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.)