Mechanical Engineering Commons^™

Numerical Investigation On Lightning Survivability And Residual Strength Of Scarf-Patched And Z-Pinned Cfrp Composites, Logan Hales

All Graduate Theses and Dissertations, Fall 2023 to Present

Carbon fiber reinforced polymer (CFRP) composites are critical in aerospace applications yet remain vulnerable to lightning strikes due to orthotropic electrical conductivity and poor thermal resistance. Over the past decades, lightning-strike damage in pristine CFRP has been extensively investigated. However, the response of damaged and subsequently repaired laminates remains poorly understood, raising concerns about the structural integrity of repaired aircraft. This study aims to develop a sequentially coupled thermo-structural modeling framework to quantify how two common composite repair strategies (scarf patching and z-pinning), along with patch size, pin material, and configuration, influence lightning-induced damage and the residual flexural strength of …

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 …

Porous Hydrophobic Adsorbent Coatings For Carbon Dioxide Capture, Samuel Babatunde Olushola

Theses and Dissertations

This work presents the development of a porous, hydrophobic zeolite 13X coating for the separation of carbon dioxide (CO₂) from flue gas or natural gas. Zeolite 13X was combined with yeast, glucose, and sodium alginate as pore-forming agents, and with polytetrafluoroethylene (PTFE) and Polydimethylsiloxane (PDMS) as hydrophobicity-inducing agents to enhance water resistance while maintaining CO₂ access to the adsorbent. The study explored PTFE/13X mass ratios ranging from 0 to 2.33 to investigate the interplay between hydrophobicity and CO₂ uptake. The wettability of the coating was characterized by using a temporal water contact angle (WCA) measurement. Increasing …

An Experimental Study On Turbine-Based Energy Harvesters For Thermal Underwater Gliders, Stephen Edward Coster

Theses and Dissertations

Buoyancy-driven underwater gliders have been optimized for long-duration missions primarily for continual monitoring of the ocean’s water column. However, longer missions and higher-powered sensors have increased the energy requirements of gliders. While current solutions aim to increase battery capacity, the development of energy-harvesting systems (EHMs) could greatly improve mission capabilities in both ability and duration. This thesis discusses the experimental testing of an underwater glider with an EHM as detailed in the theoretical study, “Development of a Turbine-Based Ocean Thermal Energy Harvesting Mechanism Applied to the Underwater Glider” by Hongbo Hou, PhD. The rear-mounted turbine captures energy using the kinetic …

Cylindrical Versus Spherical Self-Similar Capillary Cavity Collapse, Karl Cardin, Christophe Josserand, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Drop tower experiments have been performed to study the capillary collapse of large high-aspect-ratio cavities. Cavities are formed by momentarily impinging the free surface of a liquid bath with a jet of air in the microgravity environment of a drop tower. The collapse may give rise to a jet and three distinct jetting regimes are identified. Simulations are performed to further investigate the phenomena. The abrupt emergence of a thin high velocity jet is observed experimentally and numerically at a specific initial cavity aspect ratio. Different power laws are identified in different regions of the cavity during the collapse providing …

Optimization Of A Point Absorber Wave Energy Converter (Wec), Rutwa Dilipkumar Nagar

Electronic Theses and Dissertations

This study examines the performance and optimization of a point absorber wave energy converter with a partially submerged spherical float. A comprehensive open-source computational framework integrates frequency-domain hydrodynamic analysis with time-domain simulation using Capytaine, BEMIO, and WEC-Sim. Hydrodynamic coefficients such as added mass, radiation damping, and excitation forces are calculated and integrated into the governing equation of motion using the Cummins formulation. A parametric analysis varies the float diameter and geometric configurations across several cases. Hydrodynamic coefficients and response amplitude operators are assessed to analyze system behavior and resonance characteristics. Results indicate consistent trends in normalized added mass, with radiation …

The Pid-Based Three Quadcopter Uavs Formation Control Under External Disturbance, Vo Van An, Trinh Luong Mien

Makara Journal of Technology

This paper presents the design and evaluation of a formation control strategy for three quadcopter UAVs, based on a PID controller in a leader–follower structure, under the influence of external disturbances. Each UAV employs a six-degree of-freedom dynamic model and utilises a cascade PID control architecture, in which the inner control loop stabilises the attitude. In contrast, the outer control loop regulates position and maintains the formation. The PID parameters are tuned using the Ziegler–Nichols method to ensure simple implementation and low computational cost. The performance of the control system is evaluated through simulations in the MATLAB environment for two …

Evaluation Of Quantification Methods Applied To Overlapping Ftir Features, Benjamin P. Diehl

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

Quantifying overlapping FTIR spectral features is critical for electrochemical analysis but often requires complex deconvolution. This work systematically evaluates several area ratio and proxy-based quantification methods using a controlled synthetic spectral model with varying signal-to-noise ratio, peak spacing, width, background, and data resolution. Constrained peak fitting and fixed-window integration consistently exhibit near-perfect monotonicity (Spearman ≈ 1.000) and linearity (Pearson ≈ 0.999–1.000) across all conditions. In contrast, derivative and moment-based metrics show sensitivity to peak overlap, width, and background. These results demonstrate that physically grounded area-based methods provide the most robust and reliable quantification of overlapping FTIR features.

External Force Control Of Transitional And Turbulent Flows, Cesar Alberto Leos

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Turbulence in wall-bounded flows governs momentum transport, drag, and energy efficiency in a wide range of engineering systems, yet its response to external forcing remains incompletely understood across transitional and high Reynolds number regimes. This dissertation investigates an active flow control strategy based on spanwise external forcing and demonstrates how it modifies the dynamics of transitional and turbulent channel flows with the objective of identifying the mechanisms through which forcing alters transition, flow physics, and turbulent drag reduction.

Firstly, direct numerical simulations are performed to examine the subcritical transition under external forcing. The onset and sustenance of turbulence are shown …

Vacuum Modification Of The Surface Properties Of T15k6 Hard Alloy By Plasma–Chemical Synthesis Of Tin-Cu Coatings, Aleksandr Semenov, Dmitriy Tsyrenov, Nikolay Ulakhanov, Irina Semenova, Undrakh Mishigdorzhiyn, Wen Ma, Simon C. Tung, George E. Totten

Mechanical and Materials Engineering Faculty Publications and Presentations

The design and main parameters of a plasma–chemical reactor containing two compartments are presented. One compartment houses a vacuum-arc evaporator, while the other houses a planar magnetron. The compartments are separated by a diaphragm with a dosing slot for injecting copper vapor into the TiN synthesis compartment. The conditions for the synthesis of superhard TiN-Cu composite coatings are experimentally determined. Based on established process parameters for TiN synthesis in a nitrogen-containing plasma by Ti evaporation using a vacuum-arc discharge, it is proposed to apply TiN-Cu coatings by injecting Cu vapor into the TiN synthesis area and sputtering Cu using a …

Lockheed Martin & U.S. Navy Air Pallet For Materials Handling, Samantha Ryan, Ryan Zerneke, Joshua Bible, Justin Conner, Brycen Haner, Nevan Juteram, Alexander Lacy, Gavin Lanka, Henry Lewis

Mechanical and Civil Engineering Student Publications

The purpose of this project is to design, manufacture, and deliver an Air Pallet capable of lifting heavy loads and positively engaging with the Drive Tractor for movement. This project was developed to address current maintenance hazards and difficulty, structural integrity concerns, and increase system reliability for our customers Lockheed Martin and the United States Navy.

3d Filament Recycler, Connor Easley, Stephan Jean-Baptiste, Armando Loynaz, Brody Paulk, Meagan Prouty, Tai Roberts, Jack Salcedo, Vanessa Tohorton, Alex Tremblay, Ruhaan Zaveri

Mechanical and Civil Engineering Student Publications

The purpose of the project is to design and manufacture an integrated system for the L3HSDC that can recycle 3D filament waste by shredding, heating, extruding, and spooling it.

The Matear System, Kylie Strong, Adel Siraeva, Julianna Bartus, Lilly Davies, Cameron Deen, Rayna Doty, Amiana Mata, Jack Minners, Matthew Skwiot

Mechanical and Civil Engineering Student Publications

The MATEAR attachment collects regolith simulant and uses compression and heat to form brick-like building blocks for sustainable infrastructure. It mounts to the Clearpath Robotics Husky A200 rover provided by the team’s faculty advisor.

Lockheed Martin & U.S. Navy Drive Tractor, Nicolas Czincila, Andrew Pestone, Santiago Florez-Tascon, Kalvin Long, Nick Norman, Joseph Phan, Ashlynn Redding, Brandon Ribeiro, Noah Rodriguez, Diana Viherek, Mckenzie Winder

Mechanical and Civil Engineering Student Publications

The purpose of this project is to design and manufacture a manually operated, pneumatic-assisted Drive Tractor system for transporting heavy loads with the Air Pallet. This project was developed to improve maneuverability, reduce operator effort, and increase system reliability within industrial environments for our customers Lockheed Martin and the U.S Navy.

Sparcc – Solar Panel Augmentation Via Regulated Cooling And Cleaning, Zachary Rodgers, Connor Fromme, Mohammed Al Jahwari, Jack Connor, Nicolas Hubley, Adrian Kingdollar, Iain Leroy, Maria Jesus Munoz, Ashton Stringer

Mechanical and Civil Engineering Student Publications

Problem Statement: Solar energy is the fastest-growing source of energy in the world. Solar cells lose efficiency by 0.35-0.7% per degree Celsius and up to 98% from debris build up. The primary objective of SPARCC was to improve cell efficiency through cooling and cleaning. A brush system with water spray was implemented to clean the panels, and a passive cooling system that utilizes a solar chimney, heat sinks, and phase change material to clean and cool.

Automatic Determination Of Mechanical Properties From Molecular Dynamic Stress-Strain Curves Using Regression Fringe Response, Josh Kemppainen, Tristan Muzzy, Travis Wavrunek, Gregory Odegard

Michigan Tech Publications

Molecular dynamics (MD) simulations have become a powerful tool for studying polymers, designing new materials, and composites. Mechanical behavior in MD simulations are typically evaluated through stress-strain curves. However, MD-generated stress-strain curves are often obscured by thermal noise from atomic vibrations. This noise complicates the reliable derivation of mechanical properties and hinders objective and reproducible analysis. The noise in the stress-strain curves has been removed by using a Butterworth low-pass filter, enabling clearer interpretation of stress-strain data. Building on this, a novel analysis framework the Regression Fringe Response (RFR) is introduced to systematically determine the Young's modulus, yield strength, and …

Transitional And Turbulent Dynamics In Viscoelastic Wall-Bounded Flows, Alexia Martinez Ibarra

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The addition of small amounts of long-chain polymers to a turbulent flow has been reported to modify the flow phenomena when compared to Newtonian flows, resulting in a significant skin-friction reduction. Although polymer-induced drag reduction has been extensively studied through both experimental and numerical studies, a unified and predictive understanding of the phenomenon is still lacking. This dissertation focuses on better understanding of this phenomenon, particularly on the transitional regime, which remains largely unexplored but is of utmost importance for both practical and fundamental purposes.

Firstly, direct numerical simulations are performed to study the effect of polymers on the laminar-turbulent …

Cast In Steel: Horseman's Axe, Sam A. Morris

Create@State

Cast in Steel is a competition between universities across North America started by the Steel Founders Society of America. The competition is centered around giving students the opportunity to learn about casting and the steel industry in general. A prompt of a weapon or tool with some level of historical significance is given to all the teams. The prompt for the 2026 Arkansas State University team, was a Horseman’s Axe. The team designed their rendition of a horseman’s axe, worked with Southern Cast Products as their local industry parter, and fabricated a finished axe to represent Arkansas State University as …

Analysis For Predicting Surface Temperature And Combustion Of Heavy-Duty, Pre-Chamber-Enabled, Hydrogen Engines, Tony Spezia

Master's Theses (2009 -)

Hydrogen as an alternative fuel shows great promise to help reduce greenhouse gas emissions from heavy duty engines. However, the challenge for hydrogen engines is that hydrogen has very different combustion properties compared to conventional hydrocarbon fuels. Hydrogen has very high flame speeds, very low ignition energy, and very wide flammability limit. These properties result in hydrogen engines being prone to abnormal combustion. Abnormal combustion makes hydrogen engines difficult to control or can cause catastrophic damage to the engine, so it is important to avoid conditions where abnormal combustion occurs. Hot spots along the combustion chamber walls are often the …

Techno-Economic Analysis Of Hybrid Systems As A Solution For Electricity Supply During The Dry Season At The Bakaru Run-Of-River Hydropower Plant, Zamharir Aditya Febri, Mohammad Akita Indianto, Sheila Tobing

Journal of Materials Exploration and Findings

Within the South Sulawesi power system (Sulbagsel), the Bakaru Hydro Power Plant serves as a key facility expected to provide consistent and reliable electricity supply. However, since the Bakaru plant operates under a Run of River scheme, its energy output is highly dependent on river discharge rates. In 2024, a significant decrease in water flow was recorded between August and October, which led to a drastic reduction in power generation. To address this challenge, a hybrid energy system is proposed to ensure continuous load coverage, particularly during the dry season. The optimal configuration of this hybrid system was modeled and …