Littérature scientifique sur le sujet « Non-Destructive Techniques (NDTs) »
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Articles de revues sur le sujet "Non-Destructive Techniques (NDTs)"
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Roselli, Ivan, Angelo Tatì, Vincenzo Fioriti, Irene Bellagamba, Marialuisa Mongelli, Roberto Romano, Gerardo De Canio, Mariarosaria Barbera et Marina Magnani Cianetti. « Integrated approach to structural diagnosis by non-destructive techniques : the case of the Temple of Minerva Medica ». ACTA IMEKO 7, no 3 (24 octobre 2018) : 13. http://dx.doi.org/10.21014/acta_imeko.v7i3.558.
Texte intégralRésumé :
In the present paper an integrated approach of a wide range of non-destructive tests (NDTs) was applied to study an archeological ruined building located in Rome, the so-called Temple of Minerva Medica. Applied NDTs focused on the monument properties and environmental conditions affecting its structural behavior (geometry, thermal and mechanical properties, microclimatic monitoring, ambient vibration response). Two surveys were performed in August and December 2016 combining 3D laser scanning, thermal infrared, air temperature and relative humidity acquisitions. In addition, high resolution digital images were acquired and processed by stereo-photogrammetry Structure from Motion (SfM) methodology, carried out for detailed reconstruction of the crack pattern of the monument. In order to obtain information on the integrity and consistency of the masonry, a sonic testing of each pillar was also performed. The integration of the above NDTs provided quite complete and comprehensive understanding of the structural behavior and state of the building, reducing the amount of invasive measurements further needed.
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Salvatici, Teresa, Sara Calandra, Irene Centauro, Elena Pecchioni, Emanuele Intrieri et Carlo Alberto Garzonio. « Monitoring and Evaluation of Sandstone Decay Adopting Non-Destructive Techniques : On-Site Application on Building Stones ». Heritage 3, no 4 (6 novembre 2020) : 1287–301. http://dx.doi.org/10.3390/heritage3040071.
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This paper focuses on the characterization approach to evaluate the decay state of Pietra Serena of historic buildings in Florence (Italy). Pietra Serena is a Florentine sandstone largely used in the city especially during the Renaissance; it is a symbol of cultural heritage of Florence and constitutes a large part of the city center, which was named a World Heritage Site by UNESCO in 1982. Unfortunately, many environmental factors negatively affect the stone, increasing damage and the danger of falling material. Any detachment of stone fragments, in addition to constitute a loss in cultural heritage, can be dangerous for citizens and the many tourists that visit the city. The use of non-destructive techniques (NDTs) as ultrasonic and Schmidt hammer tests can quantitatively define some mechanical properties and help to monitor the decay degree of building stone. In this study, the NDTs were combined with mineralogical, petrographical, chemical and physical analyses to investigate the stone materials, in order to correlate their features with the characteristics of the different artefacts in Pietra Serena. Correlations between the NDTs results and the compositional characteristics of the on-site stone were carried out; such discussion allows to identify zones of weakness and dangerous unstable elements.
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Civera, Marco, et Cecilia Surace. « Non-Destructive Techniques for the Condition and Structural Health Monitoring of Wind Turbines : A Literature Review of the Last 20 Years ». Sensors 22, no 4 (18 février 2022) : 1627. http://dx.doi.org/10.3390/s22041627.
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A complete surveillance strategy for wind turbines requires both the condition monitoring (CM) of their mechanical components and the structural health monitoring (SHM) of their load-bearing structural elements (foundations, tower, and blades). Therefore, it spans both the civil and mechanical engineering fields. Several traditional and advanced non-destructive techniques (NDTs) have been proposed for both areas of application throughout the last years. These include visual inspection (VI), acoustic emissions (AEs), ultrasonic testing (UT), infrared thermography (IRT), radiographic testing (RT), electromagnetic testing (ET), oil monitoring, and many other methods. These NDTs can be performed by human personnel, robots, or unmanned aerial vehicles (UAVs); they can also be applied both for isolated wind turbines or systematically for whole onshore or offshore wind farms. These non-destructive approaches have been extensively reviewed here; more than 300 scientific articles, technical reports, and other documents are included in this review, encompassing all the main aspects of these survey strategies. Particular attention was dedicated to the latest developments in the last two decades (2000–2021). Highly influential research works, which received major attention from the scientific community, are highlighted and commented upon. Furthermore, for each strategy, a selection of relevant applications is reported by way of example, including newer and less developed strategies as well.
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Lerma, Carlos, Júlia G. Borràs, Ángeles Mas, M. Eugenia Torner, Jose Vercher et Enrique Gil. « Evaluation of Hygrothermal Behaviour in Heritage Buildings through Sensors, CFD Modelling and IRT ». Sensors 21, no 2 (14 janvier 2021) : 566. http://dx.doi.org/10.3390/s21020566.
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Architectural heritage, building materials and interior space are highly susceptible to temperature and relative humidity. A better knowledge of the hygrothermal dynamics inside buildings allows an adequate conservation of heritage. This work compares three non-destructive techniques (NDT), such as temperature and relative humidity sensors, finite element simulations (CFD) and thermographic pictures (IRT). The work has made it possible to carry out an assessment of the risk of condensation over a year and to identify affected periods and areas of the building. Sensors and IRT pictures provide real data to validate CFD simulations, facilitating a global analysis of the building. The results provided reflect a great concordance between the NDTs used.
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Qin, Renyuan, Denvid Lau, Lik-ho Tam, Tiejun Liu, Dujian Zou et Ao Zhou. « Experimental Investigation on Interfacial Defect Criticality of FRP-Confined Concrete Columns ». Sensors 19, no 3 (24 janvier 2019) : 468. http://dx.doi.org/10.3390/s19030468.
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Defects between fiber reinforced polymer (FRP) and repaired concrete components may easily come out due to misoperation during manufacturing, environmental deterioration, or impact from external load during service life. The defects may cause a degraded structure performance and even the unexpected structural failure. Different non-destructive techniques (NDTs) and sensors have been developed to assess the defects in FRP bonded system. The information of linking up the detected defects by NDTs and repair schemes is needed by assessing the criticality of detected defects. In this study, FRP confined concrete columns with interfacial defects were experimentally tested to determine the interfacial defect criticality on structural performance. It is found that interfacial defect can reduce the FRP confinement effectiveness, and ultimate strength and its corresponding strain of column deteriorate significantly if the interfacial defect area is larger than 50% of total confinement area. Meanwhile, proposed analytical model considering the defect ratio is validated for the prediction of stress–strain behavior of FRP confined columns. The evaluation of defect criticality could be made by comparing predicted stress–strain behavior with the original design to determine corresponding maintenance strategies.
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Sanchez-Roda, Alejandra, Belén Oliva-Urcia et Miguel Gomez-Heras. « The Use of Magnetic Susceptibility as a Technique to Measure the Impact of Wildfires on Archaeological Heritage ». Applied Sciences 12, no 19 (6 octobre 2022) : 10033. http://dx.doi.org/10.3390/app121910033.
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Wildfires are one of the main threats of natural areas and often fires can affect protected or heritage areas and properties, in which the preservation requirements demand the use of non-destructive techniques (NDTs). The magnetic susceptibility is an NDT that provides information on the mineralogical composition of the materials but has never been applied to the evaluation of fires. Here, we combine laboratory with field analysis to test the applicability of the magnetic susceptibility for the assessment of the impacts of wildfires. The laboratory results showed an increase in the magnetic susceptibility with the temperature, more evident in the samples heated to 600 °C and above. The in situ measures revealed a spatial variation in the magnetic susceptibility, which was related to the behaviour of the fire in the area. The samples were later analysed with other magnetic destructive techniques that were used to confirm the mineralogical processes that occurred in the materials. The increase in the susceptibility values were due to the formation of iron oxides. The destructive analysis also showed the presence of minerals such as hematite and magnetite in the samples. Overall, the study allowed a first approach to test the magnetic susceptibility as a simple and fast way to measure the impacts of wildfires.
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Villasante, Antonio, Guillermo Íñiguez-González et Lluis Puigdomenech. « Comparison of various multivariate models to estimate structural properties by means of non-destructive techniques (NDTs) in Pinus sylvestris L. timber ». Holzforschung 73, no 4 (24 avril 2019) : 331–38. http://dx.doi.org/10.1515/hf-2018-0103.
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AbstractThe predictability of modulus of elasticity (MOE), modulus of rupture (MOR) and density of 120 samples of Scots pine (Pinus sylvestrisL.) were investigated using various non-destructive variables (such as time of flight of stress wave, natural frequency of longitudinal vibration, penetration depth, pullout resistance, visual grading and concentrated knot diameter ratio), and based on multivariate algorithms, applying WEKA as machine learning software. The algorithms used were: multivariate linear regression (MLR), Gaussian, Lazy, artificial neural network (ANN), Rules and decision Tree. The models were quantified based on the root-mean-square error (RMSE) and the coefficient of determination (R2). To avoid model overfitting, the modeling was built and the results validated via the so-called 10-fold cross-validation. MLR with the “greedy method” for variable selection based on the Akaike information metric (MLRak) significantly reduced the RMSE of MOR and MOE compared to univariate linear regressions (ULR). However, this reduction was not significant for density prediction. The predictability of MLRak was not improved by any other of the tested algorithms. Specifically, non-linear models, such as multilayer perceptron, did not contribute any significant improvements over linear models. Finally, MLRak models were simplified by discarding the variables that produce the lowest RMSE increment. The resulted models could be even further simplified without significant RMSE increment.
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Abdelkader, Eslam Mohammed, Mohamed Marzouk et Tarek Zayed. « Mapping Ground Penetrating Radar Amplitudes Using Artificial Neural Network and Multiple Regression Analysis Methods ». International Journal of Strategic Decision Sciences 10, no 2 (avril 2019) : 84–106. http://dx.doi.org/10.4018/ijsds.2019040105.
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Bridges are aging and deteriorating. Thus, the development of Bridge Management Systems (BMSs) became imperative nowadays. Condition assessment is one of the most critical and vital components of BMSs. Ground Penetrating Radar (GPR) is one of the non-destructive techniques (NDTs) that are used to evaluate the condition of bridge decks which are subjected to the rebar corrosion. The objective of the proposed method is to develop standardized amplitude scale for bridge decks based on a hybrid optimization-decision making model. Shuffled frog leaping algorithm is employed to compute the optimum thresholds. Then, polynomial regression and artificial neural network models are designed to predict the prioritizing index based on a set of multi-criteria decision-making methods. The weibull distribution is utilized to capture the stochastic nature of deterioration of concrete bridge decks. Lastly, a case study is presented to demonstrate the capabilities of the proposed method.
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Proietti, Noemi, Paola Calicchia, Francesco Colao, Sara De Simone, Valeria Di Tullio, Loredana Luvidi, Fernanda Prestileo, Martina Romani et Angelo Tatì. « Moisture Damage in Ancient Masonry : A Multidisciplinary Approach for In Situ Diagnostics ». Minerals 11, no 4 (13 avril 2021) : 406. http://dx.doi.org/10.3390/min11040406.
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San Nicola in Carcere, one of the minor basilicas in the historical center of Rome, was the location of a wide investigation campaign of the water-related deterioration causes, present in the lower sector of the apse and adjacent pillars, affected by water infiltrations, mould and salt efflorescence. The results obtained identify the presence of water content and related effects mainly on the sides of the apsidal wall. This work focuses on the use of five Non-Destructive Techniques (NDT) and intends to show the gains obtained by integrating widely interdisciplinary methods, namely the Infrared Thermography (IRT), the Unilateral Nuclear Magnetic Resonance (Unilateral NMR), the Acoustic Tomography (AT), the Acoustic Imaging (AI) and the Laser-Induced Fluorescence (LIF). All the techniques contribute to the rapid, non-invasive and early identification of the moisture distribution, while some of them (LIF and AI) also address the determination of some moisture effects. The integrated use of different techniques helps to take the multidisciplinary point of view necessary to formulate an effective restoration intervention based on a sound scientific rationale; nonetheless, it allows to experiment a holistic approach, verifying the potential of a wide range of NDTs available within the context of a restoration yard.
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Aslam, Huda, Md Maruf Mortula, Sherif Yehia, Tarig Ali et Manreet Kaur. « Evaluation of the Factors Impacting the Water Pipe Leak Detection Ability of GPR, Infrared Cameras, and Spectrometers under Controlled Conditions ». Applied Sciences 12, no 3 (6 février 2022) : 1683. http://dx.doi.org/10.3390/app12031683.
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Leakages from water distribution infrastructures are responsible for a considerable amount of water losses. Consequently, innovative, non-destructive techniques (NDT) of leakage detection for early recognition is vital. In this study, the leak detection abilities of Ground Penetration Radar (GPR), spectrometers, and infrared (IR) cameras were investigated, and the factors affecting the leak detection response were assessed. Three experimental setups were constructed to simulate underground pipes in dune sand. Three different pipe materials (PVC, PPR, and PE) were investigated under three levels of moisture content (MC; 2%, 5%, and 10%) and three types of leaks (hole, crack, and faulty joint). The IR camera was the most effective among the different NDTs used in this study. The IR camera detected all types of leaks at 2% and 5% MC but was inconclusive at 10% MC. Similarly, the GPR detected the leaks at 2% and 5% MC successfully but was inconclusive at 10% MC. Lastly, the spectrometer was the least reliable NDT to detect leaks. Results suggest that IR cameras and spectrometers that operate in the mid-IR range (5–25 µm) can detect leaks.
Thèses sur le sujet "Non-Destructive Techniques (NDTs)"
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Li, Xin. « Eddy current techniques for non-destructive testing of carbon fibre reinforced plastic (CFRP) ». Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/eddy-current-techniques-for-nondestructive-testing-of-carbon-fibre-reinforced-plastic-cfrp(e8aa9a3f-108d-49a4-9f32-2e6118195898).html.
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AbstractThis thesis describes research on the use of eddy current techniques for nondestructivetesting of carbon fibre reinforced plastic (CFRP). The research hasinvolved bulk conductivity testing, fibre direction characterization and 3D FEMmodeling of the CFPR and eddy current probes geometry. In the conductivity testing,how the sample thickness, fibre volume content and fibre conductivity affects thesignal from the eddy current has been evaluated. Eddy current testing shows gooddirectionality as CFRP is an anisotropic material, thus is very suitable to characterizethe fibre orientation. Direction sensitive probes have been developed and tested toreveal information about the fibre direction and layer. Computer FEM software hasbeen used to analyze the magnetic field inside the sample and probes. Specific probegeometries have been designed depending on the electrical properties of thecomposites and testing requirement. The experiment, simulation and analysis resultsshow very good agreement. However, when the measuring frequency increases, noisesand parasitic capacitance inevitably become significant and have a negative influenceon the results. Improvements and further research are proposed which are believed tomake eddy-current techniques a more feasible and efficient measurement method, willcontribute to the development and maintenance of light weight CFRP composites.
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Siu, Frederick Y. K. « Studies of microwaves applications for adhesive, weld joint and NDT technique ». Swinburne Research Bank, 2007. http://hdl.handle.net/1959.3/36854.
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Thesis (MEng) - Swinburne University of Technology, Industrial Research Institute Swinburne - 2007.A thesis submitted for fulfillment of the requirement for the degree of Master of Engineering, Industrial Research Institute, Swinburne University of Technology - 2007. Typescript. Includes bibliographical references (p. 168-193).
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Selim, Hossam. « Hybrid non-destructive technique for volumetric defect analysis and reconstruction by remote laser induced ultrasound ». Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/669481.
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This PhD thesis is devoted to the design, development and implementation of a non-contact hybrid non-destructive testing (NDT) method applied to the analysis of metallic objects that contain embedded defects or fractures. We propose a hybrid opto-acoustic technique that combines laser generated ultrasound as exciter and ultrasound transducers as receivers. This work envisages a detailed study of the detection and one, two or three-dimensional reconstruction of defects, using the proposed hybrid technique and its application as a remotely controlled non-contact NDT. Our device combines several advantages of both photonic and ultrasonic techniques, while reduces some of the drawbacks of both individual methods. Our method relay on the combination of experimental results with high-resolution signal processing procedures based on different mathematical algorithms. Our basic experimental setup uses a nanosecond pulsed laser at 532nm wavelength that impacts onto the surface of the object under study. The laser pulse is rapidly absorbed into a shallow volume of material and creates a localized thermo-elastic expansion inducing a broadband ultrasound pulse that propagate inside the material. The laser beam scans a selected area of the object surface, being remotely controlled by means of a programmable XY scanner. For each excitation point, the ultrasound waves propagate through the object are reflected or scattered by material 3D defects. They are detected by ultrasound transducers and recorded with a PC data-acquisition system for a further process and analysis. As a first step, the time of flight analysis provides enough data for the location and size of the defect in 1D view. The detection capabilities of internal defects in a metallic sample are studied by means of wavelet transform, chosen due to its multi-resolution time-frequency characteristics. A novel algorithm using a density-based spatial clustering is applied to the resulting time frequency maps to estimate the defect’s position. For the 2D visualization and reconstruction of the defects we extended the signal analysis using the synthetic aperture focusing technique (SAFT). We implement a novel 2D apodization window filtering applied along with the SAFT, and we show it removes undesired effects of the side lobes and wide-angle reflections of ultrasound waves, enhancing the reconstructed image of the defect. We move then towards the 3D analysis and reconstruction of defects and in this case we achieve and implement a fully non-contact and automatized experimental configuration allowing the scan areas on different object’s faces. The defect details are recorded from different angles/perspectives and a complete 3D reconstruction is achieved. Finally, we show our results on a complementary topic related to a particular case of the ultrasound propagation in solids. We were concerned on the physical understanding of the propagation and diffraction of ultrasound waves in solid materials from the first moment. The control of the diffraction pattern in solids, using an ultrasonic lens, would help focus/collimate the ultrasound reducing echoes and boundary reflections, resulting in a further improve NDT process. Phononic crystals have been used to regulate the diffraction and frequency response of ultrasonic waves traveling in fluids. However, they were much less studied in solid materials due to the difficulty of building the crystal and to high coupling losses. We perform detailed numerical simulations of the ultrasound propagation in a solid phononic crystal and we show focusing and the self-collimation effects. We further extend our analysis and couple our phononic crystal lens to a solid under study, showing that the diffraction control is preserved inside the target solid object trough the coupling material.Esta tesis doctoral versa sobre el diseño, estudio e implementación de un método híbrido, sin contacto, de ensayos no destructivos (NDT, non-destructive testing) para el análisis de objetos metálicos que contienen defectos o fracturas internas. Proponemos una técnica híbrida opto-acústica que combina ultrasonidos generados por impacto láser como excitador y transductores de ultrasonidos como receptores. El trabajo plantea un estudio detallado de la detección y reconstrucción en 1D, 2D y 3D de defectos presentes en un objeto metálico, usando la técnica híbrida de NDT sin contacto y controlado remotamente. Nuestro dispositivo presenta varias ventajas de las técnicas fotónicas y de ultrasonidos, reduciendo al mismo tiempo algunos inconvenientes de dichos métodos tomados por separado. Nuestro método combina resultados experimentales con simulaciones numéricas basadas en el procesado de señal de alta resolución. El montaje experimental consiste en un láser pulsado de ns a una longitud de onda de 532 nm, que impacta sobre la superficie del objeto. El pulso láser se absorbe, creando una expansión termoelástica localizada que induce un pulso de ultrasonidos de banda ancha que se propaga en el material. El láser, controlado remotamente, realiza un barrido sobre un área seleccionada de la superficie del objeto. Por cada punto de excitación, el ultrasonido se propaga a través del objeto y se refleja o dispersa en los defectos del material. Dichas ondas se detectan mediante transductores y se registran en un sistema de adquisición de datos para su ulterior procesado. En un primer paso, mediante el análisis del tiempo de vuelo, podemos localizar y determinar el tamaño del defecto en una vista 1D. Las capacidades de detección de defectos internos en una muestra metálica se estudian también mediante transformación wavelet debido a sus características de multi-resolución en tiempo y frecuencia. Se aplica un algoritmo novedoso de agrupamiento (clustering) espacial y se usan los mapas resultantes de tiempo y frecuencia para estimar la posición del defecto. Para la visualización 2D de los defectos ampliamos el análisis de la señal utilizando la técnica de focalización por apertura sintética (SAFT, synthetic aperture focusing technique). Implementamos un novedoso filtro de apodización 2D, juntamente con la técnica SAFT, y demostramos que elimina efectos no deseados, mejorando la resolución de la imagen reconstruida del defecto. El siguiente paso es un análisis y reconstrucción 3D. En este caso conseguimos una configuración experimental totalmente automatizada y sin contacto, permitiendo áreas de barrido sobre diferentes caras de un objeto. Los detalles de los defectos se registran desde diferentes ángulos, consiguiéndose una completa reconstrucción 3D. Finalmente, mostramos nuestros resultados en un tema complementario, relacionado con un caso particular de propagación de ultrasonidos en sólidos. Desde un primer momento, quisimos tener una comprensión física de la propagación y difracción de ondas de ultrasonidos en materiales sólidos. El control de los patrones de difracción en sólidos, mediante el uso de lentes ultrasónicas, ayudaría a la focalización/colimación del ultrasonido, reduciendo ecos y reflexiones en la superficie de contorno, mejorando del proceso de análisis NDT. Los cristales fonónicos se usan para regular la difracción y la respuesta en frecuencia de ondas de ultrasonido que se propagan en fluidos. No obstante, dichas estructuras se han estudiado mucho menos en materiales sólidos. Hemos realizado detalladas simulaciones numéricas de la propagación de ultrasonidos en un cristal fonónico sólido y hemos demostrado efectos de focalización y autocolimación. Finalmente hemos acoplado nuestra lente de cristal fonónico al sólido objeto de estudio, demostrando que el control de la difracción se conserva en el interior de dicho objeto a través del material de acoplamiento. Finalmente, proporcionamos una conclusión general sobre el trabajo declarado en esta tesis y un plan de trabajo futuro donde esta investigación puede extenderse y expandirse aún más a aplicaciones industriales en colaboración con el mercado de producción
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Wang, Xiaoting. « Transient thermography for detection of micro-defects in multilayer thin films ». Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25174.
Texte intégralRésumé :
Delamination and cracks within the multilayer structure are typical failure modes observed in microelectronic and micro electro mechanical system (MEMS) devices and packages. As destructive detection methods consume large numbers of devices during reliability tests, non-destructive techniques (NDT) are critical for measuring the size and position of internal defects throughout such tests. There are several established NDT methods; however, some of them have significant disadvantages for detecting defects within multilayer structures such as those found in MEMS devices. This thesis presents research into the application of transient infrared thermography as a non-destructive method for detecting and measuring internal defects, such as delamination and cracks, in the multilayer structure of MEMS devices. This technique works through the use of an infrared imaging system to map the changing temperature distribution over the surface of a target object following a sudden change in the boundary conditions, such as the application of a heat source to an external surface. It has previously been utilised in various applications, such as damage assessment in aerospace composites and verification of printed circuit board solder joint manufacture, but little research of its applicability to MEMS structures has previously been reported. In this work, the thermal behaviour of a multilayer structure containing defects was first numerically analysed. A multilayer structure was then successfully modelled using COMSOL finite element analysis (FEA) software with pulse heating on the bottom surface and observing the resulting time varying temperature distribution on the top. The optimum detecting conditions such as the pulse heating energy, pulse duration and heating method were determined and applied in the simulation. The influences of thermal properties of materials, physical dimensions of film, substrate and defect and other factors that will influence the surface temperature gradients were analytically evaluated. Furthermore, a functional relationship between the defect size and the resulting surface temperature was obtained to improve the accuracy of estimating the physical dimensions and location of the internal defect in detection. Corresponding experiments on specimens containing artificially created defects in macro-scale revealed the ability of the thermographic method to detect the internal defect. The precision of the established model was confirmed by contrasting the experimental results and numerical simulations.
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Nguyen, Ngoc tan. « Évaluation non destructive des structures en béton armé : étude de la variabilité spatiale et de la combinaison des techniques ». Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0115/document.
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Les budgets alloués aux réparations des ouvrages et du patrimoine bâti ont atteint un niveau important. Une démarche scientifique est donc réfléchie pour réduire ces budgets par la mise en place d’outils visant à optimiser et fiabiliser le diagnostic structural des ouvrages. Les méthodes de contrôle non destructif (CND) constituent l’une des voies adaptées. Ces techniques reposent sur des principes physiques bien connus et les sociétés de service en proposent aujourd’hui un emploi courant, mais de nombreux verrous subsistent. Les deux besoins majeurs des gestionnaires d’ouvrages sont celui de l’optimisation de la stratégie de reconnaissance (où mesurer ? en combien de points ? avec quelle(s) techniques(s) et quelle précision ?) et celui de la quantification des propriétés mécaniques des matériaux ou des indicateurs de durabilité telles que la résistance à la compression, l’épaisseur carbonatée, le taux d’humidité. La question est comment déduire ces propriétés et ces indicateurs des mesures faites ? Et quelles sont la précision et la fiabilité de l’évaluation ?Cette thèse s’inscrit dans le cadre de deux projets nationaux de recherche : le projet ACDC-C2D2 et le projet ANR EvaDéOS. L’objectif principal est d’analyser la variabilité issue du CND pour ensuite remonter à la variabilité spatiale des bétons en conditions réelles. Les techniques de CND considérées sont choisies parmi les plus complémentaires : radar, résistivité électrique, ultrasons et rebond (scléromètre). Les résultats sont obtenus à partir d’une large campagne expérimentale effectuée sur des dalles d’un site test et sur deux ouvrages. L’analyse de la variabilité des CND a permis d’évaluer le nombre minimal de mesures nécessaire pour un niveau de confiance souhaité. D’autre part, la corrélation spatiale des données a été modélisée par l’analyse variographique. Les résultats montrent que, dans certain cas, les mesures de CND ne sont pas spatialement indépendantes. Les longueurs de corrélation identifiées dépendent de la propriété mesurée ainsi que du béton de l’ouvrage ausculté. La connaissance de ces longueurs de corrélation est un résultat nouveau qui permettra d’une part de mieux estimer la variabilité spatiale des bétons et d’autre part d’alimenter de manière plus réaliste les calculs fiabilistes des ouvrages. Elle permet également d’identifier un pas d’échantillonnage optimal sur ouvrage dans le cadre du suivi temporel ou pour effectuer des analyses complémentaires (ex. carottage, CND complémentaire ou plus fiable) et de représenter au mieux la cartographie spatiale des propriétés du béton.Dans le cadre du projet de recherche ANR EvaDéOS, les effets de la carbonatation et des gradients de teneur en eau (gradient d’humidité) sur les techniques CND ont été étudiés. Ce travail a pour objectifs d’étudier la sensibilité des techniques de CND à évaluer ces deux indicateurs de durabilité ainsi que leur impact sur la variabilité des mesures de CND. En laboratoire, des campagnes expérimentales ont été réalisées sur corps d’épreuve ayant différentes profondeurs de carbonatation ou des gradients d’humidité. L’effet de la carbonatation a été quantifié pour certains observables : résistivité électrique, vitesse ultrasonore et rebond. En ce qui concerne la variabilité des mesures de CND, l’effet de la carbonatation est seulement notable dans le cas du béton saturé, en particulier pour la variabilité locale de la résistivité électrique et du rebond. Cet effet reste faible par rapport à l’effet du degré de saturation. Les premiers résultats montrent également que les mesures de la résistivité électrique permettraient de suivre des gradients d’humidité dans le bétonThe budgets assigned to the repair of structures and built heritage have reached an alarming level. A scientific approach is needed to reduce these budgets by implementing tools for a more reliable and optimal assessment of existing structures. Non-destructive testing (NDT) techniques constitute one of approaches adapted to real conditions. These techniques are based on well-known physical principles. Many companies offer their services in NDT domain today but many challenges remain. The two particular needs of structure managers are the optimization of the assessment strategy (where to measure? how many testing points? what technique(s) and what precision?) and the quantification of mechanical properties of materials or durability indicators such as the compressive strength, the carbonation depth, the moisture content. The questions are how to estimate these properties from measurements performed, and what are the accuracy and reliability of the evaluation?This thesis is part of two French research projects: ACDC-C2D2 and ANR EVaDéOS. The main objective is to analyze the variability of non-destructive testing (NDT) measurements for assessing the spatial variability of concrete in real conditions. NDT techniques considered are chosen as being complementary: radar, electrical resistivity, ultrasonic, rebound hammer. The results are obtained from a wide campaign of measurements, which was performed on concrete slabs of a testing site and on two existing structures. The analysis of the NDT variability makes it possible to assess the necessary minimum number of measurements for a desired level of confidence. Furthermore, the spatial correlation of the data was modeled using the variogram analysis. In some cases, the results show that NDT measurements are not spatially independent. The correlation lengths identified depend on the measured property and the concrete of the structure inspected. They are a new result, which will provide on one hand a better evaluation of spatial variability of concrete and on the other hand a more realistic input of reliability calculations of structures. The correlation length allows also the identification of an optimal sampling distance on existing structure within the monitoring time or the implementation of additional analyses (eg. core, complementary or more reliable NDT) and a better representation of the spatial mapping of concrete properties.Within the framework of the ANR EvaDéOS research project, the effects of carbonation and of moisture gradients on NDT measurements were studied. This work aims to study the sensitivity of NDT techniques for assessing these two durability indicators and their impact on the variability of NDT measurements. In laboratory, the experimental surveys were carried out on testing specimens having different depths of carbonation or moisture gradients. The effect of carbonation was quantified for several parameters: electrical resistivity, ultrasonic pulse velocity and rebound hammer. With respect to the variability of NDT measurements, the effect of carbonation is only significant in the case of saturated concrete, in particular for the local variability of electrical resistivity and rebound hammer. This effect is weak in comparison with the effect of saturation degree. The first results show also that the measurements of electrical resistivity would follow moisture gradients in concrete
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Ayvazyan, Vigen. « Etude de champs de température séparables avec une double décomposition en valeurs singulières : quelques applications à la caractérisation des propriétés thermophysiques des matérieux et au contrôle non destructif ». Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14671/document.
Texte intégralRésumé :
La thermographie infrarouge est une méthode largement employée pour la caractérisation des propriétés thermophysiques des matériaux. L’avènement des diodes laser pratiques, peu onéreuses et aux multiples caractéristiques, étendent les possibilités métrologiques des caméras infrarouges et mettent à disposition un ensemble de nouveaux outils puissants pour la caractérisation thermique et le contrôle non desturctif. Cependant, un lot de nouvelles difficultés doit être surmonté, comme le traitement d’une grande quantité de données bruitées et la faible sensibilité de ces données aux paramètres recherchés. Cela oblige de revisiter les méthodes de traitement du signal existantes, d’adopter de nouveaux outils mathématiques sophistiqués pour la compression de données et le traitement d’informations pertinentes. Les nouvelles stratégies consistent à utiliser des transformations orthogonales du signal comme outils de compression préalable de données, de réduction et maîtrise du bruit de mesure. L’analyse de sensibilité, basée sur l’étude locale des corrélations entre les dérivées partielles du signal expérimental, complète ces nouvelles approches. L'analogie avec la théorie dans l'espace de Fourier a permis d'apporter de nouveaux éléments de réponse pour mieux cerner la «physique» des approches modales.La réponse au point source impulsionnel a été revisitée de manière numérique et expérimentale. En utilisant la séparabilité des champs de température nous avons proposé une nouvelle méthode d'inversion basée sur une double décomposition en valeurs singulières du signal expérimental. Cette méthode par rapport aux précédentes, permet de tenir compte de la diffusion bi ou tridimensionnelle et offre ainsi une meilleure exploitation du contenu spatial des images infrarouges. Des exemples numériques et expérimentaux nous ont permis de valider dans une première approche cette nouvelle méthode d'estimation pour la caractérisation de diffusivités thermiques longitudinales. Des applications dans le domaine du contrôle non destructif des matériaux sont également proposées. Une ancienne problématique qui consiste à retrouver les champs de température initiaux à partir de données bruitées a été abordée sous un nouveau jour. La nécessité de connaitre les diffusivités thermiques du matériau orthotrope et la prise en compte des transferts souvent tridimensionnels sont complexes à gérer. L'application de la double décomposition en valeurs singulières a permis d'obtenir des résultats intéressants compte tenu de la simplicité de la méthode. En effet, les méthodes modales sont basées sur des approches statistiques de traitement d'une grande quantité de données, censément plus robustes quant au bruit de mesure, comme cela a pu être observéInfrared thermography is a widely used method for characterization of thermophysical properties of materials. The advent of the laser diodes, which are handy, inexpensive, with a broad spectrum of characteristics, extend metrological possibilities of infrared cameras and provide a combination of new powerful tools for thermal characterization and non destructive evaluation. However, this new dynamic has also brought numerous difficulties that must be overcome, such as high volume noisy data processing and low sensitivity to estimated parameters of such data. This requires revisiting the existing methods of signal processing, adopting new sophisticated mathematical tools for data compression and processing of relevant information.New strategies consist in using orthogonal transforms of the signal as a prior data compression tools, which allow noise reduction and control over it. Correlation analysis, based on the local cerrelation study between partial derivatives of the experimental signal, completes these new strategies. A theoretical analogy in Fourier space has been performed in order to better understand the «physical» meaning of modal approaches.The response to the instantaneous point source of heat, has been revisited both numerically and experimentally. By using separable temperature fields, a new inversion technique based on a double singular value decomposition of experimental signal has been introduced. In comparison with previous methods, it takes into account two or three-dimensional heat diffusion and therefore offers a better exploitation of the spatial content of infrared images. Numerical and experimental examples have allowed us to validate in the first approach our new estimation method of longitudinal thermal diffusivities. Non destructive testing applications based on the new technique have also been introduced.An old issue, which consists in determining the initial temperature field from noisy data, has been approached in a new light. The necessity to know the thermal diffusivities of an orthotropic medium and the need to take into account often three-dimensional heat transfer, are complicated issues. The implementation of the double singular value decomposition allowed us to achieve interesting results according to its ease of use. Indeed, modal approaches are statistical methods based on high volume data processing, supposedly robust as to the measurement noise
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Rodrigues, Diogo Farias Gonçalves Alexandre. « Plasma nitriding of AA2011 alloy and surface characterization by NDT techniques ». Master's thesis, 2015. http://hdl.handle.net/10362/16443.
Texte intégralRésumé :
Al-Cu alloys are widely used in the aerospace and automotive industries due to their high specific strength in some tempered conditions. However, due to poor corrosion and wear resistance, they are often anodized and/or painted. Plasma nitriding has been proposed as an alternative, though the developments in this technique are still in a recent stage for Al alloys.
Electrical characterization techniques are well implemented NDTs in the industry because of good accuracy associated with lower cost, compared to other methods. Some, like eddy currents and 4-point probe techniques, are often used in coating inspection.
The objective of this study was to perform Al nitriding at low temperatures to minimize the tempering initial condition damage and to assess the feasibility of eddy currents technique as a method for evaluating surface properties.
The work developed can be divided in two stages. The first one was the process tuning, done at the Shibaura Institute of Technology, in Tokyo; and the second was the electrical characterization done in Faculdade de Ciências e Tecnologia, UNL.
Low temperature nitriding of AA2011 alloy specimens was successfully achieved. Electrical conductivity results show that lift-off measurements by eddy currents testing can be related to surface properties.
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Fiorentini, Nicholas. « Intelligent solutions for supporting decision-making processes in road management : A general framework accounting for environment, road serviceability, and user’s safety ». Doctoral thesis, 2022. http://hdl.handle.net/2158/1279821.
Texte intégralRésumé :
This Ph.D. dissertation focuses on optimizing automated decision-making processes involving critical aspects of road management tasks. Specifically, the research aims to define and implement specific strategies for supplying support to decision-makers considering two leading elements: road maintenance and road safety. We propose some novel applications based on the integrated use of high-performance Non-Destructive Techniques (NDTs) and Geographical Information Systems (GISs) in order to obtain a “fully sensed” infrastructure, creating a multi-scale database concerning structural, geometrical, functional, social, and environmental characteristics. The environmental aspect is essential since climate change phenomena and extreme natural events are increasingly linked with infrastructure damage and serviceability; nonetheless, current Pavement Management Systems (PMSs) commonly rely solely on road pavement structural characteristics and surface functional performance. The high amount of collected data serves as input for calibrating different data-driven approaches, such as Machine Learning Algorithms (MLAs) and statistical regressions. Considering the aspect of road monitoring and maintenance, such models allow identifying the environmental factors that have the most significant impact on road damage and serviceability, as well as recognizing road sites with critical health conditions that need to be restored. Moreover, the calibrated MLAs enable decision-makers to determine the road maintenance interventions with higher priority. Considering road safety, the calibrated MLAs allow identifying the sites where serious road crashes can be triggered and estimating the crash count in a specified time frame. Moreover, it is possible to recognize infrastructure-related factors that significantly impact crash likelihood. Road authorities may consider the outcomes of the dissertation as a novel approach for drafting appropriate guidelines and defining more objective management programs.
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Fernandes, Francisco Manuel Carvalho Pinto. « Evaluation of two novel NDT techniques : microdrilling of clay bricks and ground penetrating radar in masonry ». Doctoral thesis, 2006. http://hdl.handle.net/1822/6034.
Texte intégralRésumé :
Tese de Doutoramento em Engenharia Civil - Ramo de Conhecimento em EstruturasO trabalho apresentado nesta tese foi desenvolvido no Departamento de Engenharia Civil da Universidade do Minho e no Departamento de Engenharia Estrutural do Politécnico de Milão, Itália. A prática moderna na conservação de edifícios históricos é uma tarefa complexa que requer um diagnóstico profundo e cuidadoso. A investigação preliminar é essencial afim de intervir correctamente e com sucesso. Os objectivos dessa investigação são recolher de informação apropriada sobre o edifício ou a estrutura, e avaliar as propriedades mecânicas dos materiais, sendo esta última uma tarefa difícil devido à complexidade de materiais e alvenarias antigos. É imprescindível conhecer o estado de conservação da estrutura, a extensão dos danos, a ocorrência de humidades, a geometria e características escondidas tais como vazios, fendas e destacamentos. Com o intuito de aumentar o conhecimento sobre materiais de construção antigos, foi efectuada a caracterização de tijolos cerâmicos provenientes de seis mosteiros Portugueses do século XII a XIX. Os resultados mostraram uma grande dispersão, evidenciando as seguintes características: porosidade e sucção elevadas e resistência à compressão baixa. A composição química indica que estes tijolos não foram fabricados com o mesmo tipo de matéria-prima que os artefactos antigos de cerâmica. As restrições à remoção de material para efeitos de amostragem ou para a realização de testes destrutivos são muito elevadas. Assim, nas últimas décadas, o uso de técnicas não destrutivas para investigação e diagnóstico de edifícios históricos aumentou de maneira significativa. No entanto, a avaliação da resistência à compressão e doutras propriedades mecânicas dos materiais antigos utilizando técnicas não destrutivas permanece um desafio. Uma metodologia semi-destrutiva recente baseada na microperfuração é apresentada neste trabalho para a caracterização de tijolos cerâmicos dos séculos XII a XIX. Os resultados mostram que é possível estimar de maneira fiável a resistência à compressão dos tijolos através de curvas de regressão usando a técnica de microperfuração adoptada neste trabalho. A substituição de materiais de construção antigos é um tema relevante para o património arquitectónico. Os materiais modernos são geralmente incompatíveis, exibindo uma resistência e um módulo de elasticidade muito mais elevados. Assim, este trabalho também inclui o estudo de tijolos fabrico tradicional, e que se destinam à substituição de tijolos antigos. Este estudo mostra que os tijolos modernos são mais duráveis mas evidenciam uma resistência à compressão semelhante. Além disso, as correlações propostas anteriormente para a resistência à compressão permanecem válidas para os tijolos modernos de fabrico tradicional. Estava prevista a construção de réplicas de paredes de alvenaria antigas com recurso aos tijolos modernos de fabrico tradicional e argamassa de cal de baixa resistência, com vazios e outras inclusões colocados no seu interior. Essas paredes seriam testadas utilizando outra técnica não destrutiva, que não se encontra facilmente disponível em Portugal. O Radar de Prospecção Geotécnica é uma técnica de investigação não destrutiva que permite detectar alterações de materiais através das suas propriedades dieléctricas. O Radar de Prospecção Geotécnica foi empregue na determinação da geometria e na detecção de características escondidas em elementos de alvenaria tais como vazios, fendas e destacamentos. A determinação dessas características é essencial devido ao elevado grau de heterogeneidade das estruturas antigas e às implicações destas no desempenho estrutural dos edifícios. Assim, através duma série de exemplos em provetes laboratoriais e in situ, o Radar de Prospecção Geotécnica foi usado para ajudar na detecção de características geométricas e para encontrar elementos metálicos e vazios em alvenaria histórica. Os ensaios em provetes laboratoriais incluem duas paredes de três panos em alvenaria de pedra para avalização geométrica dos panos exteriores, detecção de vazios e elementos de madeira, e uma terceira parede de alvenaria mais complexa, construída com um número significativo de deficiências, diferentes materiais (tijolo e pedra) e elementos com diferente geometria, simulando situações comuns em edifícios históricos. Os ensaios in situ, foram efectuados em diversos monumentos antigos localizados em vários países Europeus para avaliar o desempenho da técnica numa série de aplicações distintas. A medição no modo de reflexão (2D) com o Radar de Prospecção Geotécnica foi efectuada em todos os casos e produziu resultados satisfatórios relativamente à avaliação das características geométricas dos painéis de alvenaria assim como na localização de outras características (vazios, fendas, destacamentos) e objectos (elementos em madeira e metálicos) que se encontram frequentemente em elementos estruturais alvenaria. Técnicas de aquisição mais precisas e rotinas de processamento de sinais mais avançadas foram utilizadas quando é necessário um posicionamento mais preciso e para a avaliação das dimensões de prováveis objectos. Aquisições para a obtenção de volumes 3D foram efectuadas, permitindo obter o posicionamento tridimensional de vazios cilíndricos, de barras de aço e dum balaústre de betão. No entanto, esta técnica não reproduziu com suficiente precisão as dimensões dos objectos devido, essencialmente, à resolução da antena quando comparado com as dimensões do respectivo objecto. Para detectar camadas de pequena espessura na alvenaria, de difícil detecção através de perfis 2D em reflexão, foram efectuadas medições em modo de transmissão. A partir dos resultados dos tomogramas foi possível distinguir o material deteriorado do material são. Devido à grande quantidade de dados necessária, ao tempo dispendido durante a aquisição no local e aos recursos informáticos elevados para aplicar os algoritmos de reconstrução 3D e tomografia, essas técnicas apenas podem ser aplicadas localmente, caso as aquisições normais em modo de reflexão não permitam obter a informação necessária.
The work presented in this thesis has been developed at the Department of Civil Engineering of University of Minho, Portugal, and at the Department of Structural Engineering of Polytechnic of Milan, Italy. Modern practice in conservation of historical buildings is a complex task that requires a deep and careful diagnosis. Preliminary investigation is essential in order to intervene correctly and successfully. The objectives of such investigation are to gather adequate information about the building or structure, and to evaluate the mechanical properties of materials, being the latter a difficult task due to the complexity of old materials and historic fabrics. Necessary information is the state of conservation, the extent of damages, the presence of moisture, the geometry and hidden features such as voids, cracks and detachments. In order to increase the knowledge about ancient building materials, characterization of clay brick from historic monuments in Portugal was performed in bricks from the 12th to 19th century, collected from six monasteries. The results showed a large scatter, and the main characteristics are high porosity, high suction and low compressive strength. Chemical composition indicates that bricks are not prepared with the same raw materials as old clay artefacts. The restrictions to remove material for mechanical sampling or to carry out destructive tests are very large. Therefore, in the last decades, the use of non-destructive testing techniques for investigation and diagnosis of historical buildings has increased significantly. However, the evaluation of the compressive strength and other mechanical properties of historic materials using such techniques remains a challenge. A recent minor-destructive methodology based on microdrilling is used in this research work for the characterization of clay bricks from the 12th to 19th century. The results show that it is possible to reliably estimate the compressive strength of bricks by means of regression curves using the adopted microdrilling technique. The replacement of old material is a matter of concern in every intervention in architectural heritage. Modern materials are usually incompatible, as they present much higher strength and elastic modulus. Thus, this work addresses also the study of traditional handmade clay bricks as replacing bricks. The study shows that new bricks are more durable but exhibit comparable compressive strength. Moreover, the proposed correlations for compressive strength of ancient bricks remain valid for new traditional handmade clay bricks. Originally, it was planned to use new handmade bricks and weak lime mortars to build replicas of ancient masonry walls, with voids and other inclusions. These would be tested using another technique, which is fully non-destructive and not easily available in Portugal. Ground Penetrating Radar is a non-destructive technique that allows the detection of material changes through changes in dielectric properties. Ground Penetrating Radar was used to determine the geometry and to map hidden features of masonry such as voids, cracks and detachments. The detection of these properties is of high relevance due to the high heterogeneity of old structures, which has implications in the structural performance of buildings. Thus, through a series of examples in laboratory specimens and in situ, the Ground Penetrating Radar was used to help in the detection of geometrical characteristics and to find metallic elements and voids in masonry. The tests in laboratory specimens included two three-leaf stone masonry walls for the geometrical assessment of the exterior panels, the detection of voids and embedded wood beams, and a third complex stone/masonry wall built with a significant amount of deficiencies, construction materials and elements with different geometry, simulating typical situations on historical buildings. The experiments in situ were performed in several masonry monuments from different European countries to assess the performance of the technique for a number of applications. Radar measurements in reflection mode (2D) were carried out in every case and produced satisfactory results regarding geometry assessment of masonry leaves and in the location of features (air voids, cracks, detachments) and objects (wood beams, steel objects) that are often found in masonry structural elements. More precise acquisition techniques and advanced signal processing routines were used when more accurate positioning was needed and for the assessment of the dimensions of possible objects. Acquisitions for the construction of advanced 3D volumes were performed and allowed to obtain the three-dimensional position of cylindrical voids, steel bars and concrete baluster. However, the technique failed to reproduce adequately the dimensions of the objects due, essentially, to the resolution of the antenna when compared to the dimensions of the targets. Transmission measurements were performed to detect thin layers of masonry. The resultant tomograms identify damaged and undamaged material. Due to the significant amount of data that is necessary, the time for accurate field acquisition and the large computer resources to run 3D reconstruction and inversion algorithms, these techniques can only be applied locally, if typical 2D radargrams do fail to provide the necessary information.
Fundação para a Ciência e a Tecnologia (FCT)
Livres sur le sujet "Non-Destructive Techniques (NDTs)"
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1933-, Koerner Robert M., et Hazardous Waste Engineering Research Laboratory., dir. Nondestructive testing (NDT) techniques to detect contained subsurface hazardous waste : Project summary. Cincinnati, OH : U.S. Environmental Protection Agency, Hazardous Waste Engineering Research Laboratory, 1988.
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K, Thome D., U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Engineering. et Physical Research Inc, dir. Two new NDT techniques for inspection of containment welds beneath coatings : Final report, October 1989-March 1990. Washington, DC : Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1991.
Trouver le texte intégralChapitres de livres sur le sujet "Non-Destructive Techniques (NDTs)"
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Sbartaï, Zoubir Mehdi, Vincenza Anna Maria Luprano et Emilia Vasanelli. « Evaluation of Concrete Strength by Combined NDT Techniques : Practice, Possibilities and Recommendations ». Dans Non-Destructive In Situ Strength Assessment of Concrete, 101–16. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-64900-5_3.
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Yildiz, Fikret, Selman Uluisik, Ahmet Turan Özdemir et Hakan İmamoğlu. « Non-destructive Testing (NDT) : Development of a Custom Designed Ultrasonic System for Fruit Quality Evaluation ». Dans Nondestructive Quality Assessment Techniques for Fresh Fruits and Vegetables, 281–300. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-5422-1_12.
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Moropoulou, Antonia I., et Kyriakos C. Labropoulos. « Non-Destructive Testing for Assessing Structural Damage and Interventions Effectiveness for Built Cultural Heritage Protection ». Dans Handbook of Research on Seismic Assessment and Rehabilitation of Historic Structures, 448–99. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8286-3.ch015.
Texte intégralRésumé :
Non-destructive techniques - NDT are used in the field of built cultural heritage protection, as they are applied in-situ and do not require destructive sampling. Infrared thermography is used for materials/decay mapping, assesses the compatibility and effectiveness of restoration materials and interventions, and reveals moisture transfer phenomena within structures. Ultrasonic testing assesses the residual properties of historic materials, reveals the decay layers and evaluates the effectiveness of consolidation treatments. Ground penetrating radar reveals the internal structure of masonries, identifies and locates subsurface voids, structural cracks and incontinuities. Portable imaging systems, in conjunction with digital image processing, are used for in-situ materials characterization, and for the study of the decay typologies. Data management systems correlate data from NDTs, from other methods and from seismic/environmental impact assessment analyses to evaluate the preservation state of a historic structure and to plan interventions.
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Abdelkader, Eslam Mohammed, Mohamed Marzouk et Tarek Zayed. « Mapping Ground Penetrating Radar Amplitudes Using Artificial Neural Network and Multiple Regression Analysis Methods ». Dans Research Anthology on Artificial Neural Network Applications, 1052–76. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-2408-7.ch049.
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Bridges are aging and deteriorating. Thus, the development of Bridge Management Systems (BMSs) became imperative nowadays. Condition assessment is one of the most critical and vital components of BMSs. Ground Penetrating Radar (GPR) is one of the non-destructive techniques (NDTs) that are used to evaluate the condition of bridge decks which are subjected to the rebar corrosion. The objective of the proposed method is to develop standardized amplitude scale for bridge decks based on a hybrid optimization-decision making model. Shuffled frog leaping algorithm is employed to compute the optimum thresholds. Then, polynomial regression and artificial neural network models are designed to predict the prioritizing index based on a set of multi-criteria decision-making methods. The weibull distribution is utilized to capture the stochastic nature of deterioration of concrete bridge decks. Lastly, a case study is presented to demonstrate the capabilities of the proposed method.
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Gros, X. E. « Non-destructive Testing Techniques ». Dans NDT Data Fusion, 43—I. Elsevier, 1997. http://dx.doi.org/10.1016/b978-034067648-6/50005-0.
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« Combination of NDT techniques ». Dans Emerging Technologies in Non-Destructive Testing VI, 347–72. CRC Press, 2015. http://dx.doi.org/10.1201/b19381-12.
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« Combination of NDT techniques ». Dans Emerging Technologies in Non-Destructive Testing VI, 333. CRC Press, 2015. http://dx.doi.org/10.1201/b19381-56.
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IBARS, J. R., M. LOPEZ APARICIO, A. PORTOLES et C. RANNINGER. « MODIFIED “EPR” TESTING TECHNIQUE FOR FIELD NDT APPLICATION IN AUSTENITIC STAINLESS STEEL IGC SUSCEPTIBILITY DETECTION ». Dans Non-Destructive Testing, 394–96. Elsevier, 1989. http://dx.doi.org/10.1016/b978-0-444-87450-4.50096-5.
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Al-Ataby, A., et W. Al-Nuaimy. « Advanced Signal Processing Techniques in Non-Destructive Testing ». Dans Applied Signal and Image Processing, 127–46. IGI Global, 2011. http://dx.doi.org/10.4018/978-1-60960-477-6.ch008.
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This chapter describes some recent advances in signal processing as applied to NDT problems. This is an area that has made progress for over twenty years and its importance is gaining attention gradually, especially since the new advanced techniques in signal processing and pattern recognition.
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« Application of NDT/SHM techniques to cultural heritage ». Dans Emerging Technologies in Non-Destructive Testing VI, 395–540. CRC Press, 2015. http://dx.doi.org/10.1201/b19381-14.
Texte intégralActes de conférences sur le sujet "Non-Destructive Techniques (NDTs)"
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Buchón-Moragues, Fernando Francisco, Josep Benedito Nuez, Francisco García García et José Manuel Melchor Monserrat. « AN INTEGRATION OF NON-DESTRUCTIVE TECHNIQUES (SFM–GPR–TLS) AS A VIRTUAL TOOL FOR ARCHAEOLOGICAL STRATEGY : THE CASE OF THE ROMAN SITE OF THE PLAZA DE LA MORERÍA IN SAGUNTO (SPAIN) ». Dans ARQUEOLÓGICA 2.0 - 9th International Congress & 3rd GEORES - GEOmatics and pREServation. Editorial Universitat Politécnica de Valéncia : Editorial Universitat Politécnica de Valéncia, 2021. http://dx.doi.org/10.4995/arqueologica9.2021.12095.
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Integration of non-destructive techniques (NDTs) and archaeological documentation offers a high potential for contributing in archaeological research strategies. NDTs, in addition to mapping and accurately detecting a site, can be an important factor that influence decision making in archaeological strategies. This integration helps to understand spatial organisation and stratigraphic potential in order to make decisions about which levels to excavate and which to remove, especially when archaeological horizons are overlapping. This methodology is demonstrated through a study of the Roman site Plaza de la Morería located in the urban area of Sagunto (Spain). The main task was to design a suitable archaeological strategy to recover the Roman funerary space prior to the first century AD by deciding whether or not to remove the pavement of a domus from a third century AD that covered the burial remains. This article describes the methodology carried out through the combined use of NTDs based on the documented archaeological findings. The integration of the methods structure from motion (SFM), ground penetrating radar (GPR) and laser scanner (TLS), georeferenced on the same reference frame defined by topographic methods, was proposed. The high resolution of 2D and 3D virtual visalitation features of GPR technique made it possible to pinpoint and map the existence of Roman overlapped horizons and buried structures in study zone. The multidisciplinary study configured a flexible design that was crucial for adapting the strategies to each proposed phase to recover the Roman funerary space prior to the first century AD. This integration of NDTs and documented archaeological data can impact decision making process and decision made in archaeological strategies, opening new perspectives in interventions of location, study, management, conservation and planning in archaeological heritage research.
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Lenner, R., P. Ryjacek et M. Sýkora. « Resistance Models for Semi-Probabilistic Assessment of Historic Steel Bridges ». Dans IABSE Symposium, Wroclaw 2020 : Synergy of Culture and Civil Engineering – History and Challenges. Zurich, Switzerland : International Association for Bridge and Structural Engineering (IABSE), 2020. http://dx.doi.org/10.2749/wroclaw.2020.1061.
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<p>The mechanical properties of historic metal materials exhibit a considerable scatter dependent on periods of construction and the region of a producer. Assessments of historic metal bridges then need to be based on measurements and tests. The use of non- or minor-destructive tests (NDTs) is often preferred over to destructive tests (DTs) to reduce the cost of structural survey. This contribution explores the measurement errors associated with common NDT hardness techniques and quantifies uncertainties in design (assessment) values of resistance. When deriving the partial factor, the uncertainty in geometry and model uncertainty is considered along with the variability of a material property and measurement error. Numerical studies reveal the effects of measurement error and model uncertainty (bending, buckling) on assessment values of resistance. A unity mean and coefficient of variation of 12% might be adopted for the measurement uncertainty of the hardness methods under study as a first approximation. On average, the true assessment resistance is by ~15% larger than that based on a NDT survey. Model uncertainty affects the partial factor for resistance of historic metal bridges.</p>
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Krieger, Juergen, M. Krause et Herbert Wiggenhauser. « Tests and assessments of NDT methods for concrete bridges ». Dans Non-Destructive Evaluation Techniques for Aging Infrastructure & Manufacturing, sous la direction de Ronald D. Medlock et David C. Laffrey. SPIE, 1998. http://dx.doi.org/10.1117/12.300098.
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Hall, David O. « Cost-effective advances in portable radioscopic NDT of composite materials ». Dans Non-Destructive Evaluation Techniques for Aging Infrastructure & Manufacturing, sous la direction de Steven R. Doctor, Carol A. Nove et George Y. Baaklini. SPIE, 1998. http://dx.doi.org/10.1117/12.301508.
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Sener, Joseph C., Alohn F. Stanley, Matthew M. Farrar et Richard A. Jobes. « Ultrasonic NDT of bridge steel and weathering steel bridge investigation in Idaho ». Dans Non-Destructive Evaluation Techniques for Aging Infrastructure & Manufacturing, sous la direction de Ronald D. Medlock et David C. Laffrey. SPIE, 1998. http://dx.doi.org/10.1117/12.300088.
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Braggiotti, Alberto, Sergio Marinetti et Andrea Mazzoldi. « D2D : a robust transient thermography NDT technique for real-time in-field measurements ». Dans Non-Destructive Evaluation Techniques for Aging Infrastructure & Manufacturing, sous la direction de Glenn A. Geithman et Gary E. Georgeson. SPIE, 1998. http://dx.doi.org/10.1117/12.305046.
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Lhemery, A. « Multiple-technique NDT simulations of realistic configurations at the French Atomic Energy Commission (CEA) ». Dans IEE Colloquium New Applications in Modelling and Inversion Techniques for Non-Destructive Testing. IEE, 1999. http://dx.doi.org/10.1049/ic:19990107.
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Lowe, M. J. S. « A model for predicting the properties of guided ultrasonic waves, and illustration of its application to NDT ». Dans IEE Colloquium New Applications in Modelling and Inversion Techniques for Non-Destructive Testing. IEE, 1999. http://dx.doi.org/10.1049/ic:19990111.
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Küttenbaum, Stefan, Stefan Maack, Alexander Taffe et Thomas Braml. « Non-destructive testing in civil engineering : ». Dans IABSE Symposium, Guimarães 2019 : Towards a Resilient Built Environment Risk and Asset Management. Zurich, Switzerland : International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/guimaraes.2019.1132.
Texte intégralRésumé :
<p>The reassessment of bridges is becoming increasingly important. The basic requirement for analyses of structural safety is reliable knowledge about individual structures. This paper introduces the new approach to evaluate the quality of measured data gained from non-destructive testing (NDT) to provide reliable, objective, and relevant information about existing bridges. The purpose is to relate this validated knowledge to probabilistic analyses. Bridging the gap between NDT and numerical reassessments indicates reduced numerical uncertainties and residual service time extensions. This paper deals with an application of this approach using measurement data collected by ultrasonic technique at a prestressed concrete bridge.</p>
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Mathew, M. D., et K. Linga Murty. « Evaluation of Mechanical Properties of Nuclear Materials Using Non-Destructive Ball Indentation Technique ». Dans 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22150.
Texte intégralRésumé :
Integrity of structural components depends on the deformation and fracture behavior of materials. For evaluating the material condition in-service, it is generally not feasible or practical or advisable to cut samples from operating structures. Non-destructive testing (NDT) techniques are required to evaluate the mechanical properties. Although several NDT techniques such as ultrasound, magnetic strength, Barkhausen noise, microhardness etc., are employed for estimating the mechanical property degradation, these methodologies are generally empirical and indirect. Automated Ball Indentation (ABI) is a non-destructive testing technique for direct measurement of mechanical and fracture properties of metallic engineering materials. Because of the small area over which the test is carried out, it is possible to determine point to point variations in the mechanical and fracture properties, such as those that exist in weldments. Although ABI technique is non-intrusive, it is a state-of-the-art mechanical test that measures directly the current/local deformation behavior of the material. In this paper, we present results from studies on the application of ABI technique to determine tensile and fracture properties of ferritic steels, an austenitic stainless steel, a nickel base superalloy and Zircaloy in different thermo-mechanical conditions. The effects of aging and cold work on these properties were determined from the ABI tests. Gradients in mechanical properties of ferritic steel welds, particularly in the narrow heat-affected zone, were clearly established. ABI technique was found to be useful in determining the anisotropy in the tensile properties of Zircaloy cladding tubes. The technique has potential as a non-destructive method for assessing structural integrity of aged components.