Allowable fatigue shear stress
Input
Number of cycles
Basic fatigue strength
Maximum cyclic stress
Minimum cyclic stress
Result
Mean cyclic stress
Correction factor
Allowable fatigue strength
Stress range
Notes
- Based on Chapter 7 "Fatigue" of the AIJ Standard for Allowable Stress Design of Steel Structures (2019): Eq. (7.2) for the allowable fatigue strength and Eq. (7.3) in 7.4 for the mean stress correction factor. Take the reference fatigue strength from Table 7.2 of the same Standard — this site carries it on the Fatigue strength (shear stress) page.
- 7.1 of the same Standard does not cover the following. Ordinary buildings under cyclic stress from earthquakes and the like; low-cycle fatigue, meaning a fatigue life of 1×104 cycles or fewer; corrosive environments or temperatures above 150℃; and cases where the upper or lower limit of the stress amplitude exceeds F/√3 in absolute value.
- Do not include residual stress in the maximum and minimum stresses. Fatigue design works from the nominal stress on the section being designed; stress concentrations at notches and residual stress from welding are left out. That said, where a mean stress correction is applied, the maximum and minimum must be taken on values that include the stress from dead load and the like.
- The cyclic stress is assumed to be of constant amplitude.
- Which equation gives the correction factor depends on the stress ratio. The result field shows the one actually used.
- Where the Standard writes "stress intensity", this page writes simply "stress".