DISPL. REACTION FOR NOZZLE

Posted by: cowhidedan

DISPL. REACTION FOR NOZZLE - 02/01/21 09:09 AM

Hi, I'm checking some API 650 Nozzles and have modeled the nozzles using the Nozzle Flex option in Caesar. I have input the calculated radial growth and bulge rotation as a displacement. When I go to read the loads from the restraint report I am seeing the loads Rigid RZ, Rigid Y, Flex RY, Rigid X, and Flex RX. These make sens; however, there is also Displ. Reaction at the nozzle node. These loads are much higher and in searching the User Guide, I can't find a definition of what Displ. Reaction is. Can anyone help explain? Thank you
Posted by: Richard Ay

Re: DISPL. REACTION FOR NOZZLE - 02/01/21 10:57 AM

When you apply a pre-defined displacement you're actually defining a boundary condition - i.e. a restraint. The displacement multiplied by the restraint stiffness yields the "displacement reaction".
Posted by: Shady_Emam

Re: DISPL. REACTION FOR NOZZLE - 06/14/21 02:26 AM

I have a different issue related to the Nozzle Flex feature in CII.
When I use this feature for an API 650 tank nozzle, CII does not include the calculated radial growth in the analysis, although I have defined a displacement vector to be used in the Nozzle Flex menu and included that vector in the load cases.
Do I have to manually eneter the calculated values as a displacement to the nozzle node?

Update:
A work around I have figured when trying to solve the issue is that the "Optional" Vessel Node field must not be left blank, a dummy node number (not necessarily existing in the model) must be entered for the software to consider the calculated displacements.
However, no axial (in the direction of tank axis) thermal growth was calculated or considered.