Checking the pipeline designs, I use shell finite-element theory for stress simulations.
In almost every project, I find significant differences in stresses and strains between my stress simulations and stress simulations that were previously performed by somebody with the application of beam finite element theory.
For example - an error in Mises's stress generally exceeds 50% in places where the pipelines are supported by supports.
Therefore, I often have to prove the reliability of my stress simulations to the designers - which it is often quite difficult and it takes a lot of time.
I would be glad to hear the opinion of colleagues (stress engineers).