Reduction of Fatigue Damage Equivalent Loads in the Wind Turbine System Through the Use of Off Axis Plies in the Spar Caps of Composite Wind Turbine Blades

2015-07-19
Gözcü, Ozan
Farsadi, Touraj
Şener, Özgün
KAYRAN, ALTAN
In the wind turbine industry, as the requirements for fatigue life and reliability increase, to achieve these goals appropriate measures must be taken such that loads incurred due to the flexing of the blades must be alleviated. In this study, the use of different off-axis ply angles in the main spar caps of wind turbine blades is investigated for its effectiveness in reducing fatigue damage equivalent loads in the whole wind turbine system. To achieve load alleviation in the wind turbine system, bendingtwisting coupling in composite blades, generated by the use of off-axis plies in the spar caps of the blades, is exploited. Study is conducted utilizing both linear and non-linear blade models in the multibody models of the 5MW wind turbine system that are set up in two separate wind turbine multi-body dynamic codes increase the reliability of the conclusions drawn from the analyses. Transient aeroelastic analyses of the wind turbine system are performed for the power production load case using the normal turbulence model as the external wind loading. Time history results of simulations are used to calculate damage equivalent loads at the selected monitor points in the wind turbine system. The use of CFRP material in the main spar caps of the bend-twist coupled blade is specifically investigated for its effectiveness in reducing damage equivalent loads in the whole wind turbine system. Results show that with the introduction of off-axis spar cap plies in the blades, reductions in the damage equivalent loads can be achieved in the wind turbine system compared to baseline design, and reduction in fatigue damage equivalent loads in the wind turbine system is higher when the bending-twisting coupling is increased through the use of higher fiber angle in the spar cap plies.
Citation Formats
O. Gözcü, T. Farsadi, Ö. Şener, and A. KAYRAN, “Reduction of Fatigue Damage Equivalent Loads in the Wind Turbine System Through the Use of Off Axis Plies in the Spar Caps of Composite Wind Turbine Blades,” presented at the 20th International Conference on Composite Materials (19 - 24 Temmuz 2015), Kopenhag, Danimarka, 2015, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/72864.