Download or read book Investigation of Ply Waviness in Wind Turbine Blades written by Sunil Kishore Chakrapani and published by . This book was released on 2011 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nondestructive Testing and Evaluation of Fiber Reinforced Composite Structures written by Shuncong Zhong and published by Springer Nature. This book was released on 2022-04-01 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a detailed description of the most common nondestructive testing(NDT) techniques used for the testing and evaluation fiber-reinforced composite structures, during manufacturing and/or in service stages. In order to facilitate the understanding and the utility of the different NDT techniques presented, the book first provides some information regarding the defects and material degradation mechanisms observed in fiber-reinforced composite structures as well as their general description and most probable causes. It is written based on the extensive scientific research and engineering backgrounds of the authors in the NDT and structural health monitoring (SHM) of structural systems from various areas including electrical, mechanical, materials, civil and biomedical engineering. Pursuing a rigorous approach, the book establishes a fundamental framework for the NDT of fiber-reinforced composite structures, while emphasizing on the importance of technique’s spatial resolution, integrated systems analysis and the significance of the influence stemming from the applicability of the NDT and the physical parameters of the test structures in the selection and utilization of adequate NDT techniques. The book is intended for students who are interested in the NDT of fiber-reinforced composite structures, researchers investigating the applicability of different NDT techniques to the inspections of structural systems, and NDT researchers and engineers working on the optimization of NDT systems for specific applications involving the use of fiber-reinforced composite structures.

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 Effect of In plane Fiber Tow Waviness in the Strength Characteristics of Different Fiber Reinforced Composites written by Sai Bhargav Pottavathri and published by . This book was released on 2015 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study was to investigate the strength and effectiveness of certain composite materials when induced by 'in-plane fiber tow waviness' in a composite ply. Fiber waviness is usually induced by infusion processes and inherent in fabric architectures. Composite structural details like ply drops and ply joints can cause serious fiber misalignment. These are usually dependent on parameters such as ply thickness, percentage of plies dropped, and location of ply drop, the gap between the plies, mold geometry and pressure, and pressure of the resin which slides the dry fibers during the resin transfer molding process. Fiber disorientation due to fiber tow waviness in „in-plane‟ direction has been the subject of recent studies on wind turbine blade materials and other aerospace laminates with reports of compression strengths and failure strains that are borderline, depending upon the reinforcement architecture, matrix resin and environment. Waviness is expected to reduce compressive strength due to two primary factors. The fibers may be oriented in such a way that the geometry that results because of the orientation may exacerbate the basic fiber, strand, or layer buckling mode of failure. The waviness could also shift the fiber orientation of the axis of the ply longitudinal direction which eventually results in matrix dominated failures for plies normally orientated in the primary load direction (00). The longitudinal tension and compression behavior of unidirectional carbon fiber composite laminates of different materials (different grades of carbon, glass and Kevlar with different resins) were investigated using finite element analysis tool ABAQUS. Both global and local stress & strain values generated by the finite element model were validated by the traditional mechanical methods using ply/local stiffness matrix and global/reduced stiffness matrix. A precise geometry of waviness on different materials was modeled with different wave severity factor and a parametric study was conducted. Three different defects were modeled where the angle of misalignment ranged from 5 to 15 degrees with a wavelength ranged from 1 inch to 1.5 inches and amplitude which ranged from 0.05 inches to 0.1 inches. This revealed the effect of 'in-plane fiber tow waviness' on the stress distribution and loss of strength in carbon-reinforced composite materials. The results clearly show that the effect of 'in-plane fiber tow waviness' leads to resin rich areas which causes high stress concentrations and decrease in the strength ratio, leading to delamination's.

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 American Society of Composites 28th Technical Conference written by Charles Bakis and published by DEStech Publications, Inc. This book was released on 2013-11-01 with total page 1892 pages. Available in PDF, EPUB and Kindle. Book excerpt: New and unpublished U.S. and international research on multifunctional, active, biobased, SHM, self-healing composites -- from nanolevel to large structures New information on modeling, design, computational engineering, manufacturing, testing Applications to aircraft, bridges, concrete, medicine, body armor, wind energy This fully searchable CD-ROM contains 135 original research papers on all phases of composite materials. The document provides cutting edge research by US, Canadian, and Japanese authorities on matrix-based and fiber composites from design to damage analysis and detection. Major divisions of the work include: Structural Health Monitoring, Multifunctional Composites, Integrated Computational Materials Engineering, Interlaminar Testing, Analysis-Shell Structures, Thermoplastic Matrices, Analysis Non-classical Laminates, Bio-Based Composites, Electrical Properties, Dynamic Behavior, Damage/Failure, Compression-Testing, Active Composites, 3D Reinforcement, Dielectric Nanocomposites, Micromechanical Analysis, Processing, CM Reinforcement for Concrete, Environmental Effects, Phase-Transforming, Molecular Modeling, Impact.

Download or read book Advances in Wind Turbine Blade Design and Materials written by Povl Brondsted and published by Woodhead Publishing. This book was released on 2023-01-14 with total page 516 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 A Collection of the 2004 ASME Wind Energy Symposium Technical Papers at the 42nd AIAA Aerospace Sciences Meeting and Exhibit written by and published by . This book was released on 2004 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Turbine Development at Montana State University written by and published by . This book was released on 2015 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A survey of wind turbine blade manufacturers, repair companies, wind farm operators, and third party investigators has directed the focus of this investigation on several types of flaws commonly found in wind turbine blades: waviness and porosity/voids. Several commercial scale wind turbine blades were inspected for the development of metrics for the identification, analysis and disposition. Analysis of flaw geometries yielded metrics which utilize specific parameters to physically characterize a defect. Data as it relates flaw parameters to frequencies of occurrence have been complied. Basic statistical analysis shows that the frequency of flaw parameters generally follows standard distributions. A testing program was then developed around this flaw data. Results from static testing indicate that there is strong correlation between flaw parameters and mechanical response. Preliminary results from the in-field data collection effort and coupon level testing have established a protocol by which a defect in a blade can be characterized quantifiably. With this data it is possible to develop probabilistic analysis, damage progression models and criticality assessment tools that will enable improved blade design methodology and the development of a risk management framework which describes the probability of failure for blades with defects.

Download or read book Aerodynamic Investigation of Winglets on Wind Turbine Blades Using CFD written by Jeppe Johansen and published by . This book was released on 2006 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Blade System Design Study Part II Final Project Report GEC written by and published by . This book was released on 2009 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of the U.S. Department of Energy's Low Wind Speed Turbine program, Global Energy Concepts LLC (GEC)1 has studied alternative composite materials for wind turbine blades in the multi-megawatt size range. This work in one of the Blade System Design Studies (BSDS) funded through Sandia National Laboratories. The BSDS program was conducted in two phases. In the Part I BSDS, GEC assessed candidate innovations in composite materials, manufacturing processes, and structural configurations. GEC also made recommendations for testing composite coupons, details, assemblies, and blade substructures to be carried out in the Part II study (BSDS-II). The BSDS-II contract period began in May 2003, and testing was initiated in June 2004. The current report summarizes the results from the BSDS-II test program. Composite materials evaluated include carbon fiber in both pre-impregnated and vacuum-assisted resin transfer molding (VARTM) forms. Initial thin-coupon static testing included a wide range of parameters, including variation in manufacturer, fiber tow size, fabric architecture, and resin type. A smaller set of these materials and process types was also evaluated in thin-coupon fatigue testing, and in ply-drop and ply-transition panels. The majority of materials used epoxy resin, with vinyl ester (VE) resin also used for selected cases. Late in the project, testing of unidirectional fiberglass was added to provide an updated baseline against which to evaluate the carbon material performance. Numerous unidirectional carbon fabrics were considered for evaluation with VARTM infusion. All but one fabric style considered suffered either from poor infusibility or waviness of fibers combined with poor compaction. The exception was a triaxial carbon-fiberglass fabric produced by SAERTEX. This fabric became the primary choice for infused articles throughout the test program. The generally positive results obtained in this program for the SAERTEX material have led to its being used in innovative prototype blades of 9-m and 30-m length, as well as other non-wind related structures.

Download or read book Modal Analysis and SHM Investigation of CX 100 Wind Turbine Blade written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the dynamic characterization of a CX100 blade using modal testing. Obtaining a thorough dynamic characterization of these turbine blades is important because they are complex structures, making them difficult to monitor for damage initiation and subsequent growth. This dynamic characterization was compared to a numerical model developed for validation. Structural Health Monitoring (SHM) techniques involving Lamb wave propagation, frequency response functions, and impedance based methods were also used to provide insight into blade dynamic response. SHM design parameters such as traveling distance of the wave, sensing region of the sensor and the power requirements were examined. Results obtained during modal and SHM testing will provide a baseline for future damage detection and mitigation techniques for wind turbine blades.

Download or read book An Investigation Into Vibration Based Techniques for Wind Turbine Blades Condition Monitoring written by Abdelnasser Abouzid Abouhnik 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 Investigation of the Effects of Span and Chord on Torque of Wind Turbine Blade Using S809airfoil written by Sunday Chukwunweike Olunwa and published by . This book was released on 2018 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Materials and Manufacturing Methods for Wind Turbine Blades written by and published by . This book was released on 1993 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Investigation on Spoiler Attachment to Wind Turbine Blades written by Jared D. Baker and published by . This book was released on 2012 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work investigates the potential performance enhancement of wind turbines by attaching a spoiler to the root section of the blade. Passive mechanisms that improve performance often prove to be cost effective for two reasons: performance enhancement with little maintenance and no shut down time if mechanism fails. The goal is to determine whether attaching spoilers to root sections of wind turbine blades will appropriately alleviate stall that generally occurs due to the thickness of the airfoil used for structural integrity and the perceived high angle of attack. To simulate this situation, computational fluid dynamics (CFD) codes, based on finite volume method (FVM) and finite difference method (FDM) formulations capable of solving the viscous, Reynolds-averaged Navier-Stokes equations, are utilized. Further investigation is done by coupling the CFD code to a multi-body structural dynamics (MSD) code for optimization purposes of the fluid/structure interaction between the main airfoil section and the attached spoiler. Utilizing a fixed spoiler on the suction side of a wind turbine blade, there is evidence of power enhancement at the higher wind speeds but also showed a power deficit at lower wind speeds. Allowing the spoiler to rotate freely removed this deficit while maintaining appreciable power increase at the higher wind speeds.

Download or read book Wind Turbine Blade Leading Edge Erosion written by Mark Hugh Keegan and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leading edge erosion of modern wind turbine blades is a growing and developing issue within the wind industry, effecting blade performance and efficiency. Little is known, researched or published on the phenomenon and there are currently no apparent full-proof material solutions for the issue. The research presented here looks to develop a fuller understanding of the issue of leading edge erosion, through first reviewing the literature (both within and outwith wind energy) on the topic to put the issues in context, and then subsequently further exploring and investigating the key damage mechanisms associated rain droplet and hailstone impact on the blade leading edge; identified as two of the most erosive types of environmental exposure. Both numerical (finite element) and experimental methods are employed to identify the key damage mechanisms associated with each form of impact in the different possible blade material coating and substrate systems. It is found that for rain exposure, surface degradation and erosion is a real risk for classical gelcoat coating systems. Whereas, for newer flexible and more erosive resistant materials, interface damage and debonding from the substrate is the most likely form of damage creation. Hailstone impact is found to pose a heightened erosive threat in comparison to rain, based on individual impact damage creation; although it is recognised that hailstorms are far more infrequent than rain showers in most regions. However, it is predicted that for extreme hailstones of sufficient mass, significant substrate composite damage could also be created through impact on the leading edge. Future work and further research development aimed at further understanding the issues of blade leading edge erosion are also identified and discussed.