NASTRAN file translation
NASTRAN file translation
(OP)
My colleauges and I have been evaluating Algor's ability to translate NASTRAN models in order to collaborate with one of our subcontractors on future projects. The tech support people at Algor have translated a model for us, and allowed us to attempt to run the model ourselves so that we may compare results with that which our subcontractor produces in NASTRAN. However, we have yet to be able to run the model successfully. The strangest thing that happens is that we will get displacement results, but no stress results. This baffles even the Algor support personnel, so I come here hoping for any suggestions you may have as to why this happens, and how to fix it.





RE: NASTRAN file translation
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You may want to insure your loads and boundary conditions are being properly translated.
Who are you working with at Algor?
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The model shows all of the boundary conditions and loads translated correctly, but still does not return stress results for unknown reasons. The reps we are working with claim to be able to run the model successfully, so we are trying to determine where things are going wrong.
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Anyway, best wishes on your plight. Feel free to contact me at any time by phone or by e-mail. You can find my e-mail address at my VERY new website: www.borowskiengineering.com
Garland
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I've had success with the Nastran translator, although most of my models for this application have admittedly been pretty basic.
As an aerospace engineer, I'm suprised to see you even have access to Algor. I thought Nastran was the "weapon of choice" in the aerospace industry. Anyway, I wouldn't take a shot at a specific software package until I was certain that the limitation is in the software instead of my ability to use it or the translators.
Anyway, as I said in the other post, let me know if I can help in any way.
Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
www.borowskiengineering.com
RE: NASTRAN file translation
Thanks! When you say FEMAP interpreting the output, do you mean reading in the nastran input file or bulk data deck? The companies we deal with have nastran with FEMAP or PATRAN and expect the models to import without a hitch. I was considering getting a license of FEMAP so we can import Algor and export nastran. Management is not happy because we have a bunch of $$$$ in Algor already and the ALG product which is not living up to our expectations. A single license of FEMAP is more than the Algor support fees. I personally have spent a lot of time learning Algor. It was not as easy to pick it up as I thought it would be but that is water under the bridge now. I can do most of what I need with it, however. Others using it are not as supportive.
Yes, basic stuff works with the ALG translator but we never get basic models! The dynamics models have more rigid elements than elastic ones sometimes.
We originally went with Algor because another company we were working with had it. That relationship is long since gone. I do see a lot of other companies with Nastran, however, that is why we got the ALG module but I feel I am fighting an uphill battle. On one hand I wish we just got nastran but we have Algor now and we have paid for it and support for the next year.
RE: NASTRAN file translation
NENastran used to have a 2-D plain strain element (I understand they have taken this out of the latest release -- don't know why -- I had some pretty good success with it, but I understand they wanted to do some additional verification...anyway) when I brought an Algor model into FEMAP and attempted to export it into Nastran, it came through as plate elements. This is because MSC Nastran doesn't have a 2-D plain strain element. I double checked the Algor export ASCII file and it clearly stated 2-D plain strain. It wasn't Algor causing the problem, it was FEMAP import of a Nastran file.
I then had to redefine the elements as 2-D plain strain and send it to NENastran for processing. This worked fine, but that initial import was a problem.
I like having access to FEMAP because I like to "clean up" these little problems before I send the files to clients and they try and run them, but I say again, this isn't an Algor error OR an NENastran error...it has to do with FEMAP.
There are no "perfect" translators, but I have been successful writing a Nastran output file from the Algor pre-processor, processing it through NENastran and MSC Nastran, and post-processing in FEMAP or Algor. It's been a while since I've run these comparisons, but I wouldn't expect it to get worse...just better.
Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
www.borowskiengineering.com