PSI - Issue 17

Available online at www.sciencedirect.com Structural Int grity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect

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Procedia Structural Integrity 17 (2019) 29–36

ICSI 2019 The 3rd International Conference on Structural Integrity A review of present status and challenges of using additive manufacturing technology for offshore wind applications A. Ermakova a , A. Mehmanparast a *, S. Ganguly b ICSI 2019 The 3rd International Conference on Structural Integrity A review of present status and challenges of using additive manufacturing technology for offshore wind applications A. Ermakova a , A. Mehmanparast a *, S. Ganguly b a Offshore Renewable Energy Engineeri t , fi l i it , , b Welding Engineering & Laser Processing Centre, Cranfield University, MK43 0AL, UK Offshore wind is an efficient sustainable source of energy, which is a preferable alternative to burning fossil fuels in Eur pe and orldwide. About 85% of existing offshore wi d turbines are supported usin monopile f undations, 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 tech ology of additive manufacturing (AM), w ich is widely used in other industries such as aerospace and automotive, has th potential to significantly improv a lifespan of the structure by managing the residual stress fields and microstructure in the futur o opiles, and moreover reduce the manufacturing cost. In order to achieve this goal, ew materials that are used for additive manufacturing parts fabrication and their behaviour in t e harsh arin environment and under operational loading conditions need to be understo d. Also purely weldi g f brication technique mployed during AM process is likely to significantl affect crack growth behavi ur 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 tough ess and fatigue crack growth tests conducted on AM parts is summaris d 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. a Offshore Renewable Energy Engineering Centre, Cranfield University, MK43 0AL, UK b Welding Engineering & Laser Processing Centre, Cranfield University, MK43 0AL, UK Abstract Abstract 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.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. Keywords: Offshore wind; Additive manufacturing; Fatigue crack growth. Keywords: Offshore wind; Additive manufacturing; Fatigue crack growth.

* Corresponding author. E-mail address: a.mehmanparast@cranfield.ac.uk * Corresponding author. E-mail address: a.mehmanparast@cranfield.ac.uk

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 10.1016/j.prostr.2019.08.005