Consideration of Joint Efficiency in WRC 107/297 Using PV Elite / Nozzle Pro.

[TheMehanic08]

We are in process of providing calculations for a pressure vessel details as below:

Dia = 2500 mm
Design Pressure = 10 bar
Design Temp = 150 Deg C
CA = 3
MOC = SA 516 Gr. 60
Radiography = Spot
Joint Efficiency = 0.85

The nozzles loads were to be analyzed as per WRC 107 /297. We have used Code Calc 2012 to do the same. However the client has raised a question asking if the effect of joint efficiency has been considered in the WRC 107 calculations; I haven’t found any input provision in Code Calc or nozzle pro for the consideration for joint efficiency.
Hence I put forth the following questions:
• Has this to be considered? If yes how do we consider it in Code Calc & Nozzle Pro?
• If not to be considered how is this to be justified?
• If I consider doing FEA using Ansys for the analysis of local loads, is this to be considered there?

 

[prex]

You should use E<1 for shell only if the weld crosses the nozzle. Then you should multiply all the allowable stresses by E. Of course, if the nozzle has E<1, then all the allowables for it should be multiplied by E.

prex
[URL unfurl="true"]http://www.xcalcs.com[/url] : Online engineering calculations
[URL unfurl="true"]http://www.megamag.it[/url] : Magnetic brakes and launchers for fun rides
[URL unfurl="true"]http://www.levitans.com[/url] : Air bearing pads

 

[TGS4]

This is actually a very interesting question. Currently, there is no guidance on the matter in either of Section VIII, Division 1 or 2. You may able to infer down thing from UG-37 and the variable E1. But that only refers to the underlying longitudinal or circumferential welds and not the nozzle weld. Likewise there is no similar provision in 4.5.14 and 4.5.15. Similarly there is no guidance in Part 5 regarding weld joint efficiencies.

 

[jtseng123]

My recommendation only:

If you use WRC107, the stresses are at top/bottom/left/right. If no seam crossing, no need to consider joint efficient. If seam crossing, then use JE.

Same for using FEA, looking at where the stress you are interested, and see if there is any seam crossiong, adjusting allowable stress accordingly by JE.

Why no one considers joint efficient ? because industry common practice is to 100% X-ray the seam adjecent to the nozzle and under the re-pad. So, JE is always 1 at nozzle area.