Impact analysis of wind turbines subjected to ship collision and blast loading

The structural integrity of Offshore Wind Turbines (OWT) is of prime significance, due to the significant dynamic stresses generated by the extreme blast and impact loads. The detrimental damage of such loads emanates from either large inelastic localized deformations or the global rotations which to the collapse of the wind turbine over the ship. In some circumstances, however, the combination of the two is imminent. In this work, we examine two scenarios of impact and blast phenomena on offshore wind turbines. In the first, the influence of gravity loads, wind velocity, vessel angle of attack, and its initial momentum, on the localized and global deformations is discussed. A numerical FE model is developed to further investigate the damage of the OWT struck by a commercial ship. In the second scenario, we develop a mathematical model to capture the blast response of cylindrical shells utilized in the OWT. By decomposing the load into a spatial part with constant magnitude and a temporal part characterized by a piecewise function, the analytical solution is sought for two distinguishable phases. The validation of the analytical model with the FE one shows the capability of the former to capture the dynamic plastic collapse of the shell with a good degree of accuracy.