Dear all
First of all, I’d like to tell you all that I’m not a stress expert just a Caesar user and I’ve been trying to be a good one.
Turning back to my doubts, I’m specifically curious about the value of yield stress criterion chosen in the “configuration/set up” between “Von Mises theory” and “Maximum shear theory (Default)” That will give the maximum stress output differently. My questions are as follows
1. What benefit can we use this value for? For the fatigue estimation of pipe material? If I ‘m wrong, please correct or give me some directions.
2. Why is mode “Max3Dshear” yield stress criterion selection, the result of highest stress of “3D max intensity” higher than the “Allowable Stress B31.1” at some nodes whereas “Von Mises” mode will not experience. I do know that these values are derived from different fomulae but I’m concerned that whether it is alright if it's more than allowance or not.
3. Form question 1, In case that we can use this stress for some purposes; for instance, material-lifetime prediction or specific node investigation, which stress value coming from between Max3Dshear and Von Mises should I use?
Perhaps I’m misunderstanding about this value, please make me clear and give me some suggestions. Thank you very much indeed.

Best regards