Reflected Element Stresses

Experimenter
Experimenter

Hi,

 

In order to hex mesh a piece of structure, I have used the Element Reflect and Copy tool in NX. I have meshed a portion of a circular ring and used the tool to copy the mesh around the full diameter. 

 

The mesh is part of .fem file in a larger afem. When I run a SOL101 solution, the full ring deflects as expected, and the displacements are all non-zero. However, only the portion of the ring that formed the original mesh (the mesh that the reflected meshes are seeded from) display stresses. I have ensured that the coincident nodes are merged etc and checked the model using modal free-free analyses - all seems fine. 

 

I cannot understand why my displacements of the reflected mesh are positive (non-zero), yet the stresses are zero. 

 

Any help would be greatly appreciated.

 

Thank you

3 REPLIES 3

Re: Reflected Element Stresses

Phenom
Phenom

you'll need to post a bit more than that if you want help. Can you post a picture of the stress plot for example?

Production: NX.CAE 10.0.2.6
Development: VB.NET (amateur level !)

Re: Reflected Element Stresses

Experimenter
Experimenter

Hello, thank you for your swift reply.

 

Unfortunately I cannot post photos of the plots online Smiley Sad

 

I'll do my best to explain in more detail...

 

In order to speed up hex meshing a circular / symettric structure, i have meshed a portion of the structure and used the reflect tool to generate the full model. Then used the duplicate node feature to join each mesh segment at the coincident nodes between the reflected planes. The mesh moves as a single rigid body as verified by a free free modal run - i am therefore confident that the portions of the mesh are attached as expected. 

 

All regions of the mesh displace as expected under the load conditions, but the reflected regions of the mesh show zero stresses but non-zero displacements. The stresses seem to only be calculated for the original portion of the structure i used to generate the reflected mesh. i.e there are elements on the boundaries that show a stress of 100MPa, whilst hex elements adjacent show zero. 

 

Any ideas? 

Re: Reflected Element Stresses

Phenom
Phenom

Hi, if there are differences in mesh you will find it in your DAT file. 

Two ideas:

1. Try to identify the original element mesh and the reflected mesh by means of there labels in DAT file.
There you could investigate if the property declaration is correct or different. Maybe the elements itself could "bring light into darkness" there.

 

2.Additionally, check you Solution Output Request definition.
There you can define for every single result type the method for getting results. One special way is using a Group. So if that group contains only a part of your model then the other part will not have those results.

 

2019-07-05_091859.png

 

2019-07-05_092154.png

 

2019-07-05_092345.png

 

Maybe that's your problem.

Best wishes, Michael

| Production: NX10; Development: VB, TCL/TK, FORTRAN; Testing: NX12 | engelke engineering art GmbH, Germany | 2019-07-08
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