Dear Experts,

As per latest 2010 asme b31.3 code,appendex D,SIF VALUE FOR FILLET OR SOCKET WELD SHOULD BE 1.3 MAXIMUM.However this value was 2.1 maximum in 2008 version of asme B31.3.

Now i want to know that for trunion supports attached to pipe through fillet welding stress check can i take 1.3 value to intensify the inplane/outplane stress because my design specification told to use the 2010 version of asme b31.3.

need your expert advise because this clause i have to add in my stress design basis & get it approved from the client/pmc.

thanks

If you are checking local stress by FEA or Kellog method at pipe-trunnion junction, use of SIF 1.3 shouldn't be a concern.

The fillet weld referred to in B31.3 (2010) App D note 13 is the weld geometry on the back of a socket welded flange {328.5.2b (3)}. Note 13 also references socket weld fittings (like sockolets) in which a blended weld toe is used.

It stretches the bounds of credibility to apply this to a fillet weld on a trunnion, which may be only one or two sizes below the run pipe. Also I don't think I have ever seen a welder grind a smooth contoured to on a trunnion or similar pipe attachment.

In my opinion, stick to simple old Kelloggs or use FE.

Thanks for your advise.

but my point is if b31.3 is allowing designed to check stresses at trunion by intensifying it by a factor of 1.3( as per 2010 edition) or 2.1(as per 2008 edition),then we should consider the same in analysis because that is the most authentic basis for design.
why to go for kellog or fea?
So i want to know can i use 2.1 or 1.3 for stress intensification of trunion?

Maybe you are familiar with WRC's stress (SIF factors)... so you would answer a question: when you evaluate stress at nozzle-shell junction, you are interested first on weld SIF there, as "the most authentic basis for design"? You may answer to a similar question for your case.

MoverZ said "stick to simple old Kelloggs or use FE" because both of them address to the real troubles in trunnion-pipe.

Both Notes 13 in B31.3 edn 2008 and 2010 refer to Fillet welded joint or socket weld flange/fittings and mention explicitly a geometry according to Fig. 328.5.2.C/ 328.5.2.B etc. It is not your case and you cannot extrapolate them to your case because, for these configurations, the main concern is "fatigue performance of the weld" as Note 13 in 2010 edn explains.
IMO, the difference between editions is "blending the toe of the fillet weld smoothly into the pipe wall" as an improvement of the fatigue performance of weld.

Best regards.

PS. Peng's book has two sub-chapters "6.8.2 Kellogg’s Choking Model" and "6.8.3 WRC-107 Stress Evaluation" that would help you.

Dear all,

Following the above, could you please provide any reference for any calculation sheet based on the Kellogg’s Choking Model, preferable in native format?

Thank you for the reply.

Dear all,
I have found an old topic http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=showflat&Number=3537#Post3537
where reference is done to the original MW Kellogg paper?

We are preparing a calculation sheet for the trunnions calculation, and it will be useful to have this paper so to check the correctness application of such calculation.
Is there anyone could submit a scanned copy of the original MW Kellogg paper?
Thank you in advance.