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Optistruct model

Hello,

I have this question about Optistruct results:

I have this model, applied with constraints and loads.

An optistruct analysis is performed with weight objectives to minimize volume, and one of the results is shown underneath:

image.png.b9268048dcb45088888e01db5ed0faa5.png

This is not the final result, but I am wondering: is there a possibility to import this result back into CAD software?

Since it is for 3D-printing purposes I will need to be able to translate this mesh, refine this, and preferably save it as STL in the end.

Any idea's?

Best regards,

Joep

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Altair Forum User

Hi @Joep

Of course, you can. Please use OSSmooth module to export the optimized model to CAD formats or .stl format

Select the OSSmooth panel on the post page.
Choose either OSSmooth (for geometry), FEA topology or FEA topography.
Select the OptiStruct input file (<prefix.fem> and/or <prefix.sh> and/or <prefix. grid>) using the file= browser. For topology use only .sh file
Edit the OSSmooth input data by making selections on the screen.
Click OSSmooth.
OSSmooth (for geometry) will write a new <prefix.oss> file with the screen settings and load the geometry recovered into HyperMesh if the data format is IGES, STL, or Nastran. FEA topology and FEA topography will update the model in HyperMesh without outputting the result; if required, data can be exported from HyperMesh.

Please also refer to Interpretation of Topology Optimization Results on OptiStruct help

Altair Forum User

Hello,

I have also found this excercise:

https://connect.altair.com/CP/SA/training/self_paced/optimization/content/opt6/pdf/Ex4a.pdf

I think I am doing something wrong:

Should I:

-first perform the optimization?

<?xml version="1.0" encoding="UTF-8"?>

-Then save the optimized model?

Since If I perform your number 3.

3. Select the OptiStruct input file (<prefix.fem> and/or <prefix.sh> and/or <prefix. grid>) using the file= browser. For topology use only .sh file

I think it goed wrong here.

Thanks!!

Best regards,

Joep

Altair Forum User

Hi @Joep

Since If I perform your number 3.

3. Select the OptiStruct input file (<prefix.fem> and/or <prefix.sh> and/or <prefix. grid>) using the file= browser. For topology use only .sh file

I think it goed wrong her

Can you share an image or explain what goes wrong?

Altair Forum User

Hello,

Thanks for the reply.

I have tried some other things but I am not sure When to apply Ossmooth.

Should I first perform the optimization analysis? And then save this file? As .fem or .sh?

Or should I do this before the optimization?

I can select the model I am working in at that moment but then it does not work correctly.

Se picture:

<?xml version="1.0" encoding="UTF-8"?>

Thanks for help again in advance.

Best,

Altair Forum User

I managed to export something in STEP!

But, it seems my last models do not save as .fem anymore..

Can this have any reason?

best.

Altair Forum User

@Joep

I am sorry, could you please explain what you mean by 'But, it seems my last models do not save as .fem anymore'

You can perform OSSmooth after optimization. You can e use the existing .fem file and .sh file will be written in your working directory after the optimization.

Altair Forum User

Hello Prakash,

The problem seems to be that I cannot find .fem files of most of the parts. Is there a specific method to save as .fem?

I have some .fem files of previous tests.

And another question; after I have performed the optimization, I can use OssMooth to recover and remesh, but then it seems the loads have dissapeared.<?xml version="1.0" encoding="UTF-8"?>

When I apply a load I get the following errors:

<?xml version="1.0" encoding="UTF-8"?>

Is this because there are elements which are not properly connected after performing Ossmooth?

Thanks in advance,

Best regards,

Joep

Altair Forum User

Hi @Joep

You can use Export option to save the solver file as .fem

When using OSSmooth, have you used Reanalysis option?

This will retain loads and boundary conditions unless they are not on design space.

I see that the property used is PCOMPP and after remeshing the new model has solid elements.