Comparing Fatigue Life Estimations of Composite Wind Turbine Blades using different Fatigue Analysis Tools

In this paper, fatigue lifetime prediction of NREL 5MW reference wind turbine is presented. The fatigue response of materials used in selected blade cross sections was obtained by applying macroscopic fatigue approaches and assuming uniaxial stress states. Power production and parked load cases suggested by the IEC 61400-1 standard were studied employing different load time intervals and by using two novel fatigue tools called ALBdeS and BECAS+F.

The aeroelastic loads were defined thought aeroelastic simulations performed with both FAST and HAWC2 tools. The stress spectra at each layer were calculated employing laminated composite theory and beam cross section methods. The Palmgren-Miner linear damage rule was used to calculate the accumulation damage.

The theoretical results produced by both fatigue tools proved a prominent effect of analysed design load conditions on the estimated lifetime of the wind turbine blades and are good starting points for future fatigue analysis using other methods.