When analyzing piping connected to low nozzles of storage tanks, the flexibilities calculated by Caesar II as per API 650 obviously act at the nodes defined as nozzles. But what about the radial deflection and the longitudinal rotation due to the fluid height (and temperature)? Is it correct to define these movements as displacements and rotations at the same nozzle node? And are these displacements then to be regarded as primary or secondary loads?

What is the opinion of this group?

All the best,

Veit Bockemühl

www.esn-gmbh.com

The displacement and rotation computed by the API-650 routine can be included in the model. To incorporate these values, I suggest adding them to the "nozzle CNODE", since this will put them on the other side of the computed stiffnesses. Applying these values to the nozzle node defeats the benefit of computing and applying the nozzle stiffnesses.

As to the "primary versus secondary" issue, my opinion is that it depends on how the tank cycles, and how often.