Collision Safety Analysis of Offshore Wind Turbines

Some offshore wind farms in Europe have been built and numerous projects are on the drawing tables. It is necessary to study the effects of these wind farms with respect to the safety of shipping in order to estimate the related risks to people, ship traffic and the environment. Here the formal risk definition is the product of collision frequency (collision rate) and collision consequence (size of ship damage or emission of harmful substances). This paper puts emphasis on the methods of the determination of the consequences. For offshore wind farms within the German Exclusive Economical Zone (EEZ) the so-called “Collision Friendly Foundation Design (CFFD)” is required by the responsible authorities. In case of a ship collision with such a foundation type, the ship will not be damaged or more generally spoken emission of harmful substances will be minimal. Within this paper ship/offshore structure collision modeling is presented as an example for a nonautomotive application of LS-DYNA. Shortcomings within the code special to this and other shipbuilding applications are emphasized in order to highlight the need for further development of the code besides automotive applications. LS-DYNA is the most commonly used code in ship crashworthiness analysis.