I was asked by an interviewer "How do you model a nozzle and related piping?"
"Modeling the equipment and nozzle, CNOD flange of piping..." I replied.
He was like "No, you assume piping and nozzle are anchored together. It's wrong. Piping is very flexible at this point"
Unfortunately, he did not explain me how I should model it.
Have I been always wrong?

Sometimes it is, sometimes it isn't.
In terms of strain loading, a stiffer model produces more conservative results. So ending with a rigid connection to a piece of equipment is an easy choice - until those results indicate redesign. At this point, then, that connection should be evaluated for available flexibility. If added flexibility is justified, then add it to the model. (Not at the flange connection but at the intersection of the nozzle with the equipment wall.)
I have see people attempt to add flexibility at a pump nozzle using the load and distortion limits defined in API 610. To me this is incorrect. Some nozzles are best left rigid.

Dear All,

For Tank API 650 Nozzle flex, I tried both ways for Tank/Nozzle Modeling, but I get different resluts
1st method : Model the Nozzle flex and caesar will automatically add the displacement eg D1 at the tank optional node, i have to define my vector D1 of course il load cases.
2nd method : I model the tank as rigid, put the nozzle flex and enter manually the displacement D1 which is a radial deflection due to fluid and temp ( because caesar will not do that automatically when a rigid model of tank is present).

I think I shall have a identical results!!!!

Share your experience plz

Guys,

No reply !!!!!

Compare the displacements of your tank wall nodes. If they match, then the models are similar.