Numerical Study on Fatigue Behavior of Grouted Connection in Offshore Wind Turbine Under Axial Load

With the increasing size and power of offshore wind turbines (OWT), new challenges had been brought to the development of offshore wind technology. Under wind and wave loadings, grouted connections of the OWT support structure can be damaged from fatigue problems, and therefore it is the key part of the design. Research has been carried out to determine the parameters that affect the fatigue behaviour of grouted connections through experiments and numerical simulations. In this paper, a numerical analysis of four parameters was carried out. The numerical model was built and verified by the static test results. By setting four parameters of fatigue load upper limit, longitudinal error, transverse error, and load eccentricity, the influence of different parameters on the fatigue life of grouted connections was analysed by using the fatigue life analysis method of the grout layer. It was found that the fatigue life decreases when the load upper limit increases; the distance between the lowest shear and the bottom edge of the outer tube is a key parameter when there is a longitudinal error, and it is recommended that the longitudinal error does not exceed this value; the fatigue life of grout layer is inversely proportional to the transverse error; the eccentricity has a great influence on the fatigue life of the grouted connection.