Weld Path Strength

[DeathRay009]

Hi,

Its been while that I have found myseld stuck whenever I look at the weld strength calculation of ASME VIII Div. 1. First, I kind of see the reason behind it, but cant for the life of me figure out the failure path except for the 2-2(kindly see the attached pic), kindly help me figure out the other two and how or when are they caused.


Thanks.

 

[JStephen]

If I'm looking at that right:
1-1: Pulls the repad off the shell and shears the neck
3-3: Pulls the repad off the shell and ruptures the shell at the attachment to the neck
For "normal" fittings, some of those combinations may never control, but at some variation of thickness/thinness/repad size/ opening size, presumably they do.

 

[DeathRay009]

But what is the load path behind them to cause such a stress. Thats what I am pondering about. As far as I understand, 2-2 path is to check for the circumferential stresses (Correct me if I am wrong).

 

[JStephen]

It is for tension in the plate, pulling left and right in the figure shown, all three would correspond to circumferential stress.

 

[DeathRay009]

If they are all for circumferential stress, why are we analyzing them in isolation, shouldnt they all complement each other?