WRC 537 interpretation

[alexlazoTechnipFMC]

Hi to everyone,
can anyone tell me if there is any restriction for WRC 537 application in case for external attachments (for example Cross plates) welded directly to the cylindrical pressure vessel and w/o pad reinforcement (see attached file for attachment design and welded side has marked in yellow).
basically, a doubt is which length for c1 & c2 (length of rectangular loading in circumferential & longitudinal direction).
is correct to apply:
c1 = 75 mm
c2 = 175 mm

thanks in advance.

 

[TGS4]

Have you actually read WRC 537? Do you have a copy.

 

[alexlazoTechnipFMC]

yes, I've hard copy.

 

[SnTMan]

I doubt that exact shape can be analyzed per WRC-537. Which is why we design things we can successfully analyze rather than try to analyze whatever we can imagine.

Put a pad under it.

Regards,

Mike

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

 

[alexlazoTechnipFMC]

dear Mike,
thanks for your advice.
the issue is:
the attachments have been fabricated and welded to the vessel (vessel thk = 73 mm) and W/O PAD.
vendor has been preformed WRC analytical verification and my concern is if values for c1 & c2 can be considered as indicated in may 1st message?
I've understood from your message that an approach is completely wrong. is this correct?
thanks again.
Alek

 

[BJI]

Exclude the gusset in the weak axis direction, this should be conservative for your main loading axis (but not overly conservative if adequately sized, based on the bracket configuration). Run the lateral direction with both gussets individually to check they are not limiting. A pad is probably not required for this shell thickness relative to the bracket, also might cause issues with thermal loading, if applicable. Even with the geometry approximation you would still need to comply with the size limitations in WRC 107.

 

[MrPDes]

With the clip being so thin and tiny compared to the shell thickness, I expect the structure of the clip would self destruct long before the shell experienced even minor stresses. Perhaps an inward radial load could cause damage to the shell. An outward radial load would cause the clips attachment welds to fail before the shell experienced elevated stresses.
Perhaps you should also be assessing the stresses within the clip as well.

 

[SnTMan]

alexlazoTechnipFMC, given that I'd follow BJI's suggestion. Run it as 1) a 10 x 350 clip, and 2) as a 10 x 150 clip, same loading for each. Understand that the WRC 537 is looking at stresses in the shell only.
The clip itself possibly needs its' own analysis.

Regards,

Mike

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

 

[alexlazoTechnipFMC]

dear ALL,
thank you very much for your comments/indications.
this confirms my concern regarding to shell - attachment connection, and i've brought out 2 conclusions:
1. WRC 537 should be avoided in this kind of junction
2. here is more concern for external attachment than the shell itself due to thick plate used for PV.
thanks again and Cheers.
Alek

Alek