I presently processing a non-linear fatigue which has bolt loading, flange push back of that bolt loading and cycling 150psi pressure under the dome of the pressure vessel.  Unfortunately when I process the fatigue, the bolt load and flange force also vary, which isn't what happens in real life.  Speaking of which, the results are not close either.

Therefore I need to isolate only the varying pressure of the vessel.  Any fatigue experts, I am not, can offer a potential solution to this multi-load problem?  Tx!

Phil