The fatig98ue limit values (
σTzul
,
σLzul
, and
τzul
), are calculated based
on the following regimes of Stress Ratio ®,
Reference: the DVS1608 regulation document section 7.2.2.
For nominal stress (longitudinal
σLzul
and transverse
σTzul
)
Regime 1:
(Rσ> 1)
σzul=54⋅1.04−x(MPa)
Regime 2:
(− ∞ ≤ Rσ≤ 0)
σzul=46⋅1.04−x⎛⎝11+Mσ1+Rσ1−Rσ⎞⎠(MPa)
Regime 3:
(0 < Rσ< 0.5)
σzul=42⋅1.04−x⎛⎜⎝11+Mσ3(1+Rσ1−Rσ)⎞⎟⎠(MPa)
Regime 4:
(0.5 ≤ Rσ< 1)
σzul=36.5⋅1.04−x(MPa)
Mτ
is the mean stress sensitivity, the
exponent x in the above equations is queried from the below notch detail
tables:
For shear stress,
τzul
,
Regime 2:
(−1 ≤ Rτ≤ 0)
τzul=28⋅1.04−x⎛⎝11+Mτ1+Rτ1−Rτ⎞⎠(MPa)
Regime 3:
(0 < Rτ< 0.5)
τzul=26.5⋅1.04−x⎛⎜⎝11+Mτ3(1+Rτ1−Rτ)⎞⎟⎠(MPa)
Regime 4:
(Rτ≥ 0.5)
τzul=24.4⋅1.04−x(MPa)
Mτ
is the mean stress sensitivity, the
exponent x in the above equations is queried from the below notch detail
table:
The grinding bonus and the thickness factor is applied to the
calculated fatigue limit for longitudinal and transverse and just the
thickness factor to the calculated shear fatigue limit.