Universal mesh model converter/translator (.bdf, .cdb, .k, .inp etc.)

[Calcul8it]

Hi

I'm looking for a standalone program that can convert Ansys .cdb to Nastran .bdf or LSprepost .k or practically any other format.

I have for several years been translating between .bdf and .cdb in Ansys Workbench FEmodeler with increasing frustration. The two major issues are, 1. it requires an Ansys license and 2. that not all element types are converted (or are converted wrong).

So is there a program that only does this? I.e. converts text-/ascii-based input files (input decks) between the most used FE model formats?

Thanks guys.

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[ThomasH]

Hi

I suppose you could use a general preprocessor (like Femap) to import the Ansys file and the export a Nastran file. But that is probably a very expensive "file-converter". Other than that I have never heard of any software that does what you ask for and only that. Femap handles several of the format you mentioned but not all of them.

Regards

Thomas

 

[Calcul8it]

Hi ThomasH

Thank you for your answer. Yeah, as you guessed, it is not really the kind of solution I'm looking for.

It's probably the same kind of translation Ansys Workbench offers, but I'm searching for a solution that is reliable and doesn't require an expensive licens.

Thanks anyway.

Christian


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[GregLocock]

Presumably your decks are in ASCII and the format is defined?

Time to hire a keen graduate and let him loose in an appropriate language. I did it and don't see why I should be the only one.

Failing that Hypermesh is supposed to be good at that sort of thing, if your brain works like that.

Cheers

Greg Locock


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[Calcul8it]

Thanks for the answer GregLocock.

To develop my own code is coming more and more the option for me. I was just expecting that this would be a code/program that already exists out there since we are so many FEA engineers exchanging models between different formats.

And yes, decks/input files are in ASCII format (.bdf, .cdb, .k etc.).

Christian

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[mlamping]

I think the silence in this thread says much about the initial request to avoid an expensive pre-processing license. It's quite difficult given the open ended nature of your question.

I've supported I-deas, FEMAP, and NX pre/post processing packages. All of them are able to create run ready input files for multiple solution types and multiple solvers from the same model. Are they perfect? No. Is the development effort required to support a broad element library, multiple analysis types, and multiple solvers modest? No.

As an example NX supports NX Nastran, MSC Nastran, ABAQUS, ANSYS, NX Thermal/Flow, and admittedly limited support for LS-DYNA (but that is growing). Specific to NX Nastran, NX 8.0.0 is able to write run ready input files for the following solution sequences:

101, 103 (multiple flavors), 105-112, 129, 153, 159, 200, 601, and 701.

NX also reads the same set of input files listed above to recreate the model in the pre-processor.

You can generate a similar list for FEMAP, but a shorter one for I-deas. And again, the same model created for Nastran can be used for the other solvers. My point is this: translation is not trivial work. We have a development group devoted entirely to export/import translations.

One could certainly write their own programs for translation. Input formats are well known. Your chances of success increase as the complexities of your models decrease too. If you only do one or two solution types with a limited element library, you may very well be better off developing your own translation application. The difficulty with your question is that there are no details regarding your typical model content or analyses. So the assumption is that you want broad support across a complete element library and analysis types. Doing that on your own would consume ALOT of resource. Broad support is what you are paying for with that license. AND when something fails to translate, please hit your vendor over the head! I do that too with our development staff.

Regards,
Mark

Mark Lamping
Siemens PLM Software

 

[Calcul8it]

Hi Mark

Appreciate you reply here. My experience using translators embedded in commercial FEA programs is that they are 'of course' not perfect but they are still having errors in some elementary translations (like translating beam orientations and cross-sections, like translating shell pressures or Ansys CE's/Nastran MPC's).

So if I can't fully rely on a commercial translator then why not use a free or stand-alone converter that can do the job just as good. To me it doesn't seem right that everyone is pulling their hair out trying to translate or are developing their own translator.

Anyway, I think you're right about the silence - there probably isn't that nice little tool that converts models among the big FEA distributions out there.

BR
Christian
Calcul8.it

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