Numerical crashworthiness analysis of an offshore wind turbine monopile impacted by a ship

The consequences of collision events can range from minor structural damages of the
supporting structure to complete collapse of the wind turbine, which may lead to disruptions of the electricity production and, at worst, to sinking of the striking ship with probability of loss of human lives or/and pollution. For all these reasons, a collision risk analysis becomes mandatory at the pre-design stage in order to identify the collision scenarios having the greatest probabilities of occurrence, to estimate the consequences of collision events and to ensure safe operations through the wind farm service life. The goal of this paper is to outline the behavior of the monopile foundations during ship collision by performing non-linear finite element simulations. Many collision scenarios are analyzed in order to study the sensitivity of the monopile to various parameters like impact striking ship velocity, nacelle mass, wind direction, soil stiffness, vertical location of the impact point, wind orientation … The internal energy dissipated by deformation of the monopile, the crushing force and the indentation of the crushed area are compared for different situations, as well as the overall displacements of the supporting structure.