Seismic analysis of offshore wind turbines on bottom-fixed support structures

Alati, Natale; Failla, Giuseppe; Arena, Felice

doi:10.1098/rsta.2014.0086

Cited by 58 publications

(42 citation statements)

References 22 publications

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“…Alati et al [35] studied the seismic responses of bottom-fixed OWTs under different earthquakes and the soil effect was considered. They found that the resultant demands of tower-base moment and tower-top displacement were significantly increased by the earthquakes.…”

Section: Introductionmentioning

confidence: 99%

Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation

Yang

Bashir

et al. 2019

Ocean Engineering

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Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation http://researchonline.ljmu.ac.uk/id/eprint/10382/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively. , J (2019) Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation. Ocean Engineering, 178. pp. 215-228. Abstract: This paper investigates the effects of nonlinear soil behaviours on the structural responses of offshore wind turbines (OWTs) subjected to wind, wave and earthquake loadings. A novel seismic analysis framework (SAF) is developed for the assessment of seismic behaviours of OWTs with flexible and fixed foundations. The SAF consists of an improved QuakeDyn module that is implemented into an open source tool (FAST). SAF has been validated through benchmark studies using numerical tools and the results show good agreements. Fully coupled nonlinear simulations have been performed for OWTs with fixed and flexible foundations under operational, parked and emergency shutdown states. The flexible foundation is modelled using nonlinear p-y curves obtained using LPILE. For all the examined operating conditions, notable differences of magnitude and variation in the responses between the flexible and fixed cases are observed, indicating the need for soil effects to be accounted in seismic behaviour analysis of wind turbines. It is further observed that the earthquake induces more severe vibrations on wind turbines with a flexible foundation compared to the one with a fixed base. Also, aerodynamic damping dissipates more energy from earthquake excitation resulting in a smaller tower-top fore-aft displacement. The shutdown triggered by the earthquake causes a 34% increase in the mudline bending moment for the flexible foundation case, while a decreasing trend is observed for the fixed foundation model. Similar observations are made  Corresponding author: lichun_usst@163.com 2 / 41regarding the tower-top displacements. The observations imply that ignoring the soil effect may lead to misjudgement of the consequence of an emergency shutdown. The relative orientation of the ground motion with respect to the wind direction causes significant difference in the seismic behaviour of the wind turbine. This confirms that it is necessary to interchange the horizontal components of an earthquake in order to consider the intersectional effect between ground motion and wind.

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Section: Introductionmentioning

confidence: 99%

Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation

Yang

Bashir

et al. 2019

Ocean Engineering

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“…The critical effect of the earthquake loading on these energy infrastructures has been further corroborated by the detailed research of Alati et al ., who studied the seismic response of an offshore horizontal axis wind turbine assumed with either a tripod or a jacket supporting system. Particularly, a multi‐hazard environment was considered under the combined exposure of wind, wave and earthquake, while the latter was represented by 49 pairs of strong ground motions horizontal components recorded during past seismic events.…”

Section: Seismic Evaluation Of Wind Turbines Based On Numerical Simulmentioning

confidence: 99%

“…Similar conclusion has been drawn elsewhere, while the higher rotor blade modes, captured only by a full system model, were also found important for the seismic response because they may correspond to the region of maxima spectral accelerations. 46,47,75,98 With such a motivation to study an integrated bladetower-foundation model subjected to the seismic loading, Jin et al 99 utilized the MBS approach and an artificial accelerogram (PGA = 0.36 g), which was imposed to perform RHA, induced high fluctuation (over 180%) for the section forces (i.e., bending moments and axial force) mainly at the tower's base. This variation in critical demand measures because of the sudden earthquake occurrence was found to disturb the wind turbine performance in terms of energy harness signifying the adverse seismic implications on wind turbines even in case of no imposed structural damages.…”

Section: Seismic Analysis Of Wind Turbines Within a Deterministic Framentioning

confidence: 99%

Wind turbines and seismic hazard: a state-of-the-art review

2016

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Wind energy is a rapidly growing field of renewable energy and as such, intensive scientific and societal interest has been already attracted. Research on wind turbine structures has been mostly focused on the structural analysis, design and/or assessment of wind turbines mainly against normal (environmental) exposures while, so far, only marginal attention has been spent on considering extreme natural hazards that threat the reliability of the lifetime-oriented wind turbine's performance. Especially, recent installations of numerous wind turbines in earthquake prone areas worldwide (e.g., China, USA, India, Southern Europe and East Asia) highlight the necessity for thorough consideration of the seismic implications on these energy harnessing systems. Along these lines, this state-of-the-art paper presents a comparative survey of the published research relevant to the seismic analysis, design and assessment of wind turbines. Based on numerical simulation, either deterministic or probabilistic approaches are reviewed, since they have been adopted to investigate the sensitivity of wind turbines' structural capacity and reliability in earthquake-induced loading. The relevance of seismic hazard for wind turbines is further enlightened by available experimental studies, being also comprehensively reported through this paper. The main contribution of the study presented herein is to identify the key factors for wind turbines' seismic performance while important milestones for ongoing and future advancement are emphasized.

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“…In the theme issue, the papers by Muskulus [55] and by Alati et al [56] present numerical studies on offshore wind turbines under normal and extreme loading conditions of particular interest.…”

Section: Design Load Casesmentioning

confidence: 99%

“…Alati et al [56] investigate the seismic response of the baseline NREL 5 MW wind turbine [44], mounted on two different bottom-fixed substructures for transitional waters, a tripod and a jacket. The study is carried out by fully coupled nonlinear time-domain simulations on full system models (i.e.…”

Section: Design Load Casesmentioning

confidence: 99%

New perspectives in offshore wind energy

Failla

Arena

2015

Phil. Trans. R. Soc. A.

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The design of offshore wind turbines is one of the most fascinating challenges in renewable energy. Meeting the objective of increasing power production with reduced installation and maintenance costs requires a multi-disciplinary approach, bringing together expertise in different fields of engineering. The purpose of this theme issue is to offer a broad perspective on some crucial aspects of offshore wind turbines design, discussing the state of the art and presenting recent theoretical and experimental studies.

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Seismic analysis of offshore wind turbines on bottom-fixed support structures

Cited by 58 publications

References 22 publications

Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation

Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation

Wind turbines and seismic hazard: a state-of-the-art review

New perspectives in offshore wind energy

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