Download or read book Detection and Localization of Damage in Fiber Reinforced Polymer Bars Using Acoustic Emission Detection Micro Computed Tomography and Scanning Electron Microscopy Techniques written by Maha Ghaib and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fiber reinforced polymer (FRP) rebars have been used for reinforcing concrete structures for the last quarter of the century. The advantages of using FRP are: high strength to weight ratio, corrosion resistance, durability, and high tensile strength. It would be beneficial to have non-destructive testing (NDT) methods that have the potential to detect damage at loads well below failure. This is particularly important for FRP rebars as they do not exhibit any external signs of damage until brittle failure. However, internal damage in FRP rebars increases with increasing tensile loads. Acoustic emission (AE) signal has proved to be a useful tool for monitoring damage in FRP materials. However, FRP rebars have received little attention. In this work damage progression in different types of FRP rebars subjected to tension was studied using AE, SEM and μCT. One possible mechanism for damage progression is the growth of voids entrapped in FRP rebars during their manufacture. These voids are a weakened region within the bars. When the bar is subjected to stress these regions can grow in size. In this work the growth of the voids within the bar is interpreted as the progression of damage. Internal voids and their growth were observed using micro computed tomography (μCT) and scanning electron microscopy (SEM) and compared to AE results. Strong correlation was observed between the void volume growth determined using μCT analysis and cumulative energy of AE. This work also demonstrated improved methods used to locate the source of AE signals that occurred in FRP rebars subjected to tension. An artificial neural network (ANN) was used to reduce the uncertainty in determining the AE source location. The ANN had improved accuracy, compared to the conventional source location methods by factor of 1.6 and 3 for GFRP and CFRP samples respectively. The source location results obtained with the ANN were also compared to μCT void volume analysis along the length of the bars after tension testing.
Download or read book Acoustic Emission Testing written by Christian U. Grosse and published by Springer Science & Business Media. This book was released on 2008-07-12 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic Emission (AE) techniques have been studied in civil engineering for a long time. The techniques are recently going to be more and more applied to practical applications and to be standardized in the codes. This is because the increase of aging structures and disastrous damages due to recent earthquakes urgently demand for maintenance and retrofit of civil structures in service for example. It results in the need for the development of advanced and effective inspection techniques. Thus, AE techniques draw a great attention to diagnostic applications and in material testing. The book covers all levels from the description of AE basics for AE beginners (level of a student) to sophisticated AE algorithms and applications to real large-scale structures as well as the observation of the cracking process in laboratory specimen to study fracture processes.
Download or read book Vibration based Techniques For Damage Detection And Localization In Engineering Structures written by Ali Salehzadeh Nobari and published by World Scientific. This book was released on 2018-05-04 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the oil and gas industries, large companies are endeavoring to find and utilize efficient structural health monitoring methods in order to reduce maintenance costs and time. Through an examination of the vibration-based techniques, this title addresses theoretical, computational and experimental methods used within this trend.By providing comprehensive and up-to-date coverage of established and emerging processes, this book enables the reader to draw their own conclusions about the field of vibration-controlled damage detection in comparison with other available techniques. The chapters offer a balance between laboratory and practical applications, in addition to detailed case studies, strengths and weakness are drawn from a broad spectrum of information.
Download or read book Damage Precursor Identification Via Microstructure Sensitive Nondestructive Evaluation written by Brian John Wisner and published by . This book was released on 2017 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Damage in materials is a complex and stochastic process bridging several time and length scales. This dissertation focuses on investigating the damage process in a particular class of precipitate-hardened aluminum alloys which is widely used in automotive and aerospace applications. Most emphasis in the literature has been given either on their ductility for manufacturing purposes or fracture for performance considerations. In this dissertation, emphasis is placed on using nondestructive evaluation (NDE) combined with mechanical testing and characterization methods applied at a scale where damage incubation and initiation is occurring. Specifically, a novel setup built inside a Scanning Electron Microscope (SEM) and retrofitted to be combined with characterization and NDE capabilities was developed with the goal to track the early stages of the damage process in this type of material. The characterization capabilities include Electron Backscatter Diffraction (EBSD) and Energy Dispersive Spectroscopy (EDS) in addition to X-ray micro-computed tomography (Îơ-CT) and nanoindentation, in addition to microscopy achieved by the Secondary Electron (SE) and Back Scatter Electron (BSE) detectors. The mechanical testing inside the SEM was achieved with the use of an appropriate stage that fitted within its chamber and is capable of applying both axial and bending monotonic and cyclic loads. The NDE capabilities, beyond the microscopy and Îơ-CT, include the methods of Acoustic Emission and Digital Image Correlation (DIC). This setup was used to identify damage precursors in this material system and their evolution over time and space. The experimental results were analyzed by a custom signal processing scheme that involves both feature-based analyses as well as a machine learning method to relate recorded microstructural data to damage in this material. Extensions of the presented approach to include information from computational methods as well as its applicability to other material systems are discussed.
Download or read book The Detection of Damage Induced Acoustic Emission in Advanced Composite Materials Using Embedded Optical Fibre Sensors written by Suzanne Marie Ferguson and published by . This book was released on 1990 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Detection and Location of Ballistic Damage in Composite Materials Using Acoustic Emission Methods written by J. F. Jaminet and published by . This book was released on 1985 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Non Destructive Evaluation NDE of Polymer Matrix Composites written by Vistasp M. Karbhari and published by Elsevier. This book was released on 2013-06-30 with total page 729 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increased use of polymer matrix composites in structural applications has led to the growing need for a very high level of quality control and testing of products to ensure and monitor performance over time. Non-destructive evaluation (NDE) of polymer matrix composites explores a range of NDE techniques and the use of these techniques in a variety of application areas.Part one provides an overview of a range of NDE and NDT techniques including eddy current testing, shearography, ultrasonics, acoustic emission, and dielectrics. Part two highlights the use of NDE techniques for adhesively bonded applications. Part three focuses on NDE techniques for aerospace applications including the evaluation of aerospace composites for impact damage and flaw characterisation. Finally, the use of traditional and emerging NDE techniques in civil and marine applications is explored in part four.With its distinguished editor and international team of expert contributors, Non-destructive evaluation (NDE) of polymer matrix composites is a technical resource for researchers and engineers using polymer matrix composites, professionals requiring an understanding of non-destructive evaluation techniques, and academics interested in this field. - Explores a range of NDE and NDT techniques and considers future trends - Examines in detail NDE techniques for adhesively bonded applications - Discusses NDE techniques in aerospace applications including detecting impact damage, ultrasonic techniques and structural health monitoring
Download or read book Acoustic Emission written by Valentyn Skalskyi and published by Springer. This book was released on 2023-08-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents topical theoretical and experimental studies for developing advanced methods of detecting materials fracture and assessing their structural state using acoustic emission. It introduces new mathematical models characterizing the displacement fields arising from crack-like defects and establishes a new criterion for classifying different types of materials fracture based on specific parameters obtained from wavelet transforms of acoustic emission signals. The book applies this approach to experimental studies in three types of materials—fiber-reinforced composites, dental materials, and hydrogen-embrittled steels.
Download or read book Image Correlation for Shape Motion and Deformation Measurements written by Michael A. Sutton and published by Springer Science & Business Media. This book was released on 2009-04-21 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Image Correlation for Shape, Motion and Deformation Measurements provides a comprehensive overview of data extraction through image analysis. Readers will find and in-depth look into various single- and multi-camera models (2D-DIC and 3D-DIC), two- and three-dimensional computer vision, and volumetric digital image correlation (VDIC). Fundamentals of accurate image matching are described, along with presentations of both new methods for quantitative error estimates in correlation-based motion measurements, and the effect of out-of-plane motion on 2D measurements. Thorough appendices offer descriptions of continuum mechanics formulations, methods for local surface strain estimation and non-linear optimization, as well as terminology in statistics and probability. With equal treatment of computer vision fundamentals and techniques for practical applications, this volume is both a reference for academic and industry-based researchers and engineers, as well as a valuable companion text for appropriate vision-based educational offerings.
Download or read book A Global Method for the Identification of Failure Modes in Fiberglass Using Acoustic Emission written by V. Arumugam and published by . This book was released on 2011 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The various failure mechanisms in bidirectional glass/epoxy laminates loaded in tension are identified using acoustic emission (AE) analysis. AE data recorded during the tensile testing of a single layer specimen are used to identify matrix cracking and fiber failure, while delamination signals are characterized using a two-layer specimen with a pre-induced defect. Parametric studies using AE count rate and cumulative counts allowed damage discrimination at different levels of loading and Fuzzy C-means clustering associated with principal component analysis were used to discriminate between failure mechanisms. The two above methods led to AE waveform selection: On selected waveforms, Fast Fourier Transform (FFT) enabled calculating the frequency content of each damage mechanism. Continuous wavelet transform allowed identifying frequency range and time history for failure modes, whilst noise content associated with the different failure modes was calculated and removed by discrete wavelet transform. Short Time FFT finally highlighted the possible failure mechanism associated with each signal.
Download or read book Unsupervised Structural Damage Detection and Localization Using Deep Learning and Machine Learning written by Zilong Wang and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many data-driven approaches have been developed in recent decades to address problems with damage detection for civil infrastructure. According to training modes of the statistical models or neural networks adopted in the studies, these data-driven damage detection methods can be roughly categorized into supervised modes and unsupervised modes. Supervised damage detection approaches require the recorded data (i.e., ground truth data) from the undamaged and various damaged structural scenarios to train statistical models or neural networks. Then, the trained models or networks can be utilized to detect damage using future data measured from unknown structural scenarios. However, acquiring numerous training datasets from various damage scenarios for the monitored structures is time-consuming and costly, and it is hard to obtain many damage scenarios for the infrastructures in service. To address these challenges encountered in practice, structural damage detection in unsupervised learning mode has become increasingly interesting to researchers. The proposed unsupervised damage detection methods in my study require only the data measured from undamaged structural scenarios or baseline structures in their training processes. This thesis aims to propose novel unsupervised damage detection methods to address the problems facing structural damage detection and localization. Specifically, a novel unsupervised damage detection approach using a deep learning technique is proposed for detecting damage in a simulated multi-story frame and a laboratory-scale steel bridge model in Chapter 3. Additionally, a comparative study with an advanced unsupervised damage detection approach using deep restricted Boltzmann machines is carried out to evaluate their effectiveness of detecting light damage in the steel bridge. In Chapter 4, an unsupervised novelty detection method based on an original technique of fast clustering is developed to roughly locate the damage positions in a small-scale building frame. To verify the effectiveness of the developed method for structural damage localization, several existing machine learning and deep learning methods are developed and converted to the uniform unsupervised novelty detection mode in Chapter 5 for extensive comparative studies.
Download or read book Acoustic Emission Damage Detection for Bonded Metal Elastomer Components written by Daniel Jaep and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Bonded metal-elastomer components are seeing increased use in multiple applications due to their combination of damping and structural properties. These components may be safety/flight critical for rotorcraft or used in earthquake resistance of skyscrapers in highly populated areas. As such, testing is required to ensure all parts in a production batch are free from manufacturing defects. However, the manufacturing process for these components can be subject to random, difficult to track defects such as regions of poor bonding or inclusions of hardened rubber from previous batches. Should a fault be found through traditional mechanical testing, more parts from the same batch may be destructively tested to verify if the fault effects the entire batch, or a small subset. This methodology for finding manufacturing defects can lead to costly increases in post-manufacture testing. Therefore, there is a need for a non-destructive testing methodology that can distinguish between healthy bonded components and defective bonded components. Acoustic emission (AE) is a desirable solution to this need, as it is a passive form of non-destructive evaluation that can be incorporated into pre-existing mechanical testing methods. The objective of this research is to determine the feasibility of using AE for bonded elastomeric fault detection and develop a test methodology for recently manufactured components. Fully synched load, elongation, and AE data were collected for this purpose. Patterns between the various AE parameters and mechanical behavior were studied in order to determine failure indicators for these bonded materials. Energy per hit, hit amplitude, and hit rate were generally the AE parameters that best indicated certain mechanical phenomena. When a bonded component was cycled to the same load, fewer and lower amplitude hits were typically seen, indicative of the stress softening Mullin's effect. Conversely, prior to cohesive failure AE signals were higher in amplitude and energy in the seconds precipitating the loss of load carrying capability. Results show that AE, while difficult for rubbery materials, is capable of indicating faults and failure in bonded elastomer components. Finite element analysis (FEA) was also utilized to aid in the determination of testing methodology. Specifically, FEA was used for determining the optimal placement of AE transducers for any given geometry due to the ability to model any geometry and reduce the number of physical tests that needed to be conducted. Simulations were used to determine the most sensitive sensor location for a variety of distinct AE source locations. Results comparing the average peak value and Q-factor for a frequency response of each 'pseudo-sensor' location on the finite element model guided how transducers would be placed on physical components to evaluate the greatest amount of material in the least amount of time possible.
Download or read book Fatigue of Textile and Short Fiber Reinforced Composites written by Valter Carvelli and published by John Wiley & Sons. This book was released on 2017-03-10 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers several aspects of the fatigue behavior of textile and short fiber reinforced composites. The first part is dedicated to 2D and 3D reinforced textile composites and includes a systematic description of the damage evolution for quasi-static and tensile-tensile fatigue loadings. Acoustic emissions and digital image correlation are considered in order to detect the damage modes’ initiation and development. The acoustic emission thresholds of the quasi-static loading are connected to the “fatigue limit” of the materials with distinctions for glass and carbon reinforcements. The second part is devoted to the fatigue behavior of injection molded short fiber reinforced composites. Experimental evidence highlights the dependence of their fatigue response on various factors: fiber and matrix materials, fiber distribution, environmental and loading conditions are described. A hybrid (experimental/simulations) multi-scale method is presented, which drastically reduces the amount of experimental data necessary for reliable fatigue life predictions.
Download or read book Emerging Technologies in Non Destructive Testing VI written by Danny Van Hemelrijck and published by CRC Press. This book was released on 2015-11-24 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-Destructive Testing (NDT) is of worldwide significance, and is strongly related to the detection of damage in engineering structures (buildings, bridges, aircrafts, ships, pressure vessels, etc.) using non-invasive techniques (ultrasound, X-rays, Radar, neutrons, thermography, vibrations, acoustic emission, etc.). Emerging Technologies in Non-D
Download or read book Delamination in Wood Wood Products and Wood Based Composites written by Voichita Bucur and published by Springer Science & Business Media. This book was released on 2010-11-02 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last quarter century, delamination has come to mean more than just a failure in adhesion between layers of bonded composite plies that might affect their load-bearing capacity. Ever-increasing computer power has meant that we can now detect and analyze delamination between, for example, cell walls in solid wood. This fast-moving and critically important field of study is covered in a book that provides everyone from manufacturers to research scientists the state of the art in wood delamination studies. Divided into three sections, the book first details the general aspects of the subject, from basic information including terminology, to the theoretical basis for the evaluation of delamination. A settled terminology in this subject area is a first key goal of the book, as the terms which describe delamination in wood and wood-based composites are numerous and often confusing. The second section examines different and highly specialized methods for delamination detection such as confocal laser scanning microscopy, light microscopy, scanning electron microscopy and ultrasonics. Ways in which NDE (non-destructive evaluation) can be employed to detect and locate defects are also covered. The book’s final section focuses on the practical aspects of this defect in a wide range of wood products covering the spectrum from trees, logs, laminated panels and glued laminated timbers to parquet floors. Intended as a primary reference, this book covers everything from the microscopic, anatomical level of delamination within solid wood sections to an examination of the interface of wood and its surface coatings. It provides readers with the perspective of industry as well as laboratory and is thus a highly practical sourcebook for wood engineers working in manufacturing as well as a comprehensively referenced text for materials scientists wrestling with the theory underlying the subject.
Download or read book Structural Health Monitoring 2000 written by Fu-Kuo Chang and published by CRC Press. This book was released on 1999-09-07 with total page 1104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprising 102 papers presented by researchers from all over the world, the proceedings of this workshop contain current information about a variety of structural health monitoring technologies, as well as their current and potential applications in various fields. Emphasis is placed on those technologies that are promising for future applications in industry and government and the infrastructures that are needed to support such technological development. The content of the workshop is divided into keynote presentations (ten altogether), aerospace applications, general applications, civil applications, integration and systems, sensors, and signal processing and diagnostic methods. Includes the editor's summary report on the results of the panel discussions and presentations from the First International Workshop on Structural Health Monitoring held at Stanford U. in September 1997. Annotation c. Book News, Inc., Portland, OR (booknews.com)
Download or read book Full Field Measurements and Identification in Solid Mechanics written by Michel Grediac and published by John Wiley & Sons. This book was released on 2012-12-17 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: This timely book presents cutting-edge developments by experts in the field on the rapidly developing and scientifically challenging area of full-field measurement techniques used in solid mechanics – including photoelasticity, grid methods, deflectometry, holography, speckle interferometry and digital image correlation. The evaluation of strains and the use of the measurements in subsequent parameter identification techniques to determine material properties are also presented. Since parametric identification techniques require a close coupling of theoretical models and experimental measurements, the book focuses on specific modeling approaches that include finite element model updating, the equilibrium gap method, constitutive equation gap method, virtual field method and reciprocity gap method. In the latter part of the book, the authors discuss two particular applications of selected methods that are of special interest to many investigators: the analysis of localized phenomenon and connections between microstructure and constitutive laws. The final chapter highlights infrared measurements and their use in the mechanics of materials. Written and edited by knowledgeable scientists, experts in their fields, this book will be a valuable resource for all students, faculties and scientists seeking to expand their understanding of an important, growing research area
