I´ve prepared a simple 5 m pole example to play around with the different Karamba3D analysis types as well as with cross-section optimization component. MyBeamTest.gh (80.6 KB)
Using the BeamView component and first order analysis (Th.I), the expected Nx and Mz results are obtained (see Fig.1) for the example load case (20 kN force along +y axis and 10 kN force along -z axis.
Fig.1 Using Th.I analysis
However, in the second order analysis (Th.II) the Nx forces are significantly deviating from the expected -10 kN result (see Fig.2).
Fig.2 Using Th.II analysis
I figured out that this behavior would be related to the projection of the 20 kN transverse force along the local element system of reference, but the deviation from the vertical axis seems too small to produce around 0.42 kN effects. Note that Gravity forces were not considered.
Do you agree? Am I missing something?
PS: I´m using Karamba3D 2.0.0 - build 210212 WIP for RHINO 6