ABSTRACT
This paper deals with a stochastic approach to analysis mode II fatigue delamination for composite blades of wind turbines and simulates fatigue delamination development and the failure probability of the structures. Based on existing studies, various Paris law models are used to predict the propagation of the fatigue crack growth on mode II, and reproduce the crack length subjected to cyclically repeated loadings. Combined with failure probability of the blades, the remaining service time is estimated by stochastic m ethods such as gamma process and fatigue crack lengt h evolution is predicted. The failur e time of wind turbin e blades for mode II is estimated by the fatigue crack growth of stochastic process with its pre-determined critical crack width. A numerical example is investigated to analysis the fatigue damage process for wind turbine composite blades and the failure probability of blades under different cases is predicted by stochastic gamma process. The results show that the Paris m odel with gamma process provides a good prediction on the failure time of the delamination fatigue growth, and this stochastic method for reliability analysis can be used determining optimum maintenance strategies.
