Fatigue Assessment of Monopile Supported Offshore Wind Turbine under Non-Gaussian Wind Field

Abstract

The vibration of offshore wind turbines caused by external loads is significant, which will cause fatigue damage to offshore wind turbines. Wind load is the main load during the operation period of the wind turbine, and available studies have shown that the external wind field often exhibits certain non-Gaussian characteristics. This article aims to obtain the fatigue assessment of the monopile foundation of the wind turbine under the non-Gaussian wind fields. A 5 MW wind turbine is selected in this article, and OpenFAST is applied to simulate the wind load. By comparing the Mises stress time histories of the pile foundation at a different depth, the fatigue analysis of the critical spots of the pile foundation is obtained. In the analysis of fatigue damage, the rain flow counting method is adopted, and the two-segment S-N curve is selected to analyze the fatigue life of the critical spots. The results show that, by taking the non-Gaussian characteristic of the wind field into account, the fatigue life of the monopile foundation decreases. Therefore, attention should be paid to the influence of non-Gaussian characteristics of wind fields on the fatigue life of monopile-supported wind turbines.