Fatigue evaluation - ASME BPVC VIII DIV 3 KD-300

[bday]

Hi,
question on the type of the stresses needs to be considered.

for simplicity lets say that equivalent alternating stress intensity is equal to the alternating stress intensity - so without mean stress correction

where:
alternating stress intensity = range of the shear stress

assuming that SN data are expressed in Stress amplitude vs Number of Cycles - shall we divide calculated alternating stress intensity by half (to have amplitude stress) and then compare this value with SN data?

or for some reasons alternating stress intensity (shear stress range) shall be directly compared with SN data.

Thanks
bday