scholarly journals Structural Reliability Assessment of Offshore Wind Turbine Jacket Considering Corrosion Degradation

2021 ◽  
Author(s):  
C. REN ◽  
Y. Aoues ◽  
D. Lemosse ◽  
E. CURSI
Keyword(s):  
Wind Turbine ◽  
Structural Reliability ◽  
Reliability Assessment ◽  
Offshore Wind ◽  
Offshore Wind Turbine

Probabilistic Analysis of the Fatigue Life of Offshore Wind Turbine Structures

2020 ◽  
Author(s):  
Abraham Nispel ◽  
Stephen Ekwaro-Osire ◽  
João Paolo Dias
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Structural Reliability ◽  
Research Question ◽  
Limit State ◽  
Fatigue Loading ◽  
Offshore Wind ◽  
Design Parameters ◽  
Offshore Wind Turbine ◽  
Loading Conditions

Abstract The structural response of the main components of offshore wind turbines (OWTs) is considerably sensitive to amplification as their excitation frequencies approach the natural frequency of the structure. Furthermore, uncertainties present in the loading conditions, soil and structural properties highly influence the dynamic response of the OWT. In most cases, the cost of the structure reaches around 30% of the entire OWT because conservative design approaches are employed to ensure its reliability. As a result, this study aims to address the following research question: can the structural reliability of OWT under fatigue loading conditions be predicted more consistently? The specific aims are to (1) establish the design parameters that most impact the fatigue life, (2) determine the probability distributions of the design parameters, and (3) predict the structural reliability. An analytical model to determine the fatigue life of the structure under 15 different loading conditions and two different locations were developed. Global sensitivity analysis was used to establish the more important design parameters. Also, a systematic uncertainty quantification (UQ) scheme was employed to model the uncertainties of model input parameters based on their available information. Finally, the framework used reliability analysis to consistently determine the system probability of failure of the structure based on the fatigue limit state design criterion. The results show high sensitivity for parameters usually considered as deterministic values in design standards. Additionally, it is shown that applying systematic UQ produces a better approximation of the fatigue life under uncertainty and more accurate estimations of the structural reliability. Consequently, more reliable and robust structural designs may be achieved without the need for overestimating the offshore wind turbine response.

scholarly journals Uncertainty Quantification for Fatigue Life of Offshore Wind Turbine Structure

2021 ◽  
Author(s):  
Abraham Nispel ◽  
Stephen Ekwaro-Osire ◽  
Joao Paulo Dias ◽  
Americo Cunha
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Uncertainty Quantification ◽  
Structural Reliability ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Loading Conditions ◽  
Model Input ◽  
Input Parameters ◽  
The Impact

Abstract This study aims to address the question: can the structural reliability of an offshore wind turbine (OWT) under fatigue loading conditions be predicted more consistently? To respond to that question this study addresses the following specific aims: (1) to obtain a systematic approach that takes into consideration the amount of information available for the uncertainty modeling of the model input parameters, and (2) to determine the impact of the most sensitive input parameters on the structural reliability of the OWT through a surrogate model. First, a coupled model to determine the fatigue life of the support structure considering the soil-structure interaction under 15 different loading conditions was developed. Second, a sensitivity scheme using two global analyses was developed to consistently establish the most and least important input parameters of the model. Third, a systematic uncertainty quantification (UQ) scheme was employed to model the uncertainties of model input parameters based on their available-data-driven and physics-informed-information. Finally, the impact of the proposed UQ framework on the OWT structural reliability was evaluated through the estimation of the probability of failure of the structure based on the fatigue limit state design criterion. The results show high sensitivity for the wind speed and moderate sensitivity for parameters usually considered as deterministic values in design standards. Additionally, it is shown that applying systematic UQ not only produces a more efficient and better approximation of the fatigue life under uncertainty, but also a more accurate estimation of the structural reliability of offshore wind turbine's structure during conceptual design. Consequently, more reliable, and robust estimations of the structural designs for large offshore wind turbines with limited information may be achieved during the early stages of design.

scholarly journals Comparative Study of Structural Reliability Assessment Methods for Offshore Wind Turbine Jacket Support Structures

2020 ◽  
Vol 10 (3) ◽  
pp. 860 ◽  
Author(s):  
Abdulhakim Adeoye Shittu ◽  
Ali Mehmanparast ◽  
Lin Wang ◽  
Konstantinos Salonitis ◽  
Athanasios Kolios
Keyword(s):  
Reliability Index ◽  
Structural Reliability ◽  
Reliability Assessment ◽  
Probability Of Failure ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Support Structures ◽  
Structural Components ◽  
Support Structure ◽  
Design Constraints

Offshore wind turbines (OWTs) are deployed in harsh environments often characterized by highly stochastic loads and resistance properties, thus necessitating the need for structural reliability assessment (SRA) to account for such uncertainties systematically. In this work, the SRA of an OWT jacket-type support structure is conducted, applying two stochastic methods to predict the safety level of the structure considering various design constraints. The first method refers to a commercial finite element analysis (FEA) package (DesignXplorer© from ANSYS) which employs direct simulations and the six sigma analysis function applying Latin hypercube sampling (LHS) to predict the probability of failure. The second method develops a non-intrusive formulation which maps the response of the structure through a finite number of simulations to develop a response surface, and then employs first-order reliability methods (FORM) to evaluate the reliability index and, subsequently, the probability of failure. In this analysis, five design constraints were considered: stress, fatigue, deformation, buckling, and vibration. The two methods were applied to a baseline 10-MW OWT jacket-type support structure to identify critical components. The results revealed that, for the inherent stochastic conditions, the structural components can safely withstand such conditions, as the reliability index values were found acceptable when compared with allowable values from design standards. The reliability assessment results revealed that the fatigue performance is the design-driving criterion for structural components of OWT support structures. While there was good agreement in the safety index values predicted by both methods, a limitation of the direct simulation method is in its requirement for a prohibitively large number of simulations to estimate the very low probabilities of failure in the deformation and buckling constraint cases. This limitation can be overcome through the non-intrusive formulation presented in this work.

scholarly journals Reliability Updating of Offshore Wind Substructures by Use of Digital Twin Information

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5859
Author(s):  
Dawid Augustyn ◽  
Martin D. Ulriksen ◽  
John D. Sørensen
Keyword(s):  
Wind Turbine ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Structural Reliability ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wave Loading ◽  
Soil Stiffness ◽  
Digital Twins ◽  
Fatigue Damage Accumulation

This paper presents a probabilistic framework for updating the structural reliability of offshore wind turbine substructures based on digital twin information. In particular, the information obtained from digital twins is used to quantify and update the uncertainties associated with the structural dynamics and load modeling parameters in fatigue damage accumulation. The updated uncertainties are included in a probabilistic model for fatigue damage accumulation used to update the structural reliability. The updated reliability can be used as input to optimize decision models for operation and maintenance of existing structures and design of new structures. The framework is exemplified based on two numerical case studies with a representative offshore wind turbine and information acquired from previously established digital twins. In this context, the effect of updating soil stiffness and wave loading, which constitute two highly uncertain and sensitive parameters, is investigated. It is found that updating the soil stiffness significantly affects the reliability of the joints close to the mudline, while updating the wave loading significantly affects the reliability of the joints localized in the splash zone. The increased uncertainty related to virtual sensing, which is employed to update wave loading, reduces structural reliability.

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