Issues with Cross-Section Properties component

Grasshopper Karamba3D
1

Dear Karamba developers,

I´m playing around with your Cross-Section Properties component to figure it out how to use angular cross-sections TestCroSec2.gh (48.9 KB). In particular, I´m trying to customise a pre-existent CS and follow what it is said in this post.

Unfortunately, I´ve found two inconsistencies:

  1. The Section Modulus (W) seems to be flipped in Disassemble component output. According to EuroCode3 (EN1993-1-1:2005), Wely and Welz correspond to the elastic section modulus about principal (strong) and secondary (weak) axis, respectively. However, they seem to be reversed. Please, compare the manual results (in red and blue group boxes) with the values obtained from a disassembled “T” CS provided by your CS Range Select component (gray group box).

    image
    image2684×1220 499 KB

  2. The Modify Cross-Section component apparently does not update all W outputs properly. While Wely+ is updated, Wely- is not. Something similar happens for Welz- and Welz+ outputs.

    image
    image2686×1221 500 KB

Please, would you confirm whether am I right or not?

Do such these inconsistencies affect Karamba analyses? I´m particularly interested in EC3 related components, e.g. OptiCroSec or Utilization.

PS: I´ve verified that CS properties for the first row angle profile in this table match those computed with your CSProps component.

PPS: My Karamba3D version is 2.2.0.11-220214 for RHINO 7

2

Dear @Vigardo,
when you try to add angular cross sections be aware that their principal axes of inertia are inclined with respect to the local beam coordinate system. A load in local Z-direction therefore causes a sideways displacement.
I tested the results for a HEB140 half section using Karamba3D 2.2.0.17-221010.
The moments of resistance refer to the local element coordinate system. Wz = ±39.26cm3 and Wy+=41.58cm3 and Wy-=-9.36 are correct (see e.g. Stahlbau, Formeln und Tabellen, G. Luza, M. Palka, ISBN 978-3-7068-4166-5, Manz Verlag, Wien, 2001).
The sign of Welz is switched in the ‘Disassemble Cross Section’-component. Thanks for the hint! I will change that. It does not impact the cross-section design procedures.
I tried to reproduce the bug regarding the ‘Modify Cross Section’-component but got correct results (see here:
TSectionProperties.gh (23.6 KB)
)
Thanks for verifying the CSProps-component!
– Clemens

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