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Fatigue Analysis - "you need one or more static, nonlinear, blah blah blah"

Question asked by Roy Dean on Apr 29, 2014
Latest reply on Apr 30, 2014 by Roy Dean

So I'm trying to run a fatigue analysis on a pressure vessal.    I've got a nonlinear analysis  that is run over 7.5 seconds, and has a "base pressure" and a "peak pressure".  That non-lin analysis runs perfectly.... lets call it "Nonlinear 2".  It's an axi-symetric 2d simulation, fwiw.

 

So I created a fatigue study, and I go to "loading", right click and select "Add event".

 

A window pops up that says:

"You need one or more static, nolinear [sic] or linear dynamic to perform Fatigue Analysis."

 

So I've got my "Nonlinear 2" analysis that works perfectly, but for whatever reason Fatigue doesn't like it.   I'll try running non 2-d simplification, but in the meantime I'd still like to know for sure if that's the issue.

 

Additionally, I'm finding it all but impossible to apply S-N curves to the materials....   I can create new materials with S-N curves, but my EPDM managed materials won't let me save the S-N curves to the material definitions.   Additionally, you don't seem to be able to edit the S-N data in the generic materials interface....seems like you can only do it by accessing the material THROUGH a valid fatigue study (which seems ridiculous).

 

Am I missing something here?

 

---Roy

(yet again frustrated)

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