Fatigue Life Estimation for Using Fuzzy Mathematics

Structural components subjected to variable loading may usually tend to fatigue failure. With the accumulation of fatigue damages, some accidents will occur. Therefore, how to predict fatigue life of the structure component is a very important problem. Although many damage models have been put forward, the most widely used one is the linear damage model. The model is often referred to as Miner's rule, whereas it is fuzzy when the stress that the structural components subjected to is slightly lower than the fatigue limit. The fuzzy factor are taken into account and the new approach is given. In order to apply Miner's rule conveniently, the two-dimensional fuzzy Miner's rule is investigated. At the same time, different membership functions are studied, which have important influence on the result of estimating fatigue life. The structural fatigue life of ×× airplane is estimated by adopting the two-dimensional fuzzy Miner's rule. By comparing the result with that of two-dimensional Miner's rule, the conclusion is drawn that the accuracy increased about 7%.