Dissertations / Theses on the topic 'Ultrasonic array'
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Wang, Ji-yong 1967. "Hybrid ultrasonic array." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/84216.
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Felice, Maria Victoria. "Ultrasonic array inspections for complex defects." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687061.
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The aim of this thesis is to develop a simulation-assisted methodology for optimising ultrasonic array inspections and to apply it to an industrial problem. In particular, the focus is on inspections for complex defects and the motivation behind the work is an aerospace engine component that may suffer from stress corrosion cracking. Unlike fatigue cracks, these cracks are typically branched and are therefore difficult to detect with ultrasonic inspections. The development of the simulation-assisted methodology consists of two key parts. The first part is to implement a computer model that correctly simulates the interaction of ultrasound with complex cracks, while being efficient enough to be used in an optimisation exercise. An efficient Finite Element method and the Kirchhoff Approximation are compared with regards to their capability for simulating the ultrasonic scattering from complex cracks, and the Finite Element method is found to be preferable. This method is combined with ray tracing to obtain a hybrid model that simulates ultrasonic array data from the cracks and the complete model is successfully validated experimentally. The second part of the development of the methodology is to establish a process of obtaining real crack shapes to input into the hybrid model. The process which is developed involves the use of X-ray Computed Tomography to obtain high-resolution images of cracked parts and then segmenting the images. The computer model and real crack shape extraction process are used together to optimise the detection capability of an ultrasonic array inspection for the aerospace engine component. The signal-to-noise ratios obtained with a selection of array designs are compared with each other and with those obtained using a single element ultrasonic probe. The sizing capability of the array inspections is also investigated and the use of the Half-Skip Total Focusing Method to size cracks is analysed in detail.
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Nadkarni, Aditya. "Reflector geometry specific modeling of an annular array based ultrasound pulse-echo system." Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-091207-114218/.
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Poon, Wai Tsun William. "The performance of large element ultrasonic array transducers." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411096.
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Smith, Peter Raymond. "Ultrasonic phased array techniques using switched-mode excitation." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/4570/.
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Ultrasound is predominantly an ‘active’ sensing modality, with information obtained by transmission of an acoustic wave, followed by analysis of received signals. Transmission occurs when electrical signals are converted to acoustic signals. This thesis covers the design and application of these electrical signals to an array transducer. As an introduction, the development of a bespoke ultrasound array research platform is discussed. This enabling technology is built around switched-mode excitation: a method of approximating an analogue waveform by selecting between discrete voltage levels. The use of switched-mode methods has led to three major topics of research. Firstly, a transmit beamformer architecture that provides fine control of excitation sequence timing using embedded-phase locked loops is presented. This enables accurate implementation of firing sequences or phasing between transducer elements, thus minimizing time-quantization error, and providing an improved representation of the expected pressure field. An introduction to transmit beamforming is given, the impact of timequantization is discussed, and the transmit beamformer’s performance is demonstrated. Secondly, a method of arbitrary waveform generation using switched-mode excitation is described. The method encodes width-modulated sequences of three or five discrete voltage levels, that, once passed through a transducer, give close approximation to the desired arbitrary waveform. Applications include: power control, pulse shaping, and array apodization. Each application is demonstrated by simulation and experimentation. An extension to the method is shown for ‘chirp’ coded imaging, demonstrating the capability for generation of frequency modulated waveforms. The improvement in image quality when compared with conventional square-wave, ‘pseudo-chirp’ excitation signals is shown. Lastly, the performance of the width-modulated signals is further extended so as to remove unwanted third-harmonic content whilst still maintaining pulse amplitude control.Removal of the third harmonic reduces harmonic distortion, has benefits in applications such as harmonic imaging, and extends the use of switched-mode operation with wide bandwidth transducers.
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Duxbury, David. "Calibration and control of advanced ultrasonic array technology." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/27618.
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Ultrasonic inspection is the primary method of Non-Destructive Evaluation (NDE) for the detection of planar flaws in engineering components. In recent years phased array technology has been adopted for use in NDE following success in related fields, such as medical and sonar applications. Phased array technology provides increased flexibility relative to single element monolithic transducers and the development of controlling hardware with large numbers of parallel channels has allowed the use of large phased arrays able to focus at long range, and offer increased performance. Full Matrix Capture (FMC) is a method of recording data using a phased array transducer that allows image reconstruction to be performed for any inspection technique than could be deployed using delay laws applied to the transmit voltage pulses applied to the array and receiving amplifiers. FMC technology provides a step change in inspection flexibility, and also provides the opportunity to take advantage of imaging techniques that are not practical to implement using phased arrays in the conventional way. However, existing inspection calibration procedures defined in standards do not allow these benefits to be fully realised. This thesis reports the development of a calibration framework designed for FMC based inspection for both rigid and conformable wedge mounted arrays. A large part of this work has been the development of acceptance limits on transducer performance variations. The developments of these limits have required a significant amount of modelling work, often using a Monte Carlo approach. To accommodate this, modelling tools have been developed to investigate the effect of array element directivity, sensitivity, and relative phase on system performance. For conformable phased arrays the effect of surface profile measurement accuracies has also been assessed. The developed calibration framework includes the tools necessary to monitor transducer performance throughout an inspection, with minimum impact on inspection duration. A means of calibrating imaging tools against known reflectors, in accordance with established industrial practice, has also been produced.
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Bowler, Adam I. "Strain Measurement in Solids using Ultrasonic Array Speckle Images." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525470.
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Qian, Yichen. "Design of high frequency ultrasonic array transducers for medical imaging." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/336225/.
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Ultrasonic transducers have been widely used in the medical applications. High frequency array transducers have recently attracted many research interests, since it provides not only the electronic beamforming but also the very fine image resolution. The transducers are usually either annular or linear arrays. This study concentrates on the design of both types of array in high frequency applications. The annular array is firstly investigated, and an optimized design of array geometry is developed including the kerfs influence which is usually neglected in the design of high frequency arrays. The improved imaging performance is found by this optimized design. More interestingly, the conventional annular array with element having the same surface area has a relatively large sidelobe closest to the main lobe. Two methods are applied to suppress the sidelobe. The method of using high-impedance single matching to enlarge the element bandwidth only shows very limited lobe suppression, however, a novel matching approach is found. Another method of changing the array geometry from equal area elements to equal width ones successfully suppressed the sidelobe. The imaging results suggest that the novel equal width array shows a good improvement. The linear array is then analyzed. The kerfs influence again is found to be significant for the array especially for high frequency. It is essential to use a high attenuated kerfs material in the linear array design. More importantly, the limitation of current fabrication techniques forces the linear array to concede a high grating lobe in the imaging field if it operates in a relatively high frequency. A novel linear array is developed to suppress the grating lobe without using advanced fabrication techniques. The imaging results show that the novel linear array has a general reduction of -6dB for the lobe suppression. The novel design made the linear array operate in a very high frequency without strong grating lobe, and the array can be fabricated by current techniques.
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Russell, Jonathan. "The development and implementation of advanced ultrasonic phased array technology." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5684.
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Ultrasonic inspection is the primary technique for the detection of planar flaws within the nuclear industry. Current inspections are typically limited to the application of rigid wedge, single element transducers to components with regular surface geometry. This thesis addresses some of the limitations of this approach and develops new methods and techniques that are suitable for application in an industrial environment. Inspection modelling is a cost effective technique for inspection design and qualification; it can be used to aid understanding of the inspection process, and provides valuable insight into inspection data interpretation. In this work semianalytical and numerical modelling tools have been used to accurately and efficiently simulate the ultrasonic inspection of large complex components. Modelling tools have also been applied to aid in the design of a membrane coupled conformable phased array device. The membrane coupled array is a low-cost, robust device that uses a conventional phased array coupled to the outer surface of the component under test via a water path encapsulated by low-loss membrane. Early design of this device was performed by Long and Cawley at Imperial College, London. The work reviewed in this thesis discussed the further development of this membrane coupled device and its application for the inspection of a specific target application component. The target application is a safety critical, thick-walled stainless steel section of pipework that contains an austenitic weld. The current inspection of this component is carried out by first removing the component weld cap and then mechanically raster scanning a large number of rigid wedge single element transducers. Weld cap removal is an expensive time consuming task that can lead to excessive wall thinning and the exposure of small surface breaking defects. The motivation for this work is to provide complete inspection of the weld and heat affected zone with the weld cap in place. It is also designed to improve inspection speed and accuracy, and to reduce the amount of user intervention required to complete the inspection in a hostile environment Inspection results from the 2nd and 3rd generation membrane coupled device on multiple test-pieces representative of the target application are presented. These results demonstrate that the membrane coupled device can be used to detect defects in locations that cannot be inspected using conventional techniques. The amount of scanning required can be significantly reduced, simplifying the inspection and helping to improve inspection speed by over 60% in comparison to the single element approach.
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Zeng, Xiaozheng. "Ultrasound phased array simulations for hyperthermia." Diss., Connect to online resource - MSU authorized users, 2008.
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Medina, Gomez Lucia. "An investigation of air-coupled ultrasonic 3D ranging systems." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263416.
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Purekar, Ashish Sudhakar. "Piezoelectric phased array acousto-ultrasonic interrogation of damage in thin plates." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3402.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Luker, L. Dwight. "Investigation of a cylindrical nonacoustic-wavenumber calibration array." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15885.
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Battle, David John. "Maximum Entropy Regularisation Applied to Ultrasonic Image Reconstruction." University of Sydney. Electrical Engineering, 1999. http://hdl.handle.net/2123/842.
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Image reconstruction, in common with many other inverse problems, is often mathematically ill-posed in the sense that solutions are neither stable nor unique. Ultrasonic image reconstruction is particularly notorious in this regard, with narrow transducer bandwidths and limited - sometimes sparsely sampled apertures posing formidable difficulties for conventional signal processing. To overcome these difficulties, some form of regularisation is mandatory, whereby the ill-posed problem is restated as a closely related, well-posed problem, and then solved uniquely. This thesis explores the application of maximum entropy (MaxEnt) regularisation to the problem of reconstructing complex-valued imagery from sparsely sampled coherent ultrasonic field data, with particular emphasis on three-dimensional problems in the non-destructive evaluation (NDE) of materials. MaxEnt has not previously been applied to this class of problem, and yet in comparison with many other approaches to image reconstruction, it emerges as the clear leader in terms of resolution and overall image quality. To account for this performance, it is argued that the default image model used with MaxEnt is particularly meaningful in cases of ultrasonic scattering by objects embedded in homogeneous media. To establish physical and mathematical insights into the forward problem, linear equations describing scattering from both penetrable and impenetrable objects are first derived using the Born and physical optics approximations respectively. These equations are then expressed as a shift-invariant computational model that explicitly incorporates sparse sampling. To validate this model, time-domain scattering responses are computed and compared with analytical solutions for a simple canonical test case drawn from the field of NDE. The responses computed via the numerical model are shown to accurately reproduce the analytical responses. To solve inverse scattering problems via MaxEnt, the robust Cambridge algorithm is generalised to the complex domain and extended to handle broadband (multiple-frequency) data. Two versions of the augmented algorithm are then compared with a range of other algorithms, including several linearly regularised algorithms and lastly, due to its acknowledged status as a competitor with MaxEnt in radio-astronomy, the non-linear CLEAN algorithm. These comparisons are made through simulated 3-D imaging experiments under conditions of both complete and sparse aperture sampling with low and high levels of additive Gaussian noise. As required in any investigation of inverse problems, the experimental confirmation of algorithmic performance is emphasised, and two common imaging geometries relevant to NDE are selected for this purpose. In monostatic synthetic aperture imaging experiments involving side-drilled holes in an aluminium plate and test objects immersed in H2O, MaxEnt image reconstruction is demonstrated to be robust against grating-lobe and side-lobe formation, in addition to temporal bandwidth restriction. This enables efficient reconstruction of 2-D and 3-D images from small numbers of discrete samples in the spatial and frequency domains. The thesis concludes with a description of the design and testing of a novel polyvinylidene fluoride (PVDF) bistatic array transducer that offers advantages over conventional point-sampled arrays in terms of construction simplicity and signal-to-noise ratio. This ultra-sparse orthogonal array is the only one of its kind yet demonstrated, and was made possible by MaxEnt signal processing.
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Wan, Li. "Modeling and optimal design of annular array based ultrasound pulse-echo system." Link to electronic thesis, 2001. http://www.wpi.edu/Pubs/ETD/Available/etd-0418101-100413/.
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Thesis (M.S.)--Worcester Polytechnic Institute.Title from title screen. Keywords: optimal design; modeling; object identification; ultrasound pulse-echo system; annular array. Includes bibliographical references (p. 159-162).
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Prado, Vander Teixeira [UNESP]. "Ultrasonic non-destructive testing of plate-like structures using piezoelectric array transducers." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/111127.
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000799830.pdf: 4517190 bytes, checksum: 4566f2d205fed1f4cb035a7c44ec4214 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Esta tese apresenta o estudo e implementação de técnicas de inspeção de estruturas delgadas tipo placa utilizando arrays de transdutores piezelétricos e ondas acústicas guiadas, associados a métodos de formação e composição de imagens. A detecção de danos em estruturas através de ondas guiadas e arrays de transdutores é um campo de pesquisa de grande importância, principalmente em áreas como a aeroespacial e de geração de energia, que utilizam estruturas delgadas e que exigem inspeção eficaz e completa, visando confiabilidade e segurança. O emprego de ondas acústicas guiadas permite inspecionar grandes áreas utilizando sensores sem a necessidade de realizar varreduras pela peça, de maneira não-destrutiva. Além disso, apresenta sensibilidade a diversos tipos de defeitos, como furos, corrosão, variação de espessura e defeitos superficiais. São estudados aspectos de propagação de ondas, diferentes modos de propagação e dispersão, assim como as principais características dos arrays e a formação de imagens. Os estudos teóricos são acompanhados por simulações usando os softwares MATLAB e PZFlex para obtenção dos modos de propagação das ondas, interação com defeitos e diagramas de radiação dos transdutores, cujos resultados são validados por meio da análise experimental em placas de materiais isotrópicos (alumínio). Montou-se um array linear de transdutores piezelétricos com 16 elementos na borda de uma placa de alumínio com defeitos artificiais. Os sinais provenientes de todas as possíveis combinações dos pares transmissor-receptor foram adquiridos para a utilização de técnicas de abertura sintética. A primeira contribuição deste trabalho é um método para detecção dos defeitos baseado na fase instantânea dos sinais. Substituindo-se a informação de amplitude dos sinais pela fase instantânea (IP) no método de formação de imagem, ...
This thesis presents the study and implementation of non-destructive testing techniques of platelike structures using piezoelectric array transducers and guided acoustic waves, associated with beamforming techniques and image compounding methods. Damage detection in structures using guided waves and arrays is a promising research area, especially in the aerospace and energy fields, where the use of plate-like structures demands thorough inspection due to the high safety levels of operation. Guided acoustic waves techniques can be used to inspect relatively large areas without the necessity of moving the transducers, in a non-destructive way. There are different propagation modes that can be coupled to the plate, and each mode is sensitive to specific types of defects, like notches, delamination and surface defects. Wave propagation, different propagation modes and dispersion characteristics, as well as arrays characteristics and imaging algorithms, are studied. MATLAB and PZFlex simulations are used to get further insight in the theoretical aspects, to obtain dispersion curves, interaction with defects and array response. Experimental results validate the simulations with isotropic materials (aluminum). A 16-elements piezoelectric linear array is mounted at the border of an aluminum plate with artificial defects. The signals related to all combinations of transmit-receive pairs are obtained with burst excitation, for use with synthetic aperture (SA) techniques. The first contribution of this work is a method for defect detection based on the instantaneous phase of the aperture data. The instantaneous phase (IP) image is obtained by replacing the amplitude information by the instantaneous phase in the conventional SA beamforming. From the analysis of the IP image, a threshold level is proposed in terms of the number of signals used for imaging. This threshold is applied to the IP image, resulting ...
FAPESP: 10/02240-0
FAPESP: 10/16400-0
FAPESP: 13/00330-0
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Kelly, Stephen P. "An air-coupled ultrasonic array scanning system for rapid through transmission NDT." Thesis, University of Strathclyde, 2000. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24320.
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Within the aerospace industry there is an increasing requirement to investigate the structural integrity of the new composite materials that are now being used frequently in the manufacture of aircraft. The complexity of the material manufacture necessitates that evaluation is required prior to final production and it is the development of a novel approach to this testing that constitutes the focus for the work of this Thesis. Existing techniques frequently utilise ultrasonic signals to interrogate the sample under investigation, however, these are cumbersome and scan speed is invariably slow when testing of large samples is considered. This is because large samples are normally tested using a through transmission approach, where narrow jets of water are used to couple the ultrasonic signal through the propagation channel. The fundamental basis of the proposed approach is the removal of the water couplant, enabling a receiver array to be employed, and thus scan large areas more quickly. Flexibility would also be increased with this technique due to a capability to scan moisture sensitive parts. In order to achieve this, however, the considerable problem of the acoustic impedance mismatch at each solid/air boundary would have to be overcome. Firstly, a narrowband, relatively low frequency approach is selected. It is concluded however, that in order to maximise the scan speed benefit, parallel data acquisition from the receiver array elements must be achieved and no signal averaging must be performed. A small array element pitch and focussing are deemed necessary in the pursuit of adequate defect detection resolution. It is important to select the most appropriate transducer technology for coupling in air and a comprehensive comparison of two relevant technologies (piezocomposite and electrostatic) is carried out. Piezocomposites are found to be superior in terms of sensitivity, robustness and focusing capability. A novel acoustic matching layer is developed to improve coupling from the transducers to the air load. This is investigated microscopically and acoustically and a linear model is developed to enable the design for the most successful operation. Prototype air-coupled systems are produced and scan results compared favourably with the results using water-coupled techniques.
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Blum, Frank. "A focused, two dimensional, air-coupled ultrasonic array for non-contact generation." Thesis, Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04072004-180005/unrestricted/blum%5Ffrank%5F200312%5Fms.pdf.
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DeRidder, W. Nick. "Analysis of a non-contact laser-fiber optic array for generation of ultrasound." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/17502.
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Forbes, Thomas Patrick. "Electrohydrodynamics and ionization in the Array of Micromachined UltraSonic Electrospray (AMUSE) ion source." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33852.
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The focus of this Ph.D. thesis is the theoretical, computational, and experimental analysis of electrohydrodynamics and ionization in the Array of Micromachined UltraSonic Electrospray (AMUSE) ion source. The AMUSE ion source, for mass spectrometry (MS), is a mechanically-driven, droplet-based ion source that can independently control charge separation and droplet formation, thereby conceptually differing from electrospray ionization (ESI). This aspect allows for low voltage soft ionization of a variety of analytes and flexibility in the choice of solvents, providing a multifunctional interface between liquid chromatography and mass spectrometry for bioanalysis. AMUSE is a versatile device that operates in an array format, enabling a wide range of configurations, including high-throughput and multiplexed modes of operation. This thesis establishes an in-depth understanding of the fundamental physics of analyte charging and electrokinetic charge separation in order to enhance droplet charging and ionization efficiency. A detailed electrohydrodynamic (EHD) computational model of charge transport during the droplet formation cycle in the AMUSE ion source is developed, coupling fluid dynamics, pressure and electric fields, and charge transport in multiphase flow. The developed EHD model presents a powerful tool for optimal design and operation of the AMUSE ion source, providing insight into the microscopic details of physicochemical phenomena, on the microsecond time scale. Analyte charging and electrohydrodynamics in AMUSE are characterized using dynamic charge generation measurements and high-spatial-resolution stroboscopic visualization of ejection phenomena. Specific regimes of charge transport, which control the final droplet charging, have been identified through experimental characterization and simulations. A scale analysis of the ejection phenomena provides a parametric regime map for AMUSE ejection modes in the presence of an external electric field. This analysis identifies the transition between inertia-dominated (mechanical) and electrically-dominated (electrospraying) ejection, where inertial and electric forces are comparable, producing coupled electromechanical atomization. The understanding of analyte charging and charge separation developed through complimentary theoretical and experimental investigations is utilized to improve signal abundance, sensitivity, and stability of the AMUSE-MS response. Finally, these tools and fundamental understanding provide a sound groundwork for the optimization of the AMUSE ion source and future MS investigations.
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Tyler, N. J. "Investigation of a piezo-polymer array transducer for pulse-echo ultrasonic material examinations." Thesis, Cranfield University, 1992. http://dspace.lib.cranfield.ac.uk/handle/1826/4182.
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The aim of this investigation was to make a flexible array of pulse-echo ultrasound transducers by etching two orthogonal linear arrays of conducting elements into the metallisation of either side of a sheet of PVdF. These would then be multiplexed under computer control in an X-Y raster, thereby forming an image of subsurface defects in a material specimen. A potential source model was used to predict the sensitivity of a single element air-backed transducer far from resonance. Initial investigations confirmed the predictions, and reaffirmed the results of previous workers. In making a prototype array, it was found necessary to use a bi-laminar arrangement with a central ground plane, due to difficulties with crosstalk and charge leakage into the specimen materials. The radiation pattern of this array was tested and found to agree with the predictions for Fraunhofer (Far-Field) radiation. A 10 MHz analogue to digital converter was constructed to interface with the IBM-PC clone as a transient recorder, through a data capture program written in 'C'. However, the electrical noise generated by the PC was found to interfere strongly with the signal from the array transducer. A wide-band amplifier and full-wave rectifier was then added to the multiplexer and A/D converter, and the system enclosed in an electrically isolated environment, which made it possible to obtain clear signal data from the transducer. Non-linear regression was implemented in the software, to smooth the data and locate echo peaks, and the most frequently occurring peak separation was used to indicate sample thickness at that location in a false-colour mapping on the screen of the PC.
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Lane, Christopher John Leslie. "The development of a 2D ultrasonic array inspection for single crystal turbine blades." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.651312.
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The aim of this thesis is to design and evaluate a non-destructive evaluation (NDE) system for the inspection of single crystal turbine blades. Turbine blades are the components within jet-engines that convert the hot, high-pressure gas exiting the combustion stage into mechanical power. During operation, these components are highly stressed and are surrounded by extremely high gas temperatures. As such, there is the potential for defects to initiate in-service. One way to ensure the structural integrity of these engine components is by periodically inspecting them for defects. The ability of the inspection to be performed in situ is highly advantageous, as this eliminates the cost and time delay associated with removing the turbine blades from the engine prior to inspection. A 20 ultrasonic phased array system was chosen for this project, as these systems can perform rapid volumetric inspections whilst being portable enough to be used in situ. Modem turbine blades are manufactured from single crystal nickel-based superalloys for the excellent mechanical properties these materials exhibit at elevated temperatures. However, these materials are elastically anisotropic. The propagation of ultrasonic waves through anisotropic materials is far more complex than the isotropic case. This causes significant difficulties when inspecting anisotropic single crystal components with ultrasonic arrays. Therefore, analytical models are developed to predict the propagation of ultrasonic waves in anisotropic materials. These models are used to correct an ultrasonic imaging algorithm to account for the anisotropic behaviour. To implement the corrected algorithm effectively, the orientation of the crystal in the component under inspection must be known. Therefore, crystallographic orientation methods using 20 ultrasonic arrays are developed and evaluated. The corrected algorithms and crystallographic orientation methods are used to develop an in situ 20 ultrasonic array inspection for a specific high-pressure single crystal turbine blade. The inspection is designed to detect and size cracking in the root section of the turbine blade. The developed inspection system is fully evaluated in a quantitative manner for its defect detection sensitivity and sizing capability.
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Baiotto, Ricardo. "Imaging methodologies applied on phased array ultrasonic data from austenitic welds and claddings." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/186162.
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A crescente tendência de utilização de materiais austeníticos soldados e cladeados em componentes críticos em alguns setores industriais, como nas indústrias de óleo&gás e nuclear, leva a um aumento na demanda sobre ensaios não-destrutivos confiáveis na avaliação de sua integridade estrutural. Dentre os métodos utilizados na inspeção de soldas cladeados austeníticos estão os métodos de ultrassom por phased array, que são normalmente utilizados na detecção e localização de defeitos. No entanto, componentes com esse tipo de microestrutura são difíceis de inspecionar por phased array devido a anisotropia e inomogeneidade causadas pela microestrutura de grãos grosseiros que costumam levar ao aumento do nível de ruído, ao deslocamento de indicações e ao surgimento de indicações falsas. Sendo assim, a seleção de um método de phased array apropriado precisa levar em conta a habilidade do método em superar os problemas causados pela anisotropia e inomogeneidade. Esta tese apresenta dois métodos de imagem por phased array ultrassônico não-convencionais pensados como formas de ajudar na determinação da integridade de componentes onde soldas e cladeados austeníticos estão presentes. Ambos os métodos tem como base o método de foco total (TFM), sendo que o primeiro é uma extensão do método de leis de atraso adaptativas chamado Método de Foco Total de Atraso Adaptativo (ADTFM) e o segundo método usa fatores de coerência associado à imagens de TFM. A partir dos métodos de imagem aplicados é possível aumentar significativamente a qualidade das imagens por ultrassom em comparação com as imagens padrão obtidas por TFM, especialmente quando foi possível utilizar ambos os métodos combinados.The increasing trend to use austenitic welded and cladded materials in critical components employed in some industrial sectors, such as the oil&gas and nuclear industries, leads to an increasing demand for their non-destructive assessment by reliable non-destructive methods. Among the methods used to access the integrity of austenitic welds and claddings are the Ultrasonic Phased Array methods, which are usually used to detect the presence and determine the position of defects. However, austenitic welds and claddings are challenging to inspect with Phased Array methods due to the anisotropy and inhomogeneity caused by their coarse grain microstructure, which is capable of increasing noise levels, misplace indications and create false indications. Therefore, the selection of an appropriate phased array method needs to take into account the method’s ability to overcome the impairment caused by anisotropy and inhomogeneity. This thesis presents two non-conventional methods based on ultrasonic phased array imaging techniques designed to assist the structural integrity assessment of components where austenitic welds and clads are present. Both proposed methods are based on the Total Focusing Method (TFM); the first approach is an expansion of the adaptive delay laws concept named Adaptive Delay Total Focusing Method (ADTFM), while the second method uses the coherence weights combined with the TFM images. From the imaging methods applied it was possible to significantly increase the quality of the ultrasonic images in comparison with the standard TFM, primarily when it was possible to combine both approaches.
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Okumura, Shigeaki. "Array Signal Processing for Accurate Medical Ultrasound Measurements." Kyoto University, 2018. http://hdl.handle.net/2433/232419.
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Lukacs, Marc. "Single element and linear array high-frequency ultrasonic transducers using PZT sol-gel composites." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/NQ42956.pdf.
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Hall, James Stroman. "Adaptive dispersion compensation and ultrasonic imaging for structural health monitoring." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41159.
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Ultrasonic guided wave imaging methods offer a cost-effective mechanism to perform in situ structural health monitoring (SHM) of large plate-like structures, such as commercial aircraft skins, ship hulls, storage tanks, and civil structures. However, current limits in imaging quality, environmental sensitivities, and implementation costs, among other things, are preventing widespread commercial adoption. The research presented here significantly advances state of the art guided wave imaging techniques using inexpensive, spatially distributed arrays of piezoelectric transducers. Novel adaptive imaging techniques are combined with in situ estimation and compensation of propagation parameters; e.g., dispersion curves and transducer transfer functions, to reduce sensitivity to unavoidable measurement inaccuracies and significantly improve resolution and reduce artifacts in guided wave images. The techniques can be used not only to detect and locate defects or damage, but also to characterize the type of damage. The improved ability to detect, locate, and now characterize defects or damage using a sparse array of ultrasonic transducers is intended to assist in the establishment of in situ guided wave imaging as a technically and economically viable tool for long-term monitoring of plate-like engineering structures.
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Engholm, Marcus. "Ultrasonic Arrays for Sensing and Beamforming of Lamb Waves." Doctoral thesis, Uppsala universitet, Signaler och System, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-122189.
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Non-destructive testing (NDT) techniques are critical to ensure integrity and safety of engineered structures. Structural health monitoring (SHM) is considered as the next step in the field enabling continuous monitoring of structures. The first part of the thesis concerns NDT and SHM using guided waves in plates, or Lamb waves, to perform imaging of plate structures. The imaging is performed using a fixed active array setup covering a larger area of a plate. Current methods are based on conventional beamforming techniques that do not efficiently exploit the available data from the small arrays used for the purpose. In this thesis an adaptive signal processing approach based on the minimum variance distortionless response (MVDR) method is proposed to mitigate issues related to guided waves, such as dispersion and the presence of multiple propagating modes. Other benefits of the method include a significant increase in resolution. Simulation and experimental results show that the method outperforms current standard processing techniques. The second part of the thesis addresses transducer design issues for resonant ultrasound inspections. Resonant ultrasound methods utilize the shape and frequency of the object's natural modes of vibration to detect anomalies. The method considered in the thesis uses transducers that are acoustically coupled to the inspected structures. Changes in the transducer's electrical impedance are used to detect defects. The sensitivity that can be expected from such a setup is shown to highly depend on the transducer resonance frequency, as well as the working frequency of the instrument. Through simulations and a theoretical argumentation, optimal conditions to achieve high sensitivity are given.
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Martinez, Garcia Jairo Andres. "A Novel Ultrasonic Method to Quantify Bolt Tension." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4145.
Full textAbstract:
The threaded fasteners are one of the most versatile methods for assembly of structural components. For example, in bridges large bolts are used to fix base columns and small bolts are used to support access ladders. Naturally not all bolts are critical for the operation of the structure. Fasteners loaded with small forces and present in large quantities do not receive the same treatment as the critical bolts. Typical maintenance operations such tension measurements, internal stress checking or monitoring of crack development are not practical due to cost and time constrains. Although failure of a single non-critical fastener is not a significant threat to the structure's stability, massive malfunction may cause structural problem such as insufficient stiffness or excessive vibrations.
The health of bolted joints is defined by a single parameter: the clamping force (CF). The CF is the force that holds the elements of the joint together. If the CF is too low, separation and bolt fatigue may occur. On the other hand, excessive CF may produce damages in the structural members such as excessive distortion or breakage. The CF is generated by the superposition of the individual tension of the bolts. The bolt tension, also referred as bolt preload, is the actual force that is stretching the bolt body. Maintaining the appropriate tension in bolts ensures a proper CF and hence a good health of the joint.
In this thesis, a novel methodology for estimating the tension in bolts using surface acoustic waves (SAWs) is investigated. The tension is estimated by using the reflection of SAWs created by the bolt head interference. Increments in the bolt tension raise the points of interaction between the waves and the bolt head (real area of contact), and hence the position of the reflective boundaries. The variations are estimated using the "conventional linear synthetic array" imaging technique. A singular transducer is actuated from predefined positions to produce an array of signals that are subsequently arranged and added to construct an acoustic image.
Three sets of experiment are presented in this research for validating the proposed concept: tension estimation of a ¼ inch stainless steel bolt, a ½ inch stainless steel bolt and ¼ inch grade 8 bolt. Acoustic images of the surface of the clamped plate illustrate a clear trend in the position of the reflective boundary when torque is changed. In all cases, the torque increments increase the real area of contact and therefore the position of the reflective boundary. As expected, the real area of contact grew from the bolt head center to the perimeter, which causes an effect of apparent movement of the boundary. This research proves the potential of the ultrasonic imaging methodology to measure applied tension. The result showed that the system can be used to successfully inspect tension in bolts of ½ and ¼ inches. The methodology investigated in this thesis is the first steps towards the development of bolt tension sensor based on surface acoustic waves.
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Osman, Ahmad. "Automated evaluation of three dimensional ultrasonic datasets." Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00995119.
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Non-destructive testing has become necessary to ensure the quality of materials and components either in-service or at the production stage. This requires the use of a rapid, robust and reliable testing technique. As a main testing technique, the ultrasound technology has unique abilities to assess the discontinuity location, size and shape. Such information play a vital role in the acceptance criteria which are based on safety and quality requirements of manufactured components. Consequently, an extensive usage of the ultrasound technique is perceived especially in the inspection of large scale composites manufactured in the aerospace industry. Significant technical advances have contributed into optimizing the ultrasound acquisition techniques such as the sampling phased array technique. However, acquisition systems need to be complemented with an automated data analysis procedure to avoid the time consuming manual interpretation of all produced data. Such a complement would accelerate the inspection process and improve its reliability. The objective of this thesis is to propose an analysis chain dedicated to automatically process the 3D ultrasound volumes obtained using the sampling phased array technique. First, a detailed study of the speckle noise affecting the ultrasound data was conducted, as speckle reduces the quality of ultrasound data. Afterward, an analysis chain was developed, composed of a segmentation procedure followed by a classification procedure. The proposed segmentation methodology is adapted for ultrasound 3D data and has the objective to detect all potential defects inside the input volume. While the detection of defects is vital, one main difficulty is the high amount of false alarms which are detected by the segmentation procedure. The correct distinction of false alarms is necessary to reduce the rejection ratio of safe parts. This has to be done without risking missing true defects. Therefore, there is a need for a powerful classifier which can efficiently distinguish true defects from false alarms. This is achieved using a specific classification approach based on data fusion theory. The chain was tested on several ultrasound volumetric measures of Carbon Fiber Reinforced Polymers components. Experimental results of the chain revealed high accuracy, reliability in detecting, characterizing and classifying defects.
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Lorentzon, Marcus. "Phased Array Ultrasonic Testing of Austenitic Stainless Steel Welds of the 11 T HL-LHC Dipole Magnets." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-150098.
Full textAbstract:
A routine non-destructive test method based on Phased Array Ultrasonic Testing (PAUT) has been developed and applied for the inspection of the first 11 T dipole prototype magnet half shell welds, and the test results are compared with the radiography and visual inspection results of the same welds. A manual scanner and alignment system have been developed and built to facilitate the inspection of the 5.5 m long welds, and to assure reproducibility of the PAUT results. Through the comparison of distance readings and signal amplitude for different focus lengths, a focal law with focus at 25 mm sound path has been selected for the routine inspection of the 15 mm thick austenitic stainless steel 11 T dipole welds. The defocusing properties (beam spread) due to the cylindrical geometry of the half shells and the sound path distance to the area of interest were taken into account. Dedicated sensitivity calibration weld samples with artificial defects (side-drilled-holes) have been designed and produced from 11 T dipole prototype austenitic stainless steel half shell welds. These provide representative calibration for the strongly attenuating and scattering austenitic stainless steel weld material. One scan with two phased array probes aligned parallel to the weld in 2 mm distance from the weld cap edge, and one scan with the probes aligned parallel to the weld in 12 mm distance from the weld cap edge are sufficient to show if the inspected welds fulfil the requirements of weld quality level B according to ISO 5817. The standard test duration for the two scans of the two 5.5 m long horizontal welds of the 11 T dipole magnets is about one day, provided that no defects are found that need to be characterized in more detail.
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WAN, Li. "Modeling and Optimal Design of Annular Array Based Ultrasound Pulse-Echo System." Digital WPI, 2001. https://digitalcommons.wpi.edu/etd-theses/219.
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The ability to numerically determine the received signal in an ultrasound pulse-echo system is very important for the development of new ultrasound applications, such as tissue characterization, complex object recognition, and identification of surface topology. The output signal from an ultrasound pulse-echo system depends on the transducer geometry, reflector shape, location and orientation, among others, therefore, only by numerical modeling can the output signal for a given measurement configuration be predicted. This thesis concerns about the numerical modeling and optimal design of annular array based ultrasound pulse-echo system for object recognition. Two numerical modeling methods have been implemented and evaluated for calculating received signal in a pulse-echo system. One is the simple, but computationally demanding Huygens Method and the other one is the computationally more efficient Diffraction Response for Extended Area Method (DREAM). The modeling concept is further extended for pulse-echo system with planar annular array. The optimal design of the ultrasound pulse-echo system is based on annular array transducer that gives us the flexibility to create a wide variety of insonifying fields and receiver characteristics. As the first step towards solving the optimization problem for general conditions, the problem of optimally identifying two specific reflectors is investigated. Two optimization methods, the straightforward, but computationally intensive Global Search Method and the efficient Waveform Alignment Method, have been investigated and compared.
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Chou, Tsung-nan. "The integration of an ultrasonic phased array and a vision system for the 3D measurement of multiple targets." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362887.
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Prado, Vander Teixeira. "Ultrasonic non-destructive testing of plate-like structures using piezoelectric array transducers = Ensaios não-destrutivos por ultrassom de estruturas tipo placa utilizando arrays de transdutores piezelétricos /." Ilha Solteira, 2014. http://hdl.handle.net/11449/111127.
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Orientador: Ricardo Tokio HigutiCo-orientador: Oscar Martinez-Graullera
Banca: Claudio kitano
Banca: Samuel da Silva
Banca: Nicolas Leonardo Pérez Alvarez
Banca: Joaquim Miguel Maia
Resumo: Esta tese apresenta o estudo e implementação de técnicas de inspeção de estruturas delgadas tipo placa utilizando arrays de transdutores piezelétricos e ondas acústicas guiadas, associados a métodos de formação e composição de imagens. A detecção de danos em estruturas através de ondas guiadas e arrays de transdutores é um campo de pesquisa de grande importância, principalmente em áreas como a aeroespacial e de geração de energia, que utilizam estruturas delgadas e que exigem inspeção eficaz e completa, visando confiabilidade e segurança. O emprego de ondas acústicas guiadas permite inspecionar grandes áreas utilizando sensores sem a necessidade de realizar varreduras pela peça, de maneira não-destrutiva. Além disso, apresenta sensibilidade a diversos tipos de defeitos, como furos, corrosão, variação de espessura e defeitos superficiais. São estudados aspectos de propagação de ondas, diferentes modos de propagação e dispersão, assim como as principais características dos arrays e a formação de imagens. Os estudos teóricos são acompanhados por simulações usando os softwares MATLAB e PZFlex para obtenção dos modos de propagação das ondas, interação com defeitos e diagramas de radiação dos transdutores, cujos resultados são validados por meio da análise experimental em placas de materiais isotrópicos (alumínio). Montou-se um array linear de transdutores piezelétricos com 16 elementos na borda de uma placa de alumínio com defeitos artificiais. Os sinais provenientes de todas as possíveis combinações dos pares transmissor-receptor foram adquiridos para a utilização de técnicas de abertura sintética. A primeira contribuição deste trabalho é um método para detecção dos defeitos baseado na fase instantânea dos sinais. Substituindo-se a informação de amplitude dos sinais pela fase instantânea (IP) no método de formação de imagem, ...
Abstract: This thesis presents the study and implementation of non-destructive testing techniques of platelike structures using piezoelectric array transducers and guided acoustic waves, associated with beamforming techniques and image compounding methods. Damage detection in structures using guided waves and arrays is a promising research area, especially in the aerospace and energy fields, where the use of plate-like structures demands thorough inspection due to the high safety levels of operation. Guided acoustic waves techniques can be used to inspect relatively large areas without the necessity of moving the transducers, in a non-destructive way. There are different propagation modes that can be coupled to the plate, and each mode is sensitive to specific types of defects, like notches, delamination and surface defects. Wave propagation, different propagation modes and dispersion characteristics, as well as arrays characteristics and imaging algorithms, are studied. MATLAB and PZFlex simulations are used to get further insight in the theoretical aspects, to obtain dispersion curves, interaction with defects and array response. Experimental results validate the simulations with isotropic materials (aluminum). A 16-elements piezoelectric linear array is mounted at the border of an aluminum plate with artificial defects. The signals related to all combinations of transmit-receive pairs are obtained with burst excitation, for use with synthetic aperture (SA) techniques. The first contribution of this work is a method for defect detection based on the instantaneous phase of the aperture data. The instantaneous phase (IP) image is obtained by replacing the amplitude information by the instantaneous phase in the conventional SA beamforming. From the analysis of the IP image, a threshold level is proposed in terms of the number of signals used for imaging. This threshold is applied to the IP image, resulting ...
Doutor
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Prego, Borges Jose Luis. "Lamb: a simulation tool for air-coupled lamb wave based ultrasonic NDE systems." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/6376.
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La técnica de las ondas de Lamb acopladas por aire representa un importante avance en el área de los Ensayos No Destructivos (END) de materiales laminares.Sin embargo la compleja naturaleza de las vibraciones mecánicas encontradas en acústica, hacen que el análisis y el estudio de esta área del conocimiento sea un tema muy complejo. De allí que la posibilidad de contar con una herramienta de simulación de software que permita la evaluación y prueba de diferentes configuraciones de excitación y recepción acústica utilizando la flexibilidad de un modelo de computadora sea de una gran utilidad y ayuda.
El objetivo de la presente tesis es proveer al área de los END con un software de simulación gratuito: The LAMB Matlab® toolbox basado en el modelo del software libre de la GNU.
El software es capaz de simular el comportamiento de sistemas de END basados en ondas de Lamb acopladas por aire en láminas isótropas simples utilizando transductores tipo array.
El programa se basa en un arreglo tipo C-scan de un sistema de END y está compuesto por tres bloques principales: 1) Excitación, 2) Propagación y 3) Recepción.
La verificación individual del funcionamiento de dichos módulos se presenta a lo largo de la tesis mediante una serie de comparaciones entre simulaciones y datos experimentales provenientes de diferentes pruebas. Por otro lado, la validación del programa completo se llevo a cabo por medio de experimentos en láminas de cobre y aluminio; utilizando un sistema real de END por ondas de Lamb acopladas en aire mediante arrays cóncavos.
La influencia negativa en el desempeño general de dicho sistema de END real basado en este tipo de transductores se comprobó efectivamente mediante el simulador desarrollado. Esto se debió fundamentalmente al efecto de directividad de los sensores individuales en los transductores y a la simetría cóncava de los arrays.
Para emular este comportamiento la tesis presenta un modelo geométrico bidimensional simple de un filtro espacial, junto a las simulaciones de un nuevo tipo de array plano propuesto.
El programa desarrollado comprobó así mismo la naturaleza coherente de los campos acústicos emitidos en aire por las láminas sujetas a vibraciones de Lamb. Esto se realizó mediante la implementación de un conformador de haz simple de suma y demora; constituyéndose así la etapa inicial de procesamiento de señal del bloque de recepción del programa.
El objetivo principal del presente trabajo fue contribuir con un modelo operativo de simulación y prueba de nuevos diseños de arrays e implementación de estrategias de procesado de señal útiles en sistemas de END basados en ondas de Lamb acopladas por aire.
Finalmente, si bien el objetivo de la calibración del programa no se pudo conseguir; si se logró efectivamente un notable grado de similitud con un sistema de END real.
Air-coupled ultrasonic Lamb waves represent an important advance in Non- Destructive Testing and Evaluation (NDT & NDE) techniques of plate materials and structures. Examples of these advances are the characterization and quality assessment of laminate materials in manufacturing processes, the location of damaged parts in aircrafts and structure monitoring in the aerospace industry.
However the rich and complex nature of mechanical vibrations encountered in acoustics make the subject of analysis and study of these systems a very complex task. Therefore a simulation tool that permits the evaluation and testing of different configuration scenarios using the flexibility of a computer model is an invaluable aid and advantage.
The objective of this thesis is to provide the field of NDT with free open source software i.e. the LAMB Matlabrtoolbox. The toolbox is capable of simulating the behaviour of Lamb wave based NDE systems for single ideal isotropic laminates using air-coupled ultrasonic arrays. The programme usesa pitch-catch type of a Cscan NDE arrangement and is composed of three integrated sections each individually modelling a feature in the system: 1) Excitation, 2) Propagation, and 3) Reception.
For assessment of the individual modules of the toolbox the thesis presents comparisons between each section simulations and the data obtained from different acoustic experiments. The validation of the complete simulator was carried out by evaluation tests on the copper and aluminium plates by use of a real hardware prototype of a Lamb wave based NDE system with aircoupled concave arrays.
The negative impact on the performance of the real air-coupled NDE systembased on concave arrays was effectively confirmed by the programme. This was produced by the inherent directivity of the individual sensors as well as their concave arrangement. To emulate this behaviour the thesis introduces a simple two-dimensional geometric model for the inclusion of the spatial filtering effect of the sensors plus a group of simulations for a new proposed air-coupled plane array transducer.
The software also verified the spatial coherent nature of the Lamb wave fields emitted by a plate in air. This was demonstrated by the implementation of a delay and sum beamformer to constitute an initial signal processing stage in the reception section.
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Charlesworth, Chris. "Ultrasonic phased array testing in the power generation industry : novel wedge development for the inspection of steam turbine blades roots." Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/49401/.
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The thesis presented herein comprises of the work undertaken to research novel methods of Phased array ultrasonic inspection of complex steam turbine blade roots as found in the power generation industry. The research was conducted as part of the Engineering Doctorate scheme, administered by the Research Centre for Non-Destructive Evaluation (RCNDE), in conjunction with RWE npower and the University of Warwick. Steam turbine blades, and in particularly last stage blades of low pressure steam turbines, are amongst the most highly stressed components on a power generating plant. Two of the most common blade root fixing types include ‘curved axial entry fir tree roots’ (CAEFTR), and axial pinned roots, both of which are prone to cracking due to the high stresses to which they are subjected under operating conditions. Failure of the blade root fixings of such components, leading to the release of the blades, has historically led to the catastrophic failure and destruction of the whole turbine; the cost of collateral damage to plant components and the loss in generating income are seconded only by the risk these failures pose to life. Due to the high price of failure, NDT plays a critical part in the support and management of engineering maintenance, offering insight into the condition and integrity of turbine components through regular planned inspection regimes. It will be shown in this thesis how the invention of a novel continuous wedge, used to refract ultrasound into the critical regions of the blade roots, has significantly improved the ability to detect defects. Combined with the development of bespoke scanning frames these wedges facilitate the efficient and accurate acquisition of scanned data to assess the integrity of the component. By combining the latest reverse engineering, modelling and simulation tools with novel application of rapid prototyping, the author has been able to demonstrate significant reduction in design cycles whilst improving accuracy, sensitivity and repeatability of the applied inspections. Furthermore, application of this design philosophy has led to the development of inspection techniques which have facilitated the inspection of remote regions of the blade roots where manual access is limited or impossible. The developments and techniques invented during this research have been successfully deployed across numerous RWE npower and customer projects, leading to estimated savings in excess of £1m.
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Gommlich, Andreas. "Entwicklung einer neuen Methode zur Ansteuerung von Ultraschall-Phased Arrays." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-206375.
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Die Ansteuerung von Ultraschall-Phased-Arrays basiert auf zwei Vereinfachungen. Zum einen wird davon ausgegangen, dass das Schwingungsverhalten aller Einzelelemente synchron und gleichmäßig ist. Zum anderen erfolgt die Berechnung der Ansteuerungszeiten, den sogenannten Focal Laws, auf dem Ansatz der geometrischen Akustik. Beide Aspekte werden in dieser Arbeit ausführlich analysiert und neue Vorschläge für eine optimale Ansteuerung ausgearbeitet und simulativ sowie messtechnisch bewertet. Das individuelle Schwingungsverhalten der Einzelelemente von Phased Arrays liegt in einer Vielzahl von Toleranzen der Einzelkomponenten und der Fertigungsschritte begründet. Für die quantitative Bewertung kann die mechanische Auslenkung mittels Laser-Doppler-Vibrometrie lokal erfasst und evaluiert werden. Die Kompensation individueller Latenzzeiten im Ansprechverhalten führt dann unmittelbar zu einem höheren Summensignal im anvisierten Fokuspunkt. Um den Einfluss der tatsächlichen Aperturgeometrie von Einzelelementen auf die Qualität des Summensignals des Phased Arrays zu untersuchen, wurde außerdem eine Simulationsumgebung (4D-CEFIT-PSS) entwickelt. Damit ist die Wellenausbreitung unter Berücksichtigung aller wellenphysikalischer Effekte im Halbraum möglich. Somit wurden verschiedene Aperturmodelle erstellt und sowohl im Zeit- als auch im Frequenzbereich analysiert. Die wellenphysikalische Simulation ermöglicht die Berechnung modifizierter Focal Laws, die immer zu einer Verbesserung des Summensignals im Vergleich zum Ansatz mit geometrischer Akustik führenUltrasonic linear phased array probes consist of several single elements. By exciting each element at a certain time wave fronts can be tilted, focused or both combined. This is accomplished by a set of delays which is called "focal law". Hence, the shape and the quality of the resulting wave front depends significantly on focal law calculation. This state-of-the-art method is based on two simplifications: firstly on the assumption that each single element has identical vibration behaviour, and secondly on the simple geometrical approximation of the signal propagation time. In this work both aspects will be investigate in detail. For characterization of the individual vibration behaviour the most important transducer parts and theirs acoustical properties will be presented. The theoretical view on the inner structure is completed by two measuring methods: scanning acoustic microscopy as well as computed tomography. Furthermore, the effective mechanical displacement of the transducer interface will be analyzed by Laser Doppler vibrometry. Hence, the individual vibration behaviour of the single elements can be compensated which yields an optimized superposition. To investigate the second assumption the 4D-CEFIT-PSS simulation environment has been developed. The combination of CEFIT (cylindric elasto dynamic finite integration technique) and PSS (point source synthesis) considers all effects of wave physics. A comprehensive parametric study shows the effects of geometrical aperture size concerning resulting signals in decided focal points. The differences of wave propagation in the time and frequency domain will be pointed out. Concluding, focal laws were calculated with the geometrical and the simulation based approach. The resulting wave propagation is simulated for selected focal points. The results were compared both ways, qualitatively and quantitatively. Hereby the difference between both methods was distinguishable. The outcome is a method for modified focal law calculation. Both, the consideration of the individual vibration characteristics and the application of the new focal laws result in higher signal-to-noise ratios for linear phased arrays
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Leleux, Alban. "Contrôle non destructif de composites par ondes ultrasonores guidées, générées et détectées par multiéléments." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14623/document.
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Une technique de Contrôle Non Destructif (CND) a été développée, permettant la génération et la détection d’ondes de Lamb guidées le long de grandes plaques constituées de différents matériaux (métal, polymère ou composite renforcé par des fibres). Basée sur l’emploi de nombreux éléments étroitement couplés à la plaque, cette technique d’inspection diffère du Structural Health Monitoring (SHM) classique car tous les éléments émetteurs ou récepteurs sont regroupés dans une zone très localisée, définie par la surface active d’une sonde multiélément matricielle, et ne sont pas fixés de manière permanente et distribuée au sein, ou en surface, de la structure testée. De plus, le principe (connu) du déphasage entre éléments est appliqué à la sonde pour la génération et la réception d’un mode de Lamb pur dans (ou provenant) de multiples directions le long de la plaque. Les lois de retards appliquées à ces éléments, aussi bien lorsque la sonde fonctionne en mode émission qu’en mode réception, prennent en compte la nature dispersive de l’onde de Lamb. Enfin, un traitement de signal spécifique est appliqué pour compenser la dispersion subie par les ondes guidées au cours de leur propagation le long de la pièce testée. Un prototype expérimental et sa modélisation par éléments finis sont présentés, ainsi que les mesures et les résultats simulés de ses performances en termes de sélectivité modale et de directivité angulaire. Concernant les applications de CND, la construction d’images, représentatives de toutes les parties de la pièce testée qui diffractent le mode guidé (bord de pièce, défauts, trous, raidisseurs, etc.), a permis de démontrer le potentiel (et quelques limites) de cette technique vis-à-vis d’une inspection rapide de grandes structures, y compris de zones éloignées de la sonde ou encore de zones difficiles d’accèsA technique of Non-Destructive Testing (NDT) was developed for the generation and detection of Lamb waves propagating along large plates made of different materials (metal, polymer or fibre-reinforced composite). Based on the use of many elements closely coupled to the plate, this inspection technique differs from the classic Structural Health Monitoring (SHM) because all the transmitters or receivers are grouped in a very localized area, defined by the active surface of a phased array matrix probe, and are not permanently attached and distributed within or on the surface of the test structure. In addition, the principle (known) of the phase shift between the elements is applied to the probe for generating and receiving a pure Lamb mode in (or from) multiple directions along the plate. The delay laws applied to these elements, in transmit mode or receive mode, take into account the dispersive nature of the Lamb wave. Finally, a specific signal processing is applied to compensate the dispersion suffered by the guided waves during their propagation along the test piece. An experimental prototype and its finite element modeling are presented, as well as measurements and simulation results of its performances in terms of modal selectivity and angular directivity. For NDT applications, the construction of images, representing all parts of the test piece, which diffract the guided mode (edges, defects, holes, stiffeners, etc.), has demonstrated the potential (and some limits) of this technique for a quick inspection of large structures, including areas remote from the probe or areas difficult to access
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Xie, Yuedong. "Modelling techniques and novel configurations for meander-line-coil electromagnetic acoustic transducers (EMATs)." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/modelling-techniques-and-novel-configurations-for-meanderlinecoil-electromagnetic-acoustic-transducers-emats(78777548-e2c6-468f-9a4b-12daaa29b53c).html.
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Electromagnetic acoustic transducers (EMATs) are increasingly used in industries due to their attractive features of being non-contact, cost-effective and the fact that a variety of wave modes can be generated, etc. There are two major EMATs coupling mechanisms: the Lorentz force mechanism for conductive materials and the magnetostriction mechanism for ferromagnetic materials; EMATs operated on Lorentz force mechanism are the focus of this study. This work aims to investigate novel efficient modelling techniques for EMATs, in order to gain further knowledge and understanding of EMATs wave pattern, how design parameters affect its wave pattern and based on above propose and optimise novel sensor structures. In this study, two novel modelling methods were proposed: one is the method combining the analytical method for EM simulation and the finite-difference time-domain (FDTD) method for US simulation for studying the Rayleigh waves' properties on the vertical plane of the material; the other one is the method utilizing a wholly analytical model to explore the directivity of surface waves. Both simulations models have been validated experimentally. The wholly analytical model generates the radiation pattern of surface waves, which lays a solid foundation for the optimum design of such sensors. The beam directivity of surface waves was investigated experimentally, and results showed the length of wires has a significant effect on the beam directivity of Rayleigh waves. A novel configuration of EMATs, variable-length meander-line-coil (VLMLC), was proposed and designed. The beam directivity of surface waves generated by such novel EMATs were analytically investigated. Experiments were conducted to validate such novel EMATs models, and results indicated that such EMATs are capable of supressing side lobes, and therefore resulting in a more concentrated surface waves in the desired direction. Further, another two novel configuration of EMATs, the four-directional meander-line-coil (FDMLC) and the six-directional meander-line-coil (SDMLC), were proposed and designed; results showed these EMATs are capable of generating Rayleigh waves in multiple directions and at the same time suppressing side lobes.
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Попович, О. В. "Удосконалення акустичних методів визначення типів та розмірів дефектів металоконструкцій." Thesis, Івано-Франківський національний технічний університет нафти і газу, 2016. http://elar.nung.edu.ua/handle/123456789/4841.
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Дисертація присвячена удосконаленню акустичних методів визначення типів та розмірів дефектів типу «порушення цілісності» металоконструкцій тривалої експлуатації. Виконано аналіз фактичного стану металоконструкції) довготривалої експлуатації і проблем, що виникають в процесі їх експлуатації, та методів контролю. Аналіз неруйнівних методів контролю для виявлення та визначення розмірів внутрішніх дефектів металоконструкцій показав, що ультразвукові методи контролю є найбільш інформативними, але потребують достатнього досвіду оператора для розшифрування результатів контролю. Для оцінки технічного стану металоконструкцій, виявлення порушень суцільності і визначення їх типу та розмірів, необхідно підвищити інформативність ультразвукового контролю та спростити процес прийняття рішень, шляхом використання ультразвукових фазованих решіток (УЗФР) та когерентної обробки результатів контролю. Проведено дослідження параметрів перетворювачів УЗФР, які забезпечують високу чутливість і підвищення продуктивності ультразвукового контролю для контролю металоконструкцій. Проведено експериментальне підтвердження теоретичних досліджень підвищення чутливості та інформативності контролю за допомогою УЗФР. Розроблено методику визначення роздільної здатності та чутливості УЗФР. Розроблено методику проведення експериментальних досліджень промислових об’єктів за допомогою розробленого методу контролю з УЗФР і методики виявлення та визначення типу дефектів порушення суцільності.В первой главе выполнен анализ фактического состояния металлоконструкций долговременной эксплуатации и проблем, возникающих в процессе их эксплуатации, и методов контроля. Анализ неразрушающих методов контроля для выявления и определения размеров внутренних дефектов металлоконструкций показал, что ультразвуковые методы контроля являются наиболее информативными, но нуждаются достаточного опыта оператора для расшифровки результатов контроля. Для оценки технического состояния металлоконструкций, выявление нарушений целостности и определения их типа и размеров, необходимо повысить информативность ультразвукового контроля и упростить процесс принятия решений, путем использования ультразвуковых фазированных решеток (УЗФР) и когерентной обработки результатов контроля. Второй раздел посвящен исследованию параметров преобразователей УЗФР, которые обеспечивают высокую чувствительность и повышение производительности ультразвукового контроля объектов сложной формы, в т.ч. трубных изделий. Проведено исследование основных параметров УЗФР (количество элементов, расстояние между ними, временные задержки). С целью выбора параметров УЗФР, обеспечивающие наивысшую концентрацию ультразвуковой энергии, генерируемой преобразователем и распространяется в определенном направлении было выполнено графоаналитического исследования акустического поля преобразователей с УЗФР. Для определения характера влияния изменения количества пьезоэлементов в УЗФР на распределение ультразвуковой энергии проводились построение и исследование диаграммы направленности УЗФР. В третьем разделе проведено экспериментальное подтверждение теоретических исследований повышения чувствительности и информативности контроля с помощью УЗФР. Разработан и изготовлен модельный образец сварного соединения с типичными дефектами нарушения целостности, проведены экспериментальные исследования и определены диагностические признаки объемных и плоских дефектов. Разработана методика определения разрешения и чувствительности УЗФР. Для повышения информативности контроля металлоконструкций был предложен новый подход к ультразвуковому контролю с использованием УЗФР, результатом которого является получение и обработка двумерных изображений внутреннего объема изучаемого объекта, сформированные характеристики акустических изображений для классификации дефектов на плоские и объемные. В четвертом разделе представлена методика проведения экспериментальных исследований промышленных объектов с помощью разработанного метода контроля с УЗФР и методики выявления и определения типа дефектов нарушения целостности.
The thesis is devoted to improvement of acoustic methods for determining and real sizes of defects in long term operation metal constructic. The analysis of the actual state of the hardware operation their use, and methods of control were conducted. Analysis methods for internal defects of steel structures detection and determination showed that ultrasonic control methods are most informative, but require sufficient experience of the operator to decrypt test results. There is a need to improve ultrasonic testing information and simplify decisionmaking by using ultrasound phased arrays with coherent processing results and control to evaluate die technical condition of hardware, discontinuities detection and determine their type and size. Research options of ultrasonic phased array provide high sensitivity and improved performance for metal construction control. The experimental confirmation of theoretical studies sensitization and information content control through were held. The method of determining ultrasonic phased array resolution and sensitivity is proposed. The method of experimental studies of industrial facilities using the proposed method of control with ultrasonic phased array and methods of detection and determination of such defects discontinuity were developed.
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Hosseini, S. "Electronically focused ultrasonic transmitting arrays." Thesis, University of Portsmouth, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305749.
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This work describes a thirty-two channel programmable transmitter unit for driving an ultrasonic transmitting array using transducers with thickness resonances of up to 2 MHz. It has been developed to allow the performance of time delay focussed transmitting arrays to be thoroughly investigated before their eventual use in an imaging system. The unit will produce a pulse or continuous wave output which is programmable using either a microprocessor or a computer, in both amplitude and delay or phase. The unit's operation is discussed in some detail and the experimental underwater 1 MHz transducer array used for the functional tests is described. Results are presented showing the performance of the transmitting unit when used with this array and demonstrate that the system provides an effective tool by which a proper assessment of time delay focussing may be made. A computer prediction technique·has been introduced. The computer prediction of the field in the region in front of a focussed ultrasonic array has been obtained by the summation of the fields due to the individual array elements. The shape of the short duration acoustic pulses due to the individual elements is determined.by the electrical drive and transducer characteristics. The prediction technique is valid for any pulse shape which can be represented mathematically, however the results presented here have been limited to the pulse shape used in the experimental work. The algorithm used is suitable for a wide range of array formations and the close agreement of the practical and the simulation work shows the validity of the prediction technique. The experimental array has been used as the basis of a detailed investigation into the resolving power of focussed arrays and a number of results have been derived from this investigation. These are used to support extensive simulation studies and computer prediction techniques. The validity of the simulation techniques is assessed and the effect of considering each transducer in the array as a single small but finite sized centrally placed element is compared with that where each transducer is represented by a number of synchronously driven Huygens radiators. The significance of these results with respect to imaging is discussed. The effect on performance of system error is investigated and an assessment of the tolerance of the time delay technique to these errors is made.
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Neild, Adrian. "Ultrasonic air-coupled capacitive arrays." Thesis, University of Warwick, 2003. http://wrap.warwick.ac.uk/2663/.
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A model is developed which is capable of predicting the pressure field of a rectangular source, as measured by a finite-sized receiver. This novel method treats the problem in a new way, which allows an integration to be performed over the area of the receiver. Previously it has only been possible to model two circular transducers coaxially aligned. The model is used to identify a receiver, which can be used to measure the highly focussed pressure field from a phased array, with only a negligible effect due to the receiver size. Productions from the model are compared to experimental data, and show a good correlation. A parabolic mirror used to focus the field from a circular device in air has been studied, and a model developed to predict the pressure field produced by this device. This is done by an approximation of the mirror surface to a grid of finely spaced points. The model correlates well with measured results. In addition, an image of a defect in a solid sample was produced. Arrays are then used to image solid samples in air. This is done using three techniques. The first is a combined phased source and receiver, which is shown to locate a wire accurately and to measure a step in the surface of a sample. A 2-D array is shown to image a defect in a composite plate, and the potential for a fast through-transmission air-coupled system is indicated. In addition, two post-processing techniques are used on data recorded using an array receiver, to locate an object in air. Of these two techniques, ellipse crossing is shown to have better results for large signal to noise ratios, and SAFT for lower ratios. The combination of theoretical modelling and experimental observations has indicated that the transducers and arrays constructed for use in air are well-understood, and that their characteristics can be predicted.
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Vasseur, Julien. "Fiabilité prévisionnelle de la tenue en service de composants mécaniques en présence d’amas de porosités détectés et caractérisés par contrôle non destructif ultrasonore." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2020. http://www.theses.fr/2020MTLD0002.
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Ces travaux de thèse ont pour objectif de définir une méthodologie permettant d’estimer de manière réaliste la durée de vie d’une structure en alliage d’aluminium (aluminium 7075-T6) contenant des amas porosités. Le choix technique retenu vise à détecter et caractériser ces porosités au moyen de contrôles non destructifs (CND) par ultrasons et de corréler les images ultrasonores obtenues à des mesures de fatigue. Dans le cadre de nos travaux, ce problème est ramené à une étude 2D où l’amas de porosités est représenté par un ensemble de trous-génératrices usinés, dont les caractéristiques géométriques sont totalement contrôlables, contrairement à celles de la porosité réelle. En partie ultrasonore, un effort particulier est apporté dans la prise en compte des effets de diffusion multiple existant entre les défauts lors du contrôle. Une étude comparative du modèle d’imagerie ainsi développé est menée en confrontant nos simulations à d’autres simulations d’imagerie simplifiées (effectuées sur le logiciel CIVA) mais également à des mesures expérimentales. En partie fatigue, une résolution d’un cas très complexe s’avère nécessaire, puisqu’il implique des possibilités de multi-amorçage et de couplage local de modes de sollicitation. Ce problème de la propagation de la fissure en fatigue est résolu par la méthode G-Ө. Nous montrons l’efficacité de la méthodologie employée en comparant les résultats de durée de vie qu’elle permet de prédire et ceux trouvés expérimentalement par essais de fatigue. Enfin, afin de faire le lien entre le domaine du CND et celui de la mécanique de la rupture, nous présentons une méthode permettant d’estimer la tenue en fatigue d’une éprouvette au vu de son imagerie obtenue suite à son contrôle ultrasonore. Cette démarche permet ainsi de proposer une méthodologie originale couplant le contrôle ultrasonore et la fatigue, en mettant en place un chaînage entre les deux domaines pour la fiabilisation de la prédiction de la durée de vie des structures en fatigueThis work aims at defining a methodology for the lifetime estimation of aluminum alloy structures (aluminum 7075-T6) according to the properties of porosity clusters contained in the sample. We chose to use advanced ultrasonic imaging techniques to detect and characterize these porosities and then to correlate the ultrasonic images obtained with fatigue measurements. In the framework of our study, the problem is simplified with a 2D study where the cluster of porosities is represented as a set of side-drilled holes (SDH) whose geometric characteristics are fully controllable, unlike those of real porosity. A special effort is made to estimate the effects of multiple scattering due to wave interactions between defects. A comparative study of the imaging model thus developed is carried out by comparing our simulations including multiple scattering with other simplified simulation results (carried out on CIVA software) but also with experimental measurements. Concerning fatigue study, a phenomenological approach is suggested to take into account multi-cracks initiation and local multi-mode behaviour generated by the cluster of defects. Therefore, crack propagation is solved by a G-Ө finite element method for prediction of the fatigue lifetime of different samples with different cases of cluster of defects. Numerical and experimental results were compared showing that the suggested methodology gives realistic lifetimes despite of complexity of the studied cases. Finally, the overall originality of this thesis consists in making a direct link between NDT results and fatigue calculation. Thus, a method for estimating the fatigue life of a specimen based on inversed ultrasonic images of defects is suggested and applied on some studied cases
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Aschy, Ameni. "Imagerie ultrasonore de strucutres composites hétérogènes." Thesis, Le Mans, 2018. http://www.theses.fr/2018LEMA1008.
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Ce travail de thèse a pour objectif de développer une méthodologie visant à imager les défauts dans les structures composites moyennant les ultrasons multiéléments. Plus précisément, la motivation essentielle réside dans la difficulté d’application des méthodes ultrasonores conventionnelles pour le contrôle de structures composites épaisses et hétérogènes. En effet, l’application de ces méthodes est d’autant plus difficile en présence d’anisotropie structurelle où les paramètres vitesse et atténuation changent de façon importante en fonction du trajet ultrasonore considéré. Cela pourrait même se compliquer en présence de dispersion fréquentielle des propriétés viscoélastiques du matériau composite. Les méthodes d’imagerie étudiées sont appliquées dans le cas de structures composites hétérogènes de forte épaisseur. Dans un premier temps, les paramètres vitesse et atténuation des ondes élastiques de volume se propageant dans le composite sous différentes incidences ont été déterminées.Ce travail a également permis de remonter aux caractéristiques viscoélastiques par méthode inverse.Les différents paramètres trouvés par méthodes directe et inverse sont ensuite intégrés au modèle direct de calcul de trajets ultrasonores pour corriger les effets d’anisotropie dans l’imagerie Total Focusing Method (TFM) et Plane Wave Imaging (PWI) et étudier ainsi les possibilités d’amélioration de la détection et de la caractérisation des défauts pouvant exister au sein des structures composites étudiées. Enfin, il est important de souligner que ce même travail discute de la nécessité de connaître le tenseur d’élasticité pour une prise en compte optimale de l’anisotropie. À cet effet, une comparaison avec un modèle simplifié mettant en jeu les vitesses de groupe est proposéeThis work aims to develop a methodology to image defects in composite structures by using Phased Array ultrasonic techniques. More specifically, the essential motivation lies in the difficulty of applying conventional ultrasonic methods for the control of thick and heterogeneous composite structures. Indeed, the application of these methods is more difficult in the presence of structural anisotropy where the velocity and the attenuation parameters change significantly depending on the ultrasound considered path. This could be more complicated in the presence of the viscoelastic properties frequency dispersion of the composite material. The studied imaging methods are applied in the case of heterogeneous and thick composite structures. First, the velocity and attenuation parameters of the elastic volume waves propagating in the composite under different incidences is determined. This work also allowed to go back to the viscoelastic characteristics by inverse method. The various parameters found by direct and inverse methods are then integrated into the direct ultrasound path calculation model to correct the anisotropy effects in the Total Focusing Method (TFM) and Plane Wave Imaging (PWI) imagery and thus to study the possibilities of improvement of the detection and characterization of defects that may exist within the studied composite structures. Finally, it is important to emphasize that this same work discusses the need of the tensor of elasticity for an optimal characterization of the anisotropy. For this purpose, a comparison with a simplified model involving group velocity is proposed
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Pao, Tsang-Long. "Ultrasonic tapered phased arrays for three-dimensional imaging." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/13541.
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Pomeroy, Simon. "Ultrasonic phased arrays for robotics modelling and experimental implementation." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254469.
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Munro, W. S. H. "Ultrasonic phased arrays for use in imaging and automatic vehicle guidance." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334215.
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Campbell, M. A. "An evaluation of monolithic phased arrays for Non destructive testing." Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381502.
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Yoon, Young Joong. "Ultrasonic phased arrays with variable geometric focusing for hyperthermia applications." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/16969.
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Azar, Lawrence 1973. "Ultrasonic phased arrays of the condition assessment of concrete structures." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50432.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.Vita.
Includes bibliographical references (leaves 107-112).
by Lawrence Azar.
S.M.
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Dziewierz, Jerzy. "2D ultrasonic phased arrays for quantitative characterisation of complex defects." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26012.
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Ultrasonic inspection can be consideredas one of many ways the technical system - installation or vehicle - can be made economical and safe. Contemporary ultrasonic systems are capable of detecting a wide variety of mechanical defects and flaws that may or may not affect the operation of a given product. Ultrasonic testing techniques are widely accepted for quality control and material testing. Moreover, the technology is proven, well-understood and widely used. Upon detecting a flaw, a decision has to be made to ensure the component is fit for the purpose: is the flaw acceptable or is repair of the given part or its replacement? Here, 2D ultrasonic phased arrays hold promise to quickly deliver detailed, 3D resolved information about the extent and nature of the flaw. This information can then be used to develop and justify the technical and economic decision concerning the existing state of the product. In effect, an opportunity exists for significant cost savings by using ultrasonic 2D phased array systems for defect characterisation. The interest of the work is to establish a process of designing and manufacturing of piezoelectric, 2D phased array ultrasound probes for application in non-destructive evaluation of materials. Furthermore, implementation of practical signal processing method is investigated. In the first part of the work the sensor mechanical and electrical design is addressed. The properties of piezoelectric ceramic composite materials are studied. Detailed numerical models have been used to analyse conditions required for crafting materials of desirable properties. A novel technique has been demonstrated that allows design of well-behaved triangular cut piezoelectric composite. Built into a single array element (of hexagonal shape by taking 6 triangular pillars) this new composite exhibits properties comparable to a reference rectangular composite (sensitivity of 0.60nm/V for hexagonal, 0.62nm/V for square; and inter-element crosstalk of -21.2dB for hexagonal and -21.9dB for square element). This composite then allows building of compact, dense-layout 2D phased array transducers with hexagonal or sparse element layout. The benefits of hexagonal element layout over classic, rectangular layout have been analysed theoretically and showed to be beneficial. Importantly, using hexagonal elements enables increasing the aperture of individual array elements by approximately 10% without the corresponding drop in acceptance angle. This in turn allows a commensurable rise in the sensitivity of the sensor or alternatively, reduction in array element count for a given overall array aperture by over 20% without the corresponding drop in the image quality measurements/levels. In the second part of the work, the problem of high output impedance of the miniature ultrasonic sensor is addressed by means of an in-probe miniature signal conditioning circuit. This improved the response amplitude of the element by 36dB and shortened its impulse response by a factor of 1.6. The novelty and practical benefit in this case lies in the fact that no high power components are needed in the probe body. In the third part of this work, an emerging General-Purpose Graphics Processing Unit (GPGPU) computer architecture is considered for the opportunities it offers to rethink the implementation of algorithms typically used in ultrasonic signal processing. Single-way beamforming, and two-way TFM and PCF beamforming have been developed for execution on the new platform, and show increase in performance of over 930 times compared to CPU processor. This software platform has been further enhanced by a new approach to solving the refracted ray Time of Flight problem in a way that is particularly well suited for this architecture. This resulted in a further increase of performance, i.e. 56x over the best published result found in the literature. The unprecedented performance and low cost of this new approach enables industrial deployment of advanced beamforming methods, as well as building of practical CAD tools for engineering and education.