Fatigue Analysis as per ASME VIII Div.2

[iguisa]

Hello,
we are designing a pressure vessel as per ASME VIII Div.1 and it works in cyclic service, so we use ASME Div.2 for the fatigue analysis. We have a program called nozzlepro, with which we can perform the fatigue anaysis but this program only allows the temperature to be variable (the pressure stays as a constant). But this is not our case, because both T and Pr are variable. Could anyone give us a tip about how to proceed in this case?
Thank you!

 

[condesinc]

Run multiple nozzle pro runs with each pressure you need, manually differentiate stresses from pressure

 

[TGS4]

If your tool doesn't do what you need it to do, then you are using the wrong tool.

For a fatigue analysis, make sure that you are checking the longitudinal weld seams, the circumferential weld seams, the head-to-shell joints, all of the nozzle connections, external support clips, saddle/skirt connection, and many other locations.

 

[DSB123]

TGS4,
Think you meant to say "the whole vessel"

 

[davefitz]

Try the method defined in the european norm codes, such as EN-12952-3 , or the older german boiler code TRD 301 annex 1. It provides a means of adding thermal stress to the pressure caused stress, and the means of adding differnt stress cycles is vai the rainflow cycle counting algorithm