Review of methods to assess the structural response of offshore wind turbines subjected to ship impacts

This paper presents a literature review of analytical, numerical, and experimental methods for evaluating the structural response of Offshore Wind Turbines (OWT's) during ship collision events. The different energy transfer mechanisms involved throughout a collision against fixed or floating OWT substructures are examined, whilst documenting some of the most common procedures in the assessment of wind load effects, soil-structure interaction, mooring lines contribution and hydrodynamic coupling. A survey of internal mechanics and external dynamics approaches developed for ship-structures collision events is carried out with a discussion on their potential application in analyses involving different types of substructures. Moreover, different hydrodynamic coupling schemes found in the literature are studied, highlighting the importance of hydro-effects in the collision analysis. Common practices in the use of metallic and cementitious material constitutive models in ship-collision analysis are also presented, whereas the structural behaviour of reinforced concrete structures submitted to impact loads, which has been rarely studied outside high-velocity impact/blast applications, is discussed in the current context. Finally, some of the most important limitations of the analytical and numerical models used in ship-OWT collisions are identified, from which suggestions are provided for future research endeavors.