Basquin's law
Basquin's law of fatigue states that the lifetime of the system has a power-law dependence on the external load amplitude, t f ∼ σ 0 − α {\displaystyle t_{f}\sim \sigma _{0}^{-\alpha }} , where the exponent α {\displaystyle \alpha } has a strong material dependence. It is useful in expressing S-N relationships.