Download or read book A Framework for Aerostructural Analysis of Wind Turbine Blades written by Benjamin Yan and published by . This book was released on 2011 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: As international growth in wind energy steadily increases and the world gradually moves away from fossil fuels, advanced computational tools are required to produce accurate and fast predictions in wind turbine performance, and to allow efficient design cycles using advanced materials and manufacturing methods. Currently, aerostructural analysis often employs the relatively fast but inaccurate Blade Element Momentum (BEM) theory, while accurate but slower Computational Fluid Dynamics (CFD) methods are generally used for aerodynamic analysis alone.To bridge the gap between speed and accuracy, a 3D panel code, TriPan, was coupled with an advanced structural Finite Element Method (FEM) code, TACS, to perform aerostructural analysis for wind turbine blades. In addition, the framework allows the replacement of the panel solver by higher fidelity solvers to increase the accuracy of the overall aerostructural solution.

Download or read book Aero structural Design Investigations for Biplane Wind Turbine Blades written by Perry Moses Sablan Roth-Johnson and published by . This book was released on 2014 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large wind turbine blades are being developed at lengths of 85-125 meters, in order to improve energy capture and reduce the cost of wind energy. Bending loads in the inboard region of the blade make large blade development challenging. The "biplane blade" design was proposed to use a biplane inboard region to improve the design of the inboard region and improve overall performance of large blades. This work uses a "structures-first" approach with aero-structural analyses to (1) examine the feasibility of the biplane blade, (2) determine how the dimensions of the biplane inboard region affect performance, and (3) compare the aero-structural performance of a 100-meter biplane blade to the Sandia SNL100-00 reference blade. Two-dimensional CFD simulations were used to compare the aerodynamic performance of a biplane with a thick monoplane. The lift-to-drag ratio and the maximum lift coefficient is significantly greater for the biplane than the thick monoplane for angles of attack of 0-15 degrees. Analytical methods and beam finite elements with cross-sectional analysis were both used to examine the performance of biplane blade structures. These structures varied in complexity from isotropic spars to composite spars to composite full blades. In each case, biplane blade structures were compared to monoplane blade structures of the same length, mass, and complexity. Simple load cases were applied to each structure and their displacements, bending moments, axial forces, and stresses were compared. Similar performance trends are identified with both the analytical and computational models. Parametric analyses show that gap-to-chord ratios bewteen 1.0-1.2 and joint length-to-span ratios of about 0.5 give good aero-structural performance. At the tip, the biplane blade increases flapwise structural efficiency by 20-40%, depending on the load. Edgewise structural efficiency was decreased by 27-35% at the tip. The benefits for the inboard region could lead to mass reductions in wind turbine blades. Innovations that create lighter blades can make large blades a reality, suggesting that the biplane blade is an attractive design for large (100-meter) blades.

Download or read book Structural Analysis of Composite Wind Turbine Blades written by Dimitris I Chortis and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book concerns the development of novel finite elements for the structural analysis of composite beams and blades. The introduction of material damping is also an important aspect of composite structures and it is presented here in terms of their static and dynamic behavior. The book thoroughly presents a new shear beam finite element, which entails new blade section mechanics, capable of predicting structural blade coupling due to composite coupling and/or internal section geometry. Theoretical background is further expanded towards the inclusion of nonlinear structural blade models and damping mechanics for composite structures. The models effectively include geometrically nonlinear terms due to large displacements and rotations, improve the modeling accuracy of very large flexible blades, and enable the modeling of rotational stiffening and buckling, as well as, nonlinear structural coupling. Validation simulations on specimen level study the geometric nonlinearities effect on the modal frequencies and damping values of composite strips of various angle-ply laminations under either tensile or buckling loading. A series of correlation cases between numerical predictions and experimental measurements give credence to the developed nonlinear beam finite element models and underline the essential role of new nonlinear damping and stiffness terms.

Download or read book Wind Turbine Airfoils and Blades written by Jin Chen and published by Walter de Gruyter GmbH & Co KG. This book was released on 2017-12-04 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind Turbine Airfoils and Blades introduces new ideas in the design of wind turbine airfoils and blades based on functional integral theory and the finite element method, accompanied by results from wind tunnel testing. The authors also discuss the optimization of wind turbine blades as well as results from aerodynamic analysis. This book is suitable for researchers and engineers in aeronautics and can be used as a textbook for graduate students.

Download or read book Advances in composite wind turbine blades A comparative study written by Adam Chehouri and published by diplom.de. This book was released on 2014-03-01 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the wind industry, the current trend is towards building larger and larger turbines. This presents additional structural challenges and requires blade materials that are both lighter and stiffer than the ones presently used. This study is aimed to aid the work of designing new wind turbine blades by providing a comparative study of different composite materials. A coupled Finite-Element-Method (FEM) - Blade Element Momentum (BEM) code was used to simulate the aerodynamic forces subjected on the blade. For this study, the finite element study was conducted on the Static Structural Workbench of ANSYS, as for the geometry of the blade it was imported from a previous study prepared by Cornell University. Confirmation of the performance analysis of the chosen wind turbine blade is presented and discussed including the generated power, tip deflection, thrust and tangential force for a steady flow of 8m/s. A homogenization method was applied to derive the mechanical properties and ultimate strengths of the composites. The Tsai-Hill and Hoffman failure criterions were both conducted to the resulting stresses and shears for each blade composite material structure to determine the presence of static rupture. A progressive fatigue damage model was conducted to simulate the fatigue behavior of laminated composite materials, an algorithm developed by Shokrieh.

Download or read book Advances in Wind Turbine Blade Design and Materials written by Povl Brondsted and published by Elsevier. This book was released on 2022-10-15 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Wind Turbine Blade Design and Materials, Second Edition, builds on the thorough review of the design and functionality of wind turbine rotor blades and the requirements and challenges for composite materials used in both current and future designs of wind turbine blades. Reviews the design and functionality of wind turbine rotor blades Examines the requirements and challenges for composite materials used in both current and future designs of wind turbine blades Provides an invaluable reference for researchers and innovators in the field of wind

Download or read book Bio based Wind Turbine Blades written by Rachel Koh and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wood, once the material of choice for wind turbine blades, was phased out in the late 20th century as the growing size of blades imposed stricter material requirements and glass- and carbon-fiber composites gained industry popularity. However, the last several years have seen great advances in bio-based composite materials technology, including flax, hemp, and wood composites and laminates. These materials are increasingly utilized in high-performance, structurally demanding applications, largely because they are a more sustainable choice than many other engineering materials. Today, as the first glass-fiber wind turbine blades are ready to retire, wind developers are presented with an enormous challenge in disposing of these difficult-to-recycle blades. Through bio-based materials, the potential exists for these composite structures to be carbon neutral, renewable, and recyclable. In comparison to glass and carbon composites, bio-based composites offer numerous advantages. In addition to the environmental benefits, these materials have excellent specific strength and stiffness properties, meaning that they are very strong and very stiff but also lightweight. This has made plant-based fibers especially attractive for use in large wind turbine blades because of how critical a blade's mass is for turbine design. However, there are several unique challenges to the commercial use of bio-based composites compared to glass and carbon composites. These challenges include: limited availability of experimental data; a limited understanding of how bio-based materials behave under complex loading conditions; and the lack of a standard framework for computational modeling of these materials. This dissertation expands the current bodies of knowledge on wood laminates, flax composites, and wind turbine blade design by addressing these potential limitations. First, the treatment of shear properties of laminated wood is addressed by comparing several existing methods for determining shear strength and stiffness and proposing a new method based on tension and compression test data of multiaxial laminates. Second, a yield criteria analysis explains how wood laminates under multiaxial stress may be integrated into commercial finite element software for structural design. Third, a similar methodology is used to make failure criteria recommendations for multiaxial flax-fiber laminates. Finally, these results are used in combination with an aero-structural optimization routine to produce examples of large bio-based and hybrid wind turbine blade designs. The techniques developed herein have broad implications for the design of bio-based composite structures worldwide.

Download or read book Advances in wind turbine blade design and materials written by D.J. Lekou and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chapter discusses the topic of probabilistic analysis of wind turbine blades. First, structural analysis models, the definition of ‘failure’ and the treatment of random variables will be explored, focusing on the challenges involved in a probabilistic design depending on the choices made during each step. Next, the various probabilistic methods (Monte Carlo method, first-order reliability method, Edgeworth expansion method, response surface method) will be described. Issues arising out of the use of composite material structures, in applications such as wind turbine blades, as well as other aspects relating to wind energy applications will be highlighted, and techniques will be discussed through examples.

Download or read book Advances in wind turbine blade design and materials written by J. G.Holierhoek and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aeroelasticity concerns the interaction between aerodynamics, dynamics and elasticity. This interaction can result in negatively or badly damped wind turbine blade modes, which can have a significant effect on the turbine lifetime. The first aeroelastic problem that occurred on commercial wind turbines concerned a negatively damped edgewise mode. It is important to ensure that there is some out-of-plane deformation in this mode shape to prevent the instability. For larger turbine blades with lower torsional stiffness and the possibility of higher tip speeds for the offshore designs, classical flutter could also become relevant. When designing a wind turbine blade, it is therefore crucial that there is enough damping for the different modes and that there is no coincidence of natural frequencies with excitation frequencies (resonance). An effective aeroelastic analysis is also important, and the tools used for such an analysis must include the necessary detail in the structural model.

Download or read book Investigation Into Integrated Free form and Precomputational Approaches for Aerostructural Optimization of Wind Turbine Blades written by Ryan Timothy Barrett and published by . This book was released on 2018 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: A typical approach to optimize wind turbine blades separates the airfoil shape design from the blade planform design. This approach is sequential, where the airfoils along the blade span are pre-selected or optimized and then held constant during the blade planform optimization. In contrast, integrated blade design optimizes the airfoils and the blade planform concurrently and thereby has the potential to reduce cost of energy (COE) more than sequential design. Nevertheless, sequential design is commonly performed because of the ease of precomputation, or the ability to compute the airfoil analyses prior to the blade optimization. This research investigates two integrated blade design approaches, the precomputational and free-form methods, that are compared to sequential blade design.

Download or read book Wind Turbine Aerodynamics and Vorticity Based Methods written by Emmanuel Branlard and published by Springer. This book was released on 2017-04-05 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book introduces the fundamentals of fluid-mechanics, momentum theories, vortex theories and vortex methods necessary for the study of rotors aerodynamics and wind-turbines aerodynamics in particular. Rotor theories are presented in a great level of details at the beginning of the book. These theories include: the blade element theory, the Kutta-Joukowski theory, the momentum theory and the blade element momentum method. A part of the book is dedicated to the description and implementation of vortex methods. The remaining of the book focuses on the study of wind turbine aerodynamics using vortex-theory analyses or vortex-methods. Examples of vortex-theory applications are: optimal rotor design, tip-loss corrections, yaw-models and dynamic inflow models. Historical derivations and recent extensions of the models are presented. The cylindrical vortex model is another example of a simple analytical vortex model presented in this book. This model leads to the development of different BEM models and it is also used to provide the analytical velocity field upstream of a turbine or a wind farm under aligned or yawed conditions. Different applications of numerical vortex methods are presented. Numerical methods are used for instance to investigate the influence of a wind turbine on the incoming turbulence. Sheared inflows and aero-elastic simulations are investigated using vortex methods for the first time. Many analytical flows are derived in details: vortex rings, vortex cylinders, Hill's vortex, vortex blobs etc. They are used throughout the book to devise simple rotor models or to validate the implementation of numerical methods. Several Matlab programs are provided to ease some of the most complex implementations.

Download or read book Aerodynamics of Wind Turbines 2nd edition written by Martin O. L. Hansen and published by Routledge. This book was released on 2013-05-13 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behaviour of a turbine. The new material includes a description of the effects of the dynamics and how this can be modelled in an ?aeroelastic code?, which is widely used in the design and verification of modern wind turbines. Further, the description of how to calculate the vibration of the whole construction, as well as the time varying loads, has been substantially updated.

Download or read book A Dynamic Analysis of Wind Turbine Blades Using Panel Methods and Finite Element Structural Analysis written by Don C. Jones and published by . This book was released on 1995 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Turbine Blade Design System Aerodynamic and Structural Analysis written by Soumitr Dey and published by . This book was released on 2011 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ever increasing need for energy and the depletion of non-renewable energy resources has led to more advancement in the "Green Energy" field, including wind energy. An improvement in performance of a Wind Turbine will enhance its economic viability, which can be achieved by better aerodynamic designs. In the present study, a design system that has been under development for gas turbine turbomachinery has been modified for designing wind turbine blades. This is a very different approach for wind turbine blade design, but will allow it to benefit from the features inherent in the geometry flexibility and broad design space of the presented system. It starts with key overall design parameters and a low-fidelity model that is used to create the initial geometry parameters. The low-fidelity system includes the axisymmetric solver with loss models, T-Axi (Turbomachinery-AXIsymmetric), MISES blade-to-blade solver and 2D wing analysis code XFLR5. The geometry parameters are used to define sections along the span of the blade and connected to the CAD model of the wind turbine blade through CAPRI (Computational Analysis PRogramming Interface), a CAD neutral API that facilitates the use of parametric geometry definition with CAD. Either the sections or the CAD geometry is then available for CFD and Finite Element Analysis. The GE 1.5sle MW wind turbine and NERL NASA Phase VI wind turbine have been used as test cases. Details of the design system application are described, and the resulting wind turbine geometry and conditions are compared to the published results of the GE and NREL wind turbines. A 2D wing analysis code XFLR5, is used for to compare results from 2D analysis to blade-to-blade analysis and the 3D CFD analysis. This kind of comparison concludes that, from hub to 25% of the span blade to blade effects or the cascade effect has to be considered, from 25% to 75%, the blade acts as a 2d wing and from 75% to the tip 3D and tip effects have to be taken into account for design considerations. In addition, the benefits of this approach for wind turbine design and future efforts are discussed.

Download or read book MARE WINT written by Wiesław Ostachowicz and published by Springer. This book was released on 2016-08-30 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a holistic, interdisciplinary overview of offshore wind energy, and is a must-read for advanced researchers. Topics, from the design and analysis of future turbines, to the decommissioning of wind farms, are covered. The scope of the work ranges from analytical, numerical and experimental advancements in structural and fluid mechanics, to novel developments in risk, safety & reliability engineering for offshore wind.The core objective of the current work is to make offshore wind energy more competitive, by improving the reliability, and operations and maintenance (O&M) strategies of wind turbines. The research was carried out under the auspices of the EU-funded project, MARE-WINT. The project provided a unique opportunity for a group of researchers to work closely together, undergo multidisciplinary doctoral training, and conduct research in the area of offshore wind energy generation. Contributions from expert, external authors are also included, and the complete work seeks to bridge the gap between research and a rapidly-evolving industry.

Download or read book Stochastic Methods for Unsteady Aerodynamic Analysis of Wings and Wind Turbine Blades written by Manuel Fluck and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Advancing towards `better' wind turbine designs engineers face two central challenges: first, current aerodynamic models (based on Blade Element Momentum theory) are inherently limited to comparatively simple designs of flat rotors with straight blades. However, such designs present only a subset of possible designs. Better concepts could be coning rotors, swept or kinked blades, or blade tip modifications. To be able to extend future turbine optimization to these new concepts a different kind of aerodynamic model is needed. Second, it is difficult to include long term loads (life time extreme and fatigue loads) directly into the wind turbine design optimization. This is because with current methods the assessment of long term loads is computationally very expensive -- often too expensive for optimization. This denies the optimizer the possibility to fully explore the effects of design changes on important life time loads, and one might settle with a sub-optimal design. In this dissertation we present work addressing these two challenges, looking at wing aerodynamics in general and focusing on wind turbine loads in particular. We adopt a Lagrangian vortex model to analyze bird wings. Equipped with distinct tip feathers, these wings present very complex lifting surfaces with winglets, stacked in sweep and dihedral. Very good agreement between experimental and numerical results is found, and thus we confirm that a vortex model is actually capable of analyzing complex new wing and rotor blade geometries. Next stochastic methods are derived to deal with the time and space coupled unsteady aerodynamic equations. In contrast to deterministic models, which repeatedly analyze the loads for different input samples to eventually estimate life time load statistics, the new stochastic models provide a continuous process to assess life time loads in a stochastic context -- starting from a stochastic wind field input through to a stochastic solution for the load output. Hence, these new models allow obtaining life time loads much faster than from the deterministic approach, which will eventually make life time loads accessible to a future stochastic wind turbine optimization algorithm. While common stochastic techniques are concerned with random parameters or boundary conditions (constant in time), a stochastic treatment of turbulent wind inflow requires a technique capable to handle a random field. The step from a random parameter to a random field is not trivial, and hence the new stochastic methods are introduced in three stages. First the bird wing model from above is simplified to a one element wing/ blade model, and the previously deterministic solution is substituted with a stochastic solution for a one-point wind speed time series (a random process). Second, the wind inflow is extended to an $n$-point correlated random wind field and the aerodynamic model is extended accordingly. To complete this step a new kind of wind model is introduced, requiring significantly fewer random variables than previous models. Finally, the stochastic method is applied to wind turbine aerodynamics (for now based on Blade Element Momentum theory) to analyze rotor thrust, torque, and power. Throughout all these steps the stochastic results are compared to result statistics obtained via Monte Carlo analysis from unsteady reference models solved in the conventional deterministic framework. Thus it is verified that the stochastic results actually reproduce the deterministic benchmark. Moreover, a considerable speed-up of the calculations is found (for example by a factor 20 for calculating blade thrust load probability distributions). Results from this research provide a means to much more quickly analyze life time loads and an aerodynamic model to be used a new wind turbine optimization framework, capable of analyzing new geometries, and actually optimizing wind turbine blades with life time loads in mind. However, to limit the scope of this work, we only present the aerodynamic models here and will not proceed to turbine optimization itself, which is left for future work.

Download or read book Hybrid Anisotropic Materials for Wind Power Turbine Blades written by Yosif Golfman and published by CRC Press. This book was released on 2016-04-19 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on rapid technological developments in wind power, governments and energy corporations are aggressively investing in this natural resource. Illustrating some of the crucial new breakthroughs in structural design and application of wind energy generation machinery, Hybrid Anisotropic Materials for Wind Power Turbine Blades explores new automat