Mechanical Engineering Commons^™

Design For Repairability: Analyzing The Evolution Of Smartphone Repairability To Generate Design Insights, Pranav Peddinti

Master's Theses

Smartphones are a major part of daily life, allowing people to communicate, browse the internet, shop, and enjoy entertainment. However, smartphones tend to be replaced quickly and therefore contribute to the growing electronic waste problem. The lifecycle of a smartphone can be extended by designing them to be more repairable, making it easier for owners and users to perform the repairs themselves. By only replacing failing components, the device can be in use longer, reducing the waste and pollution generated by replacing the device entirely. Therefore, product designers and engineers must focus on designing smartphones to be more repairable. Design-for-repairability …

Enhanced Triboelectric Effect Using Functionalized Multiwalled Carbon Nanotube-Coated Fiber Mats For Biomechanical Energy Harvesting, Fernando Viesca, Diego De Leon, Kevin Alejandro, Rigobert Ybarra Jr., Md. Wasikur Rahman, Victoria Padilla, Horacio Vasquez, Karen Lozano, M. Jasim Uddin

Mechanical Engineering Faculty Publications

Triboelectric nanogenerators (TENGs) have emerged as a cutting-edge technology for developing self-powered wearable electronic devices. In this study, TENGs were fabricated using two fiber mats: forcespun polytetrafluoroethylene (FS-PTFE) microfibers and electrospun polyvinyl alcohol (ES-PVA) nanofiber (NF) mats. The FS-PTFE mats were coated with functionalized multiwalled carbon nanotubes (MWCNTs). Functionalized MWCNTs were dispersed in water-based solutions containing three different surfactants—sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and Triton X-100 to enhance fiber interaction. The NF mats were subsequently immersed in aqueous systems. The surfactant facilitated the uniform deposition of COOH-MWCNTs onto the FS-PTFE fibers, serving as a negative layer, while ES-PVA mat …

Computational Insights Into Nucleosome Dynamics In Epigenetics Using Molecular Dynamics Simulations, Rutika Patel

Dissertations, Theses, and Capstone Projects

Nucleosome core particles (NCP) are the building blocks that form a highly organized and compact chromatin structure. Nucleosomes package DNA in the nucleus of eukaryotic cells. The NCP consists of about 147 base pairs of DNA wrapped around the histone octamer, with 1.65 superhelical turns in a left-handed manner. The histone octamer is composed of two copies of H3, H4, H2A, and H2B. Together with histone H1 and linker DNA, they further assemble into a higher-order chromatin structure. The nucleosome complex is stabilized by electrostatic interactions between positively charged histone residues and the negatively charged DNA backbone. To effectively access …

Design And Development Of A Resonance Ignition System Using Gaseous Propellants, Benjamin J. Hoefer

Master's Theses

This work presents the development and experimental evaluation of a resonance igniter (RI) operating with premixed gaseous propellants. Resonance ignition is a non-electrical ignition concept in which an underexpanded jet impinges on a closed-end Hartmann–Sprenger tube (HST), generating cyclic compression and expansion waves that rapidly heat gas near the tube endwall. A modular experimental system was designed and built to investigate resonance ignition using methane–air and methane–oxygen mixtures. The system includes a supplemental configuration that may probe for mixture conditions favorable to ignition, informing RI testing. Pressure and temperature measurements were used to characterize pressure control, mixture pressure ratio (MPR), …

Development Of A Video-Based Tool To Measure Motor Asymmetry In Infants At Risk For Hemiparesis, Roha Ali

Master's Theses

Congenital hemiparesis is a unilateral motor impairment stemming from brain injury in utero or early postnatally. Hemiparesis can be difficult to detect in early infancy with current clinical tools. Yet, early identification of motor asymmetry could play a key role in the design of effective early intervention and rehabilitation strategies. This thesis presents the development and validation of a video-based tool designed to extract infant limb movement data using DeepLabCut’s (DLC) machine learning network. The pipeline was developed using videos of typically developing (TD) infants and infants with Asymmetric Perinatal Brain Injury (APBI), all at or under 3 months corrected …

Characteristic Stress And Strain Optimization Of Cardiovascular Catheters With Laser-Cut Hypotubes Using Finite Element Analysis, Kyle E. Hirth

Master's Theses

Cardiovascular catheter systems rely on laser-cut hypotubes to balance flexibility and structural integrity required for minimally invasive surgical procedures.  Optimizing these mechanical characteristics remains a significant challenge.  This study aims to investigate the influence of key laser-cut geometric parameters on the mechanical performance of hypotubes through finite element analysis.

Commercially representative laser-cut hypotubes were modeled and a finite element model was developed.   Geometric design parameters were varied across a design space consisting of pitch values ranging from 0.006 in. to 0.018 in. and cuts per revolution (CPR) ranging from 2.5 – 4.5.  For each pitch and CPR combination, loading stiffness …

Aerodynamic Design And Structural Evaluation Of A Global Minimum Torque Inspired Multirotor Propeller, Zeke Bukovansky

Master's Theses

This thesis develops a repeatable design, CAD, aerodynamic postprocessing, structural screening, and manufacturing feasibility workflow for a 22-inch global minimum torque inspired multirotor propeller. Matched MIL and GMT geometries were compared at a 35 N, 4000 rpm static-hover operating condition using BEMT/XFOIL aerodynamic postprocessing, with diameter, blade count, chord distribution, airfoil schedule, and target thrust held constant. The final modeled comparison predicted a modest 1.5% reduction in torque and shaft power for the GMT case while maintaining the same thrust target. CAD construction, MATLAB reduced-order beam model, Abaqus screening, and manufacturing planning were used to identify geometry level structural and …

Design And Optimization Of A Bluff Body For Energy Harvesting Of Transverse Galloping Induced By Low-Speed Wind Using Bernstein Polynomial Equations, Youssef Wael Abdelmoneim

Theses and Dissertations

In this thesis, a computational framework is proposed for optimizing the aerodynamic shape of bluff bodies used in galloping-based wind energy harvesters. The system targets low-wind speed environments, where normal wind turbines are not effective, offering a potential alternative to batteries used for powering small electronic devices such as wireless sensors. The design relies on the galloping effect, where airflow around a bluff body induces transverse oscillations that drive an energy conversion mechanism. To generate efficient bluff body geometry, the Class-Shape Transformation (CST) method is used to define a wide range of candidate shapes with minimal design parameters. These shapes …

A Generative Ai-Driven Computational Framework For Industry-Scale Discovery Of Novel Battery Materials, Joy Datta

Dissertations

The growing demand for sustainable, high-energy-density electrochemical storage has motivated the exploration of multivalent-ion batteries based on earth-abundant elements such as aluminum, calcium, magnesium, and zinc. While multivalent charge carriers offer higher theoretical energy density than lithium, their practical deployment is hindered by sluggish ion transport, strong ion-host interactions, and structural degradation of electrode materials. Identifying host materials that can reversibly accommodate multivalent ions while maintaining structural integrity remains a fundamental challenge. The dissertation develops a scalable, end-to-end computational framework that integrates density functional theory (DFT), machine learning (ML), and generative artificial intelligence (GenAI) to accelerate the discovery of next-generation …

Toward Learning-Based Reconstruction And Part Decomposition Of Man-Made 3d Geometry: Neural Implicit Representations And Scalable Supervision, Shen Fan

Dissertations

Digital three-dimensional (3D) models are central to engineering design, analysis, and manufacturing, but learning pipelines for man-made geometry often operate on sampled carriers that do not preserve all of the structure present in exact CAD representations. This dissertation studies learning-based reconstruction and part decomposition for structured man-made 3D geometry, from general object benchmarks to CAD-derived datasets, with a focus on neural implicit representations trained from signed-distance samples, point clouds, and tessellated meshes. The goal is to make these models more accurate, more part-aware, and more consistently supervised.

First, signed distance function (SDF) reconstruction with implicit neural representations is improved through …

Hydrodynamic Analysis And Cfd Modeling Of Pawec Interacted With Regularwaves Using Cfx, Ahmed Elbaz

Mechanical Engineering

The multiplicity of renewable energy sources represents the biggest challenge for environmental scientists and engineers. This research presents a mathematical model and a numerical study using the high-performance ANSYS-CFX software to analyze the dynamic behavior of the point absorberwave energy converter (PAWEC). Two different models were constructed to predict the hydrodynamic response of the wave energy converter in both free and forced oscillations under the action of incident regular waves and external mechanical damping. The differential equations are solved analytically using RKFOM. CFX multiphase model is constructed to solve the 3D Unsteady Reynolds Averaged Navier–Stokes Equation (URANS) using the two-way …

Coupled Ferroelectricity And Phonon Chirality, Xiang-Bin Han, Cong Yang, Rui Sun, Xiaotong Zhang, Thuc Mai, Zhengze Xu, Aryan Jouneghaninaseri, Xiaoning Jiang, Rahul Rao, Yi Xia, Multople Additional Authors

Mechanical and Materials Engineering Faculty Publications and Presentations

Recognizing the coupling between ferroelectricity and chirality in optically active ferroelectrics opens a route for manipulating chirality via ferroelectricity under an external electric field, enabling control over chirality-dependent quantum states. Here, we report the experimental demonstration of the coupling between ferroelectricity and phonon chirality in the molecular ferroelectric triglycine sulfate. By electrically switching the crystal chirality, we achieve reversible and device-compatible control of phonon chirality, as revealed by in situ time-resolved magneto-optical Kerr effect measurements. The Kerr rotation reverses with electric-field switching, while phonon chirality vanishes in the paraelectric phase and is tunable in the racemic ferroelectric state. Furthermore, density …

Du Undergraduate Showcase Abstracts: Research, Scholarship, And Creative Works, Sophia Wismar, Henry Staats, Allison Metzler, Chloe Puckett, Rachel Levine, Christa Kilpatrick, Scott Wolf, Joe Walsh, Grace Doolittle, John Engebreston, Zoe Lopez, Christopher Aaby, Audrey Duff, Timothy Sisk, Katelyn Lamberton, Angela Narayan, Gilkah Argueta, Habiba Samir, Girena Tesfazghi, Genet Kenore, Sinit Tesfamariam, Effley Brooks, Abi Newell, Megan Doherty, Natalie Baer, Lexi Blood, Talya Riciputi, Jessica Jimenez, Devin Hernandez, Lynn Clark, Taj Kumar, Sunil Kumar, Allen Rutman, Mira Pronobis, Tess Carson, Anna Sher, Frankie Stroud, Tamra Pearson D'Estree, Alyssa Wilson, Emily Melnick, Jenalee Doom, Yihang Gao, Gwendolyn Geiger, Noah Gettle, Scott Nichols, Clare Ayoub, Cara Dienno, Sunny Walker, Zoe Hansen, Maya Wheeler, Addison Rice, Patrick Martin, Sanjana Acharya, Daniel Mcintosh, Amanda Mckellips, Calli Cain, Justin Blake, Peter Sokol-Hessner, Natalie Miller, Max Weisbuch, Sophia Dellota, John Macikas, Charlotte Snow, Mark Siemens, Zoe Lynch, Alex Huffman, Prachi Shah, Jason Roney, Halcyon Levi, Nicole Herzog, Andrea Koly, Daniel Linseman, Annie London, Xi Yang, Avery Zwisler, Jane Smith, Chaz Contag, Michael Kerwin, Lucy Rand, Grace Schroeder, Michelle Rozenman, Nissa Tapper, Guiming Zhang, Mateo Mazariego-Halpern, Keith Meyer, Julie Do, Dakota Park-Ozee, Travis Herink, Kara Neu, Jonathan Plomin, Eve-Odine Duchaufour, Debbie Gale Mitchell, Tennyson Anderson-Stricklin, Lily Treitz, Samantha Rosenberger, Sierra Griffith, Finley Joseph, Daniel Sampson, Emmy Davis, Skyler Kasnoff, Evon Lopez, Vivian Nguyen, Cassy Young, Franklin Sellner, Martin Tobon, Ila Graham, Zach Billings, Holden Hedit, Decatur Boland, Paul Kosempel, Cory Chandler, Jay Mahoney, Sam Dragan, Susan Dagget, Yarrow Ator, Heidi Vuletich, Owen Weber, Andrew Kloeppel, Petersen Gray, Mandi Schaeffer-Fry, Razleen Bassra, Bryanna Rodriguez, Christina Blue, Taubie Sanders, Rachel Epstein, Luke Milburn, Camryn Evans, Ezra Martinez, Mary Westwood, Gabri Notov, Robin Tinghitella, Lilou Cabrol, Eli Barbour, Juliet Mendik, Selma Myers, Zac Wise, Noah Fahlin, Michelle Knowles, Abigail Hopper, Michael Greenberger, Romi Laclair, Sarah Watamura, Sabrina Efroymson, Casey Barker, Sydney Seltzer, Bryn Yehle, Jennifer Hoffman, Sara Garcia, Ryuka Nagamine, Trevor Briggs, Remy Le Boeuf, Elena Krone, Eileen Farrell, Regan O'Rourke, Elena Roel, Greg Mortimer, Ali Ayoub, Stefani Langehennig, Caitlin Turk, Logan Scmid, Stefan Chavez-Norgaard, Karen Kim, Tatiana Peccedi, Courtney Cassidy, John Sebesta, Rhianna Lewis, Janice Bening-Lacek, Vivian Lawless, Mckenna Hanson, Jeffrey Amidon, Riya Joshi, Ram Ambre, Brady Worrell, Perrin Schneider, Ali Azadani, Brooke Agulnek, Lyndsie Salvagio, Elise Siemanowki, Yan Qin, Andre Allen, Melodie Nguyen, Megan Livengood, Abby Reams, Saffron Hartreeve, Bri Wylie, Sarah Brookman, Mariah Loiacono, Green Russo, Abhia Lodhi, Gabrielle Welsh, Nika Spehar, Shahked Levin, Evrim Baykal, Kimberly Chiew, Jocelyn Torres, Kailey Hicks, Mykaela Tanino-Springsteen, Audrey Bellows, Akam Chahal, Madeline Tepper, Shannon Murphy, Alexa Fonseca, Deborah Han, Cassandra Perez, Oluwatoyin Alaba, Julia Roncoroni, Vy Nguyen, Nana Burn, Sarah Sasse, Rubin Tuder, Anthony Gerber, Nancy Lorenzon, Christine Vohwinkel, Camryn Gunter, Tristan Weber, Sam Rommel, Brian Michel, Muskan Fatima, Alannah Oleson, Kira Frey, Edward Garrido, Beckett Morris, Kerstin Haring, Drew Middleton, Abigail Walpert, Liam Dee, Gabby Ishaw, Cole Carnes, Maddie Weiser, Claire Fox, Valeriia Vlasenko, Kateri Mcrae, Riley Smith, Abigail Templin, Kushani Rajapaksha

DU Undergraduate Research Journal Archive

Abstracts from the DU Undergraduate Research Showcase.

Electropulse Annealing: Phase Composition Of Tial6v4, Vaughn Eckhardt, Ethan Croke, Ian Baker, Russ Taylor

Wetterhahn Science Symposium Posters

Titanium alloy TiAl6V4 is the most ubiquitous titanium alloy used for dental care, aerospace manufacturing, and for high performance vehicles. The material typically undergoes a thermal heat  treatment, but electropulse annealing is another process that involves sending current through the material to heat it up at a quicker rate. The rate of post-annealing cooling is high, and around the material's critical point, its two components, alpha and beta phase, change in relative concentration. After testing multiple current densities and temperatures, in general, as the current density that the sample received during electropulse annealing decreased, both the alpha and beta phases …

Isometric Force Characterization Of Braided Pneumatic Actuators, Ben Bolen, Mohammad Elzein, Lawrence Pang, Alexander Hunt

Mechanical and Materials Engineering Faculty Publications and Presentations

Artificial muscles such as braided pneumatic actuators (BPAs) offer many advantages for robotic systems, including high durability and strength-to-weight ratios. However, their use in robotic systems is still extremely limited, in part due to their poor force, length, and pressure characterization. In this work, a test setup is created to compare force produced by Festo fluidic BPAs with leading models. Our analysis of the data has resulted in (1) the development of new equations to calculate force as functions of pressure and contraction for Festo BPAs with uninflated diameters of 10 mm and 20 mm, and (2) a novel equation …

Entropy-Constrained Closure For Steady, Quasi-One-Dimensional Flow Of Ideal Gases, Andrew A. Oliva

Michigan Tech Publications

An entropy-constrained closure is developed for steady quasi-one-dimensional flow of a calorically perfect ideal gas. Net irreversibility is represented by a prescribed entropy change between the inlet and outlet or, equivalently, by a stagnation pressure ratio together with the stagnation temperature ratio implied by the energy balance equation. The thermodynamic constraint, enforced through Gibbs relation together with conservation of mass and energy, yields an algebraic mapping from the inlet flow state, area ratio and prescribed stagnation property ratios to the outlet flow state. The momentum balance is retained only as an auxiliary post-processing relation and may be used to infer …

Sentience, Sheetal Agrawal

Masters Theses

The increasing urgency for sustainable and adaptive systems has driven research toward embedding intelligence directly into materials rather than relying solely on external sensing and control systems. This thesis explores how smart material1 embedded systems can be designed to recognize and respond to environmental signatures, defined as measurable patterns such as temperature fluctuations and mechanical forces. Central to this investigation is the integration of shape memory alloys, particularly Nitinol, with geometry-based actuation mechanisms that amplify material behavior into functional system responses.

The central argument is that designing with smart materials is a design problem, not primarily a materials science problem …

Data Driven Estimation Of Pore Size Using 1d Light Emissions For Laser Powder Bed Fusion Additive Manufacturing, Jose Galarza, Jorge Barron, Luis Jimenez, Tamer Oraby, Jianzhi Li, Farid Ahmed

Manufacturing & Industrial Engineering Faculty Publications

The quality assurance of the Laser Powder Bed Fusion Process (LPBF) has been extensively investigated over the last decade for in-situ monitoring of metal additive manufacturing. The process inherently generates voids within the bulk of the part, which can detrimentally affect the quality of the printed part. The characterization of these voids by estimating their size and identifying their geometrical features remains a challenge. This study introduces a Machine Learning (ML) based framework for estimating void sizes of varying geometries using layer-wise one-dimensional (1D) average light intensity signal obtained from the optical tomography system during the 3D printing of metallic …

From Frames To Strains: Analytically Modeling Inelastic Deformation Under Mapped Single-Site Impacts From High-Speed Footage To Internal State Variable Codes, Joby Milo Anthony

Doctoral Dissertations and Projects

This work adds insight to the physical phenomena of microstructural and stress strengthening of metal components by the inelastic deformation from Surface Mechanical Attrition Treatment (SMAT). Impact behaviors observed by high-speed footage of a Crank-Slider Mechanism (CSM) are examined in the context of analytically moving rigid bodies in spacetime and resolving kinematics upon impact until restitution via Finite Element Analysis (FEA). A Coupled Discrete-Finite Element Model (CDFEM) leverages Bammann plasticity, Horstemeyer damage and void nucleation, growth, and coalescence and Cho recrystallization Internal State Variable (ISV) models to show the localization of plastic strain and onset of recrystallization under any single …

An Open-Source Linear Actuated-Quartz Tube Furnace With Programmable Ceramic Heater Movement For Laboratory-Scale Studies Of Combustion And Emission, Casey Coffland, Ryan Bixler, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

The Linear Actuated Quartz Tube Furnace (LA-QTF) is an instrument engineered to heat and combust materials under controlled conditions, capable of achieving flaming and smoldering states. A ceramic ring furnace is linearly actuated parallel to the length of a quartz tube. The mode of combustion depends on temperature, fuel composition, and oxygen availability; the LA-QTF regulates combustion by controlling the temperature and position of the ring furnace, and airflow within the tube. The LA-QTF can maintain temperatures between 23 °C and 530 °C for extended time periods, with stable temperatures over long-duration (∼120 min) experiments. Flow rate is dependent on …