Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"C-scan"”.
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Neural Network Prediction of Ultimate Compression After Impact Loads in Graphite-Epoxy Coupons from Ultrasonic C-Scan Images
… 24-ply graphite-epoxy coupons from ultrasonic C-scan images. The 24-ply graphite-epoxy coupons were manufactured with bidirectional preimpregnated tape and cut into 21 coupons, 4 inches by 6 inches each. The coupons were impacted at known impact energies of 10, 12, 14, 16, 18, and 20 Joules in …
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Advanced Projection Ultrasound Imaging with CMOS-based Sensor Array: Development, Characterization, and Potential Medical Applications
… of a projection imaging system. Three C-scan prototypes, which included prototypes #1, #2 and an ultrasound mammography system, were constructed. Systematic and Evaluative studies included ultrasound CT, 3-D ultrasound, and multi-modality investigations were also performed. Furthermore, a …
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Nondestructive inspection and characterization of complex engineering materials via ultrasound techniques.
… of an oblique-incidence through transmission c-scan ultrasound technique. As laminated composites are incorporated into new aircraft, there is an increased desire for nondestructive methods for not just damage inspections but also for characterizing the material properties of the part …
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Nondestructive inspection of load induced damage in fiber reinforced polyphenylene sulfide
… nondestructive testing methods, including C-scan, ultrasonic attenuation, acoustic emission, X-ray radiography, and edge replication, were applied to study the damage developed under quasi-static tension loading of this material. The C-scan, edge replication, and X-ray radiography tests were …
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Impact damage resistance and tolerance of advanced composite material systems
… these materials. The damage area detected by C-scan is observed to develop linearly with the impact velocity for impact velocities higher than a threshold value. Brittle material systems have lower threshold velocities and higher damage area growth rates than toughened systems. The impact damage …
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Intelligent Non-destructive Measurement and Evaluation Techniques for Aircraft Composites
… image reconstruction for ultrasonic C-scan, ultrasonic 3D reconstruction, and polynomial fitting techniques for infrared thermography inspection. These researches focus on the improvement and optimization of current ultrasonic testing and infrared thermography inspection. They are …
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An investigation of stiffness reduction as an indicator of fatigue damage in graphite epoxy composites
… Nondestructive testing techniques such as C-scan and edge replication were also performed to aid in the observation of damage development. Results describe the response of each laminate orientation in tension-tension fatigue, including a record of changes in the stiffness properties at …
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Computerized Ultrasonic Raytracing Model for C-scans of Solid Steel Bridge Pins
… the results of computerized ultrasonic C-scanning of solid steel bridge pins using a raytrace model. The raytrace model was developed to facilitate interpretation of data obtained from an ultrasonic C-scanning system for the Virginia Transportation Research Council (VTRC). The report …
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Residual Compressive Strength Prediction of Carbon/Epoxy Laminates Subjected to Low Velocity Impact Damage
… <p>Using the pixel data from the ultrasonic C-scan image of the impact damage, in conjunction with CAI testing, and analyzing it with a backpropagation neural network, correlations on ultimate compressive strength can be made. This analysis demonstrates the ability of a neural network to …
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Impact response of interleaved composite materials
… laminate did not show any ultrasonic C-scan indication up to an impact of 2.45 ft-lb. The increase of delamination with increasing impact energy was slower in the interleaved specimen. The eddy current method is not effective in detecting damage in the interleaved laminate because of the …
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Investigation of constraint effects on flaw growth in composite laminates
… techniques include replication, ultrasonic c-scan, ultrasonic attenuation, acoustic emission, x-radiography, thermography and stiffness measurement. The effects of constraint on the response of composite materials can be classified in two categories: (a) in-plane effects and (b) …
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Numerical Study For Acoustic Micro-Imaging Of Three Dimensional Microelectronic Packages
… is implemented with a 230MHz virtual raster scanning transducer with a spot size of 17µm. The Virtual Transducer was designed to reduce the total numerical elements from hundreds of millions to hundreds of thousands. Thirdly, two techniques are invented to analyze and evaluate simulated …
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A self healing smart syntactic foam based grid stiffened sandwich structure
… and constrained shape recovery, respectively. C-scan and visual observation were also conducted to visualize impact damage and evaluate the degree of sealing achieved. It is found that the shape memory functionality of the SMP based syntactic foam can be utilized for the purpose of sealing impact …
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Estudio de soldaduras eléctricas por arco metálico con protección de gas (MIG/MAG) en acero naval: comparación de técnicas de inspección no destructivas basadas en imágenes digitales, identificación y clasificación de defectos
… de dos formas distintas. Una vista superior (B-Scan) de inicio a fin de la soldadura y 250 vistas seccionales (C-Scan), una cada mm de inspección. Los datos brutos se procesaron numéricamente y se interpolaron sobre una malla regular mediante técnicas de interpolación objetiva. El conjunto de …
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Frequency dependent heat generation during vibrothermographic testing of composite materials
… damage severity was inspected by ultrasonic C-scan and edge replication. From comparison of two plots of the degree of heating versus exciting frequency, either the area under the curve or the number of vibrothermal peak frequencies, the severity of the damage can be qualitatively identified.
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Damage Assessment and Strength Predictions in S-Glass/Epoxy Laminates Subjected to Low Energy Impact
… combined technical approaches of ultrasonic C-scan and neural networks. To accomplish this, each test specimen was ultrasonically C-scanned after impact testing. A MATLAB computer program was then used to convert the image files into numeric data, which they were presented to a backpropagation …
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Ultrasound field measurement and modelling for non-destructive testing
… Circuit packaging in electronic industry using scanning acoustical microscopy. The relationship among resulting ultrasonic C-scan images, destructive mechanical failure measurement, degradation cycles have been observed. The result is promising indicating the SAM is a very useful tool for weak …
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Development of self-healing techniques for fiber reinforced composites
During the last decades, fiber reinforced composites (FRPs) are year by year replacing metals due to their high stiffness and high strength in combination with low specific weight and corrosion resistance. However, during their service life, these composites due to their laminated structure (no …