scholarly journals Integrated structural optimisation of offshore wind turbine support structures based on finite element analysis and genetic algorithm

2017 ◽  
Vol 199 ◽  
pp. 187-204 ◽  
Author(s):  
Theo Gentils ◽  
Lin Wang ◽  
Athanasios Kolios
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Support Structures ◽  
Structural Optimisation ◽  
Element Analysis

Design and Optimization of Composite Offshore Wind Turbine Blades

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
M. Tarfaoui ◽  
O. R. Shah ◽  
M. Nachtane
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Skin Thickness ◽  
Wind Turbine Blades ◽  
Element Analysis

In order to obtain an optimal design of composite offshore wind turbine blade, take into account all the structural properties and the limiting conditions applied as close as possible to real cases. This work is divided into two stages: the aerodynamic design and the structural design. The optimal blade structural configuration was determined through a parametric study by using a finite element method. The skin thickness, thickness and width of the spar flange, and thickness, location, and length of the front and rear spar web were varied until design criteria were satisfied. The purpose of this article is to provide the designer with all the tools required to model and optimize the blades. The aerodynamic performance has been covered in this study using blade element momentum (BEM) method to calculate the loads applied to the turbine blade during service and extreme stormy conditions, and the finite element analysis was performed by using abaqus code to predict the most critical damage behavior and to apprehend and obtain knowledge of the complex structural behavior of wind turbine blades. The approach developed based on the nonlinear finite element analysis using mean values for the material properties and the failure criteria of Hashin to predict failure modes in large structures and to identify the sensitive zones.

Finite Element Analysis of Large Diameter Grouted Connections

2007 ◽  
Author(s):  
Lars P. Nielsen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Large Diameter ◽  
Wind Farms ◽  
Element Model ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Joint Research ◽  
Element Analysis

When considering offshore monopile foundations designed for wind turbine support structures, a grouted connection between the monopile and an overlapping transition piece has become the de facto standard. These connections rely on axial loads being carried primarily by the bond between the steel and grout as shear. Given the critical nature of the grouted connection in a system with zero redundancy, the current design verification requirement is that a finite element analysis is performed to ascertain the viability of the connection with respect to combined axial and bending capacity whilst pure axial capacity is handled as a decoupled phenomenon using simple analytical formulas. The present paper addresses the practical modeling aspects of such a finite element model, covering subjects such as constitutive formulations for the grout, mesh density, and steel/grout interaction. The aim of the paper is to discuss different modeling approaches and, to the extent possible, provide basic guidelines for the minimum requirements valid for this type of analysis. This discussion is based on the accumulated experience gained though the independent verification of more than 10 currently operational offshore wind farms that have been certified by DNV, as well as the significant joint research and development with industry captured in the DNV Offshore Standard for Design of Offshore Wind Turbine Structures DNV-OS-J101. Moreover, general observations relating to the basic subjects such as overall geometric extent of the model, inclusion of secondary structures, detail simplification, boundary conditions, load application etc. are presented based on the authors more than 3 year involvement on the subject at DNV.

scholarly journals Structural optimisation of wind turbine towers based on finite element analysis and genetic algorithm

2016 ◽  
Author(s):  
Lin Wang ◽  
Athanasios Kolios ◽  
Maria Martinez Luengo ◽  
Xiongwei Liu
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Structural Design ◽  
Structural Optimisation ◽  
Element Analysis ◽  
Wind Turbine Tower ◽  
Wind Turbine Towers ◽  
Optimisation Model

Abstract. A wind turbine tower supports the main components of the wind turbine (e.g. rotor, nacelle, drive train components, etc.). The structural properties of the tower (such as stiffness and natural frequency) can significantly affect the performance of the wind turbine, and the cost of the tower is a considerable portion of the overall wind turbine cost. Therefore, an optimal structural design of the tower, which has a minimum cost and meets all design criteria (such as stiffness and strength requirements), is crucial to ensure efficient, safe and economic design of the whole wind turbine system. In this work, a structural optimisation model for wind turbine towers has been developed based on a combined parametric FEA (finite element analysis) and GA (genetic algorithm) model. The top diameter, bottom diameter and thickness distributions of the tower are taken as design variables. The optimisation model minimises the tower mass with six constraint conditions, i.e. deformation, ultimate stress, fatigue, buckling, vibration and design variable constraints. After validation, the model has been applied to the structural optimisation of a 5MW wind turbine tower. The results demonstrate that the proposed structural optimisation model is capable of accurately and effectively achieving an optimal structural design of wind turbine towers, which significantly improves the efficiency of structural optimisation of wind turbine towers. The developed framework is generic in nature and can be employed for a series of related problems, when advanced numerical models are required to predict structural responses and to optimise the structure.

scholarly journals Dynamic Characteristics of an Offshore Wind Turbine with Tripod Suction Buckets via Full-Scale Testing

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Yun-Ho Seo ◽  
Moo Sung Ryu ◽  
Ki-Yong Oh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Dynamic Characteristics ◽  
Full Scale ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Element Analysis ◽  
Integrated Framework ◽  
Operational Conditions

The dynamic characteristics of an offshore wind turbine with tripod suction buckets are investigated through finite element analysis and full-scale experiments. In finite element analysis, an integrated framework is suggested to create a simple yet accurate high fidelity model. The integrated framework accounts for not only the strain dependency of the soil but also for all dynamics in the seabed, including those of the soil, suction bucket skirt, and cap. Hence, the model accurately describes the coupling effect of translational and rotational motions of the seabed. The prediction results are compared to the experimental results obtained via full-scale testing in four stages during construction and in several operational conditions. The comparison shows that the stiffness of the suction bucket cap and strain dependency of the soil play a significant role in predicting natural frequency, suggesting that these two factors should be considered in finite element analysis for the accurate prediction of dynamic responses of an offshore wind conversion system. Moreover, dynamic analysis of the strain and acceleration measured during operational conditions shows that strain is more robust than acceleration with regard to the characterization of the overall dynamics of an offshore wind conversion system because the natural frequency of an offshore wind turbine is very low. It can be inferred that the measurement of strain is a more effective way to monitor the long-term evolution of dynamic characteristics. The suggested integrated framework and measurement campaign are useful not only to avoid conservatism that may incur additional costs during load calculation and design phases but also to establish an intelligent operation and maintenance strategy with a novel sensing technique.

Finite Element Analysis of Composite Offshore Wind Turbine Blades Under Operating Conditions

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Tarfaoui ◽  
M. Nachtane ◽  
H. Boudounit
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Energy Demand ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Element Analysis

Abstract World energy demand has increased immediately and is expected to continue to grow in the foreseeable future. Therefore, an overall change of energy consumption continuously from fossil fuels to renewable energy sources, and low service and maintenance price are the benefits of using renewable energies such as using wind turbines as an electricity generator. In this context, offshore wind power refers to the development of wind parks in bodies of water to produce electricity from wind. Better wind speeds are available offshore compared to on land, so offshore wind power's contribution in terms of electricity supplied is higher. However, these structures are very susceptible to degradation of their mechanical properties considering various hostile loads. The scope of this work is the study of the damage noticed in full-scale 48 m fiberglass composite blades for offshore wind turbine. In this paper, the most advanced features currently available in finite element (FE) abaqus/Implicit have been employed to simulate the response of blades for a sound knowledge of the mechanical behavior of the structures and then localize the susceptible sections.

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