Download or read book Fatigue Analysis and Testing of Wind Turbine Blades written by Peter Robert Greaves and published by . This book was released on 2013 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract:This thesis focuses on fatigue analysis and testing of large, multi MW wind turbine blades. The blades are one of the most expensive components of a wind turbine, and their mass has cost implications for the hub, nacelle, tower and foundations of the turbine so it is important that they are not unnecessarily strong. Fatigue is often an important design driver, but fatigue of composites is poorly understood and so large safety factors are often applied to the loads. This has implications for the weight of the blade. Full scale fatigue testing of blades is required by the design standards, and provides manufacturers with confidence that the blade will be able to survive its service life. This testing is usually performed by resonating the blade in the flapwise and edgewise directions separately, but in service these two loads occur at the same time. A fatigue testing method developed at Narec (the National Renewable Energy Centre) in the UK in which the flapwise and edgewise directions are excited simultaneously has been evaluated by comparing the Palmgren-Miner damage sum around the blade cross section after testing with the damage distribution caused by the service life. A method to obtain the resonant test configuration that will result in the optimum mode shapes for the flapwise and edgewise directions was then developed, and simulation software was designed to allow the blade test to be simulated so that realistic comparisons between the damage distributions after different test types could be obtained. During the course of this work the shortcomings with conventional fatigue analysis methods became apparent, and a novel method of fatigue analysis based on multi-continuum theory and the kinetic theory of fracture was developed. This method was benchmarked using physical test data from the OPTIDAT database and was applied to the analysis of a complete blade. A full scale fatigue test method based on this new analysis approach is also discussed.

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 2013-10-31 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind energy is gaining critical ground in the area of renewable energy, with wind energy being predicted to provide up to 8% of the world's consumption of electricity by 2021. Advances in wind turbine blade design and materials reviews the design and functionality of wind turbine rotor blades as well as the requirements and challenges for composite materials used in both current and future designs of wind turbine blades.Part one outlines the challenges and developments in wind turbine blade design, including aerodynamic and aeroelastic design features, fatigue loads on wind turbine blades, and characteristics of wind turbine blade airfoils. Part two discusses the fatigue behavior of composite wind turbine blades, including the micromechanical modelling and fatigue life prediction of wind turbine blade composite materials, and the effects of resin and reinforcement variations on the fatigue resistance of wind turbine blades. The final part of the book describes advances in wind turbine blade materials, development and testing, including biobased composites, surface protection and coatings, structural performance testing and the design, manufacture and testing of small wind turbine blades.Advances in wind turbine blade design and materials offers a comprehensive review of the recent advances and challenges encountered in wind turbine blade materials and design, and will provide an invaluable reference for researchers and innovators in the field of wind energy production, including materials scientists and engineers, wind turbine blade manufacturers and maintenance technicians, scientists, researchers and academics. - 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 energy production

Download or read book Comparison of Strength and Load based Methods for Testing Wind Turbine Blades written by and published by . This book was released on 1996 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this paper is to compare two methods of blade test loading and show how they are applied in an actual blade test. Strength and load-based methods were examined to determine the test load for an Atlantic Orient Corporation (AOC) 15/50 wind turbine blade for fatigue and static testing. Fatigue load-based analysis was performed using measured field test loads extrapolated for extreme rare events and scaled to thirty-year spectra. An accelerated constant amplitude fatigue test that gives equivalent damage at critical locations was developed using Miner's Rule and the material S-N curves. Test load factors were applied to adjust the test loads for uncertainties, and differences between the test and operating environment. Similar analyses were carried, out for the strength-based fatigue test using the strength of the blade and the material properties to determine the load level and number of constant amplitude cycles to failure. Static tests were also developed using load and strength criteria. The resulting test loads were compared and contrasted. The analysis shows that, for the AOC 15/50 blade, the strength-based test loads are higher than any of the static load-based cases considered but were exceeded in the fatigue analysis for a severe hot/wet environment.

Download or read book Wind Turbine Blade Fatigue Analysis for Development of Predictive Life Models Cooperative Research and Development Final Report CRADA Number CRD 17 00696 written by and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Small Business Voucher CRADA will focus on wind turbine blade fatigue analysis for development of predictive life models. The parties will cooperate to conduct structural validation fatigue testing that produces high quality data enabling validation of blade damage models with sensing technologies developed by Sentient.

Download or read book Comparison of Strength and Load based Methods for Testing Wind Turbine Blades written by Walter D. Musial and published by . This book was released on 1996 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this paper is to compare two methods of blade test loading and show how they are applied in an actual blade test. Strength and load-based methods were examined to determine the test load for an Atlantic Orient Corporation (AOC)15/50 wind turbine blade for fatigue and static testing. Fatigue load-based analysis was performed using measured field test loads extrapolated for extreme rare events and scaled to thirty-year spectra. An accelerated constant amplitude fatigue test that gives equivalent damage at critical locations was developed using Miner's Rule and the material S-N curves. Test load factors were applied to adjust the test loads for uncertainties, and differences between the test and operating environment. Similar analyses were carried out for the strength-based fatigue test using the strength of the blade and the material properties to determine the load level and number of constant amplitude cycles to failure. Static tests were also developed using load and strength criteria. The resulting test loads were compared and contrasted. The analysis shows that, for the AOC 15/50 blade, the strength-based test loads are higher than any of the static load-based cases considered but were exceeded in the fatigue analysis for a severe hot/wet environment.

Download or read book Comparison of Strength and Load Based Methods for Wind Turbine Blades written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this paper is to compare two methods of blade test loading and show how they are applied in an actual blade test. Strength and load-based methods were examined to determine the test load for an Atlantic Orient Corporation (AOC)15/50 wind turbine blade for fatigue and static testing. Fatigue load-based analysis was performed using measured field test loads extrapolated for extremerare events and scaled to thirty-year spectra. An accelerated constant amplitude fatigue test that gives equivalent damage at critical locations was developed using Miner's Rule and the material S-N curves. Test load factors were applied to adjust the test loads for uncertainties, and differences between the test and operating environment. Similar analyses were carried out for the strength-basedfatigue test using the strength of the blade and the material properties to determine the load level and number of constant amplitude cycles to failure. Static tests were also developed using load and strength criteria. The resulting test loads were compared and contrasted. The analysis shows that, for the AOC 15/50 blade, the strength-based test loads are higher than any of the staticload-based cases considered but were exceeded in the fatigue analysis for a severe hot/wet environment.

Download or read book Biaxial Dynamic Fatigue Tests of Wind Turbine Blades written by Falko Bürkner and published by Fraunhofer Verlag. This book was released on 2021-04-09 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Testing rotor blades of wind turbines is essential to mitigate financial risks caused by serial damages. Present day uniaxial dynamic tests are time consuming and often inaccurate regarding the applied loading. This thesis proposes a faster fatigue test method by loading the two primary directions at the same time. In addition, a more realistic test, compared to uniaxial tests, is accomplished by loading larger areas of the blade cross-sections. To achieve this, an elliptical biaxial dynamic excitation is used. To fulfill the industry requirement for cost effective tests, a relatively simple test setup was developed, still achieving an elliptical dynamic excitation of the rotor blade. Two methods for an accurate determination of the applied loadings for dynamic fatigue tests are described. These calibration tests use easily measured values and simple analysis to achieve accurate test load measurements in a cost-effective way.

Download or read book An Approach to the Fatigue Analysis of Vertical Axis Wind Turbine Blades written by Paul S. Veers and published by . This book was released on 1981 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Full scale Fatigue Tests of CX 100 Wind Turbine Blades Part II Analysis written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A General Method for Fatigue Analysis of Vertical Axis Wind Turbine Blades written by Paul S. Veers and published by . This book was released on 1983 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Data Editing for Blades of Horizontal Axis Wind Turbines written by Pratumnopharat Panu and published by LAP Lambert Academic Publishing. This book was released on 2015-11-12 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: In predicting performance of wind turbines, the blade element momentum (BEM) theory is still commonly used by wind turbine designers and researchers. This book deals with several up-to-date models added to the BEM theory to get more realistic prediction. In evaluating fatigue damage of wind turbine blade, stress-life approach and Miner's linear cumulative damage rule are mentioned. Wind turbine blades are the most critical components of HAWT. Full-scale blade fatigue testing is required to verify that the blades possess the strength and service life specified in the design. Unfortunately, the test must be run for a long time period. This problem led the blade testing laboratories to accelerate fatigue testing time. To achieve the objective, two novel methods called STFT- and WT-based fatigue damage part extracting methods are used to generate the edited stress-time history. Blade testing laboratories can use this history to accelerate fatigue testing time. STFT- and WT-based fatigue damage part extracting methods proposed in this book are suggested as alternative methods in accelerating fatigue testing time, especially for the field of wind turbine engineering.

Download or read book Full scale Fatigue Tests of CS 100 Wind Turbine Blades Part 2 Analysis written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genossenschaft des Buchgewerbes und verwandter Berufszweige written by and published by . This book was released on 1929 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Static and Fatigue Analysis of Wind Turbine Blades Subject to Cold Weather Conditions Using Finite Element Analysis written by Patricio Lillo and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Canada has aggressive targets for introducing wind energy across the country, but also faces challenges in achieving these goals due to the harsh Canadian climate. One issue which has received little attention in other countries not experiencing these extremes is the behaviour of composite blades in winter conditions. The scope of the work presented is to analyze the static stresses and fatigue response in cold climates using finite element models of the blade. The work opens with a quantification of the extremes of cold experienced in candidate Canadian wind turbine deployment locations. The thesis then narrows its focus to a consideration of the stresses in the root of the composite blades, specifically two common blade-hub connection methods: embedded root carrots and T-bolts. Finite element models of the root are proposed to properly simulate boundary conditions, applied loading and thermal stresses for a 1.5MW wind turbine. It is shown that the blade root is strongly affected by the thermal stresses caused by the mismatch and orthotrophy of the coefficients of thermal expansion of the blade root constituents. Fatigue analysis of a blade is then presented using temperature dependent material properties including estimated fatigue coefficients. It was found that the natural frequencies of a 1.5MW wind turbine blade are not significantly altered at cold temperatures. Additionally, cold temperatures slightly increase stresses in the composite blade skin when the blade is loaded, due to an increase in stiffness. Cold temperatures also lead to higher cyclic flapwise bending moments acting on the blade. However, this increase was found not to affect the lifetime fatigue damage. Finally, it was found that the cold climate as seen in Canada improves the fatigue strength of the saturated composite materials used in the blade. The predicted fatigue damage of the triaxial fabric and the spar cap layers in cold climates was therefore predicted to be half that of the fatigue damage at room temperature. This is caused solely by the temperature dependence of the fatigue coefficient b which requires further experimental verification to validate the numerical results of the current study.

Download or read book Fatigue and Corrosion in Metals written by Pietro Paolo Milella and published by Springer Nature. This book was released on with total page 965 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Testing of 12m Wind Turbine Blades written by M. Hancock and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of the New B REX Fatigue Testing System for Multi Megawatt Wind Turbine Blades written by and published by . This book was released on 2004 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The National Renewable Energy Laboratory (NREL) recently developed a new hybrid fatigue testing system called the Blade Resonance Excitation (B-REX) test system. The new system uses 65% less energy to test large wind turbine blades in half the time of NREL's dual-axis forced-displacement test method with lower equipment and operating costs. The B-REX is a dual-axis test system that combines resonance excitation with forced hydraulic loading to reduce the total test time required while representing the operating strains on the critical inboard blade stations more accurately than a single-axis test system. The analysis and testing required to fully implement the B-REX was significant. To control unanticipated blade motion and vibrations caused by dynamic coupling between the flap, lead-lag, and torsional directions, we needed to incorporate additional test hardware and control software. We evaluated the B-REX test system under stable operating conditions using a combination of various sensors. We then compared our results with results from the same blade, tested previously using NREL's dual-axis forced-displacement test method. Experimental results indicate that strain levels produced by the B-REX system accurately replicated the forced-displacement method. This paper describes the challenges we encountered while developing the new blade fatigue test system and the experimental results that validate its accuracy.