Hi all,

The nozzle loads in CII are exceeding allowable forces and moments. I'm trying to study to calculate nozzle flexibility by FEM. What is the basis document for reference? As what I know is ASME section III, div.1. But it seems to wide to search. I'm appreciate if any one can point out which paragraph I should read for reference in ASME

Also if after incorporating nozzle flexibility and the nozzle still be failed. Repeat FEM (by latest piping loads) with ASME section VIII, div.2, appendix.4 for verification. Is it correct understanding?

My question may be classical. I have tried to search, however I cannot find good answer.

Regards,

Van

B31.3 takes into account the "Restraint Flexibility"; IMO this gives enough support to consider also the "nozzle flexibility".

"after incorporating nozzle flexibility, the nozzle still failed"- by which criteria they failed? If these criteria are imposed by stress specification or other project documents, you should comply with. In case you have the freedom to qualify nozzles by FEA, you can do it- again IMO.

Hi Magriog,

You can understand my idea as below steps:

#1. Run CII, and piping loads > allowable loads

#2. Qualify the nozzle by FEA/FEM with input piping loads from CII (comply with ASME VIII).
+ If nozzle stress < ASME VIII allowable stress --> FINISH.
+ If nozzle stress > ASME VIII allowable stress, then calculate nozzle stiffness (nozzle flexibility) and go to #3

#3. Input nozzle stiffness into CII. Run again CII,
+ If piping loads < allowable loads --> FINISH.
+ If piping load > allowable loads, go to #4

#4: Qualify again nozzle by FEM with new piping loads in #3. If failed, change piping rout.

I want to confirm my understanding is OK as mentioned above or not. And I want to calculate nozzle stiffness by FEM, not by other methods.

Regards,

Van