Trunnion Checks using Kellogg "Choking" method

[DSB123]

Hi All,
Just wanted to solicit views regarding the use of the "Kellogg" Trunnion check that is used widely. As I see it the method is applicable to "trunnions" which are attached to pipe (or bends) where they are remotely positioned (i.e. straight pipe either side of the trunnion or bend with not fittings such as flanges etc close to the trunnion).

My question is - Can the method "really" be used where the trunnion is located on say a short pipe spool with a flange at either end as this must affect the stress distribution in the pipewall ?

Has anyone considered this situation?

 

[C2it]

Many parameters affect local stress in a trunnion attachment which are not addressed by the simple Kellogg check, for example, any limitation on diameter ratio. I agree that local stiffening is also neglected. The Kellogg method deos not address elbow attachements.

At best the calc should be considered as a rough check, a comparison to endless numbers of similar designs, apparently functioning acceptably in the field. It is by no means a valid stress calculation.

FE-Pipe will do a very quick finite element check and give reliable results for any trunnion.

 

[DSB123]

Thanks Cit for the quick response. Your comments concur with my own. However this method is used to check/assess nearly all trunnions used in the oil & gas industry no matter whether they are on straight pipe, elbows or affected by local fittings.

Just another question. You say FE-Pipe addresses trunnions. I know that Fe-bend can be used for trunnions on bends but where can you check trunnions on straight pipe in FE-pipe?

 

[C2it]

DSB123 ... you are not limited to the prescribed templates in FE-Pipe, you can build your own entirely, as I have done many times, or modify an existing one.

To build a simple straight pipe trunnion would be quite simple, but would need a sensitivity check on the juncture mesh to ensureyou are not missing anything.

 

[DSB123]

Hi C2it,
I thought that was the case but I just wanted to check that there was no simplified approach as is the case with FEBend.

Cheers again.