Session: 09-05-03 Wave Energy: Mooring and Control

Submission Number: 157318

Investigation on the Effects of Stiffness Model on the Fatigue Damage of the Moorings for a Wave Energy Converter 

Rising of energy demand and greenhouse gases have increased attention for renewable sources, where offshore waves offer high potential. WECs can capture up to 90% of wave energy, while mooring systems, essential for WEC reliability, can account for 30% of costs. Synthetic lines are cost-effective due to their high strength-to-weight ratio, though their viscoelastic and viscoplastic behaviour introduces plastic deformation and damping, known as dynamic stiffness. Previous analysis have shown that the application of different dynamic stiffness models may affect the dynamic behaviours of the moorings and the floating systems (Depalo et al., 2022 and Vidal et al., 2024).Fatigue in synthetic cables is significantly higher than in constant stiffness or decoupled models, warranting special focus.

The present study will investigate the effects of the dynamic stiffness model on the fatigue damage assessments in the moorings of a synthetic, three-leg moored wave energy converter using fully coupled numerical analysis with the DNV software SIMA. The WEC prototype concept WaveEL 3.0, developed by the Swedish company Waves4Power will be used in the analysis considering the environmental condition of Figueira da Foz, Portugal. The mooring tensions and dynamic response will be analysed by considering both quasi-static stiffness and dynamic stiffness approaches. Both the Syrope model proposed by DNV (Falkenberg et al., 2019) and the bi-linear model recommended by ABS (ABS, 2021) will be utilized for comparisons.

Presenting Author: Shan Wang Centre for Marine Technology and Ocean Engineering (CENTEC), Instituto Superior Técnico

Presenting Author Biography: Dr. Shan Wang is a tenured assistant professor at the Department of Mechanical Engineering, Instituto Superior Técnico (IST), University of Lisbon. She received her PhD from the University of Lisbon in 2016, funded by the Portuguese Foundation for Science and Technology, and her thesis was awarded a "pass with distinction and honor." Dr. Wang has supervised and co-supervised 12 master’s students and 4 joint PhD students, published 84 peer-reviewed papers, and achieved an h-index of 21 with 1385 citations (Scopus). She is a member of the Editorial Board of Ocean Engineering, the Journal of Marine Science and Engineering, and Marine Energy Research, and is an associate board member of the Journal of Marine Science and Application. Dr. Wang has also been a guest editor for special issues in leading journals. She has contributed to eight funded projects, leading two FCT-funded projects on CFD simulations of floating bodies and playing key roles in EU-funded projects such as EXTREME SEAS, ELASTMOOR, ARCWIND, and NATURSEA_PV.