Min fillet weld size 1

[Chiller]

Does anyone have any ideas to how you would size fillet welds around wrapper plates to a pressure vessel that is also in cyclic service? Also how would the fatigue stresses be calculated?
For example - a horizontal vessel on two supports with wrapper plates.
The vessel supports have been checked to PD5500 annex Y, however, there is no guidance to the sizing of welds. In theory the wrapper plate need not be welded to the shell but as this vessel is going on a FPSO it would certainly receive some loading. At present I can only check the welds for shear loading.

Appreciate any inspiration
Thanks in advance

 

[prex]

If your vessel is not a micro vessel or a giant one I would make a fillet leg of 8 mm, supposing your plate is 8 to 12 mm thick, as most common.
As you correctly state this weld has practically no stress, so its size is related to that of the joined plates (not too small and of course not more than plate thickness). prex
motori@xcalcsREMOVE.com

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[Chiller]

The vessel is is 4.2m dia at 37 thk
the wrapper plate is 37thk

What would you suggest?

ASME suggest a min of 1/4"

 

[prex]

Well ASME minimum is really a minimum!
With your thicknesses you could be generous using a fillet leg of 12, just to be sure that it cannot be done in a single pass: in this way there is better assurance of correct adhesion to base metals. prex
motori@xcalcsREMOVE.com

http://www.xcalcs.com

Online tools for structural design