UG-37 "Ar Lost" nozzle calculation reference

[staticmh]

Hi Folks!

I'm performing a nozzle calc which is "Set in" , NPS-2" with below details and I am unable to understand that from where PV Elite is considering "Ar Lost" value and subtracting from the A41 and A42.

This nozzle is located on vessel dish with below details:

Outer weld size (neck to RF Pad) : 8mm
Outer element (RF Pad) weld size : 8mm
Head nominal thickness : 10mm
Head minimum thickness (A/F) : 8mm
RF Pad thickness : 10mm
Shell thickness : 10mm
Material (Head, shell / Nozzle) : SA-516 Gr. 60N / SA-106 Gr. B

Eventhough, there is not any reference available in ASME SEC VIII Div. 1 figure UG-37.1 & PTB-4. Please advice, if someone have any idea on the basis on the calculating "Ar Lost"

 

[staticmh]

https://www.eng-tips.com/userinfo.cfm?member=Cobra17[/URL]]

Kindly advice on it.

 

[Some Curious Guy]

Its appropriate if you ask this to your software support people. I do not use PVLite hence I am only guessing this.

In a radial nozzle you can imagine the fillet weld shape as a right angled triangle. In an inclined nozzle or a tangential nozzle the shape of weld can be oblique triangle. I can guess that Arlost might be factor to account for non right angled triangle weld shapes. This might be due to recent introduction of UW-16(h) para in code.

Please ask PVElite support and let us know if this is really the case.

 

[SnTMan]

staticmh, I seem to recall running across this in the past, but the details escape me.

Can you share a sketch of your nozzle detail?

Please do contact Support and let us know what they say, if anything

EDIT: staticmh, is it possible that the entire weld is not within the limits of reinfocrement?

Regards,

Mike



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

 

[staticmh]

@some Curious Guy :

Thank you for your valued feedback.
I actually already inititate the clarification to software support team and even they dont know yet the basis and same populated ahead to their USA based developer and validation team.

Regarding geometrical shape of welds with different nozzle configuration e.g. Radial, offset or hillside , already under my knowledge but the aspect is the "Ar Lost" only which is still under my research and will update you surely.

Thanks.

 

[staticmh]

@SnTMan

I always got positive firm feedback from you which really help me alot. Thanks for your valued time.

Coming to the point:
1. Yes sketch attached :

2. Contacted to support team and so far no positive response received with demonstrative calculation.
3. Your point gave me an idea of connection with "Ar lost" even i noticed now that A42 "element weld" is outside the reinforcement limit + A41 "Nozzle neck to RF Pad weld" is also partially can seen outside the "red line" "reinforcement limit" may be that is subtracting area from the overall weld area calculation. still need to look in depth from this angle.

but would be appreciate to have your opinion as well on it.

 

[SnTMan]

staticmh, first, thanks for the kind words

Second, I believe Ar Lost is the representation of the portion of the weld outside limits of reinforcement. Ar Lost (15.125) is the area of a triangle (two really) with leg of 5.5 mm. The balance inside the limits is an area of 16.875, again one either side of the nozzle centerline. See the attached.

Question is, why are these limits so resticted? This should be an input in PVE, I think.

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

 

[staticmh]

SnTMan, Thank you for your clarification, your explanation is legit and cross verified it correct!

This is default nozzle reinforcement limits which software is calculating based on the head thickness & RF pad thickness. and Yes you are right we can define the nozzle reinforcement limits.

 

[SnTMan]

staticmh, yes of course, happy to help

I had assumed from A42 = zero that the limits were restriced along the vessel wall, but it seems the limit is restricted along the nozzle wall as well.

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