Karamba: How to consider buckling length in DSTV export?

Hello,

I have used ModifyElem component to modify the buckling lengths in my Karamba model, which is a steel truss structure. The problem is, that when I export the model with ExToDStV component, the dstv file doesn't seem to consider the buckling lengths that I've set. In other words, when I import the dstv-file to Rfem, the effective length factor is always 1 for every element and I have to set them again manually.

Is there a way, to consider the buckling length in dstv export?

Best regards

Ilari Pirhonen

Replies to This Discussion

Permalink Reply by Ilari Pirhonen on February 10, 2017 at 4:20pm

Hey,

Here are the two dstv files. In Rfem is set the effective length factors to 0.9 for top chord and 0.75 for the diagonals. After exporting dstv from Rfem, I tried importing the same file back to Rfem. The result was, that the effective length factors were again back to 1. And I can't find anything that could be related to buckling factor from the element definitions of the file exported from Rfem.

Maybe the dstv file format doesn't even support storing the buckling length data?

Attachments:

Truss_karamba.stp, 8 KB
Truss_rfem.stp, 9 KB

Permalink Reply by Ilari Pirhonen on February 11, 2017 at 12:53pm

Hey,

Thanks a lot for help man! But I think I will still have a problem, that propably can't be solved so easily with a script. I tried yesterday setting the buckling length factors in Rfem and wrote the dstv export file (attached in the previous message: Truss_rfem). I tried reading reading it back into Rfem, and after conversion the buckling length factors weren't there anymore. So I think that the file format doesn't allow storing the buckling length information. That's bad...

Another possible solution could be this plug-in: http://www.food4rhino.com/app/rhinodlubalrstab

Maybe the buckling length problem is solved there. So far I have not managed to install the plug-in succesfully and I'm not sure if the link is even compatible with Rfem yet.

Permalink Reply by Ilari Pirhonen on February 12, 2017 at 6:17am

Hey,

I got another idea. I can could easily copypaste the buckling lengths manually to Rfem as a list. The buckling lengths should be picked from the beam list of the Karamba model. Could you help me making a prototype of a VB or Pyton script, that picks the buckling lenghts? I'm not familiar with scripting and don't know any commands how to filter the right elements from the beam list, which contains a lot of unnecessary stuff.

The idea is presented in the image (attachment). The other attachment (gh-file) is a beam list, that we can use for testing the script.

Thanks!

Ilari

Attachments:

script idea.png, 106 KB
beamlist.gh, 18 KB

Permalink Reply by Ilari Pirhonen on February 13, 2017 at 2:55pm

Thanks a lot man! Works very nicely. Lately I've been learning some basics of programming and it will be a good excercise to translate that to python. :)

RSS