| Summary: | Offshore wind energy considered as the future of green energy, has known a consistent growth globally over the past decades with Europe being a major player followed by the US and Canada. The first large scale offshore wind farm of 160 MW (Horns Rev) was built at 14 m from the west coast of the Danish North sea site in 2002. This market of sustainable energy has also extended to other regions in the world most especially in Asia.[17] There is a large potential market for offshore wind turbines in northern regions with extreme cold climate such as Northern Asia, North America and Northern Europe. According to the European Wind Energy Association (EWEA), approximately 20% of the European offshore wind turbines producing in total 10 GW will be installed in the Baltic Sea by 2020. Offshore wind turbines in Northern regions with extreme cold conditions will experience additional ice loads apart from aerodynamic and hydrodynamic loads.[30] The main purpose of this research was to aid in the development of a tool, for structural design purposes of offshore wind turbines, that describes different environmental load conditions and site specific soil properties. This tool was to enable the user to easily select site specific environmental and soil properties, run a simulation and possibly generate an optimized wind turbine substructure. This thesis consisted of research on wind energy and finite element numerical simulations using the engineering software Abaqus. This study focused on the modelling of the structural response of monopile offshore wind turbines under aerodynamic, hydrodynamic and ice loads taking into consideration the soil-structure interaction. A specific site at the Gulf of Bothnia (Tahkoluoto) made of glacial till seabed type was used as a case study. To arrive at a conclusion, the lateral response and Eigenfrequency of a 5 MW baseline offshore wind turbine under dynamic ice, wind and wave loads was evaluated considering the soil-monopile interaction idealized using the coupled spring foundation model. ...
|
|---|