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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 31 for “"Bondline"”.
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Characterization of the wood/isocyanate bondline
… a technique for probing the cure chemistry and bondline morphology of pMDI-bonded wood composites. A 99% ¹⁵N-enriched pMDI resin with desirable adhesive properties was synthesized. A series of model cellulose/¹⁵N-pMDI composites, cured as a function of cellulose precure moisture content, were …
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Molecular investigation of the wood/pMDI adhesive bondline
… more molecular information about the pMDI-wood bondline, and to further improve the bonding performance. In order to correlate molecular phenomena with macroscopic performance of wood-adhesive bondline, low frequency molecular motions in wood were probed using dynamic mechanical analysis (DMA) …
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A study of the behavior of the GRP hat-stiffened panel bondline under high strain rate loading
Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1995, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.
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A Photoelastic Investigation into the Effects of Cracks and Boundary Conditions on Stress Intensity Factors in Bonded Specimens
… conducted. Photoelastic specimens containing a bondline are subjected to a constant displacement boundary condition created by bonded end grips. Specimens containing various crack orientations are analyzed to determine stress intensity factors at the induced crack tips. Specimens containing …
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Moisture-Cure Polyurethane Wood Adhesives: Wood/Adhesive Interactions and Weather Durability
… of isocyanate cure chemistry in wood bondline. MPUR and a CPUR were employed to investigate whether wood/adhesive interactions influence PUR properties. Wood interactions significantly altered PUR hard/soft domain size distribution (atomic force microscopy, AFM), thermal transition …
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Stress Intensity Factor Distributions in Bimaterial Systems - A Three Dimensional Photoelastic Investigation
… bimaterial specimens, suggesting the presence of bondline residual stresses (rather than elastic modulus mismatch) as the primary contributing factor. The second series of tests involves the bonding of mutually translucent photoelastic materials whose elastic module differ by a ratio of …
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BOND STRENGTH EVALUATION IN ADHESIVE JOINTS USING NDE AND DIC METHODS
… defects such as kissing or weak bonds in the bondline interface. Also, there are shortcomings of existing non-destructive evaluation (NDE) methods to non-destructively detect/characterize these interfacial defects and reliably predicting the bond shear strength. As a result, adhesive bonding …
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Parametric investigation of the mechanical response of two-dimensional composite scarf joints via finite element modeling
… region, and equilibrium considerations along the bondline, and by the local joint features manifested at the tips of the adherends at the ends of the joint region and through ply-by-ply level mismatch in stiffness properties within the adherend. The global peaks in the magnitudes of strains occur …
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Nondestructive inspection and characterization of complex engineering materials via ultrasound techniques.
… technique for inspecting damage at the bondline between a carbon fiber reinforced laminated composite and aluminum. The sample was inspected from both the aluminum side as well as from the composite side, and the areas of delamination were successfully identified. The novelty of this …
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Studies of PF Resole / Isocyanate Hybrid Adhesives
… wood specimens indicated the dependence of bondline fracture energy on the blend ratio. The 75/25 PF/PMDI blend exhibited a high fracture energy with a fast cure speed and processable viscosity. Exposure to water-boil weathering severely deteriorated the fracture energies of the hybrid …
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Uncertainty quantification applied to the analysis and design of a hypersonic inflatable aerodynamic decelerator for spacecraft reentry
… to the flexible thermal protection system bondline temperature for a ballistic Mars entry trajectory, subject to uncertainties in the material thermal properties and important flowfield variables from the initial study. The uncertainty in the bondline temperature is compared to its …
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Fundamental Analysis of Wood Adhesion Primers
… red oak; both primers dramatically improved bondline toughness and durability. Relative to HMR, the reduced crosslink density in a-HMR did not impair primer efficacy. In contrast, the pMDI primer was ineffective; it reduced bondline toughness and durability. Solvent-submersion, torsional …
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A feasibility study of PVDF piezoelectric sensors to detect damage in adhesive joints
… techniques to attach them near the adhesive bondline. PVDF sensors have been successfully used as NDT transducers in pulse-echo, through-transmission, and acousto-ultrasonic techniques to monitor curing, to detect porosity and crack propagation in different model joint geometries. The …
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Fabrication Refinements of Advanced Packaging Techniques for Medium-Voltage Wirebond-less Multi-Chip Power Modules
… requirements. It is essential to have a uniform bondline between the substrates to achieve all bond connections and improve reliability. Silver sintering is also used to attach the molybdenum (Mo) post interconnects. These interconnects allow for sandwich-structure modules with low inductances; …
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Organic Fillers in Phenol-Formaldehyde Wood Adhesives
… particle size effects on fracture energy and bondline thickness, but no clear size effects on penetration. Regarding corn cob residue and walnut shell, particle size effects on fracture energy were statistically significant, but magnitude of the difference was rather small. Classified corn cob …
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Durable Sandwich Structure Joining Technology for NASA's Ares V Launch Vehicle
… interface along the splice plate bondline of the DRJ are compared with those from a conventional splice joint (CSJ) configuration for a series of linearly increasing bondlines thicknesses and joint overlap lengths. The parameter studies indicate the DRJ configuration's adhesive …
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Adhesive Bonding of Low Moisture Hickory Veneer with Soy-based Adhesive
… lathe check characterization, and adhesive bondline thickness and penetration depth measurement. Impact of wood region and type (hickory versus red oak) was assessed by comparing wood buffering capacity and delamination following three-cycle water soaking. Dry and wet shear strength values …
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An interdisciplinary study of cathodic debonding in elastomer/metal adhesive bonds
… is reported. The generation of OH⁻ ions at the bondline due to an imposed cathodic current from an external source is suspected to be the predominant cause of failure. A surface analysis study was performed early in this research for the purpose of identifying the cause(s) of failure. …
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Performance Evaluation and Durability Studies of Adhesive Bonds
… the characterization of fracture energy vs. bondline thickness trends through fewer tests than those required during a conventional "one at a time" characterization approach, potentially offering a significant reduction in characterization times. The second chapter investigates the adhesive …
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Understanding the Role of N-Methylolacrylamide (Nma) Distribution in Poly(Vinyl Acetate) Latex Adhesives
… had the highest proportion of water-phase NMA. Bondline images and SEM micrographs both indicated that the integrity of Latex 1 was least affected by the accelerated aging treatments.
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