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Solid Max Principal Stress - No results for TET MESHING

Experimenter
Experimenter

Hi all.

I am with some problems to obtain results for a solid mesh on FEMAP (integration with solver NASTRAN NX).

The mesh type used is HEX MESHING but in some chamfers, is necessary to create a triangular element.

 

The problem is that when NASTRAN export the results to FEMAP, there are no results in solid stress to those elements. Displacements are normal, only the stress are not reading for some error that I can found.

I am putting an image to illustrate this issue.

 

If some one could help me, I will be very grateful.

Thanks.

 

(Grey elements with no results in the image).

6 REPLIES

Re: Solid Max Principal Stress - No results for TET MESHING

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Marcelo,

For me one reason could be that your mesh is disconnected (new nodes not merged), then no stress results. Plot stress results + deformed shape, and ask for free edges, or post your model here and we will take a look to it.

Best regards,
Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Solid Max Principal Stress - No results for TET MESHING

Experimenter
Experimenter

Dear Blas.

 

I took a look in the free edge and everything is okay.

 

Also this FEM gives the results for displacements but only for tension there is no results.

 

DISPL.jpg

 

Here in the company that I work, I noted that this is happening after the AUTODESK NASTRAN received an update (from 2015 to 2016 version).

 

The people that has the 2015 version, the same model has the normal results in all elements.

Are there some configuration that could be missed in this update ?

 

Thanks for all help.

 

Best Regards,

Marcelo Miranda.

Re: Solid Max Principal Stress - No results for TET MESHING

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Then you got the answer, the update of the other FEA solver changed the format of data stored in the output results file for wedge elements .... hopefully next update of FEMAP will support it!!

Best regards,
Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Solid Max Principal Stress - No results for TET MESHING

Siemens Phenom Siemens Phenom
Siemens Phenom

I need a little more clarification. At the beginning of your post you mention "integration with Nastran NX", but later talk about "Autodesk Nastran 2015/2016".  Which product are you running.. they are quite different? And, which FEMAP interfaces are you using to read the results?

 

If you are really running Autodesk Nastran, then I would suggest that you should report this to them. Autodesk Nastran is a later version of NEi/Nastran and which typically wrote its results either to a FEMAP binary neutral file.  If that is the path you are using, then there is nothing we can do on the FEMAP side as they must be writing results for wedge elements incorrectly from the 2016 version.

 

If you are using a different program or a different file, then let us know a few more specifics.

Re: Solid Max Principal Stress - No results for TET MESHING

Experimenter
Experimenter

Hi Grudy.

 

Sorry to the misunderstood.

 

Well, I use FEMAP v11.1.2 64-bit version. When I create an analysis, I mark at the analysis program NEi NASTRAN.

 

When I run the analysis, the AUTODESK NASTRAN 2016 open to run all calculations and later, when the analysis end, I close the window and the results goes automatically to FEMAP.

 

After those steps is where I am finding the problem with some elements to check the solid principal stress.

I will check with Autodesk if there is some issue with version 2016.

 

Thanks for the answer and have a nice day !

 

Re: Solid Max Principal Stress - No results for TET MESHING

Siemens Phenom Siemens Phenom
Siemens Phenom

I believe given the process that you describe, Autodesk Nastran would still be writing the FEMAP Binary Neutral File. The format specification of this file and the interface we use to read it has not changed, so as I said, I suspect that Autodesk Nastran is writing the file incorrectly from their 2016 version.