Fatigue Endurance Limit (Estimate)
Fatigue Endurance Limit (Estimate)
For preliminary fatigue design, a steel’s endurance limit is taken as about half its ultimate strength before applying correction factors.
The estimate is S_e = 0.5·S_ut. where S_ut is the ultimate tensile strength.
Inputs
S_ut := 600 MPa=600 MPa
Take half the ultimate strength.
S_e := 0.5·S_ut=300 MPa
Results
This is a starting point only; surface finish, size, loading and reliability factors reduce it. Above about 1400 MPa the rule caps rather than continuing to rise.
Assumptions & limitations
- Steel, fully reversed bending.
- Before Marin correction factors.
- Rough first estimate only.