Fatigue Analysis-Goodman criteria

[nitinfem1]

Hi all,

Lets say,
I have 2 load cases, LC1 and LC2.
For LC1, the principal stresses are S11,S12,S13.
For LC2, the principal stresses are S21,S22,S23.

To calculate mean and alternating stresses.

If S11>S21, then mean = (S11+S23)/2; Alternating stress = (S11-S23)/2.

If S11<S21,then mean = (S21+S13)/2; Alternating = (S21-S13)/2.

Then I input mean and alternating stress values for each node in Goodman formula and find whether the ratio is less than or greater than 1.

I appreciate if anyone can throw some light on this approach.

Thanks