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Browse all Theses and Dissertations

2019

Ph.D. in Engineering

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Full-Text Articles in Engineering

As-Manufactured Modeling Of A Mistuned Turbine Engine Compressor Evaluated Against Experimental Approaches, Daniel L. Gillaugh Jan 2019

As-Manufactured Modeling Of A Mistuned Turbine Engine Compressor Evaluated Against Experimental Approaches, Daniel L. Gillaugh

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As-manufactured rotors behave quite differently than nominal, as-designed rotors due to small geometric and material property deviations in the rotor, referred to as mistuning. Traditional integrally bladed rotor (IBR) modeling approaches assume each blade is identical. State-of-the-art IBR dynamic response predictions can be accomplished using asmanufactured models (AMM) generated via optical topography measurements and mesh morphing. As-manufactured models account for geometric deviations occurring through the machining process, material deviations and field wear, allowing each blade to respond differently. Rotor designs are intended to avoid resonance crossings throughout an engine’s operating range, but total avoidance is challenging. This has led to …


Non-Deterministic Metamodeling For Multidisciplinary Design Optimization Of Aircraft Systems Under Uncertainty, Daniel L. Clark Jr. Jan 2019

Non-Deterministic Metamodeling For Multidisciplinary Design Optimization Of Aircraft Systems Under Uncertainty, Daniel L. Clark Jr.

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To make coupled multi-physics-informed design decisions, multidisciplinary analysis, design optimization and uncertainty quantification must be present to accurately represent the full system under investigation. Unfortunately, all of these processes are computationally demanding, requiring a large number of system evaluations with identified uncertain variables, and iterative system evaluations with respect to the design variables of interest. Surrogate or metamodels are used to alleviate the computational burden in both these design exploration activities by trading accuracy with efficiency. The primary objective of this dissertation is to develop a flexible surrogate modeling technique capable of quantifying the uncertainty of multidisciplinary systems in an …


Immersive Rehearsal In A Simulated Environment (Irise), Cassandra Clouse Jan 2019

Immersive Rehearsal In A Simulated Environment (Irise), Cassandra Clouse

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Recent advancements in virtual environment (VE) technology and the growth of VE use in treating and training individuals are opening up new possibilities for rehearsal in safe and rich environments. Research has shown that VEs can be used to treat those with Post Traumatic Stress Disorder (PTSD), but very little research has been done to suggest good guidelines for creating an effective environment. This research was conducted to help inform the design of systems that let veterans rehearse potentially stressful experiences in a safe environment before having to physically step into that environment. We investigated responses to specific design components …


Processing And Properties Of Multifunctional Two-Dimensional Nanocomposite Based On Single Wall Carbon Nanotubes, Ali M. Al Mafarage Jan 2019

Processing And Properties Of Multifunctional Two-Dimensional Nanocomposite Based On Single Wall Carbon Nanotubes, Ali M. Al Mafarage

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Truly single layer (monolayer) films of unmodified zigzag single-walled carbon nanotubes by using the Langmuir-Blodgett (LB) technique have been processed successfully. Measurements of their mechanical and optoelectric properties were achieved. Different theoretical equations were used based on the results obtained from the experimental part to study the properties and structures of the produced material and their composite. The produced films were highly oriented as determined by polarized Raman spectroscopy and as shown by scanning tunneling microscopy (STM). The films have a significant amount of flexibility which makes their behavior similar to rubbery materials. They can also be deposited on different …


Strategic Decision Facilitation: An Exploration Of Alternative Anchoring And Scale Distortion Optimization In Multi-Attribute Group Decision Making, Joseph Patrick Kristbaum Jan 2019

Strategic Decision Facilitation: An Exploration Of Alternative Anchoring And Scale Distortion Optimization In Multi-Attribute Group Decision Making, Joseph Patrick Kristbaum

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Choosing between alternatives, regardless of the decision context in an organizational group setting is a difficult task. The integrity of the decision is under constant scrutiny and rarely are we ever able to characterize the magnitude of that with which we are consciously or subconsciously concerned: personal bias. This leads to long, drawn out timelines and loosely trusted decisions. This dissertation research focuses on using a traditionally, negatively viewed anchoring bias strategically in a series of experiments with a hypothesis that it can be used to positively reduce personal biases such as preference bias and judgement rooted in ambiguous or …