A review of present status and challenges of using additive manufacturing technology for offshore wind applications

Offshore wind is an efficient sustainable source of energy, which is a preferable alternative to burning fossil fuels in Europe and worldwide. About 85% of existing offshore wind turbines are supported using monopile foundations, which are made of large welded plates. The locked in residual stresses in a monopile structure have a great impact on its fatigue life. The new emerged technology of additive manufacturing (AM), which is widely used in other industries such as aerospace and automotive, has the potential to significantly improve a lifespan of the structure by managing the residual stress fields and microstructure in the future monopiles, and moreover reduce the manufacturing cost. In order to achieve this goal, new materials that are used for additive manufacturing parts fabrication and their behaviour in the harsh marine environment and under operational loading conditions need to be understood. Also purely welding fabrication technique employed during AM process is likely to significantly affect crack growth behaviour in air as well as in seawater. This paper presents a review of additive manufacturing technology and suitable techniques for offshore structures. Existing literature that reports current data on fracture toughness and fatigue crack growth tests conducted on AM parts is summarised and analysed, highlighting different steel grades and applications, with the view to illustrating the requirements for the new optimised functionally graded structures in offshore wind structures by means of AM technique. (C) 2019 The Authors. Published by Elsevier B.V.