Elastic plastic Ratcheting

[MG83]

Hi
Please tell me in order to evaluate elastic-plastic ratcheting in a vessel, which kind of load should be considered, Design pressure or operating pressure?
Thanks

 

[TGS4]

What is your Code of Construction? What does your Code of Construction say?

 

[MG83]

Asme viii div2 part5 elastic-plastic ratcheting

 

[TGS4]

Operating loads: pressure, temperature (including transient thermal gradients), static pressure, etc.

 

[MG83]

Sorry would you tell me the reference code?

And
Why we use design loads for elastic ratcheting criteria (PL+Pb+Q) instead of operating loads related to your answer for elastic-plastic analysis?

 

[DriveMeNuts]

It is you who has to select the design code.
If you were to select the design code, you would likely find your answer in that design code.

 

[MG83]

Design code is asme viii-2. I want the exact paragraph that mentioned operating pressure for ratcheting . I can't find that in 5.5.7

 

[TGS4]

It's not noted in 5.5.7. Please submit a request to the Code Committee to get that fixed (it should be fixed).

But see 5.5.6.1(b). And in the context of elastic ratcheting, check out Table 5.3, lines 10-17.

If you submitted a Code Interpretation, you would get the same answer (likely from me...).

 

[MG83]

Thank you so much.
It was very important for me because in my case, the pressure difference in design and operating mode was very high.