Engineering Commons^™

The Development Of A Phase Locked Excitation Testing Method For Full‐Scale Wind Turbine Blades, Waleed Fathi Gowharji

Doctoral Dissertations and Master's Theses

Full scale blade testing provides blade manufacturers with quantitative data regarding their blade design, manufacturing processes and durability. Structural fatigue tests are designed to assess the structural health of the turbine blade as well as simulate a lifespan worth of damage in a laboratory environment. These tests also provide a further understanding of the dynamics involved in modern turbine blades. Blade tests are typically conducted in one of the following manners: a dual-axis forced displacement, single axis or dual axis resonant configurations. Historically, fatigue testing has been performed by utilizing forced displacement systems. These systems do not allow for the …

A Comparison Of Fuel Efficiencies Between Dc-9-30 And B-737ng Aircraft For Delta Airlines At Atlanta Hartsfield Airport, Brandon Scott Newman

Doctoral Dissertations and Master's Theses

Improved fuel efficiency is one of aviation's top priorities, as it impacts the economy and the National Airspace System's environment. This descriptive study used data generated by the Total Airspace and Airport Modeler (TAAM) to show that the Boeing 737 Next Generation series aircraft would be more fuel-efficient than the McDonnell-Douglas DC-9-30 aircraft on various routes used by Delta Airlines out of Atlanta's Hartsfield-Jackson International Airport. Databases, such as Aircraft Situation Display to Industry (ASDI) and Base of Aircraft Data (BADA), were used to simulate the baseline flight route information. Simulations were performed on Boeing 737NG (-700, -800, -900) and …

Analysis Of Leo Radiation Environment And Its Effects On Spacecraft's Critical Electronic Devices, Luz Maria Martines S.

Doctoral Dissertations and Master's Theses

Spacecraft, space stations, satellites and astronauts are exposed to an increased level of radiation when in space, and it is important to evaluate the risks associated with extended radiation exposures in missions and space travel in general. The thesis focuses on the LEO radiation environment and how the particles in it interact with materials. Using existing empirical models, the exposed dosage due to the LEO space environment radiation sources, as a function of orbital altitude, orbital inclination and duration is studied. The physical processes that can result in failures and long term degradations of electronic devices due to solar radiation, …

Development Of A Higher-Order Navier-Stokes Solver For Transient Compressible Flows, Arjun Vijayanarayanan

Doctoral Dissertations and Master's Theses

A higher‐order density based navier‐stokes solver was developed for 2‐Dimensional flows using the finite volume approach. The Van leer flux‐splitting technique was used to calculate the fluxes. The second‐order spatial accuracy was achieved using the variable extrapolation method developed by Van leer called the Montone Upstream Centered Scheme for Conservation Laws (MUSCL) approach. The code development was done using Matlab. The code was verified using two validation cases. Firstly, subsonic, transonic, and supersonic flows over the 2‐D bump were simulated, and the results of the code were compared to the results from Fluent. Secondly, the shock‐tube problem was chosen, and …

Numerical Analysis Of Gun Barrel Pressure Blast Using Dynamic Mesh Adaption, Sathish Xavier

Doctoral Dissertations and Master's Theses

A Computational Fluid Dynamics (CFD) method has been applied to simulate the pressure blast of the projectile which is launched from a barrel and to investigate the pressure distribution and sound pressure level (dB) along different positions away from the gun axis and towards the fuselage of the aircraft. Fluent was employed to simulate the unsteady flow using dynamic mesh with moving boundary. Most CFD based ballistics-model requires additional thermodynamic functions which must be derived from the Noble-Abel equation of state. The unsteady, axisymmetric Navier Stokes equation systems were numerically solved using the Advection Upstream Splitting Method (AUSM) scheme; with …

Experimental Investigation And Cfd Simulation Of Active Damping Mechanism For Propellant Slosh In Spacecraft Launch Systems, Dhawal Leuva

Doctoral Dissertations and Master's Theses

Motion of propellant in the liquid propellant tanks due to inertial forces transferred from actions like stage separation and trajectory correction of the launch vehicle is known as propellant slosh. If unchecked, propellant slosh can reach resonance and lead to complete loss of the spacecraft stability, it can change the trajectory of the vehicle or increase consumption of propellant from the calculated requirements, thereby causing starvation of the latter stages of the vehicle. Predicting the magnitude of such slosh events is not trivial. Several passive mechanisms with limited operating range are currently used to mitigate the effects of slosh. An …

Innovative Double Bypass Engine For Increased Performance, Sanjivan Manoharan

Doctoral Dissertations and Master's Theses

Engines continue to grow in size to meet the current thrust requirements of the civil aerospace industry. Large engines pose significant transportation problems and require them to be split in order to be shipped. Thus, large amounts of time have been spent in researching methods to increase thrust capabilities while maintaining a reasonable engine size. Unfortunately, much of this research has been focused on increasing the performance and efficiencies of individual components while limited research has been done on innovative engine configurations. This thesis focuses on an innovative engine configuration, the High Double Bypass Engine, aimed at increasing fuel efficiency …

Integration Of Unmanned Aerial Systems In Class E Airspace: The Effect On Air Traffic Controller Workload, Jeeja S. Vengal

Doctoral Dissertations and Master's Theses

As technology rapidly advances and our imagination is no longer fantasy but instead reality, the aviation community needs to concentrate on the harsh truth of airspace safety. In the situation of integrating unmanned aerial systems (UASs) into the National airspace, UASs outside of terminal areas would generally be permitted to fly their preferred routes, and self-separate, with minimal intervention from air traffic control. From an air traffic control perspective, the integration could raise a number of human performance problems including workload extremes and passive-monitoring demands. One fundamental requirement for operation in the National Air Space is to preserve the safety …

State Of The Art Of Piloted Electric Airplanes, Nasa's Centennial Challenge Data And Fundamental Design Implications, Lori Anne Costello

Doctoral Dissertations and Master's Theses

The purpose of this study was to determine the current state of the electric airplane as primarily defined by results from NASA's Green Flight Challenge Competition. New equations must be derived in order to determine the endurance and range for electric airplanes since the standard equations depend upon weight change over a flight and the weight of an electric airplane does not change. These new equations could then be solved for the optimal velocity and altitude which were the two driving factors that could change range and endurance for a given airplane configuration. The best velocity for range and endurance …

The Propulsive Design Aspects On The World’S First Direct Drive Hybrid Airplane, Ankit Nanda

Doctoral Dissertations and Master's Theses

The purpose of this thesis is to design a safe technology demonstrator by implementing a direct drive propulsion system for a gas-electric hybrid aircraft. This system was integrated on the Embry-Riddle Eco-Eagle for the Green Flight Challenge 2011. The aim of the system is to allow the pilot to use the electric motor as an independent power source to fly the aircraft once at cruise altitude, while having a gas engine to allow for higher power capability.

The system was designed to incorporate the motor and the motor control unit provided by Flight Design and Drivetek AG alongside a Rotax …

Development And Implementation Of A Fault Mitigating Control System For A Biodiesel Plug-In Hybrid Electric Vehicle For The Ecocar: The Next Challenge Competition, Sean Christopher Carter

Doctoral Dissertations and Master's Theses

The automotive industry is continuously developing, and with it hybrid vehicle technology is a growing field of interest. The design of the electric vehicle is a pressing matter and grows in complexity with new powertrain components such as power inverters and transmission systems that use electric motors. As a control system develops, the architecture always comes back to systems engineering documentation to find safety protocols, solutions to problems through fault testing, and validating and verifying the control architecture throughout the whole process. Testing and evaluation plans are required more than ever and are constantly being updated and implemented in today's …

Nonholonomic Feedback Control Among Moving Obstacles, Stephen Gregory Armstrong

Doctoral Dissertations and Master's Theses

A feedback controller is developed for navigating a nonholonomic vehicle in an area with multiple stationary and possibly moving obstacles. Among other applications the developed algorithms can be used for automatic parking of a passenger car in a parking lot with complex configuration or a ground robot in cluttered environment. Several approaches are explored which combine nonholonomic systems control based on sliding modes and potential field methods.

On The Variation Of Gravity Wave Activity Through The Solar Cycle At The South Pole, Ryan Matthew Agner

Doctoral Dissertations and Master's Theses

Atmospheric dynamics comprise of a multitude of phenomena from various sources that affect the entire climate of the globe. Some of these phenomena include Atmospheric Gravity Waves which are ubiquitous features around the planet. They are important mechanisms for the transport of momentum and energy from the lower atmosphere to the upper atmosphere. The sun is the ultimate source of energy for the earth and the primary driver of atmospheric dynamics. The 11-year solar cycle of the sun has had a noticeable effect on the overall climate of the earth in the past. More recent work has seen the diurnal …

Assessing The Effects Of Climate Change And Addressing Solutions At L. F. Wade International Airport, Bermuda, Sebastian Romeo Phillip Brisson

Doctoral Dissertations and Master's Theses

The purpose of this thesis was to find how past trends and future predictions of climate change and associated factors would affect airport operations at the L. F. Wade International Airport. The Government of Bermuda's plans to build a new terminal were also analyzed to determine potential impacts. Predicted future trends of sea level rise and hurricane activity were assessed by analyzing previous occurrences and studies and depicted using GIS mapping data. Risk of storm surge to the L. F. Wade International Airport has become apparent, especially after Hurricane Fabian of 2003. The results of this study suggest that the …

The Effects Of System Reliability And Time Pressure On Unoccupied Aircraft Systems Operator Performance And Mental Workload, Rania Wageh Ghatas

Doctoral Dissertations and Master's Theses

Unoccupied Aircraft Systems (UAS) are in the midst of aviation`s next generation. UAS are being utilized at an increasing rate by military and security operations and are becoming widely popular in usage from search and rescue and weather research to homeland security and border patrol. The Federal Aviation Administration (FAA) is currently working to define acceptable UAS performance standards and procedures for routine access for their use in the National Airspace System (NAS). This study examined the effects of system reliability and time pressure on unoccupied aircraft systems operator performance and mental workload. Twenty-four undergraduate and graduate students, male and …

The Development And Deployment Of A Nexrad Education / Training Module For Use By General Aviation Pilots, Erin Anne Roberts

Doctoral Dissertations and Master's Theses

The purpose of this research was to investigate whether an education/ training module on NEXRAD and its products developed using Instructional Systems design criteria would be effective for General aviation pilots. Numerous studies have documented that General Aviation pilots are in need of additional education and training on weather concepts. A thorough needs analysis and literature review determined that training was the best way to address this problem. An education/training module and assessments were developed from scratch using strict instructional design criteria. Sixty students from Embry-Riddle Aeronautical University participated in live testing of the module. Participants were separated into control …

An Analysis Of The Effectiveness Of Emergency Locator Transmitters To Reduce Response Time And Locate Wreckage In U.S. General Aviation Accidents, Ajit Jesudoss

Doctoral Dissertations and Master's Theses

Emergency Locator Transmitters (ELT) help search crews to locate aircraft in distress and to rescue survivors. This study analyzed ELT data from U.S. General Aviation accidents during the period 2006 to 2010. This study examined the effectiveness of ELTs in terms of ELT Success Rate (ESR) and False Negative Rate (FNR) based on ELT-Aided. This study found a significant difference between ELT-Operated and ELT-Aided. The ESR was found to be 38.58% whereas the FNR was found to be 61.42 %. The Missing Data Ratio (MDR), where accident reports had no ELT information, was found to be above 95%. Recommendations were …

Optimizing High Volume Traffic Surges Using Discrete Event Simulation, Claire L. Johnson

Doctoral Dissertations and Master's Theses

The purpose of this applied research study is to determine the fidelity of a discrete event simulation tool called the Evacuation Simulation Prediction Tool (ESP) in predicting transit times during a high volume surge in traffic flow. The ESP tool was developed for the purpose of predicting and optimizing large-scale evacuations of counties or regions as an aide in emergency and disaster preparedness planning. The goal of the ESP model is to ascertain the balance of traffic flow capacity by managing the human factor events that impinge upon orderly highway travel without immobilizing the travel route. The objective of this …

Classification Of Marine Vessels In A Littoral Environment Using A Novel Training Database, Robert Andrew Lister

Master's Theses - Daytona Beach

Research into object classification has led to the creation of hundreds of databases for use as training sets in object classification algorithms. Datasets made up of thousands of cars, people, boats, faces and everyday objects exist for general classification techniques. However, no commercially available database exists for use with detailed classification and categorization of marine vessels commonly found in littoral environments. This research seeks to fill this void and is the combination of a multi-stage research endeavor designed to provide the missing marine vessel ontology. The first of the two stages performed to date introduces a novel training database called …

Analysis Of Effects Of Financial Factors On Profitability Of Low-Cost And Legacy Carriers, Nicholas Joseph Kleoppel

Doctoral Dissertations and Master's Theses

Since airline deregulation in 1978, there have been over 180 bankruptcy filings by airlines. Legacy and Low-Cost carriers are unique in how they operate and how they generate revenue; both business models have advantages and disadvantages. However, the Low-Cost carriers have shown increases in revenue and have been growing at increasing rates over the Legacy carriers. This study analyzed financial factors from four airlines in each business model to reveal which financial factors can help determine profitability of an airline. This researcher found significant differences between Legacy and Low-Cost Passenger Revenues, Maintenance Expenses, and Depreciation and Amortization Expenses. Additionally, there …

Supervisory Autonomous Control Of Homogeneous Teams Of Unmanned Ground Vehicles, With Application To The Multi-Autonomous Ground-Robotic International Challenge, Katrina L. Corley

Master's Theses - Daytona Beach

There are many different proposed methods for Supervisory Control of semi-autonomous robots. There have also been numerous software simulations to determine how many robots can be successfully supervised by a single operator, a problem known as fan-out, but only a few studies have been conducted using actual robots. As evidenced by the MAGIC 2010 competition, there is increasing interest in amplifying human capacity by allowing one or a few operators to supervise a team of robotic agents. This interest provides motivation to perform a more in-depth evaluation of many autonomous/semiautonomous robots an operator can successfully supervise. The MAGIC competition allowed …

Hydrostatic Pressure Testing Of A Square-Cross Section Stainless Steel Propellant Tank Manufactured Using Selective Laser Sintering, Spencer Fuller

Master's Theses - Daytona Beach

The purpose of this study was to determine if parts manufactured using metal selective laser sintering (SLS) exhibit the same isotropic material properties as conventionally made metal parts. This was accomplished by performing a hydrostatic pressure test (HPT) of a metal SLS manufactured propellant tank, constructed for a nano-satellite of the cubesat class. Strain measurements from twelve strain gage locations on the propellant tank were recorded. A finite element analysis (FEA) model, which assumes isotropic material properties, was generated and a FEA analysis was ran at several pressure loads. The tanks strain data at the corresponding pressure loads from the …

Neural Network Prediction Of Ultimate Compression After Impact Loads In Graphite-Epoxy Coupons From Ultrasonic C-Scan Images, Nikolas L. Geiselman

Master's Theses - Daytona Beach

The purpose of this project was to investigate how accurately an artificial neural network could predict the ultimate compressive loads of impact damaged 24-ply graphite-epoxy coupons from ultrasonic C-scan images. The 24-ply graphite-epoxy coupons were manufactured with bidirectional preimpregnated tape and cut into 21 coupons, 4 inches by 6 inches each. The coupons were impacted at known impact energies of 10, 12, 14, 16, 18, and 20 Joules in order to create barely visible impact damage (BVID). The coupons were then scanned with an ultrasonic C-scan system to create an image of the damaged area. Each coupon was then compressed …

Guidance, Navigation And Control Of A Fly-By-Wire Transport Category Airship Designed For Hover Cargo Delivery, Harshad H. Lalan

Master's Theses - Daytona Beach

The purpose of this thesis is to develop fly-by-wire pilot controls for a transport category airship propelled with six thrust vectoring engines, and to develop control laws to maintain position, heading, and attitude during hover and cargo operations. Owing to the large body area, most airships require that they be pointed into the wind to maintain their position. This research aims at controlling an airship attitude and position during hover cargo delivery, irrespective of the wind direction.

Control laws were developed for two primary modes of the airship: Flight (High Speed Mode) and Hover (Cargo Delivery Mode). Different sets of …

Development Of Multidisciplinary Design Optimization Process For A Large Scale Hybrid Composite Wind Turbine Blade, Jin Woo Lee

Master's Theses - Daytona Beach

Development of a multidisciplinary design optimization (MDO) of a large scale hybrid composite wind turbine blade is performed. Multiple objectives are considered in the MDO process to maximize annual energy production and lifetime profit, minimize weight and power production rate. A wind turbine blade is divided into regions and the layup sequences for each region are considered as design variables. The scale of wind turbine blade is also considered to find the optimum size of a wind turbine blade. Applied loads due to extreme wind conditions for rotor rotation and rotor stop condition are considered for finite element analysis (FEA) …

Nurturing Systems Thinking: Developing A Framework Based On The Human Factors Analysis And Classification System (Hfacs) To Improve Systems Development Processes, Arjun Vijayanarayanan

Doctoral Dissertations and Master's Theses

Large systems engineering projects have an astonishingly high failure rate. The reasons hypothesized for such a high failure rate include the neglect of nonsalient system elements such as social and human or organizational aspects of systems. Social and human factors have long been known to be critical elements of systems that are frequently ignored (e.g., Goguen, 1994). Systems engineering processes can benefit and be improved by effective utilization of a framework that helps developers expand their attention and efforts beyond the salient aspects of the system and the development process. In the aviation field, the Human Factors Analysis and Classification …

The Effect Of Shift Turnover Strategy And Time Pressure On Aviation Maintenance Technician Performance, William R. Warren

Doctoral Dissertations and Master's Theses

Aviation maintenance technicians (AMTs) provide the technical and applied knowledge required to maintain airworthiness in aircraft. In commercial aviation, maintenance tasks are performed across multiple shifts. When AMTs share a maintenance task between shifts, the shift turnover strategy used may determine if information is effectively transferred between AMTs. Ineffective shift turnover strategies are a contributing factor in many aviation accidents and incidents. Additionally, time constraints on certain maintenance tasks may cause AMTs to commit error when performing a task. The present study examined the effect of shift turnover strategy (face-to-face or written) and time pressure on error capture, accuracy, and …

Ultimate Compression After Impact Load Prediction In Graphite/Epoxy Coupons Using Neural Network And Multivariate Statistical Analyses, Alexandre David Grégoire

Doctoral Dissertations and Master's Theses

The goal of this research was to accurately predict the ultimate compressive load of impact damaged graphite/epoxy coupons using a Kohonen self-organizing map (SOM) neural network and multivariate statistical regression analysis (MSRA). An optimized use of these data treatment tools allowed the generation of a simple, physically understandable equation that predicts the ultimate failure load of an impacted damaged coupon based uniquely on the acoustic emissions it emits at low proof loads. Acoustic emission (AE) data were collected using two 150 kHz resonant transducers which detected and recorded the AE activity given off during compression to failure of thirty-four impacted …

Effects Of Online Training On Aircrew Monitoring Behaviors: A Field Study, Brian A. Potter

Doctoral Dissertations and Master's Theses

Data from aircraft accidents and line observation studies indicate that inadequate pilot monitoring is a growing safety concern. In the cockpit environment, pilots who fail to properly manage their workload commit more monitoring errors. Given the lack of training and educational programs available to pilots which emphasize improving their monitoring skills, more research is needed to assess the usefulness of types of training that can be used to improve pilots' monitoring. This research project sets out to determine if the potential exists to enhance pilots' monitoring skills through online training. For this study, 40 military helicopter pilots (participants) were divided …

Analysis Of Airport Security Screening Checkpoints Using Queuing Networks And Discrete Event Simulation: A Theoretical And Empirical Approach, Stephen Louis Dorton

Doctoral Dissertations and Master's Theses

This study utilized discrete event simulation (DES) and queuing networks to investigate the effects of baggage volume and alarm rate at the Security Screening Checkpoint (SSCP) of a small origin and destination airport. A Jackson queuing network was considered for a theoretical assessment to SSCP performance. A DES model using Arena version 12 was utilized for an empirical approach. Data was collected from both literature and by manual collection methods. Manual data was collected during the peak operating time of 6am-7am local time at the airport being modeled. The simulation model was verified and validated qualitatively and quantitatively by statistical …