Mechanical Engineering Commons^™

Multi-Material 3d Printing With Hybrid Direct Ink Writing-Volumetric Additive Manufacturing (Diw-Vam) System, Jose Zapata

Electronic Theses and Dissertations, 2020-2023

The rapid growth of 3D printing has led to many new iterations of additive manufacturing techniques. However, the current 3D printing techniques encompass only one printing method and have gradually expanded the ability to print multiple materials simultaneously. In this research, a hybrid 3D printing system is created by integrating direct ink writing (DIW) into volumetric additive manufacturing (VAM) to achieve multi-material printing. Compared to traditional DLP and SLA printing systems, the hybrid DIW-VAM system can create parts 95% faster. Meanwhile, the developed hybrid system takes advantages of DIW's precision to suspend a secondary liquid resin through extrusion into a …

A Conceptual Model For Quality 4.0 Deployment In U.S. Based Manufacturing Firms, Thomas Jones

Electronic Theses and Dissertations, 2020-2023

Manufacturing is currently undergoing a fourth industrial revolution, referred to as Industry 4.0, enabled by digital technologies and advances in our ability to collect and use data. Quality 4.0 is the application of Industry 4.0 to enhance the quality function within an organization. Quality practitioners are uniquely positioned within organizations and already possess data application skillsets. Despite a perception that Quality 4.0 will be critical to future success shared by a majority of industry, most companies have not attempted to implement Quality 4.0 strategy, and those that have report very low rates of success. The goal of this study was …

Design And Simulation Analysis Of A Bipv (Building Integrated With Pv) Air-Duct System For Residential High-Performance Development, Arash Zarmehr

Electronic Theses and Dissertations, 2020-2023

A growing number of buildings are integrating building-integrated photovoltaics (BIPV) devices to increase energy efficiency and reduce energy costs. A building's heating and cooling loads are impacted by the thermal resistance of the air duct BIPV because of the change in thermal resistance. Therefore, augmenting the efficiency of (BIPV) devices will benefit many building architectures and mechanical engineering applications. This work introduces a low-cost and low- maintenance air duct system design augmenting BIPV systems. This novel approach increases airflow velocity and decreases air temperature for BIPV, resulting in improved performance for the PV system electricity output, increased PV lifespan due …

Effect Of Autoclave Process Parameters On Mechanical Behaviors Of Carbon Fiber Reinforced Polymer Composites Fabricated Via Additive Manufacturing, Quang Hao Nguyen

Honors Undergraduate Theses

Additively manufactured carbon fiber reinforced polymers (CFRP) are vastly studied for their remarkable mechanical properties compared to most other 3D printed materials. Different methods were employed to further increase mechanical performance of CFRP 3D printed parts. The objective of the study is to investigate the effect of autoclave postprocessing on the interlaminar shear behavior between 3D printed CFRP layers. 3D printed CFRP samples were processed with nine combinations of temperature and vacuum in an autoclave. Short beam shear (SBS) tests were performed to characterize the interlaminar shear strength (ILSS) of the samples after autoclave processing. Digital image correlation (DIC) was …

Variational Autoencoder And Sensor Fusion For Robust Myoelectric Controls, Keith A. Currier

Honors Undergraduate Theses

Myoelectric control schemes aim to utilize the surface electromyography (EMG) signals which are the electric potentials directly measured from skeletal muscles to control wearable robots such as exoskeletons and prostheses. The main challenge of myoelectric controls is to increase and preserve the signal quality by minimizing the effect of confounding factors such as muscle fatigue or electrode shift. Current research in myoelectric control schemes are developed to work in ideal laboratory conditions, but there is a persistent need to have these control schemes be more robust and work in real-world environments. Following the manifold hypothesis, complexity in the world can …

Effect Of Particle Size On Mechanics Of Particle Reinforced Composites Using Photoluminescence Piezospectroscopy, Khanh Vo

Electronic Theses and Dissertations, 2020-2023

Nanoparticle reinforced composites are greatly desired by the aerospace community for a multitude of applications for their tailorable quasi-isotropic mechanical properties such as the high strength-to-weight ratio. With increasing demand of structural nanoparticulate composites, the optimization of their structural integrity and performance can be improved with a better understanding of the load transfer mechanics. Extensive nanoparticulate composites research has focused on the roles of particle shape, size, and volume fraction on the mechanical properties. Nanocomposites are often experimentally characterized through the determination of the bulk composite material properties. Load transfer research with a micro-mechanics perspective, distinguishing particle and matrix behavior, …

Machine Learning Applications In Advanced Additive Manufacturing: Process Modeling, Microstructure Analysis, And Defect Detection, Peter Warren

Electronic Theses and Dissertations, 2020-2023

Non-destructive evaluation (NDE) techniques are critical for assessing the integrity, health, and mechanical properties of materials manufactured from various methods. High fidelity NDE techniques are essential for quality control but often lead to massive data generation. Such a vast data load cannot be manually processed, this leads to a severe bottleneck for process engineers. Machine learning (ML) offers a solution to this problem by providing powerful and adaptable algorithms capable of learning patterns, identifying features, and finding hidden relationships in large sets of data. Various ML models are used in this work to improve predictions, improve measurements, detect anomalies, classify …

Investigation Of Endothelial Mechanics On Primary Cell Functions: Endothelium Permeability And Wound Healing, Sean Beverung

Electronic Theses and Dissertations, 2020-2023

The endothelium composes the inner lining of blood vessels, the heart, and lymphatic vessels. Within the cardiovascular system, it is an extremely important structure, aiding in the regulation of blood pressure with the vascular tone, recruiting immune response, regulating the transfer of material in and out of the bloodstream, and the creation of new blood vessels through angiogenesis. The endothelium is composed entirely of endothelial cells. These cells lay in a flat squamous formation and are in direct contact with blood and aid in the regulation and transfer of material in and out of the bloodstream via active and passive …

Design And Validation Of A Variable, Speed-Dependent Resistance Training Method For Muscle Hypertrophy, Alvaro Andres Aracena Alvial

Honors Undergraduate Theses

Muscle disorders and induced muscle atrophy impose critical risks to the well-being of an individual, limiting normal activities of daily living. Several resistance training methods have effectively reversed the progression of muscle atrophy. Weightlifting and hydrotherapy are the two widely practiced schemes for resistance training; however, there is the potential risk of excessive loads exerted on the muscles during weightlifting, and limited accessibility and cost are barriers to hydrotherapy. An alternative is using a resistance band. Some limitations include engaging multiple muscles/joints while only unidirectional resistance is feasible. To address these limitations, a VAriable Resistance Suit (VARS) was designed to …

Audible And Subaudible Components Of The First And Second Heart Sounds Using Phonocardiography And Seismocardiography, Daniella King

Honors Undergraduate Theses

Cardiovascular disease continues to be a leading cause of death in the United States, and a source of financial strain on the healthcare system. This prompts the need for new methods of low-cost, noninvasive technologies for cardiac monitoring to improve patient health and reduce healthcare costs. While the first and second heart sounds are common references that are listened to during auscultation of heart, seismocardiography (SCG) is a technology that detects chest sound vibrations with an accelerometer and may offer more information beyond the audible heart sounds. There is currently limited information regarding both the relationship between audible heart sounds …

Granular Jamming: Stiffness Vs Pressure And Organ Palpation Devices, Christopher H. Quach

Honors Undergraduate Theses

The intent of this thesis it to find a correlation between the stiffness of granular jammed particles and the pressure of the vacuum initiating the jamming force. Currently, granular jamming is being used to create palpation simulators for physicians to practice feeling the variety of stiffnesses of organs when healthy or ill. Because granular jamming allows for variable stiffness of any shape, it is an apt phenomenon to simulate the change of rigidity organs like the liver undergoes when diseased. For physicians to correctly identify how stiff the organ must be when using these palpation simulators, there needs to be …

Optimizing Biomechanical Models: Estimation Of Muscle Tendon Parameters And Ankle Foot Orthosis Stiffness, Sepehr Ramezani

Electronic Theses and Dissertations, 2020-2023

The complexity of the human musculoskeletal system presents challenges in accurately identifying its characteristics, particularly due to the presence of redundant actuators on a single joint. Non-invasive measures are necessary to overcome these challenges. Optimization algorithms have emerged as a crucial tool to advance subject-specific musculoskeletal modeling allows a more realistic representation of biomechanical behaviors, enhancing our understanding of human movement and enabling better clinical decision-making. Furthermore, optimization algorithms play a vital role in customizing rehabilitation and assistive devices, such as orthoses and prostheses. The current ankle-foot orthosis (AFO) stiffness measurement methods require bulky, complex designs, and often permanent modification …

Acausal Modeling Of Wind Turbines With Validation And Control Studies, Kazi Ishtiak Mohsin

Graduate Thesis and Dissertation 2023-2024

This thesis involves the modeling, validation, and control studies of a Control-Oriented, Reconfigurable, and Acausal Floating Turbine Simulator (CRAFTS), that is currently under development. CRAFTS uses Modelica®, an object-oriented, declarative, multi-domain modeling language for physical system modeling in the Dymola environment. The CRAFTS simulator facilitates rapid dynamic simulation of wind turbines with various model variants and enables control co-design.

A major emphasis of this thesis is in the validation of the CRAFTS simulator for a 15-MW land-based wind turbine through several test cases. These test cases were collaboratively developed in conjunction with other participating research entities. CRAFTS has undergone rigorous …

Adaptive Analytic Continuation For The State Transition Tensors Of The Two-Body Problem, Tahsinul Haque Tasif

Electronic Theses and Dissertations, 2020-2023

In the past few decades, Kessler syndrome (named after Donald J. Kessler) has become a point of concern in the field of Space Situational Awareness and the future of space missions. It refers to a scenario, where space debris in Earth's orbits collides and creates an exponential increase in space debris numbers leading to more collisions and more debris. In order to handle the resulting challenges like conjunction analysis, tracking, and probability of collisions, the State Transition Matrix (STM) and Tensors (STTs) of the orbit problem play a significant role. In addition, STM and STTs are ubiquitous in spaceflight dynamics, …

Processing And Characterization Of Ultra High Temperature And High Conductive Composites, Haonan Song

Electronic Theses and Dissertations, 2020-2023

There are significant challenges for materials in extreme environments for a variety of applications such as aircraft engines, gas turbines, nuclear reactors, re-entry vehicles, and hypersonic structures. Ceramic matrix composites (CMCs) could be ideal candidates to meet these stringent requirements for materials due to their high melting temperatures, high oxidation, corrosion and ablation resistance, low creep, and thermal cycling behavior in such extreme environments. Particularly, continuous fibers can bridge cracks in CMCs and therefore improve the strength and fracture toughness of composites. Metal matrix ceramics are important materials in various industries, such as aerospace and automobile. MMCs have excellent mechanical …

Modeling And Simulation Of A Power Plant Boiler Including The Dynamics Of Swell And Shrink, Richard Perman

Electronic Theses and Dissertations, 2020-2023

Renewables such as photovoltaics and wind turbines have seen consistent growth in markets across the globe. While renewables increase grid capacity and reduce the use of fossil fuels, their generation rates fluctuate subject to external factors. As the ratio of renewables to nonrenewables increases, so does variability of net load on intermediate and peaking power plants. Power plants with heat recovery steam generators (HRSG) constitute a significant proportion in these categories. There are several interconnected systems within HRSGs, including drum boilers which exhibit interesting transient phenomena known as swell and shrink. Improved understanding, dynamic modeling, and real-time simulation (RTS) of …

Experimental And Computational Heat Transfer Study Of Sco2 Single Jet Impingement, John Richardson

Electronic Theses and Dissertations, 2020-2023

The present study experimentally investigates the heat transfer capability of supercritical carbon dioxide (sCO2) single-jet impingement. The evaluated jet Reynolds number range is between 80,000 and 1,000,000, with a non-dimensional jet-to-target surface spacing of 2.8. CO2-impinging jet stagnation conditions were maintained at approximately 20 MPa and a temperature of 673 K for most experiments. The goal is to understand how changes in the aforementioned parameters influence heat transfer between the working fluid and the heated surface. Additionally, due to the elevated Reynolds numbers and difference in thermodynamic properties between air and CO2, air-derived impingement correlations may not be appropriate for …

Computational Modeling Of Respiratory Airflow In Human Distal Airways Using Hybrid Lung Model, Adnan Islam

Electronic Theses and Dissertations, 2020-2023

A major challenge in the Computational Fluid Dynamics (CFD) modeling of the human respiratory system is the complex variation of geometric scale from the trachea to the peripheral airways. The current literature on image-based lung flow analysis is limited to a few (typically 5) generations beyond the trachea. Such studies, which are limited largely by computational intensity and computational cost, also have limited accuracy. In this study we propose a hybrid methodology that enables CFD analysis from the middle to the distal airways through to the alveolar level. A hybrid lung model is generated where the middle airways are reconstructed …

Data-Driven Diagnostics And Prognostics For Complex Systems: Methods And Applications, Junchuan Shi

Electronic Theses and Dissertations, 2020-2023

Recent advances in artificial intelligence or machine learning have the potential to significantly improve the effectiveness and efficiency of diagnostic and prognostic techniques. The objective of this research is to develop novel data-driven predictive models with machine learning and deep learning algorithms that allow one to model the degradation, detect the faults, as well as predict the remaining useful life (RUL) of complex systems, including bearings, gearboxes, and Lithium-ion (Li-ion) batteries. First, an enhanced ensemble learning algorithm is developed to improve the accuracy of RUL prediction by selecting diverse base learners and features at different degradation stages. The proposed method …

A Study Of Autorotation: Samara Seed Pods And Tethered Autogyros, Jonathan Mcconnell

Electronic Theses and Dissertations, 2020-2023

This work presents an exploration of autorotational behavior, observing naturally occurring structures to provide insight into the stability and design of autorotative mechanisms. A rotor is said to be in autorotation when, in the presence of airflow, a natural rotation generates lift to either suspend or slow the descent of a rotor. This phenomenon is observed in nature in the form of samaras, a seed pod morphology evolved in parallel by maple trees and many other organisms around the world. Simulation and experimental observation of samara vertical descent behavior provides insight into the stability of naturally evolved autorotative structures. A …

An Investigation Of The Relationship Between Respiration And Seismocardiographic Signals Using Signal Processing, Machine Learning And Finite Element Analysis, Tanvir Hassan

Electronic Theses and Dissertations, 2020-2023

Cardiovascular disease (CVD) is one of the major causes of death worldwide. Disease management, as well as patient health, can be significantly improved by early detection of patient deterioration and proper intervention. Review of the patient's medical history and physical examination including stethoscope auscultation and electrocardiograms (ECG), echocardiography imaging, numerous blood testing, and computed tomography are common means of evaluating cardiac function. Seismocardiographic (SCG) signals are the vibrations of the chest wall due to the mechanical activity of the heart. These signals can provide useful information about heart function and could be used to diagnose cardiac problems. The variability in …

Exploration Of Warm-Up Protocols On Muscular Fatigue, Sahil Kapadia

Honors Undergraduate Theses

Muscular dystrophy is a genetically linked myopathy with no cure available. The lack of a cure makes early detection and treatment of muscular dystrophy imperative. When reviewing protocols examining muscular fatigue at submaximal isometric contractions, proper warm-up appeared to be absent and could have caused skewed results and conclusions. This study examines the effects of implementing a warm-up protocol before fatiguing trials. In this study, 10 adult subjects conducted fatiguing protocols with the right rectus at submaximal isometric contractions. The warm-up period included a light walk along with contractions at 20% and 33% of maximal voluntary isometric contraction (MVIC) levels. …

Probing The Effect Of Hyperglycemia On Endothelial Force Generation And Transmission, Jovani J. Gutierrez

Honors Undergraduate Theses

This thesis intends to utilize biomechanics to study the endothelial biomechanical response in a static hyperglycemic microenvironment. Hyperglycemia is a diabetic condition with abnormally high levels of glucose in the bloodstream. The effects of hyperglycemia over time lead to vascular complications resulting in patients being more prone to cardiovascular diseases. Current studies have focused on the molecular mechanisms affected by hyperglycemia; however, the mechanical mechanisms by which hyperglycemia causes vascular structural and functional changes are understudied. Therefore, to study the effects of hyperglycemia in the endothelium, Human Umbilical Vein Endothelial Cells (HUVEC) were cultured under three glucose conditions: normal glucose …

An Investigative Design Of Gas Jet Nozzles And Their Flow Field Effect On Spatial Distribution, Adam Phengsomphone

Honors Undergraduate Theses

Within this study, the presented material has the objective of providing insight and design characteristics for gas jet nozzles that experimentalists and researchers should consider when utilizing this experimental method. Firstly, this study introduces the developing history and necessity for gas jet experiments and its well-known drawbacks, eventually leading to recent studies and founded knowledge regarding the nozzle geometry dependence on the flow field. The simulation methodology of this study will be presented where the discretization of the computational domain, selection of the flow physics model, and overall design of the nozzle geometry is explained and justified. The flow field …

An Introduction To The Comparison Of Seismocardiography And Phonocardiography, Anna C. Voyatzoglou

Honors Undergraduate Theses

The intent of this thesis is to lay groundwork for examining the relationship between seismocardiography (SCG) and phonocardiography (PCG). Both are methods of measuring and describing heart mechanical function. SCG is described as chest vibrations while the heart beats, and PCG is described as acoustic chest surface signal believed to represent the heart valves opening or closing. SCG and PCG have both been used separately in clinical and research settings, but there is currently no clear comparison between the two. Therefore, there has been no way at the present to understand how one signal might inform the other. This study …

Design And Development Of Medical Devices For Multifaceted Applications, Madisyn Messmore

Honors Undergraduate Theses

The fields of biotechnology and biomedical sciences are rapidly evolving and involve the constant growth of knowledge. As a consequence, engineering design has to also remain at the cutting edge in order to not inhibit the growth of these fields. This study focuses on engineering design and analysis as it pertains to the field of biotechnology, at every step of the engineering process. More specifically, how the engineering design and analysis approach can assist in solving medical problems relating to bone diseases and biomaterials. The first part of the study focuses on a project to design and manufacture a novel …

Thermofluidic Characterization Of Carbon Dioxide Near Critical Conditions At Microscale, Anatoly Parahovnik

Electronic Theses and Dissertations, 2020-2023

This work revealed the thermo physical characteristics of near critical and supercritical carbon dioxide at the micro scale. The results include the extension of flow boiling heat transfer correlations, boiling inception, near critical bubble dynamics, thermalization mode shift, Joule Thomson effect and pressure drop evaluation. It was found that extremely low superheat temperatures are required for boiling inception near the critical conditions (i.e., T=31.4 °C, and P=7.37 MPa), and boiling heat transfer correlations were extended up to a reduced pressure of 0.99. The work also revealed a significant enhancement of the heat transfer coefficient as the critical conditions approached, which …

Data-Driven Modeling Of Mechanical Behaviors Of Additively Manufactured Materials, Ziyang Zhang

Electronic Theses and Dissertations, 2020-2023

Additive manufacturing (AM) is a revolutionary technology that greatly improves the flexibility of fabricating parts with complex structures and eliminates the cost of making molds. While AM techniques offer unique benefits over traditional manufacturing processes, it is challenging to predict the mechanical behaviors of additively manufactured parts based on design and process parameters. With recent advances in machine learning, data-driven methods have the potential to overcome such limitations. In this work, data-driven modeling frameworks were proposed to predict the tensile, flexural, and compressive behaviors of additively manufactured plastics and composites. Ensemble learning was used to predict the tensile strength of …

Vibrations Of Rotationally Periodic Structures: A Metric For Mistuning Characterization And Vibration Localization, Andres Rodriguez

Electronic Theses and Dissertations, 2020-2023

Blisk components are an integral part of jet engines and power generation systems. Composed of a single monolithic structure, integral blisks combine the blade-and-disk portion of primary components such as the fan, compressor stage, or turbine stage. This design modification increases the aerodynamic performance while decreasing the cost and eliminating time of assembly. However, these benefits come with the loss of blade-disk connection interfaces, which greatly reduces the structure's damping and its ability to attenuate unwanted structural vibrations. Blisk dynamics are impacted by mistuning, which is a disruption of the periodic symmetry of otherwise identical bladed sections. This disruption degrades …

Mean Pressure Gradient Effects On Flame-Flow Dynamics In A Cavity Combustor, David M. Smerina

Honors Undergraduate Theses

Pressure gradient confinement effects are experimentally investigated within a cavity combustor to analyze the flame interactions of premixed, cavity stabilized, flames in a high-speed combustor. Pressure gradient confinement effects are generated in a dual mode ramjet-scramjet (DMSR) by varying the wall geometry to form converging, diverging, and nominal configurations. The velocity field and flame position are captured temporally using simultaneous high-speed particle image velocimetry (PIV) and CH chemiluminescence. The evolution of the flow field and flame structure are analyzed, and the high temporal resolution of these measurements allows for the characterization of turbulence-flame interactions. Consideration of the combustion mode and …