For the cross-section design of a flat steel, I obtain abnormally high shear stresses due to the torsion in the STEEL EC3 add-on module, which can be disproved by a simple manual calculation. What is the error?
I have only defined one element. If I swap the long and short sides (that is, the thickness becomes the length), the St. Venant torsion constant is, in my opinion, calculated incorrectly.