Nastran Output for Solid Elements

Feature Requests
1

Would it be possible to export a solid element mesh (nodes and solid elements) in the Nastran format? This way I can solve it with MYSTRAN (which has standard 1D elements for connectivity of parts).

I am no able to upload sample files…but the sample output would be like the the following. Note that for the elements, the fields need to be in the correct columns (but it may not look right on this message). If there is interest in adding this feature, I can find a way to share files. Oh, the bullets should be a plus character…the forum is changing it.

BEGIN BULK
$
GRID, 1, , -1.587500E+01, 3.175000E+01, 0.000000E+00,
GRID, 2, , -9.525000E+00, 3.175000E+01, -6.350000E+00,
GRID, 3, , 9.525000E+00, 3.175000E+01, -6.350000E+00,

$
CTETRA 1 3110 1588 1668 3396 1589 7959 11331+

  •      11332    7717    7960   11333

CTETRA 2 3110 3539 2326 2325 2404 11334 10269+

  •      11335   11336   10550   10549

CTETRA 3 3110 1588 1668 3402 3396 7959 11337+

  •      11338   11332   11331   11339

CTETRA 4 3110 3363 1509 3368 3371 11340 11341+

  •      11342   11343   11344   11345

CTETRA 5 3110 1622 3371 1509 3363 11346 11344+

  •       7822   11347   11343   11340
2

Did you try converting the inp mesh with Meshio?

1 Like
3

Well, we are working on a converter as well…but that is still another step. That is the fallback plan if its not done directly (direct is just easier for everyone).

4

ABAQUS to Nastran Input Converter is a converter made by one of Mystran current developers. I’ve used this converter in the past to do some benchmarks using Mystran and comparing it to CCX.

5

Yes, that was done by one of our developers at my request actually…its a stop gap for something else. But again, I am not interested in a converter. We have a some better options for that already.

6

The Nastran converter is not planned. However, an existing open-source converter could be included in PrePoMax and used by the GUI.

1 Like
7

To be clear, I am not requesting a PrePoMax make a converter…just a direct output from PrePoMax. Just like you directly output the INP format.

If you can not do that, would you bundle the converter in PrePoMax so it would be automatic for the end user? The goal is for it to be automatic and simple for the end-user. If they have to retrieve a separate converter and then run that outside of PrePoMax, the goal of user-friendliness is lost.

8

The converter can be added to PrePoMax, but it is usually not only the mesh that needs to be exported. And creating a complete converter takes time.

So my idea was exactly what you wrote - implement it as a separate program to PrePoMax and create a GUI in PrePoMax to simplify its use for the end user.

9

No matter the converter is simple or complicated, just need ppm to call it whenever it outputted an inp file.

You could check if the converter exist. if exist, call it. New setting include converter full name(include path).

The converter will be a single exe file. For example: inp2mystran.exe
It runs like this:

Inp2mystran model.inp
10

But for this case, I specifically only need the nodes and solid elements (and not the properties, loads, solution request, etc.). So as a starting point, anything that did that would be just fine…it doesn’t need to be full one (which as you say is very complex). The developer of pyNastran has written a full calculix/abaqus to nastran/mystran converter, but that is an entirely different thing.

My hope was that if its just simple nodes and elements that it would be pretty easy to do directly from PrePoMax and a converter is a backup option. The issue with a converter is security and companies may block access, file path issues, etc. So while a converter is a “good” solution, when it comes to “good, better, best”…the “best” solution is native export to a Nastran format. I have been aware of converter options, but the real “feature request” would be a modififcation on the PrePoMax end to edget it closer the “best” solution…not just “any” solution. So any improvement from the basic external converter residing outside of the PrePoMax package would be great!