Using the three-parameter Weibull distribution function, we analyzed two kinds of fatigue life data. Three parameters estimated by the Maximum Likelihood Method are dependent on the stress, and have strong relationships between each other. Using these relationships, we proposed a new formula of Weibull distribution, which has only one parameter, shape parameter m. and three material constants. We clarified the meaning of each material constants included in the formula of the distribution function by numerical simulation. We applied this new distribution to the actual data, namely, the rotating bending test data of S 45 C and repeated internal pressure test data of A 7075-T 73 cylinders, which proved the validity of the new equation.
