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Gros, X. E. "Fusion of multiprobe NDT data." Thesis, Robert Gordon University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294936.
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Pavlakovic, Brian Nicholas. "Leaky guided ultrasonic waves in NDT." Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/7907.
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Andhee, Avinash. "A novel compact Shearographic NDT system." Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/5546.
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Includes bibliographical referencesThere is a need in industry and the NDT (Non-destructive Testing) community for quick, reliable, user-friendly and cost-effective compact NDT systems that can be used on a wide variety of materials and structures, for quality assurance and maintenance. Designing and building a compact Shearographic NDT system will enhance the capability of inspection during quality assurance and maintenance routines as well as reduce inspection time. Older compact Shearographic systems, which have been tested satisfactorily both under laboratory and field conditions at the NDT Laboratory at the University of Cape Town, have a rather restricted field of view. This is due to the proprietary shearing optics being placed in front of the camera lens, which in other words means that the field of view can only be increased by using a relatively small focal length camera lens which results in having to increase the size of the shearing optics. This would make the compact Shearographic device much larger which is counter-productive since technology enables/directs research and development toward more compact devices.
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Komárková, Tereza. "NDT kontrola zabudovaných kotev do betonu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225571.
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Non-destructive inspection using ultrasonic anchoring method is the only possible way to detect inadequate anchorage length. For rescue roads systems inadequate anchoring can have fatal consequences. Therefore, control anchoring bridge barriers should be carried out every installation of crash barriers.
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Smith, Ian Colin. "Vision based systems for hardness testing and NDT." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317273.
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The work presented in this thesis concerns the development of vision based systems for two hardness (destructive) tests, namely; the Shore and Vickers and a quality assurance non-destructive test. In each case the vision system is based on an IBM PC compatible computer fitted with a commercially available frame store. Bespoke image analysis software was written using the C language for each system. In the Shore test, hardness is judged by the maximum rebound height attained by an indenter incident on a test sample. The purpose of the vision system is to measure the rebound height automatically. Laser light is used to illuminate the indenter and a vidicon vision camera is used to view its motion. Two approaches to the problem are considered; one in which image data is analysed in real time and one in which image·data is merely stored in real time and analysed a posteriori. Non-real time analysis is shown to be superior to real time analysis in terms of accuracy and reliablity and its software implementation is discussed in detail. The Vickers test uses the size of the permanent impression left by an indenter forced into the test material under a known load as a hardness index. In this case the purpose of the vision system is to measure the size of the indentation automatically. The original image analysis algorithms are shown to be capable of analysing good quality samples but are unreliable when applied to poor quality specimens. Further, fault-tolerant, algorithms are described to provide reliable and accurate results over wide variations in sample quality.The quality assurance application involves automated visual inspection of novel ferrite components for defects. Each component is approximately 8 mm in diameter, annular in shape, and coated with aluminium. Laser light is used to illuminate individual components which arc viewed using a charge-coupled device (CCD) video camera. Image analysis algorithms for characterising defects in component geometry and surface finish arc discussed. The system is shown to capable of measuring component edge eccentricity and hole offset as well as providing a quantitative description of surface chips and cracks. The system is further shown to be capable of separately classifying surface defects extending to the edge of a component. Calculation of shape parameters for surface defects also provides a means of distinguishing cracks from surface chips.
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Begum, Rushna. "Neural network processing of impact echo NDT data." Thesis, City University London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340456.
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Henriksson, Johan. "Radar odometry based on Fuzzy-NDT scan registration." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-94492.
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Visual and lidar-based odometry for mobile robots has been thoroughlyinvestigated and performs very well in good weather conditions. However,both are sensitive to bad weather conditions with atmospheric disturbancessuch as rain and snow. Recently Radar sensors specialized for mobilerobot use have become available. Radar sensors are much more robustagainst atmospheric disturbances, which makes them an exciting alternative.This thesis presents a radar odometry pipeline that can handle both lidar andradar data with minor modifications. The results show that it outperformsthe current state of the art radar odometry solutions. While also being able tohandle 3d lidar odometry with good performance.
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Bertović, Marija [Verfasser], Dietrich [Gutachter] Manzey, and Gerd-Rüdiger [Gutachter] Jaenisch. "Human Factors in Non-Destructive Testing (NDT): Risks and Challenges of Mechanised NDT / Marija Bertović ; Gutachter: Dietrich Manzey, Gerd-Rüdiger Jaenisch." Berlin : Bundesanstalt für Materialforschung und -prüfung (BAM), 2016. http://d-nb.info/1122991371/34.
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Lowe, Michael John Stuart. "Plate waves for the NDT of diffusion bonded titanium." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/8011.
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Ciszkiewicz, Tadeusz. "NDT-based service life prediction of deteriorating water mains." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0032/MQ30747.pdf.
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Hall, Ian Damon. "Generation of high resolution tomographic images for NDT applications." Thesis, University of Strathclyde, 2001. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24263.
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Techniques for the generation of quantitative ultrasonic images in non-destructive testing have generally involved a substantial cost in terms of data storage and computational time, and have thus found limited application. Preference has therefore been given to the more straightforward imaging methods, such as main beam projection, which detect the presence of defects and provide a limited flaw sizing capability. The relatively small number of flaws requiring detailed examination, coupled with substantial increases in available data storage and computational power, have made it possible to use a number of straightforward tomographic reconstruction methods to produce high resolution images of flaws contained within the material under examination. A set of these images are then fused together using a novel fuzzy logic image fusion technique into a single image from which more accurate measurements of flaw size, shape and orientation can be made. However, if the quality of the raw A-scan data is not sufficiently high then the data will be filtered using Maximum Likelihood Deconvolution (MLD). The aim of this blind deconvolution method is to improve the time resolution and Signal to Noise Ratio of the A-scan data with only knowledge obtained from the data, this is in contrast to the majority of techniques currently used for this purpose. The three tomographic methods which have been implemented in this work are Reflection tomography, Time-of-flight Diffraction tomography and Transmission tomography. In addition a Single Bounce Image Enhancement method has been developed to improve the images. Selection of images used in the fusion process depends on the nature of the flaw, as each of these methods identifies different characteristics of the flaw shape. The components of the imaging system have been validated experimentally by the generation of high resolution images from a variety of flaws contained within cylindrical aluminium test specimens.
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Abdulgawad, Ziyad. "The application of data fusion to reinforced concrete NDT." Thesis, City University London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419001.
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Chitti, Abhishek. "ASSESS MATERIAL PROPERTIES OF CONCRETE USING COMBINED NDT METHODS." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2490.
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The aim of this research is to assess the material properties of concrete like modulus of elasticity, compressive strength, and Poisson’s ratio using various nondestructive Testing (NDT) methods like Ultrasonic Pulse Velocity (UPV) and Rebound Hammer (RH). Assessment of material properties of concrete is very important as they are used for structural design process. Various NDT methods are applied to ensure the quality of concrete specimens but they can also be used to find material properties. UPV is a NDT method which is used to test the internal condition of the concrete specimen. RH is a surface hardness testing method and can be used to test the homogeneity of the specimen. For this study, several batches of concrete samples with three different design strengths of 6000 psi, 8000 psi, and 12000 psi were casted. Modulus of elasticity and Poisson’s ratio were calculated from UPV P-wave and S-wave velocities. A Nomogram was developed by combining the longitudinal ultrasonic pulse velocities, rebound numbers, and compressive strengths measured from UPV, RH, and compressive strength tests respectively. This combined NDT correlation curve (Nomogram) can be used to estimate compressive strength of concrete if UPV and rebound values are known. The accuracy of these NDT methods were determined by comparing estimated strength to the actual strength. Furthermore, the effect of moisture content on UPV and rebound values was reviewed and also studied dynamic modulus of elasticity and its relation with static modulus of elasticity of the concrete was investigated for better understanding.
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Bertovic, Marija [Verfasser], Dietrich [Akademischer Betreuer] Manzey, and Gerd-Rüdiger [Akademischer Betreuer] Jaenisch. "Human factors in non-destructive testing (NDT): risks and challenges of mechanised NDT / Marija Bertovic. Gutachter: Dietrich Manzey ; Gerd-Rüdiger Jaenisch. Betreuer: Dietrich Manzey." Berlin : Technische Universität Berlin, 2015. http://d-nb.info/107658814X/34.
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Xie, Ningbo. "NDT-based performance prediction for wrinkled composites under compressive load." Thesis, University of Bristol, 2018. http://hdl.handle.net/1983/919cd8f3-463f-4618-b794-ede41a5b92ad.
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The work in this thesis aimed to develop a method to transfer the three-dimensional (3D) non-destructive characterised data into finite-element models containing as-manufactured structural details. Two types of fibre-misalignment defects: out-of-plane wrinkles and in-plane waviness, were investigated and a quasi-isotropic layup [45o/90 o /-45 o /0 o]ns was chosen as the representative industrial layup sequence for validation purposes. A pivotal part of the work was the development of the transfer process to automatically and faithfully convert the output of non-destructive characterisation inversion methods into finite-element models containing these two types of defect. For out-of-plane wrinkles, using this transfer method and previously validated modelling techniques, a series of models were exercised under compressive load to identify the hierarchy and interdependences of wrinkle parameters, covering the wrinkle severity, shape and extent. The outcome indicated that the maximum out-of-plane wrinkle angle from the load direction was the governing factor to influence the compressive strength and this should be the key parameter to be measured non-destructively when wrinkles are detected in the components. For in-plane waviness, it was studied both experimentally and numerically. First, the in-plane waviness was introduced into 0 plies by a specially designed rig and four waviness-severity coupons were manufactured to investigate the compressive damage process influenced by this in-plane waviness. Two High-speed cameras were used, focusing on the edge and the front face of the coupon waviness region to capture the failure modes and their sequences. X-ray CT techniques were also applied to identify the internal failure activities when the loading process was interrupted for some samples, before the ultimate damage was reached. Numerical models were then created in Abaqus/Explicit following a similar method to the out-of-plane case but requiring significant further development in order to faithfully model samples that could also be created experimentally. These were validated against the experimental recordings. Both experimental and numerical studies showed the dominant failure modes were delamination and splitting due to in-plane waviness incorporated in the samples.
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Poggi, Francesco. "Bending properties of commercial wood-based panels by NDT methods." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-66162.
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This thesis work focuses mainly on the application of non-destructive testing (NDT) methods on wood-based panels (WBP) in order to estimate the bending properties. To prove the accuracy and applicability of these methods on WBP, their results are correlated with results from a standardized static bending test. The behavior in different climate conditions and the application on panels of larger sizes is also questioned to provide an indication about strong points and boundaries of NDT methods applied on WBP.The bending properties are of major importance, especially for materials suited to bear loads. Bending stiffness, represented by the modulus of elasticity (MOE), is an expression of the deflection rate of a material under load. The bending strength, represented by the modulus of rupture (MOR), is an expression of the maximum load withstood by a material before rupture.Before testing, the material is acclimatized in three climate conditions: dry (20°C, 35% RH), standard (20°C, 65% RH) and wet (20°C, 85% RH), to understand the bending properties variation and how the NDT methods are affected by the variation in moisture content.The materials used are seven types of WBP, in particular four types of particleboards (PB), one type of high-density fiberboard (HDF), one type of dual density PB (with high and low density areas along the production direction) and one type of light-weight panel (Board-on-stiles, a composite panel of HDF, PB and paper honeycomb).To test the bending properties the following NDT methods are considered: transversal resonance vibration and longitudinal resonance vibration with the use of the BING system and the time-of-flight with the use of Fakopp Ultrasonic Timer and Silvatest Trio. The resonance vibration methods, transversal and longitudinal, are based on the relation between resonance vibration properties and bending properties of a material. The relation with bending properties also exists for the stress wave velocity (SWV) through a material, calculated with the time-of-flight method. The dynamic MOE resulting from these tests is then correlated with the static MOE and MOR from the static bending test.The NDT methods resulted to be reliable on WBP, with generally high levels of correlation between dynamic MOE and static MOE and MoR. The highest correlation value for MoE is with the transversal resonance vibration while the highest for MOR is with the longitudinal resonance vibration. The results of the dynamic MOE for all the NDT methods are higher than the static MOE, as confirmed also in the literature; the average ratio between the dynamic and the static MOE is, for example, up to 1,6 for WBP in standard climate condition, tested with Fakopp U.T.. These results are extremely higher than values suggested by previous studies. Moreover, the ratio increases with increasing relative humidity of the climate condition. The results from the tests on larger sizes suggest a possible application in this field. The time-of-flight method is suitable for in-plane uniform materials, like the PB and HDF, while the transversal resonance methods give also a good representation of the properties of the dual density PB and the light-weight panel.
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Kozáček, Vojtěch. "Experimentální stanovení závislosti parametrů NDT a pevnosti v tlaku betonu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409957.
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The diploma thesis deals with non-destructive testing of concrete as well as with the relationship between determined parameters and the compressive strength of concrete. The thesis is mainly focused on the ultrasonic pulse velocity method and the rebound hammer test. The experimental part of the thesis describes non-destructive tests performed on concrete blocks. The compressive strength was tested on the drill cores taken from the concrete blocks. The aim of this thesis is to find regression models of the relationship between the compressive strength and non-destructive parameters, and the subsequent analysis of the results.
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Drinkwater, Bruce Walton. "The use of dry coupling in ultrasonic nondestructive testing." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296521.
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Bork, Uwe. "Non-destructive evaluation of adhered metal joints using ultrasonic Lamb waves and artificial neural networks." Thesis, Keele University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241451.
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Pialucha, Tomasz Piotr. "The reflection coefficient from interface layers in NDT of adhesive joints." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/8364.
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Wilson, John. "Investigation of electromagnetic NDT&E techniques for comprehensive material assessment." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501161.
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In recent years the expectations of non-destructive testing and evaluation (NDT&E) service users have increased from simple defect detection and dimension estimation to the provision of quantitative information about material properties including microstructure, stresses, hardness, etc. Although there are many techniques available to NDT&E service providers, each have their own limitations when used in isolation. For example, magnetic Barkhausen emission measurement has good microstructure and stress characterisation capabilities, but has a limited measurement depth. which is problematic where the property of interest varies with depth, i.e. case hardening. Magnetic flux leakage can detect defects on both the surface under inspection and the opposite surface, but it is very difficult to discriminate between them. However, if two or more inspection techniques are combined in a single system, it is thought that it may be possible to overcome these limitations.
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Wang, Xiaoyue. "Integrated control systems for robotic NDT of large and remote surfaces." Thesis, London South Bank University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323885.
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Mineo, Carmelo. "Automated NDT inspection for large and complex geometries of composite materials." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26010.
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Large components with complex geometries, made of composite materials, have become very common in modern structures. To cope with future demand projections, it is necessary to overcome the current non-destructive testing (NDT) bottlenecks encountered during the inspection phase of manufacture. This thesis investigates several aspects of the introduction of automation within the inspection process of complex parts. The use of six-axis robots for product inspection and non-destructive testing systems is the central investigation of this thesis. The challenges embraced by the research include the development of a novel controlling approach for robotic manipulators and of novel path-planning strategies. The integration of robot manipulators and NDT data acquisition instruments is optimized. An effective and reliable way to encode the NDT data through the interpolated robot feedback positions is implemented. The viability of the new external control method is evaluated experimentally. The observed maximum position and orientation errors are respectively within 2mm and within 1 degree, over an operating envelope of 3m³. A new software toolbox (RoboNDT), aimed at NDT technicians, has been developed during this work. RoboNDT is intended to transform the robot path-planning problem into an easy step of the inspection process. The software incorporates the novel path-planning algorithms developed during this research and is shaped to overcome practical limitations of current OLP software. The software has been experimentally validated using scans on real high value aerospace components. RoboNDT delivers tool-path errors that are lower than the errors given by commercial off-line path-planning software. For example the variability of the standoff is within 10 mm for the tool-paths created with the commercial software and within 4.5 mm for the RoboNDT tool-paths, over a scanned area of 1.6m². The output of this research was used to support a 3-year industrial project, called IntACom and led by TWI on behalf of major aerospace sponsors. The result is a demonstrator system, currently in use at TWI Technology Centre, which is capable of inspecting complex geometries with high throughput. The IntACom system can scan real components 2.8 times faster than traditional 3-DoF scanners deploying phased-array inspection and 6.7 times faster than commercial gantry systems deploying traditional single-element inspection.
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Bale, Jefri Semuel. "The damage observation of composite using non destructive testing (NDT) method." Thesis, Paris 10, 2014. http://www.theses.fr/2015PA100067/document.
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L'objectif de ce travail de thèse est d'étudier le comportement de l'endommagement des matériaux composites sous chargement statique et fatigue par contrôle non destructif (C.N.D) thermographie et soutenu par émission acoustique et la tomographie (CT scan). Pour cela, ce unidirectionnels composite à fibres de verre (GFRP) et discontinue composite à fibres de carbone (DCFC) ont été utilisés comme les éprouvettes qui ont fourni par PSA peugeot citröen, France. Une série d'essais mécaniques a été réalisée pour déterminer le comportement de l'endommagement sous chargement statique et fatigue. Pendant tout des essais mécanique, la thermographie a été utilisé pour l'observation en temps réel pour suivre l'évolution des températures sur la surface de l'éprouvette et supporté par émission acoustique dans certaines conditions. Cette étude a utilisé une forme rectangulaire et se compose d'éprouvettes trouées et non trouées au centre de l'éprouvette. La vitesse de déplacement constante est appliquée pour observer l'effet sur le comportement de l'endommagement sous chargement de traction statique. Sous les essais de fatigue, le paramètre constant de la fréquence et de l'amplitude de stress a été étudiée pour chaque niveau de charge pour avoir les propriétés de fatigue et l'évolution de l'endommagement de l'éprouvette. La tomographie a été utilisée pour confirmer l'apparition de l'endommagement et l'etat du matériau après l'essai de fatigue. L'analyse des résultats de l'expérimentation et de l'observation NDT montré le bon accord entre les résultats mechnical et NDT thermographie avec prise en charge par l'observation de l'émission acoustique en détecter l'apparition et la propagation de l'endommagement de GFRP PRV et DCFC sous chargement de statique en traction. Les essais en fatigue montrent que la dissipation thermique est liée à l'évolution de l'endommagement et également thermographie et peut être utilisé avec succès pour déterminer la limite d'endurance (HCFS) et la courbe de Wöhler du matériau composite. Les résultats par CT scan ont mesurée avec succès les endommagements et l'état du matériau après essai de fatigue du matériau compositeThe aim of this study is to investigate the damage behaviour of composite material in static and fatigue condition with non destructive testing (NDT) thermography method and supported by acoustic emission and also computed tomography (CT) scan. Thermography and acoustic emission are used in real-time monitoring techniques during the test. On the other hand, NDT observation of tomography is used for a post-failure analysis. In order to achive this, continuous glass fiber composite (GFRP) and discontinuous carbon fiber composite (DCFC) have been used as the test specimens which supplied by PSA Company, France. A series of mechanical testing was carried out to determine the damage behaviour under static and fatigue loading. During all the mechanical testing, thermography was used in real-time observation to follow the temperature change on specimen surface and supported by acoustic emission in certain condition. This study used rectangular shape and consist of specimen with and without circular notches (hole) at the center. The constant displacement rate is applied to observe the effect on damage behaviour under tensile static loading. Under fatigue testing, the constant parameter of frequency and amplitude of stress was explored for each load level to have the fatigue properties and damage evolution of specimen. The tomography was used to confirm the appearance of damage and material condition after fatigue testing. The analysis from the experiment results and NDT observation shown the good agreement between mechnical results and NDT thermography with supported by acoustic emission observation in detect the appearance and propagation of damage for GFRP and DCFC under static loading. Fatigue testing shows that thermal dissipation is related to the damage evolution and also thermography and can be successfully used to determine high cycle fatigue strength (HCFS) and S-N curve of fiber composite material. From post failure analysis, CT scan analysis successfully measured and evaluated damage and material condition after fatigue test for fiber composite material. v
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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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Polimeno, Umberto. "Non linear spectroscopy for damage detection on aerospace materials." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535639.
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Kelly, Stephen P. "An air-coupled ultrasonic array scanning system for rapid through transmission NDT." Thesis, University of Strathclyde, 2000. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24320.
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Within the aerospace industry there is an increasing requirement to investigate the structural integrity of the new composite materials that are now being used frequently in the manufacture of aircraft. The complexity of the material manufacture necessitates that evaluation is required prior to final production and it is the development of a novel approach to this testing that constitutes the focus for the work of this Thesis. Existing techniques frequently utilise ultrasonic signals to interrogate the sample under investigation, however, these are cumbersome and scan speed is invariably slow when testing of large samples is considered. This is because large samples are normally tested using a through transmission approach, where narrow jets of water are used to couple the ultrasonic signal through the propagation channel. The fundamental basis of the proposed approach is the removal of the water couplant, enabling a receiver array to be employed, and thus scan large areas more quickly. Flexibility would also be increased with this technique due to a capability to scan moisture sensitive parts. In order to achieve this, however, the considerable problem of the acoustic impedance mismatch at each solid/air boundary would have to be overcome. Firstly, a narrowband, relatively low frequency approach is selected. It is concluded however, that in order to maximise the scan speed benefit, parallel data acquisition from the receiver array elements must be achieved and no signal averaging must be performed. A small array element pitch and focussing are deemed necessary in the pursuit of adequate defect detection resolution. It is important to select the most appropriate transducer technology for coupling in air and a comprehensive comparison of two relevant technologies (piezocomposite and electrostatic) is carried out. Piezocomposites are found to be superior in terms of sensitivity, robustness and focusing capability. A novel acoustic matching layer is developed to improve coupling from the transducers to the air load. This is investigated microscopically and acoustically and a linear model is developed to enable the design for the most successful operation. Prototype air-coupled systems are produced and scan results compared favourably with the results using water-coupled techniques.
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Rodriguez, Hernando Efrain Leon. "Automated NDT Robotic System for Storage Oil Tanks and Nuclear Pressure Vessel." Thesis, London South Bank University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506710.
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Kostan, Mario. "Design and fabrication of GaPO4 ultrasonic transducer for NDT at high temperatures." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17228.
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There is a critical need for inspection and condition monitoring of high temperature critical components such as pipelines and welds in electrical power generation and other plants operating at temperatures as high as 580°C. The high temperatures and pressures experienced in these pipelines, particularly for ageing plants lead to creep, fatigue and corrosion type defects. Safety of these plants is of paramount importance, and regular maintenance is carried out during planned outages at ambient temperatures. Ultrasonic non-destructive testing can be used to detect defects in the weld at ambient temperatures. However, at high operational temperatures, this technique cannot be applied due to the lack of high temperature transducers. This research has achieved significant advances towards enabling ultrasonic inspection and condition monitoring of high temperature critical points, by developing an ultrasonic transducer around an advanced piezoelectric single crystal material, called Gallium Orthophosphate (GaPO4), which can operate at the required temperature of 580°C. Based on its reported piezoelectric and other properties, and its commercial availability, GaPO4 was chosen as a candidate active material for application in a prototype high temperature transducer. In a series of confidence building tests with the selected piezoelectric material (electrical characterisation via the impedance method), it has been demonstrated that the GaPO4 piezoelectric elements are stable when subjected to 580°C for more than 600 hours. Ultrasonic thickness gauging has shown that GaPO4 works as a functional transducer generating and receiving ultrasound waves at 580°C for at least 360 hours. Furthermore, the sensitivity of the GaPO4 transducer to detect defects with simple geometry was successfully tested through measurements on steel blocks containing artificial defects (side-drilled holes) up to the same high temperatures. Based on the characterisation results from the impedance and ultrasonic measurements, a prototype ultrasonic transducer for operation at high temperatures has been designed and manufactured. The new ultrasonic transducer was tested in a laboratory environment using a steel calibration block, high temperature couplant, SONO 1100, and an electric furnace. In the range from ambient temperatures up to the target of 580°C, the ultrasonic transducer kept a signal-to-noise (SNR) level sufficiently high, above the threshold of 6 dB, which is high enough for practical non-destructive testing and condition monitoring.
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Burnham, Kenneth C. "Structural health monitoring of wind turbine blades using guided wave NDT technique." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24547.
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Wind energy is an increasingly important contributor of power within the renewable energy sector. In the year to 2012, wind generation within the United Kingdom (UK) increased 40% meeting 6% of the UK's national electricity demand. The UK is committed to providing 15% of its energy from renewable resources by 2020. Currently, the UK has approximately 40% of Europe's entire wind resource with significant potential for development of both on and offshore wind. In recent years, the number of reports on defective blades contributing towards turbine failure has grown. Blade manufacturers have privately reported a recurring problem with the spar cap - a critical strengthening component - which when weakened by damage, hastens the onset of operational failure. The contents of this thesis consider composite materials used within the blade and the detection techniques appropriate for in-field implementation. Application of Guided Waves, in particular Lamb waves, suits the typical dimensions of the blade composite structure. Experiments were conducted to understand the characteristics of Lamb wave modes within glass fibre reinforced plastic (GFRP) to assess attenuation levels; modal propagation; and dispersion with respect to fibre orientation. Finite Element Analysis (FEA) was used to observe material characteristics and discern possible modes of wave propagation. To exploit the directional qualities of GFRP, directional Macro Fibre Composite (MFC) sensors were applied to a wind turbine blade providing low-profile, light-weight, durability and conformability with sufficient sensitivity to detect elastic disturbance over large areas. Parametric monitoring of GFRP samples under loading identified tensile stress from defect onset. Cross correlation and sliding-window correlation signal processing techniques on recorded data from the applied sparse array identified the onset of fibre damage using Guided wave modes. This technique was able to identify modal changes to specific defects providing the prospect for in-situ blade monitoring.
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Brenner, Alina-Alexandra. "Automated NDT robotic system for inspection of test objects with unknown geometry." Thesis, London South Bank University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.478907.
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Cheng, Wei. "Studies on NDT Image Denoising by Wavelet Transform and Self-Orgnizing Maps." 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147636.
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GIULIETTI, NICOLA. "Crack Analyser: a novel image-based NDT approach for measuring crack severity ." Doctoral thesis, Università Politecnica delle Marche, 2022. http://hdl.handle.net/11566/295503.
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In Europa, le infrastrutture civili e di trasporto necessitano di una manutenzione efficace e proattiva per garantire il continuo funzionamento in sicurezza durante l'intero loro ciclo di vita. I paesi europei devono ogni anno stanziare enormi risorse per mantenere il loro livello di funzionalità. Ciò fa sorgere la necessità urgente di adottare approcci di ispezione di monitoraggio più rapidi e affidabili per aiutare ad affrontare questi problemi. Il deterioramento delle strutture è più spesso anticipato dalla formazione di fessure sulla superficie del calcestruzzo. La presenza di fessurazioni può essere sintomo di diverse problematiche quali dilatazioni e ritiri dovuti a sbalzi di temperatura, assestamenti della struttura, copertura impropria fornita in fase di getto, corrosione delle armature in acciaio, carichi pesanti applicati, vibrazioni insufficienti al momento della posa del calcestruzzo o perdite d'acqua per ritiro superficiale del calcestruzzo. Diventa quindi di primaria importanza l'identificazione, la misurazione e il monitoraggio delle fessurazioni sulla superficie del calcestruzzo. I principali metodi di ispezione attualmente adottati si basano su strumenti manuali e righelli: un’attività lunga e ingombrante, soggetta a errori e scarsamente oggettiva sull'analisi quantitativa perché fortemente dipendente dall'esperienza dell'operatore. Secondo la norma UNI EN 1992-1-1:2005, la larghezza massima delle fessure del calcestruzzo ammessa per una generica classe di rischio è di 0,3 mm. Per questo motivo, per misurare in modo accurato e affidabile la dimensione della fessura, è necessario l’impiego di strumenti di misura con caratteristiche metrologiche adeguate (es. precisione e accuratezza almeno un ordine inferiore al valore da misurare). In caso contrario, la severità della fessura potrebbe essere classificata erroneamente. Questo lavoro di tesi propone un nuovo approccio automatico, basato su immagini, in grado di localizzare e misurare fessure su superfici in calcestruzzo rispettando il vincolo metrologico imposto dalla norma UNI EN 1992-1-1:2005. Utilizzando una sola immagine, il metodo sviluppato è in grado di localizzare e misurare automaticamente e rapidamente la larghezza e la lunghezza di una fessura su una superficie. Il sistema di misura sviluppato sfrutta una singola telecamera operante nel campo del visibile per acquisire un'immagine digitalizzata della superficie da ispezionare. Il componente software del sistema riceve in input la singola immagine che inquadra la crepa e fornisce in output un'immagine aumentata dove viene evidenziata la crepa e la sua larghezza e lunghezza media/max. La misura della larghezza della fessura viene eseguita perpendicolarmente alla linea centrale della fessura con una precisione sub-pixel. Il sistema di misurazione è stato implementato su uno smartphone per eseguire ispezioni manuali da parte dell'operatore e su sistemi integrati per l'ispezione remota con robot o velivoli senza pilota (UAV)). Le strategie sviluppate possono essere facilmente estese a qualsiasi altro contesto in cui sia richiesto un controllo di qualità superficiale mirato all'identificazione e misura di eventuali danni o difettosità. Europe’s ageing transport infrastructure needs effective and proactive maintenance in order to continue its safe operation during the entire life cycle; European countries have to allocate huge resources for maintaining their service-ability level. This give rise to the necessity of an urgent need to adopt faster and more reliable monitoring inspection approaches to help tackling these issues. The deterioration of structures is most often foreseen by the formation of cracks on concrete surface. The presence of cracks can be a symptom of various problems like expansion and shrinks due to temperature differences, settlement of the structure, improper cover provided during concreting, corrosion of reinforcement steel, heavy load applied, insufficient vibration at the time of laying the concrete or loss of water from concrete surface shrinkage, therefore the identification, measurement and monitoring of cracks on the concrete surface becomes of primary importance. The main currently adopted inspection methods rely on visual marking and rulers, long and cumbersome activity, prone to errors and poorly objective on quantitative analysis because it strongly depends on operator experience. According to UNI EN 1992-1-1:2005 standard , the maximum admitted concrete crack width is 0.3 mm. For this reason, to accurately and reliably measure the target dimension, it is necessary to employ measurement instruments with suitable metrological characteristics (e.g. precision and accuracy at least one order lower than the value to be measured). Otherwise, the crack severity could be misclassified. This thesis work proposes a novel automatic image-based approach able to locate and measure cracks on concrete surfaces respecting the metrological constraint imposed by UNI EN 1992-1-1:2005 standard. Using only one image, the developed method is able to automatically and rapidly locate and measure the average width and length of a crack in an existing concrete structure. The measurement system developed exploits a single camera working in the visible range to acquire a digitized image of the structure being inspected. The software component of the system receives as input the single image framing the crack and gives as output an augmented image where the crack is highlighted as well as its average/max width and length. The measure of the crack width is performed perpendicularly to the crack central line with sub-pixel accuracy. The measurement system has been deployed on a smartphone for operator-based manual inspections as well on embedded systems for remote inspection with robots or Unmanned Aerial Vehicles (UAVs). The strategies developed can be easily extended from concrete inspection applications to any other context where a surface quality control targeted to the identification of eventual damages/defects is required. The activity was triggered by an explicit need within the EnDurCrete project.
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Mohamed, Abdul Aziz Bin. "Creep life prediction of low alloy steel using neural network analysis of NDT." Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266946.
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Hosseini, S. M. R. "A study on the optimization of design of high frequency immersion probes." Thesis, Brunel University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236473.
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Hussein, Salah A.-R. Ahmed. "Characterisation of planar defects in solids using ultrasonic pulse echo techniques." Thesis, City University London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389705.
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Sibbald, Alan. "Impact hammer testing of masonry sewers." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/14419.
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Roucaries, Bastien. "Contributions au contrôle non destructif des composites carbones." Phd thesis, Toulouse, INPT, 2009. http://oatao.univ-toulouse.fr/9221/1/roucaries.pdf.
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La recherche de défauts dans les matériaux est un sujet complexe et important, en particulier lorsque la sécurité est en jeu comme dans le domaine aéronautique. Cette thèse s’inscrit dans cette problématique et s’organise en deux parties. La première partie est dédié à la détection des défaut dans les composites carbones par trois nouvelles méthodes radiofréquences permettant de détecter, en particulier, les impacts sur les peaux des composites carbones. La deuxième partie est consacrée à la détection des infiltrations d’eau dans les composites alvéolaires par une méthode multiphysique couplant une onde hydraulique non linéaire et une détection par un RADAR CW.
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Dulay, Didar Singh. "The application of electromagnetic NDT method to the inspection of non-ferrous cast materials." Thesis, Cranfield University, 2003. http://dspace.lib.cranfield.ac.uk/handle/1826/4175.
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Inspection of non-ferrous cast material is routinely carried out looking for casting defects inherent for the manufacturing process. The NDT methods employed are Radiography and Ultrasonics, primarily for sub-surface or internal defects and Penetrants fo r surface breaking defects. Electromagnetic techniques have not been used on cast material except maybe for conductivity determination. This limitation resulting fi7om the surface roughness normally associated with cast surfaces and the fact the other techniques mention above have been very successful in finding and evaluating the discontinuities sought. The possible application of Electromagnetic techniques on surfaces in the as-cast condition of non-ferromagnetic material came about because of specific problems experienced by industry. Two major investigations were offered namely; 1) Investigation of CNC material - CuNiCr [1.6%Cr] castings exhibiting oxide entrapment in the form of networks. 2) Investigation of NAB - Nickel Aluminium Bronze exhibiting selective phase corrosion on immersion in seawater. The detection and measurement of both oxide entrapment and phase selective corrosion was difficult and in cases impossible with conventional NDT methods employed for quality control of these material/component types. Time of Flight DiMaction Ultrasonics did give some 50% detectability of phase selective corrosion, but the method was found to be expensive and very time consuming. The metallurgical properties of the material and morphology of the defects have been studied for both Cupro Nickel Chromium and Nickel Aluminium Bronze cast alloys. An investigation was then conducted to study the effects of eddy current signals and their potential in detecting, both linear and cluster type defects which were predominantly interdendritic with some reported as intergranular in nature. For inspecting Cupro Nickel Chromium castings two successful eddy current methods have been developed. Detection of surface flaws was achieved by high frequency [2MHzj examination and subsurface flaws by using low frequencies [1--'IKHz] but using specifically developed sensors that provided good penetration but maintained sensitivity to the fine defects. In the case of Nickel Aluminium Bronze material, the investigation was to look at electromagnetic techniques, which best utilizes the inherent feature of permeability/conductivity associated with this non- ferromagnetic material and any changes that phase selective corrosion may produce. Some meaningful results were obtained using a combination of edd'y current excitation with detection via magneto -re s istive sensors. Testing through 30-40mm of material to detect small magnetic variation produced by only 1-2 mm of corrosion penetration was difficult to quantify. Detection and assessment however appeared hopeful when examination was carried out from the corroded surface. With quantifiable samples a meaningful technique using eddy current excitation and magneto-resistive sensor for detection can be developed.
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Nik, Zulkepeli Nik Ahmad Akram. "Real-time unsupervised incremental support vector machine for oil and gas pipeline NDT system." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/31204/.
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Current Non Destructing Testing (NDT) techniques for oil and gas pipeline inspection are accurate and reliable but there are limited numbers of continuous monitoring technique available that can automatically make real-time decisions on the status of the pipeline. Furthermore, most of the NDT methods are deployed at predetermined interval which can last for several months. Sudden onsets of defects are undetected and lead to pipeline failure and unscheduled shutdown. A reliable inspection method is required whereby the pipelines are monitored continuously and are able to provide the operators sufficient time to plan and organize shutdowns. In order to implement this, a continuous monitoring technique is needed which can detect defects automatically with minimal human intervention. Support Vector Machine (SVM) is a powerful machine learning technique for classification, however, the training phase requires batch data to find a model and this is not feasible for a continuous NDT system. This thesis proposes a novel method where the SVM training phase is able to find a model from the incremental dataset acquired from Long Range Ultrasonic Testing (LRUT) system. Results show that this method has comparable accuracy compared to the batch data method. Traditionally, SVM training data is labeled by an expert, however in a continuous monitoring NDT, it is not practical to assign an expert to label the continuously acquired data. Therefore, a novel unsupervised training technique is proposed. The technique is able to cluster the acquired data into a few clusters accurately. The performance of the proposed technique is compared to Self Organizing Map (SOM) method and shows better results. This thesis also proposes a novel method to implement a Genetic Algorithm (GA) as the Quadratic Programming (QP) solver in the SVM efficiently. Conventional SVM implement Sequential Minimal Optimization (SMO) which requires that the data be sparse for optimal operation. The performance of the method is evaluated and shows comparable result to traditional methods. As such, this thesis provides the framework to perform unsupervised continuous monitoring for oil and gas pipelines using LRUT in real time.
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Campbell, M. A. "An evaluation of monolithic phased arrays for Non destructive testing." Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381502.
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Bright, Dominic. "Accurate characterisation of surface fatigue cracks (in steels) using the AC potential drop NDT technique." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/5562.
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Includes bibliographical references.In order to maintain the desired level of safety in an industrial environment, it is important that the structural integrity of all the components and equipment being utilised by the facilty is assured. To determine the structural integrity of an engineering system precisely, not only must the depth of the flaw be established, but the crack profile and orientation must also be obtained in order to assess the extent of the crack. The present work described in this thesis discusses the development of an AC potential drop (ACPD) system as a non-destructive testing (NDT) technique for flaw detection and sizing of variously shaped and oriented surface breaking fatigue cracks. The ACPD method was reviewed to establish its viability as an NDT technique, and to understand the response of the output to fatigue cracking. The proposed system using a mains power source with a frequency of 50Hz was investigated as a means of providing a sensitive and reliable measurement device that could be employed to analyse fatigue cracks in industrial components in situ.
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Gerona, Leovigildo Mahon. "Vibration excitation of aerospace composite materials for defect determination using optical NDT techniques (ESPI/Shearography)." Master's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/13432.
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Includes bibliographical references (leaves 87-89).This project investigates the detection of structural damage in aerospace composite materials using ESPI and/or Shearography. ESPI and shearography are both laser based digital interferometric techniques used to non-destructively identify defects in small and large structures. Vibration excitation is proposed to be used as the excitation method for the above Non-Destructive Testing (NDT) techniques. The material may or may not contain any defects, in which case the flaws are to be artificially induced.
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Capace, Brunella. "NDT application in Transport Asset Management. QA/QC performance specifications in pavement construction and maintenance." Doctoral thesis, Università di Catania, 2019. http://hdl.handle.net/10761/4100.
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Nowadays, in Transport Asset Management, there is the need to identify measures to guarantee high levels of performance over time. The application of Non-Destructive Techniques, through high-efficiency equipment, turns out to be an optimal solution to ensure the quality of transport infrastructures.
Asset Management take into account the importance of monitoring the performance characteristics of the transport infrastructures and QA/QC performance-based contracts specifications in order to guarantee the preservation of environmental, social and economic resources, as well.
This study consists of two parts of research activity: in field tests and numerical simulations.
The first part consists of in situ experimental activities to investigate both road and rail transport infrastructures. The tests have shown the versatility of high-performance instruments, such as FWD, LWD, GPR and ARAN, in railway monitoring, in the evaluation of ballast conditions and sleeper/ballast interaction, and also in the reuse of volcanic ashes that after stabilization can be used in road subbase layers. The high-efficiency equipment allow a faster execution of the tests with the possibility of a higher number of measurements, the combination of several instruments at the same time with a continuous mapping of the infrastructures, performance measures and a significant cost reduction.
In the second part, the study focuses more specifically on road pavements. Considering several flexible pavements pulled out from the Italian Catalog, numerical simulations of FWD tests were carried out in the hypothesis of multilayer elastic theory with the aim to develop performance-based criteria and specifications for QC of pavement construction work.
The results allow to estimate effects of structural deficits in the perspective of future performance and Life Cycle Cost Analysis in order to quantify penalties to restore expected higher maintenance costs.
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Barkefors, Annea. "3D Synthetic Aperture Technique for Ultrasonic Imaging." Thesis, Uppsala University, Signals and Systems Group, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-121022.
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The group for non-destructive testing at Uppsala University has recently implemented the phase shift migration method, which is a method to focus images acquired unfocused using ultrasound. However, their work has been limited to 2D data, while for many applications the gathered data is 3D. This project has extended the old implementation to 3D data. The new implementation has been done in two different ways, giving one algorithm that works fast but needs much RAM, and one algorithm that takes long time but works on smaller computers, not demanding as much memory. The fast algorithm works faster than the time it takes to acquire the raw data, which makes real-time use realistic. To test the performance of the two algorithms with respect to image improvement, both against each other and against the previous 2D implementation, a number of experiments were carried out, which showed that, apart from processing time, the two new algorithms were equal in performance. The experiments also showed that the obtained resolution in both x- and y-directions matched the theoretical discussion.
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Köpke, Uwe Gerhard. "Condition monitoring of buried gas pipes using a vibrating PIG." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259460.
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Woods, Simon Nicholas. "Acoustic Inspection of Timber." Thesis, University of Canterbury. Electrical and Computer Engineering, 2006. http://hdl.handle.net/10092/3679.
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The ability to determine wood quality using non-destructive tests has enormous potential for the forestry industry in both research and commercial applications. This thesis describes some of the theory of acoustic waves in wood and how wood stiffness can be estimated by measuring the velocity of acoustic waves. Attention is paid to both resonance and stress wave timer technologies and the benefits and problems with both. A detailed description is given of the design of a new tool (Treetap 5.0) to aid in future, acoustic based, timber inspection research.
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Kan, Nathan Yu-Kwong. "Fatigue failure from internal defects in nickel base alloys." Thesis, University of Portsmouth, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308845.
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Kehoe, A. "Detection and evaluation of defects in industrial images." Thesis, University of Surrey, 1990. http://epubs.surrey.ac.uk/804357/.
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Stepto, Simon. "The effect of fibre volume on the mechanical properties of woven composite materials." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314218.
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