Hi Dorin,

Now I understand your point. To reinforce my understanding, I have run a Caesar model (a simple pipe-bend-pipe configuration) using B31 peak SIF from FEA and apply a moment load at the end. I got a max. Von mises stress of 36652.6 psi in the bend.

Similarly, I have made a same model in FEA (BC's and loads are totally the same) and got a Von Mises stress of 59280 psi on the bend.

You're right, that we cannot directly use B31 calculated stress to be used in the ASME VIII fatigue evaluation. In this case the ratio is 1.6.

So a factor of 2 is good enough instead of running FEA on each component.

Warm Regards,