Mechanical Engineering Commons^™

Optimization Of Stamped Tool Geometry Using Regression-Based Cost Models And Structural Constraints, Matthew J. Teague

Mechanical Engineering Undergraduate Honors Theses

Stamped steel paint can openers are simple tools but still require sufficient strength for the end user and low material consumption for the manufacturer. The goal of this project is to optimize the stamped design of a paint can opener by reducing material cost while maintaining structural rigidity and device performance. This was achieved in part by simplifying the tool’s geometry so that an equation for the mass could be developed analytically and checked against the simulation’s outputs. First, a 25-run design of experiments was created that varied the shaft length and the endloop diameter. Next, a CAD model for …

A Multi-Criteria Decision And Spatial Modeling Framework For Socially Informed Advanced Air Mobility Implementation Planning, Noah Wesley Bretz

Graduate Theses and Dissertations

Advanced air mobility (AAM) is an emerging mode of transportation that integrates advanced aircraft technologies, such as manned air taxis or unmanned freight drones, to transport people and goods across urban and regional environments. While these technologies promise to transform mobility, successful implementation depends heavily on community acceptance, which is shaped by multiple social factors. This study presents a multi-criteria decision framework to evaluate and prioritize the key social factors influencing AAM adoption. A literature review identified six primary social factors: safety, noise, privacy and cybersecurity, automation, environmental impact, and price and economics. The Analytical Hierarchy Process (AHP) was used …

Two Applications Of Lifting-Line Theory For The Design Of Efficient Aircraft, Amanda K. Olsen

All Graduate Theses and Dissertations, Fall 2023 to Present

Numerical lifting-line is a tool that can be used to evaluate the forces and moments of an aircraft wing. This method has limitations but it is beneficial in obtaining a large set of results with relatively little computational power. This research seeks to analyze two different flight scenarios through the use of two numerical lifting-line tools developed at the Utah State University AeroLab. The first scenario involves an aircraft in ground effect flight. When an aircraft flies close to the ground, a phenomenon called ground effect occurs where the lift is increased and the induced drag is decreased. Therefore, flying …

Effect Of Prefilmer Design On Atomization Behavior In The Pre-Vaporization Tube Of A Small-Scale Annular Gas Turbine Combustior, Amogh G. Natu, Antoine M. Fradet, Cohen Nunes, Daniel R. Guildenbecher

School of Mechanical Engineering Faculty Publications

This work investigates the influence of internal prefilmer geometry on fuel spray atomization in the prevaporization tube (PVT) of a small-scale reverse-flow annular gas turbine combustor. Four configurations are examined: a control with no prefilmer, a planar internal prefilmer, and two angled internal prefilmers at θ = 60◦ and θ = 45◦ . Double-pulsed digital in-line holography (DIH) is used to measure droplet size distributions, spray density, Sauter mean diameter (SMD), and droplet velocities at the PVT exit under conditions scaled to represent nominal ignition conditions. Results show the control design exhibits poor atomization characterized by large droplet diameters, low …

Tau Beta Pi Engineering Mentorship Program, Tyler Black

Undergraduate Honors Capstone Projects

The purpose of this project is to design and implement a student-led engineering mentorship program directed by the members of the Utah Gamma Chapter of Tau Beta Pi on the Utah State University (USU) Logan campus. Retention data show that many undergraduate students who start engineering programs change their degree before graduation due to academic and social challenges that may be mitigated by the support of a peer mentor. The Tau Beta Pi Engineering Mentorship Program selects and trains upperclassman mentors to effectively mentor underclassman engineering students.

The design of the mentorship program is an application of backward design, where …

An Experimental Study Of The Morphology Of Dna-Carbon Nanotube Hybrid Structures In Direct Dna Sequencing, Avery P. Davis

Biomedical Engineering Undergraduate Honors Theses

Hybrid structures formed between single-stranded DNA (ssDNA) and single-walled carbon nanotubes (SWCNT) have emerged as promising components in future direct DNA sequencing technologies due to their unique morphological and electronic properties. The nanoscale configuration of these hybrids, including the DNA wrapping angle, pitch, and contour behavior, directly influences their potential for stable electronic readout. This thesis presents an experimental study of DNA-SWCNT hybrid morphology using a fixed, reproducible wrapping protocol designed to minimize environmental variability and isolate the influence of DNA nucleotide sequence on hybrid structure. As described in prior work, this protocol produces well-dispersed hybrids suitable for high-resolution imaging. …

Effects Of A Passive Assistive Hamstring Device On Overground Running Kinematics And Hamstring Activation., Quinn Castner

All Theses

Hamstring strain injuries are among the most common and recurring injuries in sports, occurring most often during the terminal swing phase of gait. Despite progress in rehabilitation, the incidence of injury has only increased, suggesting a need for a novel intervention. We designed a passive, assistive, wearable device with two specific criteria in mind: to offload the hamstrings during running, and do so without hindering normal kinematic patterns. The device consists of an adjustable elastic band anchored proximally at the waist and distally just above the ankle joint center. It stretches and shortens with the hamstrings, providing passive hip extension …

Exercise-Induced Muscle Damage As A Model For Exploring The Effects Of Pain On Gait, Sydney Savage

All Theses

Persistent gait asymmetry following anterior cruciate ligament reconstruction (ACLR) is a recognized contributor to post-traumatic knee osteoarthritis, yet the independent role of pain in driving altered movement patterns remains poorly understood due to confounding factors inherent to clinical populations. This study used exercise-induced muscle damage (EIMD) as a controlled experimental model to isolate the effects of musculoskeletal pain on gait, independent of kinesiophobia, structural damage, and proprioceptive disruption. Eighteen healthy adults underwent unilateral eccentric calf-raise protocols to induce delayed onset muscle soreness (DOMS), with gait assessed at baseline, 48 hours, and 168 hours post-exercise using bilateral inertial measurement units. Outcomes …

Electrochemical Reduction Of Carbon Dioxide By In-Situ Generated Hydrogen At Porous Cu-Fe Foam-Like Catalysts: Efficiency Towards Formic Acid Formation, Aya Saada, Attia Attia

Biochemical Engineering

No abstract provided.

Safe Control Design For Quadruped Locomotion In Unstructured Environments Using Linear Transfer Operators, Sriram Sundar Krishnamoorthy Shankara Narayanan

All Dissertations

Deploying quadruped robots in unstructured, obstacle-rich environments requires control and planning methods that remain safe and reliable despite complex terrain geometry, limited sensing, and inevitable modeling errors. This thesis develops operator-theoretic tools for safe control design of robotic systems using linear transfer operators, with a focus on quadruped locomotion in unstructured environments. The central goal is to develop a unified operator-theoretic framework for safe control design based on the Perron–Frobenius (P–F) and Koopman operators. In particular, the thesis leverages \emph{density functions} to develop safe navigation frameworks in the dual space of densities. In the operator-theoretic perspective, the P–F operator governs …

Interplay Between Phase Instability And Deformation Mechanisms In Beta Titanium Alloys In Aggressive Environments, Benjamin Elbrecht

All Dissertations

Modern designs, such as commercial jet turbines, are reliant on the high temperature performance of their constituent materials. Improvements to the strength-at-temperature of materials are critical to the continued advancement of efficiency and payload capacity in these advanced applications. This dissertation presents studies that progress towards this goal through the construction of a new experimental setup for complex temperature and force profiles that also accurately captures deformation behavior through non-contact measurements. Using this setup, studies into two specialty titanium alloys were executed: discovering the microscopic mechanisms responsible for the macroscale behavior and testing in conditions closely replicating aircraft turbine operating …

Decomposition And Spectral Characterization Of Unsteady Loads In Pulse-Jet Propulsion Testing, Cesar Benitez

Theses and Dissertations

Pulsed jet propulsion systems produce inherently unsteady forces whose time-resolved characterization is essential for performance assessment, yet the measured load signal conflates aerodynamic forcing with the dynamic response of the measurement balance itself. This thesis develops a load centered framework for the dynamic characterization of a pulsed jet system, treating the measured load fluctuation as the primary physical observable rather than attempting full true-thrust reconstruction. A single-degree-of-freedom balance model identified through ringdown testing provides the structural reference scale, yielding a natural frequency of 8.5 Hz and damping ratio of 18%. Power spectral density, phase-averaging, and synchronous–residual decomposition is applied uniformly …

Examining The Effects Of Lateral Loading On Railroad Tapered Roller Bearings, Abel David Sanchez Trinidad

Theses and Dissertations

The loading conditions experienced by freight railcar bearings vary as a function of vehicle operating conditions. Under static conditions, bearings are primarily subjected to radial loads transmitted through the wheelset. During operation, however, track irregularities, braking events, railcar load imbalances, and curving introduce complex impact, longitudinal, and lateral forces in addition to the normal radial loading. These lateral forces increase friction within the bearing raceways, which could accelerate wear and potentially lead to premature spall initiation and propagation. While prior research at the University Transportation Center for Railway Safety (UTCRS) has demonstrated that vibration signatures can be used to detect …

Manufacturing Systems: Characteristics And Dynamics, Alan J. Fitzmorris

Graduate Theses and Dissertations (2019 - present)

This research answers three basic questions. First, what are the behaviors (dynamics) of a manufacturing system in the context of system performance? Are these dynamics best described as linear deterministic, periodic, nonlinear deterministic, or stochastic? Second, what are the complexity (chaotic) characteristics of a manufacturing system, namely the maximal Lyapunov exponent, correlation dimension, and Kolmogorov-Sinai entropy? Third, is there a relationship between complexity characteristics and manufacturing system performance? This research involves four high level steps: data analysis, system dynamics analysis, system complexity analysis, and correlation analysis. The data analyzed consists of concrete plant and shipbuilding shop time series performance data. …

Development Of A Simulation-Driven Evaluation System For Foreign Objects In Aircraft Structures, Daniela Garcia

Open Access Theses & Dissertations

This thesis investigates the use of simulation-driven methods to evaluate the behavior and potential impact of foreign objects within aircraft structures. Foreign Object Damage (FOD) remains a major concern in aerospace safety, as small components unintentionally left inside aircraft compartments can create uncertainty regarding their effect during flight. Although current inspection methods can detect the presence of foreign objects (FOs), they often cannot determine whether these objects pose a significant structural risk, leading to conservative maintenance decisions. To address this limitation, this work develops a simulation-based framework that integrates Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) to evaluate …

Design And Development Of A Passive Dust Protection System For Lunar Docking Operations, Simon Thengvall

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Lunar docking systems face a unique set of environmental conditions that can create significant challenges for mechanical design. Among these, the abrasive nature of lunar regolith can impair the kinematic function of traditional terrestrial mechanisms as well as contaminate critical spacecraft components such as environmental seals, causing them to fail. For crew-rated docking systems, failure of these systems not only threatens mission success, but also crew safety, so dust protection is crucial for docking components. To address the concerns of regolith intrusion, the Simple External Attachment for Lunar Openings (SEALO) is developed as a key architecture for mechanism evaluation when …

Experimental And Computational Investigation Of The Effects Of Neck Musculature During Head Impacts In American Football, Anthony P. Marino

All Dissertations

Anthropometric test devices (ATDs) are human surrogate models used to represent the human body response in the context of compliance and safety testing. These devices are used in multiple industries, including automotive and aerospace, and have recently been incorporated into impact testing for the evaluation of helmet performance in American football. The Hybrid III 50^th percentile male ATD head and neck assembly is the most commonly used surrogate for these tests, although it was developed for automotive frontal crash scenarios that induce an inertial force on the body, leading to head and neck motion primarily in the sagittal plane. …

Versatile Exoskeleton Control Paradigms For Agile Human Locomotion: Task-Agnostic And Stability-Augmented Assistance, Miao Yu

All Dissertations

Lower-limb exoskeletons have shown great potential for assisting human locomotion, but designing controllers that provide assistance across diverse locomotor tasks and under external perturbations remains a major challenge. Many existing controllers for steady-state walking rely on pre-defined reference trajectories, which constrain voluntary human motion and limit adaptability across tasks. Moreover, they usually assume stable walking, while their performance under unstable conditions remains largely unexplored. In addition, existing gait stability augmentation controllers are often reactive rather than proactive to unstable conditions. In this dissertation, we propose control frameworks that preserve voluntary human motion while addressing two major challenges: providing task-agnostic assistance …

Modernizing Plastics And Composites Manufacturing Using Hybrid Modeling Techniques, Luke Shannon

All Dissertations

Plastics and composites manufacturing encompasses a broad family of processes, including injection molding, resin transfer molding, compression molding, and extrusion, that together account for the vast majority of polymer and composite component production worldwide. These processes are inherently challenging due to the multi-physics nature of polymer processing, the vast possible combinations of resins, reinforcements, and additives, and the strong dependence of final part properties on process history. Among these processes, injection molding is one of the most widely deployed, producing high-volume components across automotive, medical, consumer electronics, and packaging industries. However, accurately monitoring and predicting process behavior in injection molding …

Development Of A Mixing-Controlled Combustion Model For 0d Engine Modeling: Using High-Order Models To Guide The Formulation Of Reduced-Order Models, James Gohn

All Dissertations

Vehicles are becoming increasingly complex to comply with the increasingly stringent regulations placed on all market sectors while still maintaining performance requirements. This increased complexity leads to increases in the cost and time it takes to develop and produce these next generation vehicles. To meet demand therefore, it becomes necessary to evaluate numerous design iterations using computer models. There are multiple levels of models that may be necessary for different purposes or use cases. All levels of modeling for virtual prototyping, however, require a level of validation and predictive ability to be useful. To this end, the following thesis presents …