Download or read book Applications of Passive Vibration Control and Damage Detection in Composite Wind Turbine Blades written by Jeffery Dwayne Tippmann and published by . This book was released on 2014 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this dissertation was to develop passive techniques for vibration control and structural health monitoring applications in structures operating in conditions of significant ambient noise. These goals were accomplished through the use of an experimental wind turbine blade that represents the materials and design of a full scale wind turbine with the inclusion of devices simulating the presence of known manufacturing defects. The vibration control aim was accomplished using a shunted array of piezoelectric elements tuned to the vibration properties of the blade skin. The macro-fiber composite (MFC) composite piezoelectric transducer was bonded to the wind turbine blade skin and connected to the tuned shunt circuit. The damage detection techniques were developed using both an aluminum plate and the experimental wind turbine blade. Two approaches using a reconstructed impulse response function are presented. The first examines the break in reciprocity of impulse response functions. A single similarity damage index was proposed and then extended into a multi-feature analysis. The second method applied linear and nonlinear beamforming techniques using an experimentally generated replica field and cross-spectral signal processing techniques. The passive reconstruction of the impulse response function between two sensors is an important topic in NDE and SHM. Previously studied methods using active pitch-catch approaches between any two sensors is well suited for structures such as wind turbine blades that experience significant amounts of noise during operation. The study of these approaches advances the understanding of passive damage detection using reconstructed impulse response functions.

Download or read book Acoustic Emission Signal Analysis and Damage Mode Identification of Composite Wind Turbine Blades written by Pengfei Liu and published by Elsevier. This book was released on 2023-05-20 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic Emission Signal Analysis and Damage Mode Identification of Composite Wind Turbine Blades covers both the underlying theory and various techniques for effective structural monitoring of composite wind turbine blades via acoustic emission signal analysis, helping readers solve critical problems such as noise elimination, defect detection, damage mode identification, and more. Author Pengfei Liu introduces techniques for identifying and analyzing progressive failure under tension, delamination, damage localization, adhesive composite joint failure, and other degradation phenomena, outlining methods such as time-difference, wavelet, machine learning, and more including combined methods. The disadvantages and advantages of using each method are covered as are techniques for different blade-lengths and various blade substructures. Piezoelectric sensors are discussed as is experimental analysis of damage source localization. The book also takes great lengths to let readers know when techniques and concepts discussed can be applied to composite materials and structures beyond just wind turbine blades. Features fundamental acoustic emission theories and techniques for monitoring the structural integrity of wind turbine blades Covers sensor arrangements, noise elimination, defect detection, and dominating damage mode identification using acoustic emission techniques Outlines the wavelet method, the time-difference defect detection method, and damage mode identification techniques using machine learning Discusses how the techniques covered can be extended and adapted for use in other composite structures under complex loads and in different environments

Download or read book Mechanics of Composite and Multi functional Materials Volume 7 written by Carter Ralph and published by Springer. This book was released on 2015-10-30 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental Mechanics of Composite, Hybrid, and Multifunctional Materials, Volume 7 of the Proceedings of the 2015SEM Annual Conference& Exposition on Experimental and Applied Mechanics, the seventh volume of nine from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on a wide range of areas, including: Multifunctional Materials Hybrid Materials Novel Composites Nano- and Particle-Reinforced Composites Additive Manufacturing of Composites Digital Imaging of Composites Damage Detection Non-Destructive Evaluation Fatigue and Fracture of Composites Manufacturing and Joining of Composites Advanced Composites Applications

Download or read book Experimental Investigation in Vibration Control and Damage Detection of Smart Composites written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Laser Doppler Vibrometer (LDV) optical instrument purchased under the DURIP grant is used for accurately measuring velocity (and displacement) of vibrating surfaces completely without contact. It is a complete, self-contained area vibration measurement and analysis system. The LDV automatically collects complete vibration data from up to thousands of individual points on a user-defined area. An important feature in scanning vibrometers is the ability to validate and improve the quality of measured data at every scan point. This overcomes problems caused by dark speckles and other unavoidable phenomena present in laser vibrometry. The system purchased is also equipped with Live and Fully Integrated Video Imaging. The equipment is particularly useful at higher frequencies (above Skit) where accelerometers become increasingly inaccurate due to their own dynamic characteristics and influences. A large number of applications that require measurements at very high frequencies and cannot be accomplished using accelerometers include piezoelectric transducers and exciters, NDE flaw detection, rotor blades, disk drive components and micro-sensors and actuators.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vibration based Damage Detection Using Machine Learning Techniques with Application to Offshore Wind Turbines written by Y. Zhang and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Passive Control of a Wind Turbine Blade Using Composite Materials written by Saad Bin Aziz and published by . This book was released on 2011 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The weight and the cost of the wind turbine are the two important considerations that make wind energy competitive with other energy source. The weight of the rotor is typically 40-80% of the total weight of the system. Thus, reducing cost by reducing the weight of the blade is an important consideration. Another important factor is the operational life of the machine, which is roughly 20 years of continuous service. Innovative design solutions are needed in order to meet the criteria of improved stiffness, fatigue life, reliability and efficiency. The directional property of anisotropic composite material can be used to passively control wind turbine blade structure. In the current research, a baseline wind turbine blade model of glass fiber and a carbon-hybrid model has been developed by replacing glass fiber in the spar cap region. In addition, the feasibility of using carbon fiber has been analyzed by comparing stress, strain and failure criteria analysis under different operating conditions.

Download or read book Polycrystalline Silicon Capacitive MEMS Strain Sensor for Structural Health Monitoring of Wind Turbines written by Maziar Moradi and published by . This book was released on 2016 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind energy is a fast-growing sustainable energy technology and driven by the need for more efficient energy harvesting, size of the wind turbines has increased over the years for both off-shore and land-based installations. Therefore, structural health monitoring and maintenance of such turbine structures have become critical and challenging. In order to keep the number of physical inspections to minimum without increasing the risk of structural failure, a precise and reliable remote monitoring system for damage identification is necessary. Condition-based maintenance which significantly improves safety compared to periodic visual inspections, necessitates a method to determine the condition of machines while in operation and involves the observation of the system by sampling dynamic response measurements from a group of sensors and the analysis of the data to determine the current state of system health. This goal is being pursued in this thesis through the development of reliable sensors, and reliable damage detection algorithms. Blade strain is the most important quantities to judge the health of wind turbine structure. Sensing high stress fields or early detection of cracks in blades bring safety and saving in rehabilitation costs. Therefore, high performance strain measurement system, consisting of sensors and interface electronics, is highly desirable and the best choice. It has been revealed that the conventional strain gauge techniques exhibit significant errors and uncertainties when applied to composite materials of wind turbine blades. Micro-electro-mechanical system (MEMS) based sensors are very attractive among other sensing techniques owing to high sensitivity, low noise, better scaling characteristics, low cost and higher potential for integration with low power CMOS circuits. MEMS sensors that are fabricated on a chip can be either bonded to the surface of wind turbine blade or embedded into the fiber reinforced composite. Therefore, MEMS technology is selected to fabricate the strain sensor in this work. Two new sensor structures that can be used for strain measurement are designed. While the proposed sensors focus on high sensitivity, they are based on simple operating principle of comb-drive differential variable capacitances and chevron displacement amplification. Device performances are validated both by analytical solutions and finite element method simulations. The transmission of strain fields in adhesively bonded strain sensors is also studied. In strain sensors that are attached to host structures using adhesive layers such as epoxy, complete strain transfer to the sensor is hindered due to the influence of the adhesive layer on the transfer. An analytical model, validated by finite element method simulation, to provide insight and accurate formulation for strain transfer mechanism for bonded sensors is developed. The model is capable of predicting the strain transmission ratio through a sensor gauge factor, and it clearly establishes the effects of the flexibility, length, and thickness of the adhesive layer and sensor substrate. Several fabrication steps were required to realize the MEMS capacitive strain sensor in our lab. Polycrystalline silicon is selected as the structural layer and silicon nitride as the sacrificial layer. Polysilicon is deposited using LPCVD and SiN is deposited by PECVD in our lab. A comprehensive material study of silicon nitride and polycrystalline silicon layers is therefore performed. The whole fabrication process involves deposition, etching, and photolithography of five material layers. Although this process is developed to realize the MEMS strain sensors, it is also able to fabricate other designs of surface micromachining structures as well. The fabricated MEMS capacitive strain sensors are tested on a test fixture setup. The measurement setup is created under the probe station by using a cantilever beam fixed on one side and free on other side where a micrometer applies accurate displacement. The displacement creates bending stress on the beam which transfers to the MEMS sensor through the adhesive bond. Measurement results are in a good match with the simulation results. Finally, a real-time non-destructive health monitoring technique based on multi-sensor data fusion is proposed. The objective is to evaluate the feasibility of the proposed method to identify and localize damages in wind turbine blades. The structural properties of turbine blade before and after damage are investigated and based on the obtained results, it is shown that information from smart sensors, measuring strains and vibrations, distributed over the turbine blades can be used to assist in more accurate damage detection and overall understanding of the health condition of blades. Data fusion technique is proposed to combine the diagnostic tools to improve the detection system with providing a more robust reading and fewer false alarms.

Download or read book Structural Health Monitoring For Advanced Composite Structures written by M H Ferri Aliabadi and published by World Scientific. This book was released on 2017-12-18 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural health monitoring (SHM) is a relatively new and alternative way of non-destructive inspection (NDI). It is the process of implementing a damage detection and characterization strategy for composite structures. The basis of SHM is the application of permanent fixed sensors on a structure, combined with minimum manual intervention to monitor its structural integrity. These sensors detect changes to the material and/or geometric properties of a structural system, including changes to the boundary conditions and system connectivity, which adversely affect the system's performance.This book's primary focus is on the diagnostics element of SHM, namely damage detection in composite structures. The techniques covered include the use of Piezoelectric transducers for active and passive Ultrasonics guided waves and electromechanical impedance measurements, and fiber optic sensors for strain sensing. It also includes numerical modeling of wave propagation in composite structures. Contributed chapters written by leading researchers in the field describe each of these techniques, making it a key text for researchers and NDI practitioners as well as postgraduate students in a number of specialties including materials, aerospace, mechanical and computational engineering.

Download or read book Introduction to Digital Speech Processing written by Lawrence R. Rabiner and published by Now Publishers Inc. This book was released on 2007 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides the reader with a practical introduction to the wide range of important concepts that comprise the field of digital speech processing. Students of speech research and researchers working in the field can use this as a reference guide.

Download or read book Passive Acoustic Detection of Wind Turbine In Flow Conditions for Active Control and Optimization written by and published by . This book was released on 2012 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind is a significant source of energy; however, the human capability to produce electrical energy still has many hurdles to overcome. One of these is the unpredictability of the winds in the atmospheric boundary layer (ABL). The ABL is highly turbulent in both stable and unstable conditions (based on the vertical temperature profile) and the resulting fluctuations can have a dramatic impact on wind turbine operation. Any method by which these fluctuations could be observed, estimated, or predicted could provide a benefit to the wind energy industry as a whole. Based on the fundamental coupling of velocity fluctuations to pressure fluctuations in the nearly incompressible flow in the ABL, This work hypothesizes that a ground-based array of infrasonic pressure transducers could be employed to estimate the vertical wind profile over a height relevant for wind turbines. To analyze this hypothesis, experiments and field deployments were conducted. Wind tunnel experiments were performed for a thick turbulent boundary layer over a neutral or heated surface. Surface pressure and velocity probe measurements were acquired simultaneously. Two field deployments yielded surface pressure data from a 49 element array. The second deployment at the Reese Technology Center in Lubbock, TX, also included data from a smaller aperture, 96-element array and a 200-meter tall meteorological tower. Analysis of the data successfully demonstrated the ability to estimate the vertical velocity profile using coherence data from the pressure array. Also, dynamical systems analysis methods were successful in identifying and tracking a gust type event. In addition to the passive acoustic profiling method, this program also investigated a rapid response Doppler SODAR system, the optimization of wind turbine blades for enhanced power with reduced aeroacoustic noise production, and the implementation of a wireless health monitoring system for the wind turbine blades. Each of these other objectives was met successfully. The use of phase unwrapping applied to SODAR data was found to yield reasonable results for per-pulse measurements. A health monitoring system design analysis was able to demonstrate the ability to use a very small number of sensors to monitor blade health based on the blade's overall structural modes. Most notable was the development of a multi-objective optimization methodology that successfully yielded an aerodynamic blade design that produces greater power output with reduced aerodynamic loading noise. This optimization method could be significant for future design work.

Download or read book Semi active Vibration Control of Wind Turbine Blades Using a Time frequency Approach written by John Arrigan and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Health Monitoring written by Daniel Balageas and published by John Wiley & Sons. This book was released on 2010-01-05 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is organized around the various sensing techniques used to achieve structural health monitoring. Its main focus is on sensors, signal and data reduction methods and inverse techniques, which enable the identification of the physical parameters, affected by the presence of the damage, on which a diagnostic is established. Structural Health Monitoring is not oriented by the type of applications or linked to special classes of problems, but rather presents broader families of techniques: vibration and modal analysis; optical fibre sensing; acousto-ultrasonics, using piezoelectric transducers; and electric and electromagnetic techniques. Each chapter has been written by specialists in the subject area who possess a broad range of practical experience. The book will be accessible to students and those new to the field, but the exhaustive overview of present research and development, as well as the numerous references provided, also make it required reading for experienced researchers and engineers.

Download or read book Passive Damage Monitoring of Wind Turbine Rotor Blades Using Cyclic Signal Processing written by and published by . This book was released on 2011 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Structural Health Monitoring 2015 written by Fu-Kuo Chang and published by DEStech Publications, Inc. This book was released on 2015-10-01 with total page 1644 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the Tenth International Workshop on Structural Health Monitoring, September 1–3, 2015. Selected research on the entire spectrum of structural health techniques and areas of applicationAvailable in print, complete online text download or individual articles. Series book comprising two volumes provides selected international research on the entire spectrum of structural health monitoring techniques used to diagnose and safeguard aircraft, vehicles, buildings, civil infrastructure, ships and railroads, as well as their components such as joints, bondlines, coatings and more. Includes special sections on system design, signal processing, multifunctional materials, sensor distribution, embedded sensors for monitoring composites, reliability and applicability in extreme environments. The extensive contents can be viewed below.