Eccentricities of load / beams

Hello,

I am conducting a topology optimization (Grasshopper/Karamba & Matlab).

For a certain load condition I want to verify if my component (consisting of 2 beams,forming a T shape, shown in fig0) becomes more efficient if beams are added (fig1).

The load condition on the initial T shape component is rather special: I have to generate eccentric loading in order to have the correct section forces in the component's beams. I solved this by using Eccentricity on Beam and the results is shown in fig2. This manipulation is just to have the correct section forces, in reality the beams lie in the same plane where the lines of fig0 are the center axes.

The question is how I have to model the additional beams? In reality, the additional beams lie in the same plane as the beams of the T shape (without any eccentricity).

I was wondering if I have to add some eccentricities as well in these additional beams to structurally model the whole component in a correct way. Or can I just add them with no eccentricity (like shown in fig3a and 3b)?

This is not really a technical Karamba problem, but more a question concerning a method of modelling.

I hope someone can give me some information on this.

Kind regards

Lara

Attachments:

Capture0.JPG, 17 KB
Capture1.JPG, 30 KB
Capture2.JPG, 21 KB

Replies to This Discussion

Permalink Reply by Lara Alegria Mira on October 25, 2013 at 4:02am

Here are the other figures.

Attachments:

Capture3a.JPG, 47 KB
Capture3b.JPG, 24 KB

Permalink Reply by Robert Vier on October 26, 2013 at 8:48am

Hi Lara,

so what is that special load condition? which loads do you apply to the eccentric structure and what should they model?

eccentricities can be quite tricky .. but you could always test their behaviour with small examples just modeling one effect

best

Permalink Reply by Lara Alegria Mira on October 28, 2013 at 4:22am

Hi Robert!

Actually I want to model specific axial and moment forces in the components. The axial forces are no problem, but to apply specific moments in a beam I use an eccentric point load, that is a point load on an eccentric beam. This is the the reason why the eccentricities come up. Is there a way to avoid the eccentricities to apply moment forces?

Best

Lara

Permalink Reply by Lara Alegria Mira on October 28, 2013 at 5:06am

Hi Robert,

Instead of working with eccentric point loads, I used the component Prescribed Displacements to model moment forces with rotations. Now I don't have to use eccentricities.

Thanks anyway!

Lara

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