Presently i am doing one tank line.while doing the analysis i have considered the settlement of the tank.but my question is vendor giving the stiffness values,radial growth of the shell,shell rotation resulting from product head.

when i am doing the analysis,i have considered the stiffness values,radial growth.but i dont know where or which restraint we exactly consider for the shell rotation.already i have read the API 650 Appendix P.but i cant get the exact thing i am looking for.


i need expert's help in this regard.

The stiffnesses and deflections are applied to the nozzle node.

Thanks for your reply.but which restraint exactly we consider for the shell rotation.my nozzle in x direction.

Let's say you're piping along 150-160-170-180, and at 180 you say you have an API-650 nozzle. CAESAR II will compute and apply the computed tank stiffnesses to node 180.

Now if you want to include the API deflection and rotation, you can't apply these to 180, since that would eliminate the effect of the stiffnesses. What you want to do is define a CNODE for 180, perhaps 1180, and apply the deflection and rotation to 1180. Set the other 4 DOFs of 1180 to zero. The computed stiffnesses will be applied between 180 and 1180, with 1180 moving as per your specified displacements.

thnaks for your reply,but my question is not how&where to apply.which restraint i should consider for shell rotation say Rx or Ry or Rz.My nozzle is in global x direction.

The applied displacements are according to the global axis. So if your nozzle pipe is in the global X direction and you have the Z-axis as vertical axis you have to apply a RY to the cnode.