Stress in Nozzle

[IdanPV]

Hello all,

I have pressure vessel with 2" nozzle attach by the method provided in ASME Section VIII Div.1 Figure UW-16.1 sketch (bb).
Note (4) stated that UW-16(f)(2) must be consider and hence, UW-15(a) requirements shall be satisfied for UG-22 loadings.

The only load in my case is internal pressure of 0.52N/mm^2.

I'm asking for help about how to calculate the Loads and Stress in the Nozzle, to satisfy UW-15(a) requirements.
Examples will be great.

 

[SnTMan]

IdanPV, you would size the welds as per Fig. UW-16.1 sketch (bb), and the Notes (UW-16(f)(2) or (f)(4)) - as applicable. Since there are no external (UG-22) loadings, UW-15(a) is complied with by meeting UG-41 requirements. For your confgiguration, Fig UG-41.1 (b), left hand side is applcable.

The "weld load", as per Code language, is easily calculated as per the Figure. The calculated "strength" of the actual detail is maybe a less obvious calculation. If you have the old Appendix L, L-7.4, Example 4 is most like your configuration. (If you have the more recent example maunual I am sure it is found there as well.) Basically you are calculating the combined strength of the groove and fillet welds, with allowables determined as per UW-15(c). Said strength must be no less than the weld load.

However before you perform any such calculations, you should determine if UW-15(b)(2) applies.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[IdanPV]

Hi Mike,
Thank you for your detailed response.
Few more questions regarding this issue:
1. all UG-36(c)(3) requirements are met, does I need to made any other strength calculations?
2. in which cases does I need to preform Nozzle loads calculation in according with WRC-107 or FEA?
3. Do you (or someone else) have any example for nozzle calculations in acc. with WRC-107?

 

[SnTMan]

IdanPV, your further questions:

1) No
2) In the case of external loads applied to a nozzle, such as from piping forces
3) These are complex calculations, typically the computer output has no detail as to the method. You would need to consult a handbook such as Moss or the source paper to find presentation of the theory, etc.

The problem with sloppy work is that the supply FAR EXCEEDS the demand