Engineering Commons^™

Development Of A Hybrid Vehicle Powertrain Test Laboratory, Bennet Samuel Soundarraj

Doctoral Dissertations and Master's Theses

During the last two years, Embry-Riddle Aeronautical University has installed and tested a fully functional eddy-current chassis dynamometer testing facility on campus. An automotive test facility requires a systems engineering approach to install, calibrate and commission a chassis dynamometer. This thesis shows that, the dynamometer test facility was successfully installed, commissioned and documented to safely support the power train development and testing. We can currently test the EcoCAR vehicle and a number of other front-wheel-drive vehicles at our university campus using the eddy current chassis dynamometer.

Robust Image-Based Visual Servo Control Of An Uncertain Missile Airframe, Murat Tunca Aygun

Doctoral Dissertations and Master's Theses

A nonlinear vision-based guidance law is presented for a missile-target scenario in the presence of model uncertainty and unknown target evasive maneuvers. To ease the readability of this thesis, detailed explanations of any relevant mathematical tools are provided, including stability definitions, the procedure of Lyapunov-based stability analysis, sliding mode control fundamentals, basics on visual servo control, and other basic nonlinear control tools. To develop the vision-based guidance law, projective geometric relationships are utilized to combine the image kinematics with the missile dynamics in an integrated visual dynamic system. The guidance law is designed using an image-based visual servo control method …

Molecular Dynamics Model Of Carbon Nanotubes In Epon 862/Detda Polymer, Guttormur Arnar Ingvason

Doctoral Dissertations and Master's Theses

The aerospace industry is interested in increasing the strength while reducing the weight of carbon fiber composite materials. Adding single walled carbon nanotubes (SWCNT) to a polymer matrix can achieve that goal by improving delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential to represent the interactions between the atoms of the polymer and the SWCNT. This …

Investigation Into The Effects Of Wire Mesh On Tensile And Impact Properties Of Fiber Metal Laminates, Shivani A. Rudradat

Doctoral Dissertations and Master's Theses

An investigational study was conducted into the tensile and impact behavior of Fiber Metal Laminates by combining 5052 alumintrm mesh or2024-T3 aluminum sheets,2.47 N (8.9 oz) or 6.67 N (24 az) ShieldStand^® S fiberglass, and Hysol EA 9313 epoxy. Testing was performed under the guidelines of ASTM D3039-00 utilizing an lnstron 8802 Servohydraulic Materials Testing Instrument for tensile tests and ASTM D3763-06 utilizing an Inston 9250 HV Dynatup Impulse Impact Testing System for impact tests. Samples were strained at arate of 2 mrn/min for tensile tests and impacted with enetgies of 10 to 40 J in l0 J increments …

Comparison Of Three Angle Of Attack (Aoa) Indicators: A Usability Study, Camilo Jimenez

Doctoral Dissertations and Master's Theses

Angle of Attack (AOA) is an important aeronautical concept used to understand the performance status of an aircraft during different flight stages. The Federal Aviation Administration (FAA) has indicated the importance of developing and encouraging the use of affordable AOA based systems to increase inflight safety. Embry-Riddle Aeronautical University's flight department decided to install AOA indicators in its fleet of Cessna 172S, to increase safety and to help student pilots better understand this important concept. This paper presents a review of AOA, visual display design principles, and usability. This experimental study examined three different AOA indicators provided by the …

Performance Analysis Of Non-Linear Adaptive Control Laws Using Hardware In The Loop Of An Unmanned Aerial System, Brendon Lyons

Doctoral Dissertations and Master's Theses

In practical applications, an Unmanned Aerial System's (UAS) baseline performance is dictated by how well it can follow a given trajectory with limited stress on the actuators. However, these can be insufficient performance metrics when the UAS is allowed to adapt to an unpredicted external influence such as turbulence or actuation failure, while maintaining a satisfactory baseline performance.

In this thesis, different control laws based on the formation flight geometry problem, nonlinear dynamic inversion and an artificial immune system adaptive mechanism , are implemented in hardware-in-the-loop as a precursor for in-flight testing. These controllers are compared based on three performance …

The Effects Of Aircraft Certification Rules On General Aviation Accidents, Carolina Lenz Anderson

Doctoral Dissertations and Master's Theses

The purpose of this study was to analyze the frequency of general aviation airplane accidents and accident rates on the basis of aircraft certification to determine whether or not differences in aircraft certification rules had an influence on accidents. In addition, the narrative cause descriptions contained within the accident reports were analyzed to determine whether there were differences in the qualitative data for the different certification categories. The certification categories examined were: Federal Aviation Regulations Part 23, Civil Air Regulations 3, Light Sport Aircraft, and Experimental-Amateur Built. The accident causes examined were those classified as: Loss of Control, Controlled Flight …

Identification Of Causal Paths And Prediction Of Runway Incursion Risk Using Bayesian Belief Networks, Benjamin Jeffry Goodheart

Doctoral Dissertations and Master's Theses

In the U.S. and worldwide, runway incursions are widely acknowledged as a critical concern for aviation safety. However, despite widespread attempts to reduce the frequency of runway incursions, the rate at which these events occur in the U.S. has steadily risen over the past several years. Attempts to analyze runway incursion causation have been made, but these methods are often limited to investigations of discrete events and do not address the dynamic interactions that lead to breaches of runway safety. While the generally static nature of runway incursion research is understandable given that data are often sparsely available, the unmitigated …

Observability And Confidence Of Stability And Control Derivatives Determined In Real Time, Alfonso Noriega

Doctoral Dissertations and Master's Theses

Stability and control derivatives of an aircraft were estimated from real flight test data in real time. A higher language block diagram library was developed for this purpose. Parameter identification techniques and requirements were used to detect and rate maneuvers present in the data. These ratings were used to blend newly calculated derivatives with previously known values by means of a Kalman filter. The Kalman filter output was used to identify the health of control surfaces actuators. Statistical and measured data were used to predict the probability that an actuator failure has occurred at any given time during the flight. …

Preliminary Design Of Blade And Disc Fixing For Aerospace Application Using Multi-Disciplinary Approach, Abdulhalim Twahir

Doctoral Dissertations and Master's Theses

The preliminary design phase of a turbine rotor has an important impact on the architecture of a new engine definition, as it sets the technical envelope of the product to be designed. Additionally, preliminary design cycle times are increasingly critical in capturing business opportunities in an ever competitive environment. Improving the accuracy of the preliminary design (pre-detailed design) is also necessary as not only does it significantly reduce the overall development of an engine, but also because any mistakes made at this stage can be extremely hard to rectify.

Previously, typical pre-detail fixing design cycle time was greater due to …

An Ergonomic Evaluation Of Aircraft Pilot Seats, Yolanda Nicole Andrade

Doctoral Dissertations and Master's Theses

Seat comfort has become increasingly important in today's society as we spend more time at consoles, instrument panels, or just online. However, seat comfort is hard to define and difficult to measure. Several measures both objective and subjective were used to evaluate seat comfort in commercially available average pilot seats. Three pilot seats, which had the same material and similar adjustments but different physical attributes, and a universal classroom seat, with different material and no adjustments, were compared by 20 volunteers using subjective and objective measures in a Latin square controlled repeated measures design. A Friedman's test was used to …

Mapping Automotive Like Controls To A General Aviation Aircraft, Christopher G. Carvalho

Doctoral Dissertations and Master's Theses

The purpose of this thesis was to develop fly-by-wire control laws enabling a general aviation aircraft to be flown with automotive controls, i.e. a steering wheel and gas/brake pedals. There was a six speed shifter used to change the flight mode of the aircraft. This essentially allows the pilot to have control over different aspects of the flight profile such as climb/descend or cruise. A highway in the sky was used to aid in the navigation since it is not intuitive to people without flight experience how to navigate from the sky or when to climb and descend.

Many believe …

Investigation Of Grid Adaptation To Reduce Computational Efforts For A 2-D Hydrogen-Fueled Dual-Mode Scramjet, Kam Keong Foo

Doctoral Dissertations and Master's Theses

A two-dimensional dual-mode scramjet flowpath is developed and evaluated using the ANSYS Fluent density-based flow solver with various computational grids. Results are obtained for fuel-off, fuel-on non-reacting, and fuel-on reacting cases at different equivalence ratios. A one-step global chemical kinetics hydrogen-air model is used in conjunction with the eddy-dissipation model. Coarse, medium and fine computational grids are used to evaluate grid sensitivity and to investigate a lack of grid independence. Different grid adaptation strategies are performed on the coarse grid in an attempt to emulate the solutions obtained from the finer grids. The goal of this study is to investigate …

Attitude Dynamics Of Debris Resulting From Upper Stage Fragmentation In Low Earth Orbit, Killian Marie

Doctoral Dissertations and Master's Theses

This thesis addresses the analysis of the attitude dynamics of pieces of space debris that could result from the fragmentation of a spent upper stage in low Earth orbit (LEO).

Up to now only whole objects of axisymmetric shape have been studied with the purpose of estimating their tumbling rates in LEO. Three shapes have been considered to be representative for the purpose of the study: a thin plate, a monocoque shell, an half conical shell and a spherical shell, and it has been assumed that they are fabricated from aluminum alloy. The motion of conducting body in a magnetic …

Collaborative Audio Transcription And Repair As A Method For Novice Pilots To Learn Approach Briefing Crew Resource Management (Crm) Skills, William A. Tuccio Ph.D.

Doctoral Dissertations and Master's Theses

The growth of aviation in scope, scale, and complexity increases the demands for student learning, including crew resource management (CRM) skills. Instructor facilitated methods have proven effective for CRM skill learning. This study investigated a method of collaborative audio transcription and repair based learning (CTRBL) offering the potential for reduced demand upon instructor resources for CRM learning. The theorybased CTRBL method was used in this study as a way for novice pilots to learn the CRM skill of conducting a crew approach briefing with a focus on risk mitigation. Learning methods used to develop the CTRBL method were drawn from …

The Effects Of Ethical Leadership And Organizational Safety Culture On Safety Outcomes, David Ronald Freiwald

Doctoral Dissertations and Master's Theses

This dissertation investigated the relationship among ethical leadership, an ethical workplace climate, safety culture, safety behaviors, and measured safety outcomes of workers in the high reliability organizations of aviation and healthcare. The primary objective was to develop a model linking these factors and assess their fit within the model. A secondary objective was to examine differences between the two populations. In this study, a 101-item instrument was used to collect and analyze employee responses on ten factors comprising the model. Structural equation modeling – path analysis was used for testing and evaluating relations using a combination of statistical analysis and …

Geometric And Pattern Recognition Combined Algorithms Applied To Digital Image Processing In Aerial Search And Rescue Applications, Jamil Efren Anaguano Correa

Doctoral Dissertations and Master's Theses

The difficult task of generating an automated target detection system from aerial imagery can be achieved through different approaches. However, the robustness of any machine vision system lays on the implementation of vision algorithms. By combining geometric and pattern recognition algorithms, a more effective machine vision scheme is developed. Three modules-Color Identification (CIM), Color Matching (CMM), and Pattern Recognition (PRM)- work as main filters to process images and predict the location of targets based on a set templates. Multiple target detection is also accomplished by implementing a hide and seek method where all matching objects are scanned individually and isolated …

Fluid-Structure Interaction And Multidisciplinary Design Analysis Optimization Of Composite Wind Turbine Blade, Naishadh G. Vasjaliya

Doctoral Dissertations and Master's Theses

A multidisciplinary design analysis optimization (MDAO) process is defined for a composite wind turbine blade to optimize its aerodynamic and structural performance by developing a fluid-structural interaction (FSI) system. The objectives are to maximize aerodynamic efficiency and structural robustness while reducing blade mass and total cost. In the previous research, a MDO process of a composite wind turbine blade has been pioneered as an effective process to develop structurally optimized blade design. Present MDAO process is defined in conjunction with structural and aerodynamic performance of the blade which is divided into three steps and the design variables considered are related …

Analysis Of Fatal General Aviation Accidents Occurring From Loss Of Control On Approach And Landing, Brittnee Nicholle Branham

Doctoral Dissertations and Master's Theses

According to the National Transportation Safety Board (NTSB), loss of control in-flight is the greatest cause of general aviation accidents. The purpose of this study was to determine the most frequently occurring probable causes and contributing factors from loss of control in-flight. This study used the Pareto principle and methodology developed by the General Aviation Joint Steering Committee to analyze accidents retrieved from the NTSB's Aviation Accident Database. The results showed that 73% of the accidents contained the contributing factor of "PILOT - Failure to maintain airspeed" across the three categories of reciprocating engine aircraft, turbine engine aircraft, and experimental-amateur …

Computing Radiation Exchange, Jonathan L. Nutzati Fontaine

Doctoral Dissertations and Master's Theses

A computational tool to simulate thermal radiation between surfaces is developed. The output is verified against cases for which the analytical solutions are available. The tool can be used as a stand-alone program, or as an interactive module for CFD. In such an application the module would augment other heat transfer boundary conditions. The tool is demonstrated by post-processing surface temperature field data from a supersonic CFD calculation. The result is a net thermal radiation surface data field - the black body radiative effluxes as functions of temperature, less the integrated influxes multiplied by their geometric view factors from other …

Validation Of New Technology Using Legacy Metrics: Examination Of Surf-Ia Alerting For Runway Incursion Incidents, Robert Edward Joslin

Doctoral Dissertations and Master's Theses

New flight deck technology designed to mitigate runway incursions may not be effective in triggering a flight deck alert to avoid high speed surface collisions for runway incursions classified as serious by legacy metrics. This study demonstrated an innovative method of utilizing expert raters and actual high-risk incidents to identify shortcomings of using legacy metrics to measure the effectiveness of new technology designed to mitigate hazardous incidents. Expert raters were used to validate the Enhanced Traffic Situational Awareness on the Airport Surface with Indications and Alerts (SURF-IA) model for providing alerts to pilots to reduce the occurrence of pilot deviation …

The Effects Of Angle-Of-Attack Indication On Aircraft Control In The Event Of An Airspeed Indicator Malfunction, Claas Tido Boesser

Doctoral Dissertations and Master's Theses

Analysis of accident data by the Federal Aviation Administration, the National Transportation Safety Board, and other sources show that loss of control is the leading cause of aircraft accidents. Further evaluation of the data indicates that the majority of loss of control accidents are caused by the aircraft stalling. In response to these data, the Federal Aviation Administration and the General Aviation Joint Steering Committee emphasize the importance of stall and angle-of-attack awareness during flight. The high-profile crash of Air France Flight 447, in which pilots failed to recover from a self-induced stall, reinforced concerns over the need for improved …

A Descriptive Analysis Of Public Comments Submitted In Response To Notice Of Proposed Rules On Air Carrier Pilot Qualification, Amy Chaffee Doolittle

Doctoral Dissertations and Master's Theses

In 2009, the crash of Colgan Flight 3407 in Buffalo, NY raised concerns regarding the adequacy of current pilot qualification standards for entering air carrier operations. In response, the U.S. Congress enacted Public Law 111-216, which requires a pilot to hold an Airline Transport Pilot (ATP) certificate in order to be qualified as a flight crewmember under 14 CFR, part 121, and also allows the Federal Aviation Administration (FAA) to modify the requirements to obtain an ATP certificate. In February 2012, the FAA issued a Notice of Proposed Rulemaking (NPRM) outlining these requirements and calling for public comments on the …

The Effects Of Sensor Performance As Modeled By Signal Detection Theory On The Performance Of Reinforcement Learning In A Target Acquisition Task, Nate Quirion

Doctoral Dissertations and Master's Theses

Unmanned Aerial Systems (UASs) today are fulfilling more roles than ever before. There is a general push to have these systems feature more advanced autonomous capabilities in the near future. To achieve autonomous behavior requires some unique approaches to control and decision making. More advanced versions of these approaches are able to adapt their own behavior and examine their past experiences to increase their future mission performance. To achieve adaptive behavior and decision making capabilities this study used Reinforcement Learning algorithms. In this research the effects of sensor performance, as modeled through Signal Detection Theory (SDT), on the ability of …

Relating Air Quality In The Work Environment To Occupational Health Disease, Hussien Awad Alumar

Doctoral Dissertations and Master's Theses

Comprehensive knowledge of the air pollutants effects on the human health generally is a crucial requirement in developing effective policies for reducing such adverse effects related to ambient air pollution. Such knowledge would be essential in helping various affected countries, including the less developed countries (LDCs), to develop effective regulatory frameworks for assessing and managing air quality in the workplaces. Developed and developing countries therefore need to develop effective techniques or strategies focused towards improving the workplace monitoring competence in diverse industrial environments. Such initiatives are essential in reducing or eliminating the industrial pollutants within the workplaces while also helping …

Hydrodynamic Impact Analysis And Testing Of An Unmanned Aerial Vehicle, Isabel Bird

Doctoral Dissertations and Master's Theses

Analysis and testing have been conducted to assess the feasibility of a small UAV that can be landed in the water and recovered for continued use. Water landings may be desirable in a number of situations, for example when testing UAVs outside of the territorial waters of the US to avoid violating FAA regulations. Water landings may also be desirable when conducting surveillance missions in marine environments. Although the goal in landing is to have the UAV lightly set down on the water, rough seas or gusty winds may result in a nose-in landing where the UAV essentially impacts the …

Investigation Of A Lagrangian-Point Propellant Depot Rendezvous Approach For An Interplanetary Mission To Mars, Joshua W. Ehrlich

Doctoral Dissertations and Master's Theses

This thesis investigates the feasibility of a refueling station for a beyond Earth orbit (BEO) mission. The propellant depot is located at the L₂ -Lagrangian point within the Earth-Moon system. This investigation determines if a refueling mission will reduce propulsive energy requirements necessary for Earth departure of a BEO-vehicle to achieve an interplanetary transfer to Mars. Furthermore, this research presents a trade study which identifies approximate total requirements for a direct and rendezvous mission to Mars as well as the necessary fuel masses to complete each approach. This analysis provides conclusive information in determining the benefits in utilizing a …

Orbital Debris Removal Technologies: A Hybrid Electrodynamic Tether And Ion Beam Shepherd Satellite Design For Fuel Efficient Contactless Debris Removal, Jorn Mumme

Doctoral Dissertations and Master's Theses

Space debris poses a serious threat to humanities efforts at space exploration as well as the expanding uses for earth-orbiting satellites. This thesis investigates the proposed technologies for the debris's removal both large and small. Focus is applied to the large debris removal technologies since the small size category is dominated by the ORION laser system. Furthermore, the large debris objects pose the most destructive threat upon impact to satellites. Electrodynamic tethers (EDT) as well as their control strategies, ion-beam shepherds (IBS), and tradition thruster methods are investigated for effectiveness and feasibility. Hybrid combinations of these technologies are investigated in …

Reduction Of Near-Field Grating Lobes In Sparse Acoustic Phased Arrays, Dylan Rudolph

Doctoral Dissertations and Master's Theses

Acoustic phased arrays with inter-element spacings of greater than one half-wavelength will produce grating lobes that decrease the usefulness of the array. With many array configurations, the near-field and far-field character of these lobes is significantly different -- an optimization of the array configuration to reduce grating lobes in the far-field can have little bearing on the performance of the array in the near-field.

The focus of this thesis is the reduction of grating lobes in the near-field by iterative optimization. Genetic algorithms are employed to choose inter-element spacings which are able to reduce the magnitude of grating lobes at …

A Preliminary Study Of Acoustic Prediction Technology Based On Detached Eddy Simulations For Supersonic Jets Impinging On Flat Plates, Yuvraj Dewan

Doctoral Dissertations and Master's Theses

An application of an existing industry tool to study supersonic jets impinging on at plates is shown. This industry tool is the commercially available CFD package ANSYS FLUENT. The supersonic jet studied is perfectly expanded with a Mach number of 1.5, and it impinges on a flat surface 4 nozzle throat diameters from the jet exit. All turbulence modeling is done using a hybrid RANS/LES technique known as Delayed Detached Eddy Simulation (DDES). A transient solution is calculated using the pressure-based coupled solver formulation with the second-order bounded central-upwind spatial discretization and second-order implicit time marching scheme. Flow features like …