Abstract
In the low-cycle fatigue design based on testing of geometrically similar models, the scatter of fatigue life is taken into account using the factor for the statistical variation in test results, Kss = 1.470-0.044γ, the formula given by the ASME Boiler and Pressure Vessel Code, where γ is the number of replicate test. In the present paper, this formula has been examined by calculating the upper confidence limit of the probability of failure PfU for the design service cycles as determined using the above formula. It was found that PfU varied with η and γ, where η was the coefficient of variation of the fatigue life. An alternative formula was proposed which made PfU independent of η and γ.
