Abstract

Monopile foundation is widely used for offshore wind turbines in water depths below 40 m. After the monopile has been driven into seabed, a transition piece (TP) is required to be installed on top of the monopile to connect the turbine tower. The installation of TP is normally carried out by crane operation in which the TP is lowered on top of the monopile. The impact between the monopile and TP may occur due to the random motion of TP in particular if a floating vessel is used for installation. In this paper, nonlinear time-domain structural analysis is performed to study the impact between TP and monopile. Vertical impact cases are presented and plastic material property was defined to consider the springback after the TP has been removed. A sensitivity analysis considering impact velocity, TP eccentricity and inclination angle about two axes is came out. The findings can be used to properly define the limiting crane tip motion, environment condition, as well as the dynamic behavior of the installation vessel.

Keywords:
maximum radial deformation, deformation shape, installation vessel, numerical simulation, final deformation shape, offshore wind turbine installation, simulation, monopile, installation, wind energy
Subjects:
Offshore Facilities and Subsea Systems, Facilities and Construction Project Management, Platform design, Offshore projects planning and execution
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2014. International Society of Offshore and Polar Engineers
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