Variability of fatigue parameters under uniaxial loading in the function of the number of cycles to failure

This paper presents the problems relating to the determination of the material constants and their assessment. The study demonstrated that the scatter of the values of the fatigue life and stresses applied for determination of the σa-Nf characteristics could have an effect on the coefficient m representing the slope of this characteristics. The phenomenon associated with the variability of a number of material parameters relating to the number of cycles to failure is discussed. In addition, the paper reports on the influence of the number of cycles to failure on the value of the notch factor. The paper also discusses the function accounting for the effect of the geometrical KW and structural KS notches based on the relation stating the dependence of Kf coefficient on the number of cycle to failure.