Fatigue Modifying Factors in API 579 - FFS
Fatigue Modifying Factors in API 579 - FFS
(OP)
Hi there.
For fatigue analysis procedure described in section B-1.5.3 of API 579 ¿In which of equations B1.30, B1.35, F.214 or F.215, fatigue modifying factors (surface finish factor, loading factor, etc.) must be applied?
Thanks!
Jairo
For fatigue analysis procedure described in section B-1.5.3 of API 579 ¿In which of equations B1.30, B1.35, F.214 or F.215, fatigue modifying factors (surface finish factor, loading factor, etc.) must be applied?
Thanks!
Jairo





RE: Fatigue Modifying Factors in API 579 - FFS
For an evaluation per B1.5.3, the Kf is applied to the stresses to calculate an effective equivalent stress, which is then compared to the S-N curve. The S-N curve is not modified.
RE: Fatigue Modifying Factors in API 579 - FFS
Jack
RE: Fatigue Modifying Factors in API 579 - FFS
There is a number of fatigue-related quantities that are not explicitly detailed, but are hidden in the S-N curves, much like the mean stress correction. The quantities that you refer to may fall under such a categorization.