Sec VIII Div. 2 Discontinuity Analysis
Sec VIII Div. 2 Discontinuity Analysis
(OP)
Hi Everyone:
Hopefully this is a simple question...
Where does the 2010 ASME Section VIII Div. 2 Code deal with discontinuity analysis for the head/shell area of a vessel? I have a horizontal cylindrical vessel with spherical heads. The 95 Code was much clearer (in my view) on how to handle the analysis. Any insight would be great, thank you.
Jason
Hopefully this is a simple question...
Where does the 2010 ASME Section VIII Div. 2 Code deal with discontinuity analysis for the head/shell area of a vessel? I have a horizontal cylindrical vessel with spherical heads. The 95 Code was much clearer (in my view) on how to handle the analysis. Any insight would be great, thank you.
Jason





RE: Sec VIII Div. 2 Discontinuity Analysis
RE: Sec VIII Div. 2 Discontinuity Analysis
RE: Sec VIII Div. 2 Discontinuity Analysis
Why are you not doing this type of evaluation to Part 4?
RE: Sec VIII Div. 2 Discontinuity Analysis
RE: Sec VIII Div. 2 Discontinuity Analysis
If I understand you correctly, you have a cylindrical shell that you have calculated its thickness per 4.3.3. And you have a hemispherical head whose thickness you have calculated per 4.3.5. And you want to now check to see if the local membrane stress as well as the local membrane-plus-bending stress is within acceptable limits at the discontinuity? And you're doing this because in the pre-2007 Editions of the Code, you were provided with formulae in Appendix 4-7 and you wanted to do the same thing?
RE: Sec VIII Div. 2 Discontinuity Analysis
You got it! I assume that the new Code looks at this local stresses for Code acceptance, but I am having issues finding specifically how the Code calls out doing it like previously.
RE: Sec VIII Div. 2 Discontinuity Analysis
If you are using the design-by-rules of Part 4, then this type of evaluation is not required (BTW, it wasn't required in the old Code, either, if you sized the wall thicknesses using the old AD-200 rules, either).
RE: Sec VIII Div. 2 Discontinuity Analysis
Thank you for the info! Then I guess the only question I have left is this: If I use part 4 to analyze my vessel, would section 4.3.11 apply to analyzing the transition from the shell to head, or do you not even have to look at the local discontinuity stresses if doing a design by part 4?
4.3.11 Cylindrical-To-Conical Shell Transition Junctions Without a Knuckle
4.3.11.1 The following rules are applicable for the design of conical transitions or circular cross-sections
that do not have a knuckle at the large end or flare at the small end under loadings of internal pressure and
applied net section axial force and bending moment. Acceptable conical transition details are shown in
Figure 4.3.8.
RE: Sec VIII Div. 2 Discontinuity Analysis
Not to get off topic, but if you did not use the thickness equation in AD-200 back in the old Code, that was the only time you had to look at discontinuity stresses like the head/shell transition?
RE: Sec VIII Div. 2 Discontinuity Analysis
To answer your second question - you are correct.