Engineering Commons^™

Machine Learning Based Analysis Of Civil Infrastructure In The Presence Of Sparse Data, Megan Butcher

Doctoral Dissertations and Master's Theses

The high computational cost of estimating engineering demand parameters (EDPs) via finite element (FE) models, which incorporate uncertainties in earthquake events and material properties, limits the application of the Performance-Based Earthquake Engineering (PBEE) framework. Previous efforts to replace FE models with surrogate models have typically focused only on building parameters, necessitating re-training for new, unseen earthquakes. This paper introduces a machine learning-based surrogate model framework that addresses both earthquake and material parameter uncertainties to predict responses for unseen seismic events. Earthquakes are characterized by their projections on an orthonormal basis, computed using Singular Value Decomposition (SVD) of a representative ground …

Machine Learning For Intrusion Detection Into Unmanned Aerial System 6g Networks, Faisal Alrefaei

Doctoral Dissertations and Master's Theses

Progress in the development of wireless network technology has played a crucial role in the evolution of societies and provided remarkable services over the past decades. It remotely offers the ability to execute critical missions and effective services that meet the user's needs. This advanced technology integrates cyber and physical layers to form cyber-physical systems (CPS), such as the Unmanned Aerial System (UAS), which consists of an Unmanned Aerial Vehicle (UAV), ground network infrastructure, communication link, etc. Furthermore, it plays a crucial role in connecting objects to create and develop the Internet of Things (IoT) technology. Therefore, the emergence of …

Analysis Of Wingtip Vortex Structure Generated By Bio-Inspired Winglets, D'Zahn A. Smith

Doctoral Dissertations and Master's Theses

Bio-inspired winglets were studied with the goal of better understanding the structure of the wingtip vortices they generate. Measurements of the tip vortex were previously carried out using stereoscopic particle image velocimetry (sPIV). The bio-inspired winglet was tested on a rectangular NACA 0012 wing section at a 5-degree angle of attack and at a chord Reynolds number of 900,000. Velocity field measurements were recorded at 0.7 and 2 chord lengths aft of the wing’s trailing edge. Compared to the wing with no attachment and a traditional blended winglet, the bio-inspired winglet’s vortex exhibited significantly less intense flow field properties. These …

Survival After Ditching In Motorized Aircraft, 1989-2022, Douglas D. Boyd, Volker C. Schick, Catherina Hippler, Jochen Hinkelbein

Publications

INTRODUCTION: Although an unintended aircraft landing on water (referred to as ditching) is a rare event, the potential for occupant injury/fatality increases immediately following the event due to adverse conditions. However, to date, few studies have addressed the subject. Herein, ditching events and post-ditching survival were investigated.

METHODS: Ditchings (1982–2022) in the United States were identified from the National Transportation Safety Board database. Occupant injury severity, aircraft type, pilot experience, flight conditions, and number of occupants were extracted. Poisson distribution, the Chi-squared test (2-tailed), Mann-Whitney U test, and Kruskal-Wallis one-way analysis of variance were employed.

RESULTS: A total of 96 …

Characterization And Analysis Of Supersonic Flow Through De Laval Nozzles At Varied Design Conditions, Sarah Baird

Doctoral Dissertations and Master's Theses

A combined numerical and experimental investigation of supersonic planar nozzles under different design conditions has been conducted. Supersonic planar nozzles are common geometries observed in supersonic wind tunnels and aircraft or rocket engines. For the important role they play in wind tunnel testing and aircraft propulsion, it is important to conduct a thorough numerical and experimental study to characterize their performance at different operating conditions. In this study, a de Laval nozzle was scanned to extract its contours and subsequently modeled to compare analytical and numerical performance expectations under design and off-design conditions. The nozzle was then installed in a …

Modeling Of Rotor Wake Vortex Dynamics And Interactions In Non-Homogenous Vertiport Environments, Garrison P. Shaw

Doctoral Dissertations and Master's Theses

The current research serves to analyze and study the effects ground forces can have on the thrust performance of a propeller in multiple different configurations. The current research utilizes an open source Computational Fluid Dynamics (CFD) software known as OpenFOAM to generate calculate and visualize these runs. The model used for this experiment is a hybrid model that employs both a Unsteady Reynolds-Averaged Navier-Stokes (URANS) and a detached eddy simulation using a hybrid Large Eddy Simulation (LES) via a KomegaSSTDDES model. This model serves to save computational time as well as allow for accurate results. The three cases run are …

Machine Learning-Based Gps Jamming And Spoofing Detection, Alberto Squatrito

Doctoral Dissertations and Master's Theses

The increasing reliance on Global Positioning System (GPS) technology across various sectors has exposed vulnerabilities to malicious attacks, particularly GPS jamming and spoofing. This thesis presents an analysis into detection and mitigation strategies for enhancing the resilience of GPS receivers against jamming and spoofing attacks. The research entails the development of a simulated GPS signal and a receiver model to accurately decode and extract information from simulated GPS signals. The study implements the generation of jammed and spoofed signals to emulate potential threats faced by GPS receivers in practical settings. The core innovation lies in the integration of machine learning …

Strength And Stiffness Optimization Of Coated Structures With Lattice Infill, Ali Tamijani, Zhichao Wang

Publications

A machine-implemented method for establishing optimized parameters defining a model of a coated structure with a lattice infill can include receiving constraints for the model of the coated structure. The machine-implemented method can also include initializing a lattice infill defined by respective lattice cells according to the constraints for the model of the coated structure. The machine-implemented method can also include optimizingthe lattice infill and a shape of the coated structure by iteratively modifyingthe lattice infill and the shape of the coated structure and evaluating a strength-based criterion. The machine-implemented method can also include generating, usingthe optimized lattice infill and …

Stiffness And Strength-Based Concurrent Shape And Fiber Path Optimization Of Continuous Fiber Composites, Zhelong He, Ali Tamijani

Publications

A computer-implemented method of optimizing a computer model including a shape and a fiber path for a continuous fiber composite can include initializing a fixed finite element mesh. The method can also include creating an updated version of the shape and the fiber path by iterating updates of the shape and the fiber path using the fixed finite element mesh. The method can also include initializing an adapted finite element mesh on the updated version of the shape and the fiber path. The method can also include creating an optimized version of the shape and the fiber path by iterating …

Localized Collocation Meshless Method For Modeling Transdermal Pharmacokinetics In Multiphase Skin Structures, Eduardo Divo

Math Department Colloquium Series

The human skin has a complicated structure with many multi-scale, biophysical effects impacting the propagation of skin-injected substances, such as partitioning, metabolic reactions, adsorption and elimination. An extended version of Fick’s second law governing the process of the compound diffusion in various skin layer is employed in the current work by considering the conservation of mass of the substance and the metabolic reaction of the substance in viable skin. Additionally, a model assuming linear coupling between the substance concentrations that are bound and unbound with blood was developed. Using such a model, a set of coupled partial differential equations are …

Assessment Of Improvement In Unpaved Roadway Performance Using 3d Geogrids Under Cyclic Loading, Munibhaskar Pagadala

Doctoral Dissertations and Master's Theses

Geogrids have been used for decades to improve the performance in both paved and unpaved road construction. This research focuses on quantifying the performance and optimizing the design of unpaved roadways using the results from an extensive cyclic triaxial testing program. Twenty-seven cyclic triaxial tests were performed, consisting of unreinforced (control) and reinforced samples using two types of 3D geogrids: Grid1 and Grid2. The samples measured 150 mm in diameter and a height of 300 mm. The tests were run under different loading sequences ranging from 41 kPa to 55 psi (6 psi to 8 psi of confining stress and …

The Elements Of Governance And Their Association With Aviation Safety Oversight Effectiveness, João Souza Dias Garcia

Doctoral Dissertations and Master's Theses

States and their respective national civil aviation authorities promote the improvement of the global civil aviation system by developing and enforcing safety regulations for aircraft design, operations, personnel training, infrastructure, and air traffic management, among other topics. For many years, the International Civil Aviation Organization (ICAO) has driven the continuous improvement of states’ safety oversight functions, supporting them in evaluating the effectiveness of these functions by conducting audits under the Organization’s Universal Safety Oversight Audit Program (USOAP). While the benefits of these assessments have been broadly recognized, scholarly literature on the factors commonly associated with safety oversight effectiveness across states …

Damage Control Measures In Composites: Focus On Damage Tolerance Of Aerospace Structures, Kais Jribi

Doctoral Dissertations and Master's Theses

Barely Visible Impact Damage (BVID) in composite materials presents a stealthy yet significant risk to structural integrity, particularly challenging due to its elusive nature. The approach adopted here diverges from traditional methodologies, focusing on the novel application of Digital Image Correlation (DIC) to map surface area changes during in-situ Compression After Impact (CAI) tests. This technique allows for an in-depth analysis of planar strains along the x and y axes, shedding light on the material's behavior under stress.

A pivotal advancement lies in developing a method for precisely identifying when BVID-induced delamination recommences. By meticulously analyzing strain pattern deviations along …

Optimization Of Human Interactions In The College Campus Model Via Simio Integration, Benjamin E. Chaback

Doctoral Dissertations and Master's Theses

College campuses are a significant part of life in some cities. Many students each year attend university, pursuing additional knowledge from faculty members. Both staff and faculty members rely on these students to have successful jobs and to ensure the university functions. Yet recently, more and more students are attending, leading to overcrowding, lower admission rates, and difficulty getting into good programs. Previous work exists on qualitative student affairs and quantitative retention data, yet little on using simulations to model this problem. This work aimed to (a) Determine the ability to successfully model human interactions/people flow on a college campus, …

Impacts Of Space Launch Operations On Florida East Coast Airspace Users, Sakurako Kuba

Doctoral Dissertations and Master's Theses

With an increasing number of space flight operations in the United States, space flight integration into the National Airspace System (NAS) is a pertinent area of research so safe and efficient operations in NextGen airspace can be achieved. The currently implemented procedure for Florida east coast launches temporarily closes the airspace to keep all air traffic operations out of the launch trajectory and potential hazard areas to maintain the safety of air traffic and space vehicles. This results in the flight deviation from the shortest flight route, leading to extended flight distance, prolonged flight time, and extra fuel burn. This …

Development Of Eagle3d Solver For Wall Modeled Les Of Transonic Flows, Spencer Moore

Doctoral Dissertations and Master's Theses

Wall modeled Large Eddy Simulation (LES) is an area of interest due to its ability to lower computational costs of LES simulation. Even with the application of wall models, LES still proves to have practicality issues when it comes to use in industry, due to the expertise, time, and computational resources required to get results. A case described by an axisymmetric transonic bump is explored utilizing the Embry-Riddle Aeronautical Universities in house unstructured finite volume multi-element CFD code, Eagle3D. Eagle3D, has been brought to the state of the art and validated against current research using this transonic bump case as …

Low Cost Magnetometer Calibration And Distributed Simultaneous Multipoint Ionospheric Measurements From A Sounding Rocket Platform, Joshua W. Milford

Doctoral Dissertations and Master's Theses

Low-cost and low-size-weight-and-power (SWaP) magnetometers can provide greater accessibility for distributed simultaneous measurements in the ionosphere, either onboard sounding rockets or on CubeSats. The Space and Atmospheric Instrumentation Laboratory (SAIL) at Embry-Riddle Aeronautical University has launched a multitude of sounding rockets in recent history: one night-time mid-latitude rocket from Wallops Flight Facility in August 2022 and three mid-latitude rockets from White Sands Missile Range during the October 2023 annular solar eclipse. All rockets had a comprehensive suite of instruments for electrodynamics and neutral dynamics measurements. Among this suite was one science-grade three-axis fluxgate magnetometer (Billingsley TFM65VQS / TFM100G2) and up …

Development Of On-The-Fly Quasi-Steady State Approximation For Chemical Kinetics In Cfd, Abhinav Balamurugan

Doctoral Dissertations and Master's Theses

This study analyzes the feasibility of On-The-Fly Quasi-Steady-State Approximation (OTF-QSSA) application for solving chemical kinetics within Computational Fluid Dynamics (CFD) simulations, aiming to reduce the computational demand of detailed mechanisms. An algorithm that dynamically identifies and designates Quasi-Steady-State (QSS) species at specific grid locations and instances during the simulation was developed. With this information, our method pseudo-delays the advancement of concentrations for these QSS species—effectively setting their rate of concentration change to zero for a set number iteration before updating using the detailed mechanism and thereby omitting the computationally intensive processes typically required for their calculation during those skipped iteration. …

Distributed Adaptive Control Methods For Uncertain Multiagent Systems With Coupled Dynamics, Islam Aly

Doctoral Dissertations and Master's Theses

For a multiagent system, a major challenge is achieving overall system stability and performance in the presence of not only uncertainties but also coupled dynamics. Another challenge for these systems is designing distributed adaptive controllers with user-assigned positions in this case and defining the convergence rate of the reference model for each agent using only local (i.e., agent-based) information. Discrete-time architectures have an advantage over their continuous counterparts as they can be directly executed on embedded hardware without the need for discretization. Yet, because of the difficulty of ensuring Lyapunov difference expressions, their designs, which are based on quadratic Lyapunov-based …

Ti Nano Powder Speckle Pattern Creation And Use In Dic Of Zno Modified Single Carbon Fibers, James Matthew Harris

Doctoral Dissertations and Master's Theses

As the use of composites continues to grow across aerospace, naval, automotive, construction, 3D printing, and other countless industries, so does the desire to continuously improve their mechanical properties. Improving the adherence of the fiber-matrix interface is one important step for amplifying the capabilities of composites. Work has been performed in modifying carbon fibers by growing zinc oxide (ZnO) nanorods in the fiber surface using a hydrothermal approach, increasing interfacial area and fiber-matrix friction. Macroscale evaluation has shown that the interfacial modification decreases the inter-ply movement and reduces the processing strains and residual stresses. To fully understand the mechanism taking …

Evaluating Flight Crew Decision-Making Through Part 121 Taxi Operations, Grant Marsh

Doctoral Dissertations and Master's Theses

With the mandate of Automatic Dependent Surveillance-Broadcast (ADS-B) going into effect at the start of 2020, commercial companies have been able to log and store information on aircraft identification, airspeed, heading, and altitude all in one database.to Now, anyone can access previously hard-to-obtain flight data for analysis using a commercially available database. While ADS-B provides information on “what is happening,” information on “why” flight crews operate aircraft in a certain way is not incorporated into ADS-B.

The National Aeronautics and Space Administration’s (NASA) Aviation Safety Reporting System (ASRS) collects reports written by flight crews, Air Traffic Control Specialists, and other …

Numerical Study In Wind Energy Extraction From Controlled Limit-Cycle Oscillations In Modified Glauert Airfoil, Ethan L. Deweese

Doctoral Dissertations and Master's Theses

Typically, wind energy harvesting technology employs wind turbines. Towards the goal of meeting increasing energy needs with renewable energy sources a novel wind energy harvesting scheme is considered, utilizing a modified Glauert (MG) airfoil experiencing aeroelastic limit cycle oscillation (LCO) from which energy may be extracted. Synthetic jet actuators (SJA)s are used along with the unique geometry of the MG airfoil to control flow separation and amplify the LCO and energy generation potential of the system. The discussed wind energy harvesting scheme could provide flexibility in allowing installations previously unsuitable to wind turbines due to geometric or low wind velocity …

Emergent Themes Of Operational Safety At Urban Air Mobility At Vertiports: The Stakeholder Perspective, Tracy Leigh Lamb

Doctoral Dissertations and Master's Theses

The emerging urban air mobility (UAM) industry is dynamic, complex, and still highly conceptual, as vertiports are not currently an operational reality in the United States. The UAM vertiport is at the epicenter of the emerging advanced aviation ecosystem, representing significant operating costs of approximately $130 million per year and more than that to design, develop, and implement. In addition to setting up and operating capital, there are considerable challenges relating to the safe design, development location, and operation of UAM vertiports, representing the confluence of human and autonomous systems, whose interdependence is not yet fully understood. UAM vertiport stakeholders …

Passenger Traits That Predict The Bystander Intervention Model Steps During An Inflight Assault On A Flight Attendant, Michael Pettit

Doctoral Dissertations and Master's Theses

Every major U.S. airline has experienced a violent inflight assault on one of their flight attendants. The problem is becoming more widespread, but industry leaders have few coping strategies. The first step toward addressing the issue is understanding the various aspects of the event, including the actions of other passengers (bystanders) who may witness the assault. There is ample literature on bystander reactions to similar events such as bullying, medical emergencies, injuries, and violent attacks, but none dedicated to a flight attendant assault or passenger reactions to it.

At the core of bystander action is the bystander effect, which postulates …

Implementation Of Path Planning Methods To Detect And Avoid Gps Signal Degradation In Urban Environments, Ayush Raminedi

Doctoral Dissertations and Master's Theses

In the modern world, various missions are being carried out under the assistance of autonomous flight vehicles due to their ability to operate in a wide range of flight conditions. Regardless, these autonomous vehicles are prone to GPS signal loss in urban environments due to obstructions that cause scintillation, multi-path, and shadowing. These effects that decrease the GPS functionality can deteriorate the accuracy of GPS positioning causing losses in signal tracking leading to a decrease in navigation performance. These effects are modeled into the simulation environment and are used as part of the path planning algorithm to provide better navigation …

Indentation Protection Of Lithium-Ion Batteries Using Woven Fiber Metal Laminates, Sida Xu

Doctoral Dissertations and Master's Theses

Lithium-ion batteries are widely used as electric power sources for smartphones, tablets, laptops, e-scooters, unmanned aerial vehicles, aircraft, electric vehicles, airport equipment, and numerous other transportable electronic devices. When these types of batteries get excessively loaded, damage can occur. To study the effects of excessive damage, lithium-ion battery modules with prismatic cells were subjected to destructive quasi-static indentation using a V-shaped stainless steel wedge indenter at different loading orientations, directions, and rates. The modules were discharged to a very low state of charge prior to testing. Force and voltage were measured as a function of displacement to monitor the damaging …

Prediction Of Handling Qualities Deficiencies For Advanced Air Mobility Aircraft, Louis Spier

Doctoral Dissertations and Master's Theses

To date, there are hundreds of Advanced Air Mobility (AAM) vehicles under development. Most of these vehicles differ significantly from traditional airplanes and rotorcraft when it comes to configuration and handling qualities. Handling qualities for traditional airplanes and rotorcraft are often very predictable. All AAM concepts currently under development feature some sort of fly-by-wire flight control system. Regulatory agencies already have decades of experience with certifying fly-by-wire airplanes. Fly-by-wire rotorcraft have proven to be significantly more difficult to certify and several flight test accidents have occurred as a result of handling qualities deficiencies, or “cliffs”. To ensure the safe and …

Mitigating Engine Unstart In Scramjets With Porous Bleeders, Ryan Lindley

Doctoral Dissertations and Master's Theses

The effectiveness of porous bleeders in mitigating unstart phenomena and enhancing isolator effectiveness in a hypersonic scramjet was investigated. Through computational fluid dynamics simulations, the impact of porous bleeder design parameters such as pressure jump coefficient and bleeder size on isolator effectiveness and unstart prevention was evaluated. Results indicated that porous bleeders delayed flow separation and reduced adverse pressure gradients, thereby enhancing isolator performance. Additionally, porous bleeders demonstrated promising capabilities in preventing full unstart events and mitigating oscillatory unstart phenomena.

Benchmarking Of A Sco2 Heat Exchanger Flow Loop, David Velasco

Doctoral Dissertations and Master's Theses

Heat transfer of supercritical carbon dioxide (sCO2) was studied experimentally by commissioning a sCO2 flow loop featuring a horizontal tube-in-tube counterflow heat exchanger with a circular cross section. The main objective was to establish experimental heat transfer research capabilities for sCO2 at Embry-Riddle Aeronautical University’s (ERAU) Thermal Science Lab. sCO2 experiences a drastic change in thermophysical properties near its critical point that results in unique heat transfer characteristics. The high pressures at which sCO2 exists make the large gradients in thermophysical and transport properties difficult to study, experimentally and numerically. However, understanding the heat transfer characteristics and thermophysical behavior of …

Conceptual Design Methodology For The Fan-In-Wing Vtol Aircraft, Brock Steinfeldt

Doctoral Dissertations and Master's Theses

The Fan-In-Wing (FIW) aircraft concept is one of the most compelling solutions for missions demanding jet-like cruise speeds and Vertical TakeOff and Landing (VTOL) capability. However, despite years of interest and documented improvements in lift-fan technology, there exists little in the way of an adequate theory for conceptual design of a fan-in-wing aircraft. To address this issue, a general conceptual design methodology has been developed as a source of guidance for the FIW designer. Through this work, the top-level requirements ranking the fan-in-wing concept above other VTOL aircraft have been defined, while a cross-comparison between the FIW concept and conventional …