Lateral buckling beam

Hello,

I want to know how to calculate a beam on lateral buckling. Can someone help me with this? Are the calculations from Karamba based on the eurocodes with or without national annex? I am working with the FREE/TRIAL package from Karamba 3d.

I hope someone can help me.

Hello @1631349hunen,
the lateral buckling calculation is based on the EC3 (see here). It is crucial to set the lateral torsional buckling length correctly via the ModifyElement-component (see here).
– Clemens

Hello,

Thank you very much for your reply. I have another question. We have learned that the bending moment around the Y axis is positive when counterclockwise and negative clockwise. Could it be the other way around in Karamba? That is how it looks on the moments line.

Bas

Hello Bas,
in Karamba3D a bending moment is positive when it causes a positive rotationincrement (according to the screwdriver rule) about the corresponding local beam axis. See here a cantilever beam under dead weight. The green arrow is the local Y-axis:

– Clemens

Hello,

Ok that’s clear for me. Sorry but I have one more question. I want to place multiple point loads on this beam with 2 supports, but it only places them at the coordinates of the supports. If I add a coordinate on the line myself, it won’t work at all. Can you help me with this?

Ligger-2 steunpunten puntlast.gh (39.0 KB)

Hello @1631349hunen,
in Karamba3D 1.3.2. it is not yet possible to place point loads along beams. Thus one has to divide the line of the beam axis using e.g. Grasshopper’s Shatter-component to create interior nodes for placing point-loads.
– Clemens

Hello,
I also found a problem when calculating the deflection at two supports. The formula (5 * Q * L ^ 4) / (384 * E * I) is not used here, but which formula is?

Bas

Hello @1631349hunen,
did you take into account shear deformations?
– Clemens

Yes, the problem is solved