CAESAR II (Latest) API-650 Nozzle Loads

[SNORGY]

After I have modeled through the tank to the tank node and then identified the associated nozzle(s) node between which the API-650 stiffnesses are to be inserted...

The preprocessor (error checker) computes the stiffnesses etc. and then I run the static analysis.

My questions are simply this:

Suppose at one nozzle, I have a rigid element from tank centreline, 20-30, with "30" being the shell node number and "300" being the nozzle node number. I open up the nozzle flex dialogue box and enter the salient nozzle and tank data. Then I connect the next piping element from node 300 to node 310 (i.e., create an element 300-310) and complete the model. Am I correct in my assumption that when I get the output and go to "Nozzle Limits", when the program returns the message (paraphrasing), "There is no data..." it is because I have not actually double clicked the "Nozzle Limit Check" during the input and actually entered the values for load limits? It seems obvious, but if true, then am I still reasonably safe in assuming that when I read the global or local element force reports at 300-310 for each load case, they reflect the loads imposed on the nozzle after the calculated flexibilities have been taken into account?

I just want to make sure I am not missing anything here.

 

[SNORGY]

Further to my question above (I think I have that issue resolved...)

In the API-650 Nozzle Flex dialogue box, where it says, "Reinforcing on Shell (1) or Nozzle (2)", there is some confusion as to if it is just "1" or "2" that the program wants entered, versus the actual reinforcement thickness.

Scrolling the mouse over the input box, it appears to be asking for units in mm (which is consistent with the three decimal places shown), whereas the documentation appears to suggest that the user just enter "1" or "2".

The way the program appears to behave, it computes the nozzle stiffnesses (during error checking) one way if "1" is entered (i.e., reinforcement on shell) , and another way if anything other than "1" is entered (i.e., reinforcement on nozzle or no reinforcement at all).

Just a minor thing...I think I have it figured out for what I am trying to achieve.

 

[richay]

The software is looking for a "1" or "2", to indicate whether or not the nozzle is reinforced. An "unreinforced" nozzle uses the first set of curves in API-650 Appendix P. A "reinforced" nozzle uses the second set of curves AND ASSUMES A REPAD EQUAL IN THICKNESS TO THE SHELL THICKNESS. This assumption is stated in the references used by API to develope Appendix P.

Richard Ay
Intergraph CAS

 

[IFRs]

API has significantly revised Appendix P, it may be good to review and compare to CAESAR

 

[xenogood]

When it is un-reinforced nozzle. Does it mean its reinforced on shell? I am not really sure how does reinforced nozzle looks like.

Attached is a picture of the nozzle. Is that considered (1)Reinforcing on Shell or (2)Reinforcing on Nozzle?

I would think it is Reinforcing on shell but what if the nozzle does not have re-pad at all. Which option do I pick?

 

[richay]

API-650 Appendix P assumes:

1) Reinforcing on the nozzle: the nozzle is sufficient that a pad is not needed.
2) Reinforcing on the shell: the nozzle needs a pad, the pad thickness is assumed to be equal to the shell.

Richard Ay
Intergraph CAS