For Div 2 Class 2, section 5.1.1.5.2 says that Part 4 Design by Rules can be disregarded (i.e. the minimum calculated 10mm thickness in your example can be disregarded in favour of a thinner Von mises derived minimum stress).
Div 2 Class 1 and Div 1 App 46 make Part 4 rules mandatory. Section...
ASME div 2 section 8.1.1 says that a pneumatic test can be substituted for a hyrotest under the following condition:
"(1) The vessel is constructed and supported such that the weight of the hydrostatic test fluid could cause permanent visible distortion."
Hydrotesting is always the preferred...
Often large trunnions are chosen to spread the load on thin shells rather than to lift big loads.
I've used the same size and design of trunnion on a 5000mm ID x 10mm carbon steel shell and there was no distortion. The welder must have really blasted it with allot of heat. My vessel was at...
From being "pretty sure" about your design, with the input from the complete strangers in this forum, what level of confidence do you now have that your design is safe? Would your confidence now exceed "I am moderately confident"?
"Equivalent" is the same as "Von Mises" and "Intensity" is the same as "Tresca".
The options I have are equivalent elastic strain, equivalent plastic strain and equivalent Total strain (and equivalent thermal and creep strain).
I'm guessing the two options you are referring to are equivalent...
It looks like a simple case of following the code rules.
What is your question?
If you are not confident of the design and don't know what questions to ask in this forum to become confident in your design, then perhaps it would be wise for your employer to find someone else to design this equipment.
In WRC 107 the solid bar graphs are used to establish stresses at the edge of the Re-Pad. These solid bar graphs are also used for stresses at the OD of nozzles with large t/d. I expect WRC 497 doesn't have these solid bar graphs.
At the OD of a pad, the stresses relating to the hole are less...
RaynondN,
From you comments here and in another current thread that you have started it appears you are using the WRC 497 parametric investigation of large idealized nozzles "without reinforcing pads" with applied loads to design a nozzle which has a reinforcing pad and additionally experiences...
For Nozzles with very wide pads, WRC 497 may provide you with some guidance on the initial thickness sizing of the Shell-Nozzle Junction, however WRC 497 will likely not be applicable at all to medium width pads. However this guidance would only be useful for an initial guestimate before...
RaymondN,
The wording says that it can be Class 1 if there is fatigue. However, the design report has to jump through all of the same hoops as a Class 2 vessel (Independent Engineer design review etc). Therefore a Class 1 vessel with fatigue is essentially a Class 2 vessel with conservative...
The d/D nozzles that you are working with are well beyond the maximum d/D allowed by WRC 107/537 and WRC 297. The stresses related to large d/D nozzles are very different to small d/D nozzles, therefore these bulletins will be of little or no help to you.
I understand that WRC 497 is a limited...
Thanks for the clarification,
From section 2.3.3.1(a) it specifies that the manufacturers design report only needs to be certified for a Class 1 vessel if it incorporates fatigue or Part 5, so essentially a Class 1 vessel with fatigue or FEA essentially has to jump through all the same...
In Europe not allot of fabricators have Div 2 Certification.
FEA not being allowed on Class 1 vessels does restrict its use to the most basic vessels. It would be good if a class 1 vessel that requires an element of FEA could use Part 5 design method using Div 1 allowable stresses (3.4 margin...
The most important thing is that the Local membrane stress at the edge of each nozzle remains with its allowables. The stress half way between the nozzle can't be greater than allowables if the stress at the nozzle edge is less than allowables.
If you choose to make less area "available" to a...
Pressure design and Fatigue design have next to nothing to do with each other and therefore can be conducted using different codes.
For vessels designed within the USA, it is logical to use the American ASME Div 2 fatigue method. If something went wrong during operation, I would expect you...
I just invented the term 'regional' stress. I think the size and nature of the saddle stresses are quite different from a typical nozzle 'local' primary stress. As stated, elastic stress classification is not an exact science. There are hotly debated interpretations and exceptions. I may be...
My assumption is that a relatively large saddle attachment causes wide ranging 'regional' primary stresses that are not really 'Local' and are also not 'General'. They are somewhere in between. Therefore 1.5×S is too non-conservative and 1×S is too conservative. So they came up with an...
With the clip being so thin and tiny compared to the shell thickness, I expect the structure of the clip would self destruct long before the shell experienced even minor stresses. Perhaps an inward radial load could cause damage to the shell. An outward radial load would cause the clips...
