Thèses sur le sujet « Ultrasonic array »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « Ultrasonic array ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
Wang, Ji-yong 1967. « Hybrid ultrasonic array ». Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/84216.
Texte intégralFelice, Maria Victoria. « Ultrasonic array inspections for complex defects ». Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687061.
Texte intégralNadkarni, 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/.
Texte intégralPoon, 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.
Texte intégralSmith, Peter Raymond. « Ultrasonic phased array techniques using switched-mode excitation ». Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/4570/.
Texte intégralDuxbury, David. « Calibration and control of advanced ultrasonic array technology ». Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/27618.
Texte intégralBowler, 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.
Texte intégralQian, Yichen. « Design of high frequency ultrasonic array transducers for medical imaging ». Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/336225/.
Texte intégralRussell, Jonathan. « The development and implementation of advanced ultrasonic phased array technology ». Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5684.
Texte intégralZeng, Xiaozheng. « Ultrasound phased array simulations for hyperthermia ». Diss., Connect to online resource - MSU authorized users, 2008.
Trouver le texte intégralMedina, 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.
Texte intégralPurekar, 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.
Texte intégralThesis 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.
Luker, L. Dwight. « Investigation of a cylindrical nonacoustic-wavenumber calibration array ». Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15885.
Texte intégralBattle, David John. « Maximum Entropy Regularisation Applied to Ultrasonic Image Reconstruction ». University of Sydney. Electrical Engineering, 1999. http://hdl.handle.net/2123/842.
Texte intégralWan, 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/.
Texte intégralTitle from title screen. Keywords: optimal design; modeling; object identification; ultrasound pulse-echo system; annular array. Includes bibliographical references (p. 159-162).
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.
Texte intégralFundação 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
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.
Texte intégralBlum, 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.
Texte intégralDeRidder, 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.
Texte intégralForbes, 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.
Texte intégralTyler, 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.
Texte intégralLane, 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.
Texte intégralBaiotto, 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.
Texte intégralThe 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.
Okumura, Shigeaki. « Array Signal Processing for Accurate Medical Ultrasound Measurements ». Kyoto University, 2018. http://hdl.handle.net/2433/232419.
Texte intégralLukacs, 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.
Texte intégralHall, James Stroman. « Adaptive dispersion compensation and ultrasonic imaging for structural health monitoring ». Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41159.
Texte intégralEngholm, 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.
Texte intégralMartinez, Garcia Jairo Andres. « A Novel Ultrasonic Method to Quantify Bolt Tension ». Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4145.
Texte intégralOsman, Ahmad. « Automated evaluation of three dimensional ultrasonic datasets ». Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00995119.
Texte intégralLorentzon, 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.
Texte intégralWAN, Li. « Modeling and Optimal Design of Annular Array Based Ultrasound Pulse-Echo System ». Digital WPI, 2001. https://digitalcommons.wpi.edu/etd-theses/219.
Texte intégralChou, 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.
Texte intégralPrado, 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.
Texte intégralCo-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
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.
Texte intégralSin 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.
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/.
Texte intégralGommlich, 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.
Texte intégralUltrasonic 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
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.
Texte intégralA 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
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.
Texte intégralПопович, 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.
Texte intégralВ 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.
Hosseini, S. « Electronically focused ultrasonic transmitting arrays ». Thesis, University of Portsmouth, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305749.
Texte intégralNeild, Adrian. « Ultrasonic air-coupled capacitive arrays ». Thesis, University of Warwick, 2003. http://wrap.warwick.ac.uk/2663/.
Texte intégralVasseur, 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.
Texte intégralThis 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
Aschy, Ameni. « Imagerie ultrasonore de strucutres composites hétérogènes ». Thesis, Le Mans, 2018. http://www.theses.fr/2018LEMA1008.
Texte intégralThis 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
Pao, Tsang-Long. « Ultrasonic tapered phased arrays for three-dimensional imaging ». Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/13541.
Texte intégralPomeroy, 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.
Texte intégralMunro, 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.
Texte intégralCampbell, 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.
Texte intégralYoon, Young Joong. « Ultrasonic phased arrays with variable geometric focusing for hyperthermia applications ». Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/16969.
Texte intégralAzar, 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.
Texte intégralVita.
Includes bibliographical references (leaves 107-112).
by Lawrence Azar.
S.M.
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.
Texte intégral