Global ETD Search

291	Investigation of the Noise Radiation from Heated Supersonic Jets Mora Sánchez, Pablo A. January 2016 (has links) No description available. Aerospace Materials Supersonic Jet Noise Crackle Mach Wave Radiation Supersonic Heated Jets
292	Flame Interactions and Thermoacoustics in Multiple-Nozzle Combustors Dolan, Brian January 2016 (has links) No description available. Aerospace Materials Gas Turbines Combustors Lean Direct Injection Thermoacoustics Nozzle Interaction Alternating Flow Pattern
293	Experimental Testing and Computational Fluid Dynamics Simulation of Maple Seeds and Performance Analysis as a Wind Turbine Holden, Jacob R. January 2016 (has links) No description available. Aerospace Materials Maple seed Computational Fluid Dynamics Turbomachinery Wind Turbine Betz Limit Boimimicry
294	Effects of Lightning on Low-Frequency Navigation Systems Latif, Shehzad A. 25 April 2008 (has links) No description available. Aerospace Materials Electrical Engineering Engineering Loran-C Low-Frequency Navigation Systems
295	Characterization of Effects of Mixed Neutron/Gamma Irradiation on NASA Glenn SiC Piezoresistive Pressure Sensors Goodenow, Debra A., B.S. 24 June 2008 (has links) No description available. Aerospace Materials Electrical Engineering Engineering Mechanical Engineering Nuclear Physics Radiation SiC radiation temperature wheatstone bridge piezoresistive
296	Reduced Order Model Development For Feedback Control Of Cavity Flows Caraballo, Edgar J. 29 October 2008 (has links) No description available. Aerospace Materials Engineering Mechanical Engineering Reduced order model Feedback control Cavity flow POD
297	An Energy-Based Experimental-Analytical Torsional Fatigue Life-Prediction Method Wertz, John Nicholas 02 September 2010 (has links) No description available. Aerospace Materials Engineering Experiments Mechanical Engineering Mechanics
298	Quantification of Fourth Generation Kapton Heat Flux Gauge Calibration Performance Hodak, Matthew Paul 02 November 2010 (has links) No description available. Aerospace Materials Mechanical Engineering heat flux thermal conductivity kapton gas turbine
299	Joining of Shape-Memory NiTi Torque Tubes to Structural Materials Fox, Gordon R. 19 June 2012 (has links) No description available. Aerospace Engineering Aerospace Materials Engineering NiTi TiNi Nitinol shape memory welding dissimilar intermetallics actuator torque torsion
300	Understanding Loading Effects and Post-Processing Effects on the Durability of Additively Manufactured Ti-6Al-4V Taylor Ann Hodes (20248788) 17 November 2024 (has links) <p dir="ltr">Additive manufacturing continues to show great promise for use in structural components due to the cost effectiveness and reduced complexity associated with optimized and targeted use of the method. However, before additive manufacturing can be widely accepted a more complete understanding of the material performance and microstructural features must be achieved. This thesis aims to further the understanding of cold dwell fatigue in additively manufactured Ti-6Al-4V and explore targeted microstructural control of additively manufactured Ti-6Al-4V through the use of printing parameter variations and hot isostatic pressing.</p><p dir="ltr">In the first portion of this thesis, experimental work was conducted to explore the effect of periodically applied load dwell and overloads on the stress-life relationship for additively manufactured Ti-6Al-4V. Samples printed using an optimized print parameter set, heat treated using hot isostatic pressing, machined, and longitudinally polished were tested across a variety of loading schemes including: constant amplitude, periodic dwell, periodic overload, and alternating periodic dwell and periodic overload. It was determined that, for the parameter set studied, periodic overload provided similar damage compared to constant amplitude cases, while periodic dwell provided greater damage compared to both constant amplitude and periodic overload cases. Additionally, a phenomenological failure prediction model for dwell, variable amplitude loading was created. The developed model combines the effects of plasticity and creep with an energy-based approach rooted in the fundamental behavior of the material.</p><p dir="ltr">In the second portion of this thesis a review of the literature is presented to explore the use of hot isostatic pressing in additively manufactured Ti-6Al-4V. The literature review holds the primary purpose of deepening the understanding of the relationships between hot isostatic pressing and microstructural control and how they are taken together to improve fatigue performance. The literature review explores many aspects of factors impacting fatigue life and how the additive manufacturing process impacts material microstructure. The final conclusion of the literature review is that 1 micrometer is the largest pore expected to achieve complete closure though hot isostatic pressing, that 40 micrometer is the critical pore size for fatigue failure, and the process for microstructural evolution during pore closure is dominated by creep and dynamic recrystallization. Using these facts targeted microstructural control can be explored to optimize fatigue performance through purposeful microstructural variations.</p> Aerospace materials Aerospace structures Metals and alloy materials Additive Manufacturing Cold Dwell Fatigue Variable amplitude loading (VAL)

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