The influence of ice jams on ice-induced vibrations of multi-legged sub-structures

The world is transforming its energy production towards more sustainable sources of energy. In Europe, there is currently 25 GW of installed offshore wind power capacity. This is expected to grow with 29 GW over the next five years. Offshore wind farms can be expensive and challenging to build, design and maintain....

Experimental study into the dependence of ice-induced vibrations on dynamic structural properties

Arctic and sub-arctic regions are more and more used to build offshore wind farms. There is a lack of model-scale tests where dynamic sturcutral properties were systematically varied to derive the influence of these properties on boundaries of the three crushing regimes. Those regimes are intermittent crushing, where both the ice load and...

Mitigation of Ice-induced vibrations of Offshore Wind Turbines by Control Idling

Offshore wind farms are being developed at locations with moderate ice conditions such as the Baltic Sea, where drifting sea ice upon interacting with offshore structures could lead to the development of a phenomenon known as Ice-induced vibrations (IIV). These vibrations are especially severe when the turbine is idling. Current mitigation...

Ice-induced vibrations of wind turbines with a jacket support structure

The offshore wind industry is a relatively new but fast growing field in the global shift towards renergy to reduce carbon emissions. However, more difficulties arise in the design of an offshore wind turbine (OWT) compared to an onshore wind turbine, as the offshore structures are exposed to more environmental influences. One of those is sea...

Ice-induced Vibrations of Vertically Sided Model Structures: Comparison of structures with circular and rectangular cross-section subjected to the frequency lock-in regime

Offshore wind energy has very recently begun expanding into subarctic regions with seasonally ice-infested waters like the Baltic Sea. For offshore wind turbines with conventional support structures such as monopiles and jackets that are typically flexible and vertically sided, the phenomenon known as ice-induced vibrations can develop. In...

Mitigating ice-induced offshore wind turbine vibrations utilizing a TMD system

Offshore wind farms in Bohai Bay may be exposed to sea ice. The possible development of ice-induced vibrations can result in periodic high amplitude oscillations of the structure, which can significantly contribute to the fatigue of the structure. The main objective of this thesis is to investigate the mitigation effects of ice-induced...

Coupled modeling of dynamic ice-structure interaction on offshore wind turbines

The offshore wind industry is growing at high pace and is already one of the major renewable energy sources in Europe. To support this growth, costs must be further decreased, amongst others by efficiently designing the support structure of the offshore wind turbines (OWT). This requires accurate prediction of environmental loading such as...