I have a CLT beam model under combined effects of out-of-plane loading, in-plane loading, and axial loading. Why is the bending normal stress from "in-plane bending" being considered as if it resulted from "axial" loading. It is the stress resulting out-of-plane bending (only!) being considered as "bending normal stress". It finally resulted in incorrect combined-stress uls verifications. Am I missing something here?
Hi MedTek,
Welcome to our community 
To consider the bending effect correctly for your design, you have to analyze the results with a result beam.
You will find more information inside this KB-Article:
https://www.dlubal.com/en/support-and-learning/support/knowledge-base/001685
Best regards
Paul Sivolgin
Hi Paul,
Thank you for your response. I understand what you mean. I, however, don't think I made my point very clear. Let me rephrase it ...
I modelled the CLT beam as a multilayer surface and I wanted to do a layer-wise ULS design check (via the 'Timber Design add-on') at surface-grid points (and/or mesh-node points). Here the stress-interaction formulations are called up on where the bending normal stress from "in-plane bending" and the normal stress from "axial loading" are treated as if they both resulted from "axial loading". Only the stress resulting from out-of-plane bending is considered as "bending normal stress" in the design checks. In the end, a uniaxial (out-of-plane) bending normal stress is interacting with an "axial normal stress" resulting from both in-plane bending (!) and axial force instead of an interaction between biaxial bending normal stresses and a normal stress from an axial load. I hope I explained it a little better. Thank you once again Paul!