Load Analysis And Fatigue Life Estimation Of The Main Shaft Of Large Wind Turbine

The development of human society is inseparable from the energy. Especially after the oil crisis in1973, the emergence of high-quality energy and advanced energy technologies are particularly important. Nowadays, the wind power technology has gained the sharper focus, which results in its rapid development. However, with the increasing of size and installed capacity of wind turbines year by year, many problems have been revealed, such as higher costs, failure-prone, and so on. In addition, the manufacturing technologies of wind energy products also meet enormous challenges. Therefore, the solutions of these problems could not only reduce the manufacturing cost of wind turbines but also increase the reliability of each of its key components. Moreover, there is still a technological gap between China’s wind turbine manufacturing and developed countries’, such as modeling for the whole turbine, analyzing for the load components, and other aspects. In this paper, experiments are conducted on a2MW wind turbine. After modeling the whole turbine, the load characteristics and the fatigue life of the spindle are studied.Firstly, the basic principles of the wind turbine were described. Then, wind turbine aerodynamic characteristics of discourse analysis theory (blade element momentum theory) were introduced. Finally, the inducing factor of tangential and axial wind turbine was discussed and the influences of the factor that effect on the dimensions of structural parameters, the aerodynamic characteristics and the wind wheel loads of the wind turbine were shown.Firstly, wind turbines whole structure analysis model was built through professional analysis software S4WT. Secondly, the operating mode of wind turbine shaft for load analyzing was established according to IEC61400-1standard. Then, the force and the moment of force of large wind turbines in various wind conditions and the spindle force and moment load conditions were calculated.So we can derived the key parts of the wind turbine load determination method, namely establishing the coordinates of blades, blade roots, hub and tower coordinate.We composite each load on each coordinate system and acquire wind dynamic load response curve of the spindle, which intuitively descripts the load characteristics of the spindle under the different operate conditions and wind conditions.We have built a main shaft three-dimensional model in Pro/E and we have analyzed the finite element by finite element analysis software ANSYS.The stress variation and limit valuation of the spindle under different wind speeds have been acquired.The location of stress limit valuation is matched with the location of fatigue failure on the spindle in reality. Based on the combination of most typical theoretical Palmgren-Miner theory of linear cumulative damage theory and wind farm, material performance data of spindle shaft, we gived a fatigue life estimation.The effectiveness of this estimation method has been proved by an example confirmation, which is satisfy the demand of20years life safety of turbine shaft.