Abstract: A new fatigue damage threshold is presented in this paper. It is well known that the logarithmic fatiguelife observes the normal distribution with a certain significance level. The fatigue damage threshold observes the normal distribution under the condition of the logarithmic fatigue life observing the normal distribution. In addition, itis proved that the lineal cumulative damage also observes the normal distribution by means of statistical testing.Therefore, the distribution configuration of the fatigue damage threshold is the same as the distribution configurationof lineal cumulative damage. The fatigue damage threshold with a reliability and a confidence is suggested in this paper.

Key words: fatigue damage threshold, cumulative damage, normal distribution