Mechanical Engineering Commons^™

Design Of A Spacecraft Power System Experiment, Jay Bakulkumar Kamdar

Masters Theses

This research delves into the design, implementation, and analysis of a controlled experimental framework for photovoltaic cell characterization and its application in spacecraft power systems. Such a system was simulated and validated by benchmarking characteristics of a photovoltaic module and implementing them in a system design simulation yielding performance data for comparative analysis. A hardware setup was developed to perform IV characterization tests under steady state thermal conditions. Experiments conducted across various thermal regulation profiles helped quantify the effects of temperature on the photovoltaic performance parameters. Active cooling reduced the steady state cell temperature by 17.9% and improved the cell …

Investigation Of Arm Stiffness Modulation During Overground Physical Human-Human Interaction, Henry Tien

Masters Theses

The vision of advancing robots capable of direct physical engagement with humans begins with an understanding of how humans interact with each other. Even rudimentary interactive tasks, such as shaking hands, provides tremendous challenges for modern robotics and current research into the biomechanics of such interactions is limited. Thus, further analysis of physical Human-Human Interaction (pHHI) will bolster efforts to enhance collaborative robot capabilities. To this end, a custom Force Perturbation Handle (FPH) was developed, including the requisite mechanical, electrical, and software systems, to investigate the unique role of arm stiffness modulation in haptic communication between humans. The novel device …

Aerodynamic Design Workflow Optimization For Fsae: Advanced Cfd And Hpc Automation, Kyle Maynor

Masters Theses

This research identifies and resolves inefficiencies in the Computational Fluid Dynamics (CFD) workflow of the Missouri S&T Racing Formula SAE Team’s aerodynamic development. Key bottlenecks were found in simulation runtime, laborious simulation preparation, an overly manual simulation submission process, and unchecked mesh quality. A fully reimagined workflow was implemented with simulation parameters to adjust vehicle attitudes. From this, an automated design sweep could be executed to generate aero maps of the developing vehicle using the Design Manager Project. A Python-based submission app handles the terminal interfacing and macro editing that significantly slowed the job submission process before. Using a university …

Design Of Real-Time And Energy-Efficient Driver Assist Systems Using Electroencephalogram And Neuromorphic Computing, Nathan Alan Lutes

Doctoral Dissertations

Despite the technological breakthroughs in advanced driver assist systems, distracted driving persists as a major challenge to roadway safety. This investigation advances the body of knowledge towards a solution by developing an individualized driver-state detection method using electroencephalogram (EEG) and neuromorphic computing to provide a less invasive and more energy efficient ADAS solution. It furthermore explores the changes in brain functional connectivity under distracted conditions to better understand brain state information that could be used for neuro-feedback intervention systems. The first contribution introduces the concept of using Convolutional Spiking Neural Networks (CSNNs) for recognition of patterns with movement-intention predictive power …

Process-Structure-Property Relationships In Laser Powder Bed Fusion Produced 17-4 Ph Steel, Ben Brown

Doctoral Dissertations

Laser powder bed fusion (LPBF) is a metal additive manufacturing method that produces non-traditional microstructures as a result of the rapid solidification and thermal cycling inherent to the process. When using LPBF-produced material in application, these unique microstructures challenge the applicability of well-developed mechanical property databases achieved by conventional heat treatments. For wider adoption of this technology, a more holistic understanding is necessary on how process attributes develop material structure, which dictate mechanical properties. This dissertation explores the process structure-property relationships in LPBF 17-4 PH steel through systematic evaluation of atmospheric processing and heat treatment effects on microstructure and mechanical …

Experimental Study Of Defects In Coaxial Wire-Based Laser Metal Deposition, Remy Mathenia

Doctoral Dissertations

This work seeks to improve the usability and capability of coaxial wire-based laser metal deposition (LMD) through the experimental study of process parameters on output geometry, directional effects, and defect formation. Wire-based LMD is a directed energy deposition (DED) strategy that uses a focused laser heat source to melt and fuse metal wire as it is deposited. This process is used to build parts layer-by-layer until a desired geometry is accomplished. LMD enables the creation of complex components at a high build rate with low material and energy waste. This work focuses on the deposition of titanium wire in the …

Sensor Embedding And Thermal Monitoring Strategies For Laser-Foil-Printing Additive Manufacturing, Tunay Turk

Doctoral Dissertations

"This work investigates Laser Foil Printing (LFP), a novel metal additive manufacturing (AM) process that fabricates parts layer-by-layer using metal foils. To enhance LFP productivity, the process steps were optimized, and an 88.1% reduction in processing duration was achieved. A unique aspect of this study was the introduction of laser polishing as an edge polishing technique within the LFP process. This innovative approach, employing an overlapping spiral pattern, leverages selective laser remelting and erosion to effectively suppress elevated edges. To stabilize the molten melt pool, a discrete spot scanning strategy was implemented. The fabricated parts were subjected to detailed analysis, …

Thermal Management For Optimal Performance Of Polymer Electrolyte Membrane Unitized Regenerative Fuel Cells, Mythy Tran, Ayodeji Demuren

Mechanical & Aerospace Engineering Faculty Publications

Hydrogen is an excellent carrier for energy storage and can be produced from various green and renewable sources. However, the cost of producing hydrogen and converting it to useful energy is much higher than fossil fuel and traditional energy generation and storage systems. Unitized regenerative fuel cells (URFC) maximize utilization of high-cost cells and their components, thus, lowering system capital cost. Improving the URFC efficiency is an effective way to lower its operating cost. This study evaluates utilization of waste heat during operation and recovery strategy to improve system efficiency of Proton Exchange Membrane (PEM) URFC. A COMSOL Multiphysics 3-D …

Advancing Wind Turbine Blade Longevity Through Innovative Trailing Edge Reinforcement Using Auxetic Tpu Structures, Gianluca Provvisiero

Open Access Master's Theses

The trailing edge of wind turbine blades represents one of the most failure prone regions due to local buckling phenomena and repeated mechanical stresses. This thesis explores a specific reinforcement strategy aimed at extending blade longevity by integrating Re-entrant honeycomb structures made of thermoplastic polyurethane (TPU) within the trailing edge. By numerically identifying and targeting high stress zones, the insertion of lightweight auxetic TPU foam enhances local stiffness and mitigates premature failure without compromising aerodynamic performance. Finite Element Analysis (FEA) simulations demonstrate the effectiveness of this approach when compared to blades models without any internal reinforcement. The methodology of this …

Development Of An Autonomous Lab-On-Paper Device For Enzymatic Activity Assays- Proof Of Concept, Cameron Hahn

Open Access Master's Theses

This work aims to build on URI’s autonomous Lab on Paper (LoP) platform technology, which was used to conduct enzyme-linked immunosorbent assays (ELISAs), to conducting enzymatic activity assays. This requires new optimizations and designs to accommodate the test. In this work we use alkaline phosphatase (ALP) enzyme as the model analyte for the proof-of-concept. To accompany the new device, new MATLAB analytical tools were written and tested, to aid in robust colorimetric signal analysis. The test fixture was designed to be reusable, when a new paper circuit and reagent vials are supplied, however, it was assumed that an eventual final …

Quantification Of The Effects Of Irradiation On The Dynamic Compressive Properties And Fracture Toughness Of Naval Materials, Keevan Winters

Open Access Master's Theses

The investigation of materials used in naval environments, especially those exposed to radiation, is crucial for ensuring the structural integrity and longevity of naval vessels. This study explores the mechanical properties of high-strength steel (HY-80), two types of epoxy-based syntactic foam (Pink and White), and polyurea, provided by General Dynamics Electric Boat. These materials were tested in both virgin and irradiated states under dynamic and quasi-static loading conditions using a Split-Hopkinson Pressure Bar (SHPB) and an INSTRON 3366 for fracture testing. The study particularly focuses on changes in strain energy density and fracture toughness as indicators of material behavior in …

Implosion Of Aluminum Cylindrical Shells Within Varying Confinement Structures, Samuel Hayden

Open Access Master's Theses

The objective of this work was to further understand the fluid-structure interaction resulting from the instability of aluminum cylindrical shells within underwater pressurized confined environments. A confined environment is defined as a restricted fluid domain in which nearby structures influence fluid motion and limit the potential energy available in the system. This work consisted of multiple experimental implosion investigations involving various confinement structures while systematically varying parameters which influence the implosion event. The first study examined the effects of varying one-dimensional fluid flow into a partially confined cylindrical structure, along with variations in the geometry of the implodable volume, while …

Flexural Response Of Inflatable Drop-Stitch Panels, Alex J. Watterson

Open Access Master's Theses

All CUI (Controlled Unclassified Information) is U.S. government property and has been removed from this thesis.

Design And Development Of A System That Characterizes Highintensity Gamma Fields From Rinsc Nuclear Fuel, Michael Peters

Open Access Master's Theses

Nuclear energy is a form of energy that utilizes the fissile nature of uranium, or other fissionable elements, to produce heat. In a uranium core, this reaction consists of a thermalized neutron being absorbed by the uranium nucleus, splitting the atom, and thus creating two subsequent fission products, along with the release of three neutrons, heat, and gamma radiation. These fission products are randomly generated elements, commonly in the form of isotopes of iodine, cesium, strontium, xenon, and barium. Although the type of fission products is known, much is still unknown about the nature of these isotopes, such as their …

Evaluation Of Polymer Coated Fabrics Subjected To Various Multiaxial Stress States, Shane Marx

Open Access Master's Theses

All CUI (Controlled Unclassified Information) is U.S. government property and has been removed from this thesis.

Tracking Control Of A String Actuated Soft Trunk Robot Using State-Space Modeling, Jacob Trivisonno

Open Access Master's Theses

Soft robots, primarily composed of compliant materials, exhibit highly complex and nonlinear dynamics, making precise control a significant challenge. Traditional control methods often struggle with these complexities, requiring more advanced and data-driven methods. In our previous work, “Automatic Control of a Soft Trunk Robot Actuated by Strings” [1], a proportional controller was developed to drive the steady-state tracking error to zero. While this method was effective, it required time-consuming manual tuning and was not easily adaptable to physical modifications of the robot.

To address these limitations, this research implements gain-scheduled feedback control with state-space models calculated through a multiple linear …

Near-Field Interactions Of A Bubble Screen And Underwater Explosion (Undex), Ian Millspaugh

Open Access Master's Theses

CUI content has been removed.

Biaxial Mechanical Behavior And Thermal Modeling Of Ductile Metals, Spencer P. Smith

Open Access Master's Theses

All CUI (Controlled Unclassified Information) is U.S. government property and has been removed from this thesis.

Analysis Of Ptfe Radial Lip Seals For Wheel Bearing Applications, Madison Vogt

Theses and Dissertations--Mechanical and Aerospace Engineering

A numerical analysis was conducted to investigate the viscoelastic effects of nonlinear materials on the sealing zone and contact pressure distribution of radial lip seals in a conventional geometric topology. The use of nonlinear materials in radial lip seal applications is desirable to improve operation and reliability of rotating machinery due to their high operating temperatures, chemical compatibility, and low friction coefficients. Examples include, but are not limited to, seals within industrial air compressors, turbine engines, aircraft landing systems, chemical processing equipment, and Freon pumps. This work focuses on analyzing the nonlinear viscoelastic response of pure Polytetrafluoroethylene (PTFE) and PTFE …

Simplified Molecular Diagnostics Methods For Environmental Testing Of Pathogens And Other Applications, Mohammad Dehghan Banadaki

Theses and Dissertations--Mechanical and Aerospace Engineering

Environmental Surveillance (ES) has emerged as a powerful tool to monitor the emergence and persistence of a pathogen within a facility or community using wastewater/water analysis. Over the past four years, implementation of ES has experienced an explosive acceleration, driven by efforts to monitor the spread of SARS-CoV-2, which has made ES a routinely used public health tool in many locations. We can now use ES to measure the emergence/presence/abundance of different viruses (e.g., SARS-CoV-2, influenza, mpox), bacteria (e.g., E. coli, V. cholerae, antibiotic-resistant strains), fungi (e.g., C. auris), and other biological markers indicative of infectious diseases. However, its broad …

Determination And Limitations Of Blocked Forces In Industrial Settings, Matthew Smither

Theses and Dissertations--Mechanical and Aerospace Engineering

Transfer path analysis methods have been used for decades to determine noise and vibration paths emanating from machinery. In its advent, the machinery source had to be disconnected from the receiver it was attached to in order to gain useful information about each. Further advances in methodology allowed for determining machinery input forces without decoupling them from the structures they were attached to. However, these methods were limited in that the machinery and structures were required to be treated as a system. Thus, any force data obtain was only useful in the configuration it was measured in. Finally, a method …

In-Situ Characterization Of Damage Mechanisms In Ceramic Matrix Composites, Cle' E. Sanchez

Theses and Dissertations--Mechanical and Aerospace Engineering

Ceramic Matrix Composites have many advantages, attracting the nuclear, aerospace, and automotive industries with their high heat stability, strength, and oxidation resistance. However, challenges are presented when machining these materials due to the brittle properties and complicated microstructure. The objective of this project was to identify damage mechanisms that occur when a CMC is orthogonally machined and the cutting mechanics are observed in-situ, followed by post-cut characterization of the as-machined surface morphology. In this analysis, the main variable is the feed rate, which can influence the damage mechanisms, such as matrix failure (matrix cracking) or fiber failure (pullout). Through this …

In Situ Bourbon Barrel Measurements Of Alcohol By Volume And Liquid Depth Using Borosilicate Glass Probes And Near Infrared Absorption Spectroscopy, Trent T. Reed

Theses and Dissertations--Mechanical and Aerospace Engineering

In pursuit of measuring different variables present in bourbon barrels, absorption spectroscopy was utilized to ensure that different ethanol and water concentrations can be differentiated using a broadband light source and near infrared spectrometer in a simple cuvette-based testing setup. The intensity and absorption plots gathered of different ethanol and water mixtures were then analyzed using proper orthogonal decomposition (POD) to break down the data into modes which represent specific variables of interest, specifically ethanol concentration or alcohol by volume (ABV). The modes were then utilized to find mode constants to represent the data taken from cuvette samples which were …

Numerical Investigation Of Wind Disturbance Around A Multirotor Uav In Crosswind And Vertical Flight, Garrison Page

Theses and Dissertations--Mechanical and Aerospace Engineering

Uncrewed Aerial Vehicles (UAVs) are being increasingly utilized in a wide range of research applications, especially in meteorology. This is due to such factors as their ease of use, maneuverability compared to other forms of data collection, and for rotor- craft, the ability to hover. However, the rotorwash generated by UAVs can introduce significant disturbances, potentially affecting measurement accuracy from sensors. While several studies have investigated the rotorwash of individual UAVs utilizing Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD), there is limited exploration into how different rotor configurations and external wind conditions influence regions of turbulent flow around …

Growth Kinetics And Stability Of Metal Halide Perovskite Nanocrystals: Influence Of Stirring Speed And Water Exposure, You-Lin Huang

Theses and Dissertations--Mechanical and Aerospace Engineering

Cesium lead bromide (CsPbBr₃) perovskite nanocrystals (NCs) have garnered significant interest due to their exceptional optoelectronic properties, including high photoluminescence quantum yield, tunable bandgap, and excellent carrier dynamics. These attributes make them promising candidates for applications in light-emitting diodes, photovoltaics, and sensing technologies. However, optimizing their synthesis and improving their environmental stability remain critical challenges. This dissertation explores the growth kinetics of CsPbBr₃ NCs, focusing on the effects of stirring speed and water exposure on their structural and optical properties.

The synthesis of CsPbBr₃ NCs was performed using both mechanochemical (MC) and antisolvent methods, enabling an …

Acoustic Characterization Of A Quadcopter Using A Test Stand, Jared Schmal

Theses and Dissertations--Mechanical and Aerospace Engineering

Unmanned Aerial Vehicles (UAVs) with multirotor propulsion and control, commonly called drones or multicopters, generate a complex acoustic field that is not entirely understood. Many components and their interactions contribute to the overall noise level and behavior of the acoustic field. However, performing acoustic measurements on a multicopter in a confined space, such as a small anechoic chamber, can be an extremely difficult and time-consuming process. A test stand was developed to allow for rapid and safe acoustic measurements in a controlled environment. The design, development, and initial measurements are discussed. The performance and acoustic response are assessed to examine …

Analysis Of Closed-Loop Dynamical Systems Using Relu Nns, Pouya Samanipour

Theses and Dissertations--Mechanical and Aerospace Engineering

This thesis develops a framework for analyzing the stability and invariance properties of closed-loop dynamical systems whose dynamics are derived from neural networks with rectified linear units (ReLUs). The ReLU neural network defines continuous piecewise affine (PWA) functions, which makes them ideal for analysis using polyhedral geometry and optimization techniques. To begin, we introduce two exact algorithms for enumerating polytopic regions of affine behavior induced by ReLU networks: a half-space-based method that checks the feasibility of activation patterns and a geometric vertex-based method. Using these methods, we are able to perform precise region-wise analysis, and these methods serve as the …

In-Situ Informed Modeling And Characterization Of Friction And Built-Up Edge In Machining Of Aerospace Alloys, Avery Hartley

Theses and Dissertations--Mechanical and Aerospace Engineering

Machining is by no means a new manufacturing process. However, it is separated from other traditional deformation processes by its extreme temperatures and strain rates. The function and life of a multitude of products and mechanical components are dependent on the material properties induced by changing the surface through machining. Furthermore, the tools used within machining are often expensive and material reserves are sparse. The understanding the mechanics of the machining process, especially related to the friction of the tool and workpiece, helps to further the life of tools and parts to minimize economic and environmental impact.

Current friction modeling …

Engineering A Novel Solvent Regenerator That Leverages Electrochemically Induced Ph Swings For Direct Air Capture And Hydrogen Generation, Emmanuel Aluhunmile Ohiomoba

Theses and Dissertations--Mechanical and Aerospace Engineering

Direct Air Capture (DAC) is considered to be a key component for achieving global net-negative emissions. However, to capture CO₂ at the low concentrations in the atmosphere requires materials with high affinity for CO₂. This makes the solvent-based chemical approach for DAC more applicable compared to physical approaches. Nonetheless, regenerating the capture solvent presents a significant challenge due to high heat requirements for thermal decomposition of carbonates. Leveraging electrochemical principles provides an opportunity to simplify the regeneration process, thus, this work focuses on engineering an electrochemical solvent regenerator for recovering alkaline solvents for DAC, with co-production of …

Machining-Induced Residual Stress Modeling Using Physics-Informed Neural Networks, Md Mehedi Hasan

Theses and Dissertations--Mechanical and Aerospace Engineering

Process-induced residual stress (RS) plays a critical role in determining the structural integrity, fatigue life, corrosion resistance, and dimensional stability of manufactured components. Tensile residual stress can be harmful to the machined workpiece by lowering fatigue strength, while compressive residual stress helps to prevent such issues. Therefore, accurate prediction and control of machining-induced residual stresses are essential for optimizing manufacturing processes and enhancing component performance. However, existing modeling approaches—empirical, analytical, and numerical—often have limited predictive accuracy, demand extensive calibration, or involve high computational costs. Traditional finite element analysis (FEA) provides modeling insights but is constrained by its high computational cost …