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#4471 - 01/06/06 05:07 PM local stress
Joe Offline
Member

Registered: 01/04/06
Posts: 20
COADE Piping Stress Analysis Seminar Note say"use WRC107 to calculate local stress"(stanchion/bend)page 3-16.Considering WRC107 limits and that it is applicable for cylindrical and spherical, Someone can give me explaination on it? Anyway, I use SIF to analyise on actual job.
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BG

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#4472 - 01/07/06 01:27 AM Re: local stress
sam Offline
Member

Registered: 02/25/04
Posts: 643
Loc: Maharastra, India
Sir,

There is no harm in using SIF of these ASME B 31.3 unlisted components like elbow stanchion or 90 deg trunions; better the SIFs come from some FEA analysis using FEPIPE.

If we have only CAESAR II, we can multiply/divide B 31.3 App D SIF/flexibility factor by some safety factor ( say 1.5 or 2), by first getting larger of unreinforced/reinforced tee & bend SIF/flexibility factor from CAESAR II.

Perhaps you are discussing about 90 deg trunions, where Coade directive of using WRC-107 for cylindrical shell/nozzle attachment is okay. But, I have seen people using 2.1(max value for fillet weld joint,socket weld flange or fitting SIF in B 31.3 App-D) as SIF in this application, the source of which some experienced forum member may be able to explain to us.

regards,

sam
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#4473 - 01/09/06 11:57 AM Re: local stress
Joe Offline
Member

Registered: 01/04/06
Posts: 20
Hi!Richard,can you tell how to use WRC107 to analyise local stress for elbow with stanchion. Thanks!
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BG

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#4474 - 01/09/06 01:17 PM Re: local stress
Richard Ay Offline
Member

Registered: 12/13/99
Posts: 6226
Loc: Houston, Texas, USA
Your configuration is "technically" outside the scope of WRC107. The recommended way to evaluate local stresses for an elbow with a stanchion is with the Finite Element method.

For a "quick", "rough" check, you can apply WRC107, but you will have to make a number of assumptions along the way, which could lead to inaccuracies in the results. I apologize for not being more specific, but I can't make these "engineering assumptions" for you.

The Course Notes don't recommend WRC107. What the notes say is "3 - local stresses at the stanchion are only as accurate as WRC107 bulletin". Personally, I don't think the accuracy is there and I suggest you go the FE route.
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Regards,
Richard Ay - Consultant

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