Fatigue analysis is no different for cyclic pressure or thermal loadings. The example in the newsletter actually did include a pressure variation.
If you have two different pressures, you could set the load cases up as follows:
- W+P1+T1+D1 (OPE)
- W+P2+T1+D1 (OPE)
- W+P1 (SUS)
- W+P2 (SUS)
- DS1-DS3 (EXP)
- DS2-DS1 (FAT) (Cyclic pressure only)
Or (as has been mentioned above), you could specify your dP as P2 and set the load cases up as follows:
- W+P1+T1+D1 (OPE)
- W+P1+P2+T1+D1 (OPE)
- W+P1 (SUS)
- W+P1+P2 (SUS)
- P2 (FAT) (Cyclic pressure only)
- DS1-DS3 (EXP)
This second set of load cases should yield identical results to the first set, <font color="0000ff">
assuming there are no expansion joints or bourdon effects in the model</font>. If so, use the first approach.
With regards to the newsletter, please e-mail me your current contact information. I will see that you get on the list (if you are not on it already).
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Regards,
Richard Ay (COADE, Inc.)