Fuzzy approach to fatigue problems in composite materials and structures

For composites static strength, fatigue damage and durability demonstrate a scatter factor of results larger than for isotropic materials. To characterize it the fuzzy set approach is proposed. Two different mechanical descriptions of fatigue life are used in order to describe the uncertainty and randomness of parameters characterizing the fatigue damage and finally the fatigue durability. The theoretical predictions representing the lower and upper bounds of a fatigue life are compared with experimental data. In general, the present analysis shows that the fuzzy set description allows us to take into account much more parameters than classical deterministic or statistical methods.