EN 13445-3 C.7.5 Limitation of primary stresses in case of tri-axial state of stress

[mrmyagi]

I am trying to understand the tri-axial stress state in steel welded structures and pressure vessels, etc.
When does this phenomena occur - i.e. when should i be cautious doing a stress analysis (in ansys mechanical)?

How should i check for this effect in ansys mechanical? EN13445-3 Annex C DBA — Method based on stress categories, limits the tensile max and min principal tensile stresses. I could check this manually, but it feels like a subtoptimal way. I would prefer if there was a way to check this automatically, or by using a python script?

Does residual stresses due to welding contribute to triaxial state of stress? From what ive understood, areas with high concentration of crossing welds run an increased risk of triaxial stress state.

Is it recommended to inculde residual stresses in the ansys model?

What are the differences from static and fatigue loading of an area that is subjected to triaxial stress?

My thoughts are all over the place, and if anyone can help me straighten this out, I'd be grateful!

 

[TGS4]

Residual stresses are not primary, and therefore would not be included in this check. I recommend trying to better understand this particular failure mode. ASME Section VIII, Division 2 refers to this as "Local Failure".