疲劳寿命计算器 — 公式
## Basquin's Law for Fatigue Life
Fatigue failure occurs when a material is subjected to repeated cyclic loading below its static strength. Basquin's equation relates stress amplitude to the number of cycles to failure.
### Formula
**Sa = Sf' × (2N)^b** or equivalently **N = (Sa / Sf')^(1/b) / 2**
Sf' is the fatigue strength coefficient (approximately the true fracture strength), b is the fatigue exponent (typically -0.05 to -0.15 for metals), and N is the number of reversals to failure (2N = cycles).
Fatigue failure occurs when a material is subjected to repeated cyclic loading below its static strength. Basquin's equation relates stress amplitude to the number of cycles to failure.
### Formula
**Sa = Sf' × (2N)^b** or equivalently **N = (Sa / Sf')^(1/b) / 2**
Sf' is the fatigue strength coefficient (approximately the true fracture strength), b is the fatigue exponent (typically -0.05 to -0.15 for metals), and N is the number of reversals to failure (2N = cycles).
计算示例
A steel component with Sf' = 900 MPa, b = -0.1, subjected to 300 MPa stress amplitude.
- Sa/Sf' = 300/900 = 0.3333
- N = (0.3333)^(1/(-0.1)) = (0.3333)^(-10)
- N = (1/0.3333)^10 = 3.0^10 = 59,049 cycles