Probabilistic Demand Models and Fragility Estimates for Offshore Wind Turbine Support Structures

Mardfekri, Maryam; Gardoni, Paolo; Roësset, José M.

doi:10.1061/41170(400)77

Cited by 8 publications

(25 citation statements)

References 7 publications

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“…Then, we develop the deformation, © Woodhead Publishing Limited, 2013 shear and moment demand models for the support structure of offshore wind turbines. The approach is consistent with the work by Mardfekri and Gardoni (2012) and emphasis is given to the additional seismic load. Finally, fragility estimates are presented for an example offshore wind turbine support structure for given values of the mean wind speed, signifi cant wave height, and spectral acceleration.…”

Section: Introductionmentioning

confidence: 87%

“…Because of these reasons, Mardfekri and Gardoni (2012) used FAST (Fatigue, Aerodynamics, Structures, and Turbulence) to compute deterministic predictions of the deformation, shear and moment demands on the support structure of wind turbines subject to wind, wave, current, and turbine operational loadings. FAST is a comprehensive aeroelastic simulator capable of predicting both the extreme and fatigue loads of two-and three-bladed horizontal-axis wind turbines.…”

Section: Deterministic Demand Modelmentioning

confidence: 99%

“…This is true in particular for the pile sizes typical of foundations of offshore wind turbines. Mardfekri and Gardoni (2012) assessed the deformation, shear, and moment demands on the support structure of offshore wind turbines subject to wind, wave, current, and turbine operational loadings properly accounting for the nonlinear soil-structure interaction. Mardfekri and Gardoni (2012) considered a continuous modeling of the pile and the surrounding soil using a 3D nonlinear fi nite element analysis in which both the soil and the pile were modeled with 3D fi nite elements.…”

Section: Introductionmentioning

confidence: 99%

“…Mardfekri and Gardoni (2012) assessed the deformation, shear, and moment demands on the support structure of offshore wind turbines subject to wind, wave, current, and turbine operational loadings properly accounting for the nonlinear soil-structure interaction. Mardfekri and Gardoni (2012) considered a continuous modeling of the pile and the surrounding soil using a 3D nonlinear fi nite element analysis in which both the soil and the pile were modeled with 3D fi nite elements. Because a complete nonlinear 3D fi nite element analysis can be quite expensive and time consuming, Mardfekri and Gardoni (2012) also proposed simplifi ed probabilistic demand models for the deformation, shear, and moment demands on the support structure of offshore wind turbines subject to wind, wave, current, and turbine operational loadings.…”

Section: Introductionmentioning

confidence: 99%

“…Mardfekri and Gardoni (2012) considered a continuous modeling of the pile and the surrounding soil using a 3D nonlinear fi nite element analysis in which both the soil and the pile were modeled with 3D fi nite elements. Because a complete nonlinear 3D fi nite element analysis can be quite expensive and time consuming, Mardfekri and Gardoni (2012) also proposed simplifi ed probabilistic demand models for the deformation, shear, and moment demands on the support structure of offshore wind turbines subject to wind, wave, current, and turbine operational loadings. The probabilistic models were calibrated using the results from the nonlinear 3D fi nite element analyses and properly accounted for the inherent uncertainties, including the statistical uncertainty (associated with the fi nite sample size) and the modeling errors (associate with the selection of the variables in the models and the model forms).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Seismic risk analysis of wind turbine support structures

Mardfekri

Gardoni

2013

Handbook of Seismic Risk Analysis and Management of Civil Infrastructure Systems

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Section: Introductionmentioning

confidence: 87%

Section: Deterministic Demand Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seismic risk analysis of wind turbine support structures

Mardfekri

Gardoni

2013

Handbook of Seismic Risk Analysis and Management of Civil Infrastructure Systems

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Multi‐hazard reliability assessment of offshore wind turbines

Mardfekri

Gardoni

2014

Wind Energy

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A probabilistic framework is developed to assess the structural reliability of offshore wind turbines. Probabilistic models are developed to predict the deformation, shear force and bending moment demands on the support structure of wind turbines. The proposed probabilistic models are developed starting from a commonly accepted deterministic model and by adding correction terms and model errors to capture respectively, the inherent bias and the uncertainty in developed models. A Bayesian approach is then used to assess the model parameters incorporating the information from virtual experiment data. The database of virtual experiments is generated using detailed three-dimensional finite element analyses of a suite of typical offshore wind turbines. The finite element analyses properly account for the nonlinear soil-structure interaction. Separate probabilistic demand models are developed for three operational/load conditions including: (1) operating under day-to-day wind and wave loading; (2) operating throughout earthquake in presence of day-to-day loads; and (3) parked under extreme wind speeds and earthquake ground motions. The proposed approach gives special attention to the treatment of both aleatory and epistemic uncertainties in predicting the demands on the support structure of wind turbines. The developed demand models are then used to assess the reliability of the support structure of wind turbines based on the proposed damage states for typical wind turbines and their corresponding performance levels. A multi-hazard fragility surface of a given wind turbine support structure as well as the seismic and wind hazards at a specific site location are incorporated into a probabilistic framework to estimate the annual probability of failure of the support iii structure. Finally, a framework is proposed to investigate the performance of offshore wind turbines operating under day-to-day loads based on their availability for power production. To this end, probabilistic models are proposed to predict the mean and standard deviation of drift response of the tower. The results are used in a random vibration based framework to assess the fragility as the probability of exceeding certain drift thresholds given specific levels of wind speed.

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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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Probabilistic Demand Models and Fragility Estimates for Offshore Wind Turbine Support Structures

Cited by 8 publications

References 7 publications

Seismic risk analysis of wind turbine support structures

Seismic risk analysis of wind turbine support structures

Multi‐hazard reliability assessment of offshore wind turbines

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

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