A Numerical Evaluation On Wind-induced Fatigue Loading And Its Effect On The Stability Of Wind Power Foundation

In recent years, wind power and other clean energy have already been developed vigorously in China, with the scale, production quality and production efficiency being enhanced greatly, the safety problems at the aspect of structure designing under the extreme conditions occurred occasionally. This paper analyzes rationally the situation of soil fatigue under the foundation under the extreme wind induced fatigue loading of the western inland large megawatt wind turbine.It is difficult to analyze the surrounding environment conditions and hard to have the field measurement works down, in addition, the existing observation records which remain limited can not been used widely in the calculation of wind vibration analysis, so we adopt the method of numerical simulation of wind load. We simulate the fluctuating wind load, and add the average wind load to the fluctuating wind to get the complete time series date. The next step we discrete the big fan’s upper structure into a multiple particles spring-mass model and get all these particles loaded by the equivalent wind loads, in order to obtain the dynamic response and the natural frequency of the modal under the extreme wind load condition. For further step, we intend to check the upper structure’s safety and reliability to test the fatigue state under the extreme situation. Finally, we want to confirm whether the wind turbine have the ability of anti-capsize, anti-slippage and anti-torsion.As the simulation results shown, for simulating the tower structure’s dynamic response under the action of random wind load for a long time, the harmonic superposition method simulating wind speed time history data provides a reliable and applicable random wind load time history data. And we will apply all these groups of wind load time history data to the simplified structure of the fan, the sorts of reaction time history data on the top of foundation are true and reasonable. Finally, for the model of soil-foundation, the simulation data shows that in the long time of extreme conditions, due to the repeated fatigue loads, the soil produces large deformation, which can lead to a fatal effect to the stability of the upper structure of the wind turbine and the working safety. This article also simulate the stability of the foundation which under-soil has already been damaged by the fatigue loading.