Applied Mechanics Commons^™

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 …

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. …

Design And Development Of A 12-Degree-Of-Freedom Quadruped Robot, Kai De La Cruz

Master's Theses

This thesis presents the design, analysis, and experimental validation of a 12-degree-of-freedom (DOF) quadruped robot developed as a research platform for legged locomotion and control. The system builds upon the Cal Poly Legged Robotics Group’s prior 8-DOF quadruped, addressing key limitations in manipulability, load distribution, and mechanical robustness by introducing a 3-DOF leg architecture.

The mechanical design emphasizes lightweight construction, structural integrity, and modularity to support future research extensions. Static and dynamic loading models were developed to inform component sizing and material selection. A carbon-fiber chassis and redesigned leg assemblies were fabricated and validated through finite element analysis and physical …

Numerical And Machine Learning Based Recreation Of Damage Morphologies Of Barely Visible Impact Damage, Oscar A. Valdez

Mechanical and Aerospace Engineering Dissertations

Composite laminates are highly sought after in the aerospace industry as they provide strength without dramatically increasing the weight of manufactured structures. However, composite laminates are susceptible to barely visible impact damage caused by routine activities. This type of damage can easily go unnoticed while significantly reducing the load-carrying capability of the laminate. Current non-destructive evaluation techniques, such as ultrasonic scanning, can reveal the damage footprint but provide no insight into delamination through-the-thickness due to the shadowing effect. Micro-computed tomography offers ply-by-ply damage resolution but is unsuitable for field inspections and is constrained by specimen size. This study aims to …

Thermal Transformations And Mechanical Properties Of All-D-Metal Mn2fecu Heusler-Type Shape Memory Alloy, Choji J. Daches, Joseph W. Newkirk, Mario Buchely

Materials Science and Engineering Faculty Research & Creative Works

All-d-metal Heusler alloys are emerging functional materials in which magnetic ordering, lattice distortion, and mechanical behavior are strongly coupled through d–d electronic interactions. This study systematically investigates the structural, thermal, magnetic, and mechanical properties of Mn₂FeCu synthesized within a Heusler-type compositional framework. SEM/EDS revealed a dual-phase FCC-based microstructure consisting of Mn–Fe–rich and Mn–Cu–rich domains, while XRD confirmed FCC symmetry with compositional partitioning rather than full L2₁ ordering. Differential scanning calorimetry identified partial melting of the Cu-rich phase near ~ 900 °C. Dilatometry showed a thermoelastic FCC → FCT transformation at ~ 770–780 °C with a recoverable strain of ~ 0.067%. …

The Effects Of Mold Flux Contamination On Oxide Scale Formation And Hydro-Descaling Efficiency During Steel Processing, Tochukwu Princewill Ojiako, Richard Osei, Mario Buchely, Haiming Wen, Simon Lekakh, Ronald O'Malley

Materials Science and Engineering Faculty Research & Creative Works

Oxide scale formation during thin-slab continuous casting has a complex structure, which is influenced by mold flux contamination, that modifies interfacial reactions during solidification, subsequent reheating, and descaling. While individual aspects of the oxidation behavior of carbon steel have been previously examined, the synergetic effects of mold flux contamination during continuous casting and subsequent reheating on scale modification and the efficiency of hydraulic descaling remain inadequately studied. This study quantitatively examines the effect of flux composition on oxide scale evolution, adhesion, and hydraulic removal in low-carbon steel under simulated industrial conditions. Slab samples with as-cast, cleaned, and flux-coated surfaces were …

Ai-Based Porosity Detection In Babbitt Bore Turning, Kaylee Leggett, Hannah Adams Gemmell, Kaisa Shingleton

Williams Honors College, Honors Research Projects

For this project, an external company reached out to the University of Akron requesting assistance with defect detection during their vertical turning operations. As babbitt is removed in a vertical turning process, it occasionally reveals defects, mainly porosity, which can lead to costly downstream failures of the part. Current inspection techniques involve use of dye penetrant, which is time consuming, labor intensive, unergonomic, and a source of human error. The goal of the project is to create an alternative inspection method using an AI-based machine-learning model. After the turning operation, a camera is deployed to perform an in-place inspection, taking …

Large Telescope Mount For Long Exposure Photos, Payne M. Landis, Anna J. Gray

Williams Honors College, Honors Research Projects

When viewing the stars through a telescope, it is common that the object you are viewing drifts out of view. Many amateur astronomers seek to capture long exposure images of the stars, planets, and galaxies with commercially available sky tracking telescope mounts. The complication is that these telescope mounts are both incredibly expensive and have low weight limits. These issues limit accessibility to these products based on the telescope. For each person, telescope parameters determine the amount of light and magnification that can be viewed, which then determines exposures time for adequate photo results. The options on the market for …

Akron Soap Box Derby Super Kids Car, Alexis Schultz, Cooper Sites, Sean Stevenson

Williams Honors College, Honors Research Projects

This project aims to redesign the All-American Soap Box Derby Super Kids vehicle to enhance safety, accessibility, and performance while maintaining full compliance with official regulations. The Super Kids program enables children with physical and cognitive disabilities to race alongside a co-pilot, but the current vehicle design presents challenges in stability, entry/exit accessibility, and control—especially following recent regulation changes that increased vehicle speed. The redesigned car will focus on improved ergonomics, lightweight construction, and structural integrity within a $1,000 budget and a 165 lb weight limit.

An iterative engineering design process will guide the project through research, CAD modeling, FEA …

Automated Soil Resetting System For Extraterrestrial Regolith Simulation, Parker W. Brennan, Anthony C. Daniels

Williams Honors College, Honors Research Projects

This project focuses on designing an automated soil resetting system for extraterrestrial regolith simulation. The system will prepare a regolith simulant testbed to a desired, repeatable density, enabling reliable wheel–terrain testing for planetary rover research. Manual soil preparation currently exposes testers to hazardous particulates and produces inconsistent results.

The proposed system will integrate mechanical and control elements to reset the soil bed safely and efficiently. A combination of raking and vibrational methods will be explored, with feedback sensors and automation to achieve target density control. The research will proceed through literature review, benchtop experimentation, prototype design, and full-scale testing over …

Evaluation Of The Long-Term Sealability Performance Of Aramid Fiber Nitrile-Based Gaskets, Salome Ramirez

Honors Undergraduate Theses

The reliability of sealed, oil-filled containers is critical for maintaining the operation of high-voltage energy systems, in which the sensitive electronics need to be isolated from the cyclic conditions associated with outdoor environments. New materials bring the possibility of extending service lifetimes and maintenance intervals. Aramid fiber nitrile-based gaskets are an attractive alternative to conventional gasket choices due to their long-term stability in various environments and compatibility with porcelain, metals, and plastics. For newly designed porcelain-to-metal fittings, understanding the behavior of the candidate gasket material under realistic loading conditions is essential to ensure long-term seal integrity and equipment safety. Traditional …

Analytical Study Of Transient Mixed Convective Radiative Jeffrey Fluid Flow With Diffusion–Thermo And Chemical Reaction, V. Sathiya, R. Vijayaragavan, B. Rushi Kumar

Mansoura Engineering Journal

This research examines the behavior of unsteady mixed convective radiative Jeffrey fluid flow over a permeable moving plate with a diffusion thermo effect. The study incorporates multiple factors, including aligned magnetic fields, heat generation, radiation, and chemical reactions. The behavior of Jeffrey fluid under these combined conditions is particularly relevant to the design of efficient heat exchangers, MHD generators, and cooling systems for electronic components. A regular perturbation technique was employed to solve the governing equations, yielding distributions for velocity, temperature, and species concentration. These solutions enabled the derivation of expressions for skin friction, Nusselt number, and Sherwood number. Through …

Critical Parameters Controlling Oxide Scale Formation And Hydro-Descaling Efficiency During Steelmaking, Tochukwu Princewill Ojiako

Doctoral Dissertations

In modern steelmaking, cast slabs are exposed to high-temperature oxidizing environments during secondary cooling, reheating, and hot rolling, resulting in the formation of multilayer oxide scales on the steel surface. These scales interact with mold-flux residues originating from the casting process (CC). The morphology, chemistry, and adhesion of oxide scale strongly influence its removability during high-pressure hydraulic descaling and ultimately determine the surface quality of hot-rolled products. However, the mechanistic relationship between oxide scale evolution, scale-steel interfacial structure, and hydraulic descaling performance remains poorly understood.

This dissertation investigates oxide scale formation, modification, and removal in low-carbon thin-slab steels produced by …

Modeling Of Transformation Temperatures In Cast Martensitic Stainless Steels-Ca6nm: Effects Of Composition, Heating Rate, And Grain Size, Ugochukwu Agbedo, Mario Buchely, Laura Bartlett, Caelan Kennedy

Materials Science and Engineering Faculty Research & Creative Works

Accurate prediction of the critical transformation temperatures Ac1 and Ac3 is one of the essential factors in the heat treatment of CA6NM cast martensitic stainless steel. In this study, the influence of alloy composition, heating rate, and prior austenite grain size on the critical temperatures was quantified using dilatometric measurements and statistical modeling. Six heat treatment conditions produced prior austenite grain sizes ranging from ~75 to 247 µm. Experimental results showed that grain size variations produced only minor changes in Ac1 and Ac3, indicating a weak dependence of transformation temperatures on prior austenite grain size within the investigated range. In …

Multiphysics Simulation And Experimental Validation Of Phase Transformation And Hardness In Jominy End-Quenched Low-Alloy Steels, J. S. Alabi, E. Heidari, M. F. Buchely, K. Chandrashekhara, S. N. Lekakh, R. J. O'Malley, V. A. Athavale, A. Kumar

Materials Science and Engineering Faculty Research & Creative Works

High-volume industrial continuous hot-rolled steel heat treatment processes involve sophisticated multi-phase modeling. The performance of a given process can be optimized by coupling phase transformation kinetics with the cooling conditions of the process. This study develops a multiphysics model to simulate an intensive quenching process for steel, which is inherently transient and highly dependent on numerous parameters. The simulated object was a Jominy end-quenched specimen geometry using two commercial steels, AISI 4130 and AISI 4140, with the goal of transferring a verified methodology to the heat treatment process for industrial heavy-section products (bars, slabs). The simulation employs thermal, mechanical, and …

In-Field Tractor Operational Load Profile Generation In Support Of Advanced Tractor Testing In Mixedmode Power, Andrew Donesky

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

This dissertation addresses the need to better characterize real-world tractor power requirements across drawbar, power take-off (PTO), and hydraulic modes to support more representative tractor testing. Conventional testing protocols, such as OECD Code 2, emphasize steady-state performance under controlled high-load conditions, which do not reflect the mixed and dynamic demands of modern field operations. To address this gap, a Tractor Instrumentation System (TIS) was developed, validated, and deployed to collect high-resolution, mixed-mode power data during planting, anhydrous ammonia application, and grain cart operations. The TIS integrates physical sensors, including custom load pins, hydraulic pressure/flow sensors, and a redesigned PTO torque …

Residential Hvac Installation Faults: Field Prevalence, Drivers, And Energy Impacts, Seyed Ali Rooholghodos

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

Faults in residential comfort systems can have detrimental effects on the performance of the system, reducing the energy efficiency, affecting indoor comfort, and shortening equipment lifespan. Many of the faults occur at installation. However, there has not previously been a systematic and nationally representative study to indicate the prevalence of the faults, meaning the distribution of faults by fault type and fault intensity. Understanding true fault prevalence is essential to be able to identify derivers, and to assess the incremental electricity consumption of the new installation systems.

This study presents on-site data from 341 new central cooling systems—air conditioners and …

Experimental And Numerical Study On The Influence Of Carbon Fiber Reinforcement On The In-Plane Compressive Properties Of 3d Printed Hexagonal Honeycomb Core Structures, Deon Wallace

All Theses

There is difficulty with numerically replicating the behavior of composite honeycomb core structures numerically due to the trouble of gathering material properties from a hollow structure. Also, complex part geometries and carbon fiber reinforcement strategies can lead to unwanted structural weaknesses and variance in material properties that may not be reflected in numerical analysis when the part is additively manufactured. In this study, edgewise compressive testing is used to characterize the mechanical behavior and performance characteristics of these structures. The experimental results indicate an increase in the Young’s moduli of the honeycomb core structures as carbon fiber concentration increases. However, …

Predicting Long-Term Creep Behavior Using Short-Term Stress Relaxation Data In Expanded Polyethylene Foam, Andrew M. Seelig

All Theses

Closed cell expanded polyethylene (EPE) foams are widely used for protective packaging due to their high energy absorption properties and recyclability. However, these foams can be subjected to sustained compressive stresses (13.78 - 36.20 kPa), depending on density and application, leading to time-dependent deformation (creep). Creep reduces cushioning performance, making its understanding critical for effective protective packaging. Two standards, ASTM D3575 and ASTM D2221, define methods for conducting compressive creep tests on foam materials, with test durations extending up to 1000 hours. Accelerated methods such as Time Temperature Superposition (TTS) and the Stepped Isostress Method (SSM) have been explored for …

Cnn-Based Hybrid Model For Detecting Blight Diseases In Potato Crops With Advanced Image Processing Techniques, Farian S. Ishengoma

Tanzania Journal of Engineering and Technology (TJET)

Potato production plays a vital role in global agriculture as a major food source for large populations. However, potato crops are highly susceptible to diseases, particularly Early Blight and Late Blight, which result in substantial yield losses. Timely detection and effective control of these diseases are essential for maintaining stable crop output. This study explores the integration of Convolutional Neural Networks (CNNs) and advanced image processing techniques to differentiate between diseased and healthy potato plants accurately. Two datasets comprising original and enhanced images were used to train four CNN models: InceptionV3, Xception, Densenet201, and Resnet152V2. The original images underwent background …