Dynamic Response Analysis for the Monopile Driving Process of Offshore Wind Turbines

Monopile is used as supporting part of offshore wind turbines (OWTs) and determines its service time. After the construction, dynamic response of monopiles has been extensively studied under external loads, such as seawater corrosion, offshore wind and pile-soil interaction. However, in the monopile driving of large-capacity OWTs, the hammering force and stress peaks increased several times over. Therefore, in this work, two finite element models were established for the monopile driving process, including the bottom-fixed model and spring-friction model. These models were verified by the construction data from engineering. From the comparison, the data in spring-friction model was more consistent with the engineering condition. It overcame the shortcomings of bottom-fixed model. The inclusion of pile-soil interaction allowed for the determination of pile penetration and lateral friction resistance. The simulation results were more accurate and had less error with engineering data. The numerical simulation was expected to provide reference data for studying the fatigue life analysis of the driving monopile.