PSI - Issue 17

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

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 17 (2019) 643–650

ICSI 2019 The 3rd International Conference on Structural Integrity Fatigue damage analysis of offshore wind turbine monopile weldments ICSI 2019 The 3rd International Conference on Structural Integrity Fatigue damage analysis of offshore wind turbine monopile weldments

Romali Biswal*, Ali Mehmanparast Renewable Energy Systems Centre, Cranfield University, UK Romali Biswal*, Ali Mehmanparast Renewable Energy Systems Centre, Cranfield University, UK

Abstract

Ab tract

Offshore wind turbines (OWT) are subjected to harsh environmental conditions in addition to the variable service loads. The present study is aimed at performing a realistic fatigue life estimation of the monopile structure using operational service loads recorded by online monitoring systems. Fatigue damage analysis has been conducted at the circumferential weld joints using finite element (FE) method by considering geometrical and material property discontinuities. Global-local modelling of the OWT was performed in as-welded condition to capture the local stress range at the weld toe, which acts as the critical site where cracks are most likely to initiate and propagate. The S-N fatigue design approach and maximum stress range at the weld toe have been used to determine the fatigue crack initiation life in monopiles. The results from the proposed approach show that a realistic life assessment can be made on monopile structures by accounting for the geometrical effects at the circumferential welds. Offshore wind turbines (OWT) are subjected to h rsh nvironment l conditi s in a dition to the variable service loads. The pres nt study is aimed at performing a realistic fatigue life estim tion of the monopile structure using operational servic loads recorded by online monitoring systems. F tigu damage analysis has been con ucted at t e circumf rential weld joints using finite element (FE) method by considering g ometrical and materi l r perty discontin ities. Global-local modelling of the OWT was performed in as-welded conditio to captur the local str ss range at the weld toe, which acts as the critical site where cracks re most likely to initiate and pr agate. The S-N fatig e design approach and maximum stress ange at the weld toe have been used to determine the fatigue crack initiation life in monopiles. The results from the proposed approach show that a realistic life assessment can be made on monopile structures by accounting for the geometrical effects at the circumferential welds.

© 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. P er-review under responsibility of the I SI 2019 organize s.

Keywords: Offshore structures; S355 steel; SCADA online monitoring; Finite element modelling; Fatigue life prediction.

1. Introduction

The resources for renewable energy sources are derived straight from the environment, hence enables power generation with little to no greenhouse gas emissions. The European Environment Agency report (EEA, 2019) shows that Europe and China have taken initiatives to advance the technology towards cleaner and greener energy, Fig. 1. The resources for renewable energy sources are derived straight from the environment, hence enables power generation with little to no greenhouse gas emissions. The European Environment Agency report (EEA, 2019) shows that Europe and China have taken initiatives to advance the technology towards cleaner and greener energy, Fig. 1.

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. * Corresponding author. Tel.: +44-1234-758331 . E-mail address: a.mehmanparast@cranfield.ac.uk * Corresponding author. Tel.: +44-1234-758331 . 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. 10.1016/j.prostr.2019.08.086

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