Abstract:

Fatigue life of aircraft structures is very important to ensure both aircraft safety and aircrew and passenger lives. The service life can be obtained by analysis of the fatigue test data. Usually, the distribution of the fatigue test data was determined by the method of combination of probability paper and correlation coefficient. However, by this method, some fatigue test data can pass both lognormal distribution test and twoparameter Weibull distribution test. The life prediction will be very different for the same fatigue test data on account of different fatigue scatter factor of different probability distributions. This leads the difficulty in life prediction and life extension of aircraft structures. This question was investigated in this paper and we conclude that the method of combination of probability paper and correlation coefficient can be adopted when the reliability is under 99%. Otherwise, the efficient Weibull distribution test should be applied. The conclusion can provide important reference for engineering.

Key words: fatigue test of structure, fatigue life, fatigue scatter factor, reliability, lognormal distribution, twoparameter Weibull distribution