The Mechanical Load Measurement And Fatigue Analysis Of Wind Turbine

The operational safety of wind turbines takes deep impact by mechanical parts. In thepast decade, the development of wind power industry is very rapid, the unit capacity andinstalled capacities are both increase continuously. The large size of wind turbine requires agood material life of mechanical part, hot topics is whether the turbine could operate safelyin its design life. Therefore, it has great significance that the load tests and fatigue analysisof the components are done. The final purpose is to predict the fatigue life accurately.First, the method of load measurement is analyzed in this paper. The relevantmeasurement of basic loads of the key position of the wind turbine is taken. Themeasurement principle, the structure and main parameters of sensors are analyzed in detail.The advantages of the full-bridge measuring method in load measurement of wind turbineare discussed, and the method has a practical project application.The hardware and software of the measurement system are introduced in this paper. Inaccordance with relevant standards a test program has been developed and the functions ofunits of the test system are described. This article points out a design program of capturematrix and data storage. The realization of automatic data collection, storage andpreprocess by using Windtest software. In the calibration, several calibration methods andtheir advantages are proposed. The human and financial resource consumed has beenreduced effectively.Finally, the fatigue of wind turbine has analyzed. Load cycles are counted andsimplified with rain-flow method and linear Goodman formula. Load spectrum andmaterial S-N curve is discussed, a measured blade load spectrum is given by programmingwith Famos. The life of the blade is calculated with linear Palmgren-Miner cumulativedamage law. The predicted life is about24years similar to the design life. The equivalentload in fatigue analysis applications is introduced.The result shows that this method could be used in engineering applications at thisstage. However, due to ignore other factors which may affect the life prediction, thismethod of fatigue analysis still requires improvement and optimization.