Multi-hazard response analysis of a 5MW offshore wind turbine

Katsanos, Evangelos; Sanz, A. Arrospide; Georgakis, Christos Τ.; Thöns, Sebastian

doi:10.1016/j.proeng.2017.09.548

Cited by 24 publications

(14 citation statements)

References 12 publications

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“…Relevant guidelines associate the tower response, specifically buckling, with two horizontal ground motion components, whereas implications of vertical components are deemed possibly irrelevant. However, the seismic vulnerability of wind turbines to vertical excitations has been recently acknowledged due to high vertical natural frequencies, though for a different performance parameter, i.e., nacelle acceleration, which triggers emergency shut‐down for a wind turbine if it exceeds a certain threshold . To this end, the second subset of records is disregarded from the total pulse‐like dataset to avoid the consideration of corresponding non‐pulse horizontal components during the selection procedure.…”

Section: Ground Motions For Dynamic Analysismentioning

confidence: 99%

Seismic vulnerability of offshore wind turbines to pulse and non‐pulse records

Ali¹,

Risi

Sextos

et al. 2019

Earthq Engng Struct Dyn

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The increasing number of wind turbines in active tectonic regions has attracted scientific interest to evaluate the seismic vulnerability of offshore wind turbines (OWTs). This study aims at assessing the deformation and collapse susceptibility of 2MW and 5MW OWTs subjected to shallow-crustal pulse-like ground motions, which has not been particularly addressed to date. A cloudbased fragility assessment is performed to quantify the seismic response for a given intensity measure and to assess the failure probabilities for pulse-like and non-pulse-like ground motions. The first-mode spectral acceleration S a (T 1 ) is found to be an efficient response predictor for OWTs, exhibiting prominent higher-mode behavior, at the serviceability and ultimate conditions. Regardless of earthquake type, it is shown that records with strong vertical components may induce nonlinearity in the supporting tower, leading to potential failure by buckling in three different patterns: (i) at tower base near platform level, (ii) close to tower top, and (iii) between the upper half of the main tower and its top. Type and extent of the damage are related to the coupled excitation of vertical and lateral higher modes, for which tower top acceleration response spectra S a,i(Top) is an effective identifier. It is also observed that tower's slenderness ratio (l/d), the diameter-to-thickness ratio (d/t), and the rotor-nacelle-assembly mass (m RNA ) are precursors for evaluating the damage mode and vulnerability of OWTs under both pulse-like and nonpulse-like ground motion records.

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Section: Ground Motions For Dynamic Analysismentioning

confidence: 99%

Seismic vulnerability of offshore wind turbines to pulse and non‐pulse records

Ali¹,

Risi

Sextos

et al. 2019

Earthq Engng Struct Dyn

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“…The differences between the results of fullycoupled and uncoupled time-domain simulations were investigated. Katsanos et al [27] also implemented the capability of seismic analysis in HAWC2. The dynamic response of an OWT under wind and wave loadings coupled with earthquake excitation has been obtained using HAWC2.…”

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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“…Wind energy, as a mature renewable energy source, has played a predominant role in the “clean energy” industry over the past decades. Therefore, many studies have been conducted on the structural analysis, design, and protection of wind turbines 1–3 . From the perspective of structural engineering, a reliable wind turbine should have the ability to resist both environmental stresses (e.g., wind, waves, and currents) and extreme natural hazards (e.g., earthquakes, hurricanes, and tsunamis).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, metaheuristic algorithms have been extensively employed to solve many engineering optimization problems, such as sensor placement optimization, 33 dynamic modal updating, 34 and damping device designation 35 . These algorithms were introduced to obtain optimal parameters of TMDs, 36–39 specifically the TMDs installed on the wind turbines 40,41 . However, these studies mainly tackled single‐objective optimizations, while multiple competing objectives such as the structural response and TMD strokes need to be considered concurrently in a TMD optimization.…”

Section: Introductionmentioning

confidence: 99%

Optimal tuned mass dampers for wind turbines using a Sigmoid satisfaction function‐based multiobjective optimization during earthquakes

Chen

Kareem

et al. 2021

Wind Energy

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Recent installation of many wind turbines in earthquake‐prone areas worldwide has increased concerns regarding their seismic performance. This study introduces a multiobjective optimization design method using a modified Sigmoid satisfaction function to efficiently minimize the seismic response by installing tuned mass dampers (TMDs) on wind turbines. Inspired by the human decision‐making process, the modified Sigmoid function was utilized to improve the satisfaction function and balance the optimization objectives. Incorporating the particle swarm optimization algorithm resulted in lower sensitivity to the combination weighting factors and significantly reduced the effort required to calibrate the weighting factors for any practical multiobjective optimization problem. To verify the efficacy of the proposed methodology, a TMD was designed on a National Renewable Energy Laboratory (NREL) 5‐MW benchmark wind turbine, with constraints on both the top displacement and TMD stroke as design objectives. The results were compared to those obtained using the conventional linear weighted sum method, thereby highlighting the advantages of the proposed method. The scope of application of the proposed method is further demonstrated by a more complex TMD design problem involving 13 design objectives with typical seismic excitations.

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Multi-hazard response analysis of a 5MW offshore wind turbine

Cited by 24 publications

References 12 publications

Seismic vulnerability of offshore wind turbines to pulse and non‐pulse records

Seismic vulnerability of offshore wind turbines to pulse and non‐pulse records

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

Optimal tuned mass dampers for wind turbines using a Sigmoid satisfaction function‐based multiobjective optimization during earthquakes

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