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 20 of 20 for “"deformation measurements"”.
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Particulate composite material internal deformation measurements using x-ray microtomography and digital volume correlation
… we employ an in-house DVC algorithm to measure deformations within a model composite material – a controlled number of one or a small finite number hard particles in a complaint polymer matrix. In-situ compression experiments are performed inside an X-ray microCT scanner on samples containing …
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Probing local thermal, mechanical, and optical properties utilizing dynamic cantilever response in contact mode atomic force microscopy
… nm) and the ability to measure dynamic surface deformation with sub-picometer precision. Measurement of dynamic surface deformation in response to a stimulus (e.g. heating or mechanical force) provides information about local material properties. This thesis presents three studies which use …
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Low coherence speckle interferometry (LCSI) for the characterisation of adhesive bonded joints
… Interferometry (LCSI) combines depth-resolved measurements of Low Coherence Interferometry and high-accuracy deformation measurements of Electronic Speckle Pattern Interferometry. Depth-resolved deformation measurements enable e.g. the characterisation of the behaviour of interfaces in …
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Moiré interferometry at high temperatures
… optical technique allowing full-field in-plane deformation measurements at high temperature by using high-sensitivity moiré interferometry. This was achieved by a new approach of performing deformation measurements at high temperatures in a vacuum oven using an achromatic interferometer. The …
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Development of specimen mounting and gripping system for planar biaxial tensile testing of biological membrane tissue
… improvements were also made to the optical deformation measurements and sample thickness measurements. Regarding the optical deformation measurements, it was found that speckling the sample with multi-coloured paints improved correlation, and the addition of Cross Polarising Line filters …
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Non-invasive ultrasound monitoring of regional carotid wall structure and deformation in atherosclerosis
… system for reliable regional structure and deformation measurements since these are more sensitive indicators of disease progression. We constructed a system for freehand ultrasound scanning based on custom software which simultaneously acquires real-time image sequences and 3D frame …
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Earth pressure balance (EPB) shield tunneling in Bangkok : ground response and prediction of surface settlements using artificial neural networks
… because this requires not only reliable ground deformation measurements in the field but also operational records of the shield. Numerous empirical and analytical relations between characteristics of traditional shields and surface and subsurface deformations exist; also 2-D and 3-D numerical …
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Improved Cranial Fracture Metrics For Assessing The Protective Benefits Of Helmet Systems
… high velocity bullets and fragmentation, large deformations have been shown to occur on the inside of non-metallic helmet shells. If these deformations contact the underlying head there is the potential to cause injury, termed as Behind Helmet Blunt Trauma (BHBT). A method of assessing BHBT is …
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Modeling the Behavior of a Type-319 Aluminum Alloy During Quenching
… model is used to predict the onset of plastic deformation in quenched parts due to effects of temperature and strain rate. The evolution of this mechanical threshold follows a Voce Law formulation. Parameters of the model are derived from rapid, uniaxial tension tests conducted on samples cast …
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Relating fatigue crack growth to microstructure via multiscale digital image correlation
… growth at multiple scales and links material deformation to microstructural properties. The optical technique of digital image correlation (DIC) is well suited for this task since it provides quantitative full-field deformation measurements at multiple length scales. The first part of this …
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Design of curved electrodes to enable large stroke -- low voltage micro actuators
… A model predicting the extent of plastic deformation was matched with actual deformation measurements. The second method utilizes the strain resulting from curing epoxy. A diaphragm is formed by etching through the handle of an SOI wafer, leaving a circular silicon membrane. After filling …
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Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets
… digital image correlation (DIC) for full-field deformation measurements. The effect of nominal core density on the observed failure mode is described. A finite element model (FEM) is developed to simulate the experiments performed in the current study. The purpose of this simulation is to …
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Investigating the Influence of Mechanical anisotropy on the Fracturing Behaviour of Brittle Clay Shales with Application to Deep Geological Repositories
… openings. This thesis investigated the deformation and failure process of a clay shale, namely Opalinus Clay, with particular focus on the influence of anisotropy on the short-term response of circular tunnels. To achieve this goal, a hybrid continuum-discontinuum numerical approach was …
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Thermal and fatigue testing of fiber reinforced polymer tie connectors used in concrete sandwich walls
… Delta Tie. The scope of this research included deformation measurements, strain measurements, temperature recordings, fatigue strength determinations, and theoretical analysis for comparison to experimental results.;The results of this research indicated that when subjected to a 100°F …
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Image-based Fine-scale Infrastructure Monitoring
… design process. This type of inspection, i.e., measurements of deflections and/or cracks, has traditionally been performed with instrumentation that requires access to, or contact with, the structural element being tested; performs deformation measurements in only one dimension or direction; …
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Behavior of Deep Reinforced Concrete Beams under Monotonic and Reversed Cyclic Load
… used for interpretation of the various deformation measurements. The results showed that part of the ultimate shear was carried in the cracked concrete. It was concluded that load reversals had little effect on the overall response. A test of deep beam provided with single bar #18 …
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Influence of Advanced Airbags on Injury Risk During Frontal Crashes
… with no airbag equipped. NASS/CDS steering wheel deformation measurements were used to identify cases in which thoracic injuries may have been caused due to steering wheel impact and deformation. The distributions of injuries for all cases were determined by body region and injury severity. These …
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Investigating Moisture Gradient-Induced Warpage of Veneers
… during the manufacturing process. Out-of-plane deformation, or warpage, of wood veneers caused by changes in moisture content affects the ability to press flat panels. To understand wood panel warpage, experimental methods are developed to create and measure moisture-induced deformation of wood …
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Quantitative understanding of the role of grain boundaries in polycrystalline deformation via multiscale digital image correlation
… we focus on slip transmission across GBs. Strain measurements with sub-grain level spatial resolution were acquired for Hastelloy X deformed plastically in uniaxial tension. The full field DIC measurements show a high level of heterogeneity in the plastic response with large variations in strain …
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Advancements of Particle-Surface Interaction Studies through Novel Measurement Technique Development and Engineering Modelling
… factor for determining the amount of plastic deformation that occurs on the flat surface. These findings are underscored in a novel coefficient of restitution model that accounts for the jagged particle shape present on typical particles and the plastic deformation of the surface material. …