FMJalink - when you speak of modification, are you referring to damage incurred in-service, or are you referring to purposeful modification, like a repair? If it is damage (of which the situation in this thread is a prime example), then the appropriate approach is to use a fitness-for-service...
I don't know. I haven't performed the necessary evaluation. I haven't seen any inspection records. I'm not willing to condemn (or approve) a vessel at first glance - that would be irresponsible of me as a professional.
It is up to the owner to determine whether the cost of such an...
r6155 - with all due respect, on what basis do you make that assertion? It has nothing to do with liking FEA or similar. I just think that an evaluation to determine fitness-for-service is warranted. That will include extensive inspection. I’ll trust the math, thank you very much.
1. Yes. We've done that type of work, too.
2. Gut feel says its a solid "maybe". What's the access like to get a high-quality laser scanning of the vessel interior?
3. Probably not.
4. This is a non-catastrophic buckling situation (a snap-through buckling, if you will). My bigger concern will...
Shell elements are really good for thin-shell analyses for demonstrating Protection Against Plastic Collapse, Protection Against Collapse From Buckling, and Protection Against Failure From Cyclic Loading: Ratcheting. They are not good for Protection Against Failure From Cyclic Loading: Fatigue...
I'm not sure that I understand the context of this question. Are you asking if the AI is going to check whether you are using valid software or pirated software?
Beyond the advice already given, I also recommend asking your employer to send you on training courses.
There are many training courses out there, however. My recommendation is to look for one where the trainer/instructor is also a member of the Code Committees. That will greatly assist with...
The approach is NOT to calculate the equivalent stress "at each point". The approach is to take the membrane (and bending) stresses of each component. Then, using the membrane and the membrane-plus-bending of the appropriate components to form the equivalent stress. It is one calculation...
Manually doing the calculations, based on the software's values of the component membrane and bending stresses (or stress ranges, when the context is for secondary bending stresses).
1. I agree that it should be zero, as well. Discuss this with ANSYS.
2. In my opinion, this would also apply to Section III. However, it is not explicitly detailed there. However, the original work that the Section VIII quotation is based on comes from WRC 429, which was written by two...
Russ - that's exactly it. The elastic-plastic analysis is perturbed by an initial imperfection, of a magnitude equal to the maximum of the tolerance, in the shape of the most likely elastic buckling mode. There is a tight correlation between the magnitude of these imperfections and the design...
I'm with jt1234 on this one. Do NOT "analyze" a standard flange using the Appendix 2 approach. That approach is appropriate for designing robust, non-standard flanges. It was never intended to "analyze" standard flanges.
For Creep-Fatigue interaction, you would need to go to Section III, Division 5, Subsection HBB. Access to that from Section VIII, Division 2 is through Code Case 2843-2.
Given that the vessel normally operates at 50 psi, you seem to have lots of room to derate the (design pressure of the) vessel. You will need to undergo a complete MOC (Management of Change) process to capture the revised design pressure. During that process, though, you may find out that the...