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 11 of 11 for “"Internal Voids"”.
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Development of a Self-Heating Consolidation Procedure for 3D-Printed Continuous Wire Polymer Composite Laminates
The voids in 3D-printed continuous wire polymer composites (CWPCs) reduce the wire-polymer adhesion, which can decrease their strength and stiffness and their in-part sensing accuracy. This thesis shows the development, implementation and effects of a consolidation procedure to reduce the voids in …
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DATA-DRIVEN MULTI-SCALE MULTI-PHYSICS MODELLING OF THERMAL STRESS AND DISTORTION IN ADDITIVE MANUFACTURING
… the proposed approach, the rough surfaces and internal voids can be well incorporated. The coupled CFD-FEM approach are utilized to simulate the two typical powder-based AM processes, i.e., powder bed based process and powder fed process. In order to reduce the computational cost and optimize …
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Moment analysis methods of ultrasonic waveforms to characterize the internal temperature and melt transition boundary for materials with irregular porosity.
… in a multitude of industries. Monitoring the internal thermal and phase states of materials is of particular interest to the petro-chemical, food, and polymer processing industries, and ultrasound has found limited investigation within the literature for such applications. In this thesis, …
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Enhancing Power Side-Channel Detection of Attacks to Additive Manufacturing Systems
… to be manufactured rapidly with complex and internal geometries. Attackers can remotely and covertly cause anomalies in these parts, which include internal voids or mechanical weaknesses that are not detectable using conventional inspection methods. In this work, we enhance the power …
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Tracking hot spot dynamics in solid state explosives with shock compression microscopy
… a 32-channel pyrometer, we found that large internal voids created high temperature hot spots via in situ gas generation and compression. We observed overdriven, detonative-like dynamics in a PBX by shocking hundreds of bulk PBX samples and interrogating them with pyrometry, high speed …
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Nondestructive evaluation for hybrid-composite girder bridges
… this arch is enclosed within an FRP shell, internal voids or honeycombs that may occur during concrete placement can go undetected. The research to be presented is focused on the application of nondestructive evaluation (NDE) technologies of thermography, ultrasonic testing, and acoustic …
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DESIGN AND SYNTHESIS OF STAINLESS-STEEL NANOPARTICLES: OXIDATION BEHAVIOR AND MORPHOLOGICAL EVOLUTION
… NPs, oxidation and the subsequent formation of internal voids. HRTEM images of oxidized alloy NPs are analyzed to understand the extent of internal void formation as a function of oxidation conditions. In chapter 4, I explore how grain boundary diffusion and interfacial thermodynamics dictates …
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Fatigue and Fracture of Electron Beam Melting Ti-6Al-4V
… in performance after HIP due to the closure of internal voids and lack-of-fusion defects. Finally, drawing on the characterization work, a Fracture Mechanics (FM)-based fatigue life model was utilized to compare predictions to as-tested results. Overall, this study demonstrated how an in-depth …
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Strength-structure relationships in carbon fibers
… thought to be one of interlinking. Surface and internal flaws, involving large crystallite misorientations, have been observed in type I fibres, and using the Reynolds - Sharp theory for fibre failure, estimates of mechanical properties for such fibres have been made which are encouragingly …
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Cyclic Properties of Natural Soil Containing Pumice Particles
… to their vesicular nature and the presence of internal voids, pumice particles are highly crushable, compressible and lightweight, rendering them problematic from an engineering point of view. For the purpose of laboratory testing, undisturbed and reconstituted NP soil samples were obtained …
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Insulation Design, Assessment and Monitoring Methods to Eliminate Partial Discharge in SiC-based Medium Voltage Converters
… –Experimental PD investigation is completed for internal void discharge, surface discharge, and point discharge representative coupons under square excitations. Based on the data and the existing knowledge about PD mechanisms, widely accepted PD models are selected. Using these physics-based …