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Showing 1 to 20 of 70 for “"delaminations"”.
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Modeling and detection of delaminations in laminated plates
… of this thesis is the analysis and detection of delaminations in plate-like structural systems, such as concrete walls, large diameter pipes, slabs and decks. The first three chapters deal primarily with the numerical 2D modeling of delaminated plates. In the first chapter, we present the …
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Effects of crack arresting delaminations in aluminum-lithium alloys
Made available in DSpace on 2010-05-19T18:38:20Z (GMT). No. of bitstreams: 4 Hernquist_Thesis_opt.pdf: 6706271 bytes, checksum: bed37ee45a2aaa5b5dd1b76036d9d235 (MD5) final thesis.docx: 53203185 bytes, checksum: 4f9e95020501b4b07c3e54b80d49fe55 (MD5) Hernquist_Mark.pdf: 6707593 bytes, checksum: …
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Vibration, buckling and postbuckling of laminated composites with delaminations
… of laminated composite plates with multiple delaminations are presented. A fInite element method based on a layer-wise laminated composite plate theory is developed to formulate the problem. Geometric nonlinearity in the sense of von Karman and the imperfection in the plate in the form of …
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Instability-related delamination growth of embedded and edge delaminations
Compressive loads can cause local buckling in composite laminates that have a near-surface delamination. This buckling causes load redistribution and secondary loads, which in turn cause interlaminer stresses and delamination growth. The goal of this research effort was to enhance the understanding …
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A parametric study of delaminations in an aluminum-lithium alloy
… the forefront of aerospace materials research. Delaminations in these alloys play a significant role in their fracture processes. Therefore, a more complete understanding of the factors that influence the behavior of these delaminations and their corresponding effect on the primary crack …
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Experimentally informed modeling of nonlinear wave propagation and phononic behavior in prescribed delaminations
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01
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Evaluation of thermographic techniques for the detection of subsurface delaminations in concrete bridge substructures
This thesis presents both an analytical and an experimental evaluation of the feasibility of using infrared thermographic techniques to detect subsurface damage in concrete. Various methods of artificial heating, required to effectively apply this technique, are presented. Four major conclusions …
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Application of fracture mechanics to predict the growth of single and multi-level delaminations and disbonds in composite structures
… prediction of laminated composites containing delaminations located between arbitrary layers in the laminate, and to extend the investigations to composite structures subjected to barely visible impact damage (BVID). The advantages of fracture mechanics-based methodologies to predict …
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Delamination buckling, postbuckling, and growth in axially loaded beam-plates
… isotropic, these cracks will be referred to as delaminations. Buckling, postbuckling, and growth of delaminations in these beam-plates will be analyzed. A finite element method in which all of the terms of the stiffness matrices are obtained by exact integration is employed to determine the …
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Compression of thick laminated composite beams with initial impact-like damage
… classifications are multiple through-thickness delaminations, isolated delaminations. damage near the surface. and matrix cracks. Specimens from each classification were compared to specimens tested without initial damage in order to determine the effects of the initial damage on the final …
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Detection of subsurface anomalies in fiber-reinforced polymer (FRP) wrapped timber bridge components using infrared thermography
… has also been presented.;Simulated subsurface delaminations were constructed in the laboratory in timber piles wrapped with FRP composite fabric. The delaminations varied in size, thickness, and severity. These delaminations were placed between the 1/8&inches; thick FRP wrap and timber surface. …
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Nondestructive evaluation of FRP composite members using infrared thermography
… anomalies such as voids, cracks, debonding, and delaminations in concrete bridge decks and pavements and in some configurations of FRP decks has been studied earlier by other researchers. These earlier studies have yielded reasonably satisfactory results though further refinement of the …
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On a generalized laminate theory with application to bending, vibration, and delamination buckling in composite laminates
… and transverse compressibility are included. Delaminations between layers of composite plates are modeled by jump discontinuity conditions at the interfaces. The theory includes multiple delaminations through the thickness. Geometric nonlinearity is included to capture layer buckling. The …
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Detection of subsurface anomalies in composite bridge decks using infrared thermography
… and filler materials. These simulated delaminations were placed between the 3/8&inches; thick wearing surface and the top of the fiber reinforced polymer (FRP) deck. The laboratory specimens were tested using the infrared imaging system. The infrared images from the delaminated …
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Delamination dynamics and vibrothermographic-thermoelastic evaluation of advanced composite materials
… were formed around imperfection areas especially delaminations. Heat generation was also found to relate to the crack size. In order to explain the above observed phenomena, the dynamic behavior of undamaged and damaged composite plates was studied over a broad frequency range. The analysis was …
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Application of digital infrared thermography for nondestructive evaluation of composite bridge components
… to detect subsurface defects such as debonds and delaminations in Fiber Reinforced Polymer (FRP) bridge decks and other composite bridge components such as beams and columns wrapped with steel or FRP jacket.;This thesis investigates the use of digital infrared thermography on FRP bridge decks both …
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Development of a portable low-cost digital shearography system
… to detect flaws such as cracks, debonds and delaminations in materials.
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X-ray Micro-Computed Tomography and Deep Learning Segmentation of Progressive Damage in Hierarchical Nanoengineered Carbon Fiber Composites
… (termed ‘nanostitch’) that primarily targets delaminations, and (ii) thin-ply morphology that targets intralaminar cracking and delaminations. Both solutions have demonstrated significant mechanical improvements via standard ex situ tests that lack underlying progressive damage understanding. …
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An investigation of the excitation frequency dependent behavior of fiber reinforced epoxy composites during vibrothermographic inspection
… concerns the frequency related behavior of delaminations in fiber reinforced composites during vibrothermography, the use of active thermography with a mechanical excitation for the nondestructive evaluation of a structure or part. Two models, one where the size and geometry of the flaw …
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Implementation of Infrared Non-Destructive Evaluation in Fiber-Reinforced Polymer Bouble-Web I-Beams
… beam through heating and monitor how it changes. Delaminations determined by others to be the critical form of deterioration, would be expected to affect the heat conduction in these beams. This project used a halogen lamp to heat the surface of the beam followed by an observation with an IR …
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