Representing Pinned Beam Elements

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Inquisitor
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Registriert: Fr 7. Sep 2012, 00:14
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Representing Pinned Beam Elements

Beitrag von Inquisitor »

I'm building a small model representing the front suspension of a car. Thanks to Z88's non-linear abilities, I can run this kind of analysis using a very soft E for the spring's material properties and expect large displacements.

Bild

The question I have... I would like to use beam elements so the tubular frame chassis will be more representative of welded tubes. I have used other FEA programs in the past that will allow me to "release" a rotation DOF of a beam end to model a pinned condition. Is this possible with Z88? Either in the GUI or even by adjusting some file parameter?

If not, is there some way of mixing beam elements (for the chassis) and using trusses for the A-Arms that are inherently pinned.

Thanks for your help.

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wehmann
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Re: Representing Pinned Beam Elements

Beitrag von wehmann »

Dear Inquisitor,

releasing DOFs of beams is not possible. The only way is to use beams combined with trusses. But the use of different element types is not supported by the GUI. Theoretically, you can create a model of different element types manually by creating the input files (z88i1.txt, z88i2.txt, ...) with an editor. An idea is to create a beam model first by using the GUI and then run a calculation without clicking "Close" after the calculation ("Z88 ran successfully"). Then you have the solver input files (z88i1.txt, ...) in the project directory. Copy them and converte the interesting elements to trusses manually. You have to correct the number of DOFs! Finally you can calculate the model by the solver. Theoretically, this way is possible, but we have no experience with it. All over that, it is not possible to calculate beam elements while capturing geometrical nonlinearities.
If you have more questions, do not hesitate to ask!

Best regards

Christoph Wehmann

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Inquisitor
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Beiträge: 39
Registriert: Fr 7. Sep 2012, 00:14
Wohnort: Atlanta, Georgia, USA

Re: Representing Pinned Beam Elements

Beitrag von Inquisitor »

When I read the documentation about doing non-linear analyses and saw the list of elements (by their numbers) I didn't look to see what types those numbers represented and it wasn't even a passing thought of mine that beams would have been excluded. It wasn't till several days after I wrote the post, that I stumbled into the fact that I can't use beams.

However, thank you for responding... because I will want to mix elements in the future and you have given me a great "How To" with your reply. 8)

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