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Showing 1 to 20 of 36 for “"guided wave"”.
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Guided Wave Structural Health Monitoring with Environmental Considerations
… variations and applied stress create on Lamb wave propagation velocity in plates is analytically modeled and validated. Two methods are developed for the analytical derivative of the Lamb wave velocity; the first uses assumes a thermoelastic material while the second expands thermoelastic …
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Phased Array Beamsteering in Composite Laminates for Guided Wave Structural Health Monitoring
<p>In this study a guided wave phased array beamsteering approach is applied to composite laminates. Current beamsteering algorithms derived for isotropic materials assume omnidirectional wave propagation. Due to inherent anisotropy in composites, guided wave propagation varies with direction and …
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A study on the behaviour of guided wave propagation in utility timber poles
… to reflect the actual behaviour of stress wave propagation in the columnar structures. Also, the anisotropic behaviour of timber and the effects of environment are not taken into account in numerous conventional non-destructive evaluations (NDE) that leads to errors regarding the condition …
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Holographic augmented reality : towards near-to-eye electroholography via guided wave acousto-optics
Near-to-eye displays act to directly project imagery into a viewer's eye and can range in instantiation from extremely simple (such as an optical viewfinder) to more complex immersive displays for applications in virtual and augmented reality. Many current schemes for near-to-eye display employ …
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Phased Array Damage Detection and Damage Classification in Guided Wave Structural Health Monitoring
… and prognosis. Among the methods developed, the guided Lamb wave based SHM can be a promising technique for damage evaluation since it provides reliable damage information through signals propagating over large distance with little loss of amplitude. While this method is effective for damage …
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Far-Infrared Guided Wave Optics Experiments Using a Waveguide Laser With a Hybrid Output Mirror
Made available in DSpace on 2014-12-12T20:54:23Z (GMT). No. of bitstreams: 1 7624062.pdf: 4810342 bytes, checksum: 3d085567b5672133f7bb1751066d812a (MD5) Previous issue date: 1976
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Microseismic guided wave eigenfunction theory with application to event depth classification in the Eagle Ford shale
The properties of guided waves that propagate in deep low-velocity zones are investigated using eigenfunction theory, and a novel application for microseismic event depth constraint to an unconventional reservoir is developed. Eigenfunctions, historically used in the analysis of Rayleigh and Love …
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Guided Wave Actuation for Enhanced Damage Identification in Carbon Fiber Reinforced Polymer Material Using Electrical Resistance Tomography
… a new hybrid NDE technique that combines wave actuation with ERT is proposed. To enable this hybrid approach, numerical simulations of the forward problem that can predict the effect of wave actuation in a composite with delamination crack on ERT measurements are developed. Discontinuous …
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Investigation of Linear and Nonlinear Torsional Guided Waves in Hollow Circular Cylinders for Damage Detection
… One of the promising options is the use of guided wave for damage detection in engineering applications, such as pipeline and truss system. Common types of damage in the structures include cracks and corrosion. Guided wave is sensitive to cracks up to micro scale. Long range inspection is …
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Integrated optics for holographic video
The goal of this research is to fabricate a guided-wave, two-axis scanner and to modify the design of the MIT holovideo system to take full advantage of the scanner's high bandwidth and two-dimensional deflection. The new display geometry will be designed to use the guided-wave scanner coupled with …
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Subduction zone wave guides : deciphering slab structure using intraslab seismicity at the Chile-Peru subduction zone
… affected by the interior slab structure. The wave field of these intraslab events observed in the forearc region is profoundly influenced by a seismically slow layer atop the slab surface. This several kilometer thick low-velocity channel (wave guide) causes the entrapment of seismic energy …
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Estimation of Adhesive Bond Strength in Laminated Safety Glass Using Guided Mechanical Waves
Based upon the guided wave energy velocity predictions for each of the laminates with different levels of adhesion, the S0 mode was selected as the most promising for use in nondestructively estimating adhesion levels in laminated safety glass. The predicted energy velocities (obtained using this …
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Spectral finite element modelling and damage identification of beam-like structures using linear and nonlinear guided waves
… approach for damage identification using guided waves. The proposed approach requires no baseline data. It can identify multiple damages such as characterising the number, location and the size of cracks in isotropic beams and delaminations in composite beams efficiently and accurately …
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Solution Of Electromagnetic Scattering Parameters And Radiation Patterns Of Arbitrary Body Of Revolution Radiators
A novel full wave analysis method to determine the scattering parameters and the radiation field intensities of arbitrary Body of Revolution (BOR) radiators consisting of impenetrable media is explored through derived components of modal analysis and the method of moments (MoM). Modal excitation is …
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Advances in Nondestructive Testing of Concrete Pavements
… of the Impact-Echo method, based on guided wave theory, is presented. This provides a closer match between theoretical and observed results, and ultimately a more accurate basis for testing. A new, time-domain based method is then proposed to address some practical shortcomings of the …
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Investigation of carburization extent from the inner diameter (ID) of ethylene furnace tubes using non-destructive examination (NDE) applied on the outer diameter (OD)
… testing to study changes in natural elastic wave frequencies, b) metallographic evaluation, c) resonant ultrasound spectroscopy (RUS), and d) computational modeling to simulate guided wave and ultrasonic phased array technique. The collaboration of the results of these experiments …
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Structural Damage Classification using Support Vector Machines
… ceramic actuators are utilized to generate guided wave signals on a set of aluminum beam coupons with different damage features, such as types, locations, and thicknesses. The short-time Fourier transform is applied to analyze the measured signals. For damage classification, the spectrograms …
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Holovideo on a stick : integrated optics for holographic video displays
… for holographic video consisting of arrays guided-wave acousto-optic devices. This platform serves as the foundation for a new family of holographic video architectures that trade off its enormous pixel bandwidth for display extent, view angle and frame rate. This dissertation work …
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Novel rare-earth-doped planar waveguide lasers
The planar guided-wave geometry is compatible with a wide range of materials, waveguide architectures and fabrication techniques. This thesis reports a series of studies of rare-earth-doped planar waveguide lasers, exploiting and extending the diverse range of possibilities that can be applied to …
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Nonlinear ultrasonic testing using a non-collinear approach: application to heat treatment of steels and to asphalt concrete mixtures
… micro-structural dependence of acoustic wave attenuation, velocity, and a non-linear parameter, non-collinear scattered wave amplitude. Specimens of various microstructures were prepared by means of heat treatment for 1045 and 4140 Steel. Nonlinear investigation was also performed on two …
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