Non standard beam cross section

Replies to This Discussion

Permalink Reply by Robert Vier on August 14, 2012 at 1:18pm

hey federico,

those are the cross sections you can work with, and i can't think of a way to incorporate other beam-cross-sections besides actually coding it.

in the next release, there will be shell-elements available which one can use to 'build' any complex cross section he/she wants.

or, do you just want to use different cross sections within a single model?

best

robert

Permalink Reply by federico Martelli on August 14, 2012 at 1:46pm

Hi Robert,

here are some screen shots. 

The first one shows you the grid or pattern of beams. the second one shows the deformation according to karamba when using a trapezoid standard cross section. and the third picture shows a simplified version of the component i would like to use as beam. 

In the screen shot you attached in your previous answer there is a Shell cross section option which I dont have in my karamba. any chance I can try that?

Thank you!

Federico

Attachments:

• Capture.JPG, 127 KB
• Capture c.JPG, 53 KB
• Capture b.JPG, 62 KB

Permalink Reply by Robert Vier on August 15, 2012 at 3:45am

Hey federico,

sorry but I can't really make sense of your pictures, I barely recognize the first and the third one..!

But okay,

the first one is a three-dimensional grid - of beam-axes? or should it be a surface? according to your second screenshot, your geometry is somehow areal .. and regarding this, how did you get this shape out of karamba?

i could probably serve with much better advice if I really understood what you are trying to do ;)

the next karamba version with shells will be released soon, i have to talk to my colleagues.. but let's see if you really need shells for this :)

best

Permalink Reply by federico Martelli on August 15, 2012 at 4:34am

Hi Robert, sorry for confusion and thanks for your reply.

You are right, it is a three dimensional grid of beam axes. What we are looking in our project is to enhance or program the deformations that will occur due to the decay of the materials used. At the moment we are using a variety of natural fibre reinforced polymers. If you look carefully in the grid image i sent you previously you can see that the beams don't run straight form node to node, but they have an angle in the middle. This angle is critical for the deformations. When testing the deformation of this grid I used a trapezoid standard cross section for the beams and this test helped me understanding the effect in the overall deformation while changing the elastic modulus in specific beams. 

Now that I understand the deformations I would like to change the geometry of the beams because the decrease in elastic modulus can be accelerated by having more sun exposure. Therefore we would like to be working with beams that have maximum sun exposure (working with shells in this case would be pretty ideal, I imagine)

Does this makes sense?

Thanks again!

(This image shows an early model straight from grasshopper of a grid of the new elements. Here we havent yet sorted connections etc and need a lot of work still but maybe helps)

Permalink Reply by Robert Vier on August 15, 2012 at 8:40am

okay thanks for clarifying, so you applied different materials to every beam in the model for changing the e-modulus?

i guess shells could also be handy for that of course.

but a good approximation (and a faster one) also might be representing a quarter of an element you showed by a beam (a line), and applying the properties you gathered from the respective surface to it...

best