Computation Method on Fatigue Life of a Full Composite Wind Turbine Blade

The generation of load spectrum for epoxy resin blade of large-scale wind turbine is researched in this paper, so are an engineering estimating method of the fatigue failure and accumulated fatigue damage. Meanwhile, Load cases are considered, calculated and evaluated. First, a 3 dimensional finite element modal for calculation of fatigue failure is proposed based on the composite laminated technology of wind turbine blades and the critical zone where fatigue failure begins is extracted. Since wind flow (loading) is random, wind distribution histogram using Rayleigh distribution function is employed to simulate wind flow with randomness in its nature on the blade, subsequently each load case is weighted by its speed range and frequency of occurrence, get to the average load of the fatigue load described matrix. Then the process of accumulated fatigue damage is simulated as a process of generalized material property degradation. Finally, fatigue failure and accumulated fatigue damage to a practical 1.0 MW wind turbine blade is calculated as an example to illustrate the process of this method.