I did a stress analysis to a pressure vessel loaded with a bending moment on one of its nozzle flanges. I used groove weld to connect the nozzle and the flange where the bending moment is located. The pressure vessel is made of my custom material, ASTM A516; the flange is made of Carbon Steel, and I intended the weld's material to be Carbon Steel as well. However, when the simulation result has come out, it seems that the stress is only (or mostly) located in the groove weld. I re-tried with different materials for the weld and the result was similar. Meanwhile, if I tested the weld to be made of the same material as the vessel's nozzle, ASTM A516, the stress distribution seems to be far more reasonable.
Do you have any solutions to this? Any advice would be helpful!
The constrains are:
1. "Fixed" on the bottom face of the base ring
2. "Gravity" activated
