Stresses over a pipe cross section

[VigAbaqusNoob]

Hi,

I have a cylinder model where I calculated the axial stress distribution over the cylinder wall using FE analysis and now need to convert these stresses into membrane and bending stresses acting over the cross section. I did linearize the through wall stresses to obtain the membrane and bending stresses acting on the wall. My supervisor said these are not the stresses acting on the cross section, which kind of puzzles me. Could someone please help me understand this ?

Thanks