I don't necessarily disagree with your contention that this is a blunt and potentially highly-conservative (but also potentially under-conservative) approach.
Your ID says that you are from Italy - is that correct? If so, I would recommend that you get involved in the ASME Section VIII, Italy...
Correct. Cylinders would have single-curvature, but any head would be doubly-curved.
Yes
For Table 6.1, classification is strictly based on the fabrication method.
Apply a fitness-for-service approach, looking for specific damage mechanisms. And note that merely exceeding yield is not a damage mechanism. We're talking: crack, bulges, dents, gouges, other gross deformations, fatigue damage (somewhat related to cracks), etc. You might need to perform some...
These stresses are pseudo-elastic stresses. That means that they are stresses that exceed yield, based on an elastic analysis/calculation. In reality, the component will experience plastic deformation, that could have a plastic strain that could be on the order of the true ultimate plastic...
@MSL68 - you are correct that Section III, XIII-3120(b)'s use of the verb "may" is a permissive in the context that you state.
For additional clarity, VIII-2, 5.2.2.2(b)(1) removes the may and simply states that "a region of stress is considered as local if the distance...".
This locality...
FYI - in the 2025 Edition of VIII-1, Appendix 2 will be "removed", with reference to VIII-2 4.16. No new methods will be introduced in VIII-2 in the 2025 Edition. However, the SWG-BFJ is working on implementing alternative rules for the 2027 Edition (fingers crossed).
That distance is measured away from the SCL, using the value of R and t for the respective components. You cannot draw a valid SCL in the junction ring (transition region) - see WRC 429 for the definitions, so the only possible option is to measure away from the SCL that is located at the...
The way that I like to think about it is as follows:
The elastic stress limits were originally based on interaction equations (think Timoshenko thin shell theory)
That basis originated prior to the advent of FEA
In that approach, you would have the "structural" elements of a shell and head (for...
VIII-1 UG-22(e) clearly states that cyclic loadings need to be considered. The best way to consider them is to perform, as a minimum, a fatigue screening assessment. For your situation, your best bet will be the Method B fatigue screening in VIII-2 5.5.2.4. Note that for your cyclic thermal...
This stress limits that you speak of are with respect to operating stresses, after the vessel has passed the pressure test. It is not unusual for plastic deformation to take place during fabrication (think cold-forming of heads, rolling of shells, etc.). Welding is going to result in...
