UW-13.1 (j) the hoop stress along the tapered transition is larger than PR/2t

[mechengineer]

https://www.eng-tips.com/viewthread.cfm?qid=497251

Point-1, Please see Fig-1 & Fig-2 as the attached, refer to Figure UW-13.1 as well, showing that the hoop stress in cylinder transition is larger than S1=PR/2t in the transition. Do you agree?
But S1 shall not allowed to be lower than 0.5S1 to ensure the overall axial strength of the cylinder at the transition small end. In another word, the longitudinal stress at the small end of the transition shall be equal or smaller than the hoop stress at the larger end of the transition.
Point 2, Fig-3, except the view of point 1, it is similar to small opening concept as well, the cylinder would not be able to crack at point B (very narrow width, Fig-3) along the cylinder generatrix. I know that the weld B in Fig-3 is not allowed by code, that being the case, how to explain Fig-1?

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1660402753/tips/Shell_to_Head___LinkedIn_ubymoe.pdf[/url]

 

[GD2]

mechengineer,
My take is the following:
Shell to Head Junction: The stresses are Primary Local (P[sub]L[/sub]) and Secondary Bending Q. Their values are not same as S[sub]1[/sub]
Fig 3. Why do you use taper welding design for same 160 sch pipe and cap?

GDD
Canada

 

[mechengineer]

@GD2,
1. How do you consider the primary membrane stress at the tapered shell?
2. You should know the code on how to consider the Primary Local (PL) and Secondary Bending Q for discontinuity joint, like the shell to head joint, which is mentioned many times in the discussion here by the current post/comment and previous one linked in the post. Suggest you go through it first.
3. Without answering point-1, just talking point-2 separately is meaningless. Are you agree to point 1?
Regards,

 

[mechengineer]

Add to my post, important point for this idea, weld B shall be considered as category A because the longitudinal stress at weld B (tw)same as hoop stress in shell (ts), ts=2*tw.
Less weld material but upgrade the weld category and more strict weld qualification/inspection.