on the shell edge are overconstrained. You're trying to constrain the motion of the shell edge twice: once through the RBE2 and once through the constraint.

 

Since the behavior of the edge is already defined by the connection of the RBE2, and additional symmetry constraint is not needed.