FIBER-COMPOSITE FATIGUE-LIFE DETERMINATION

A methodology is described for the statistical characterization of fib re composite fatigue-life data. The approach determines the most appro priate probability distribution function and then estimates the associ ated descriptive parameters. The methodology includes the determinatio n of the most accurate minimum-life estimation method. Two sets of car bon fibre composite fatigue-life data are found to be best characteriz ed by Weibull distributions, from which minimum lives may be estimated . The results of this study highlight a large difference between estim ated median and minimum fatigue lives of composite materials. One set of the samples exhibited a median life of 37022 cycles and a minimum l ife of 0 cycles, and the other a median life of 85250 cycles and a min imum life of 16000 cycles. It is concluded that minimum-life S-N plots are more appropriate for use in design engineering activities than S- N plots based, in the conventional way, on median lives. Copyright (C) 1996 Published by Elsevier Science Limited.