Aerospace Engineering Commons^™

Incorporating Industry Needs Into The Development Of An Undergraduate Degree In Commercial Space Operations, Yash Bipinchandra Mehta

Doctoral Dissertations and Master's Theses

The rapid expansion of the commercial space industry, not unlike the aviation industry in the early 20^th century, has left the industry facing unique challenges. As companies continue to expand, the need for a well-trained workforce becomes critical. The needed workforce must be specifically educated to enter the commercial space industry at graduation. To have a successful industry, a workforce must be trained in skills that meet the industry's needs. In that regard, this study consisted of a survey of leaders in the commercial space industry to identify the different skill-sets sought by the industry. The results of the …

An Investigation To Advance The Technology Readiness Level Of The Centaur Derived On-Orbit Propellant Storage And Transfer System, Nathan L. Silvernail

Doctoral Dissertations and Master's Theses

This research was carried out in collaboration with the United Launch Alliance (ULA), to advance an innovative Centaur-based on-orbit propellant storage and transfer system that takes advantage of rotational settling to simplify Fluid Management (FM), specifically enabling settled fluid transfer between two tanks and settled pressure control. This research consists of two specific objectives: (1) technique and process validation and (2) computational model development. In order to raise the Technology Readiness Level (TRL) of this technology, the corresponding FM techniques and processes must be validated in a series of experimental tests, including: laboratory/ground testing, microgravity flight testing, suborbital flight testing, …

Investigation Of Pulse Detonation Engines; Theory, Design And Analysis, Jeff Vizcaino

Doctoral Dissertations and Master's Theses

Detonation and constant volume combustion has been known to the scientific community for some time but only recently has active research been done into its applications. Detonation based engines have received much attention in the last two decades because of its simple design and potential benefits to the aerospace industry. It is then the goal of this study to provide a background into detonation theory and application and establish the basis for future detonation based research at Embry-Riddle Aeronautical University. In this paper we will discuss the experimental aspects of building, testing, and analysis of a pulsed detonation tube …

Measuring Acoustic Attenuation Of Polymer Materials Using Drop Ball Test, Yi Zhang

Doctoral Dissertations and Master's Theses

Polymers are often used for vibration damping and energy absorption. The effect of a material in reducing the strength of sound waves traveling through it is called acoustic attenuation. In the past, attenuation has mostly been evaluated in the MHz frequency range, using a pulse generator and transmitting transducer as the wave source. However, most real acoustic activities occur at frequencies up to a few hundred kHz. Here, a simple drop ball mechanism is used to generate acoustic source waves in the kHz range, and the attenuation capacities of several solid materials are measured. The recorded waveforms substantially differ between …

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 …

Validation Of Proposed Metrics For Two-Body Abrasion Scratch Test Analysis Standards: In Principle, Any Scratch Can Be Analyzed By This Method, Kenneth W. Street, Ryan L. Kobrick, David M. Klaus

Publications

Abrasion of mechanical components and fabrics by soil on Earth is typically minimized by the effects of atmosphere and water. Potentially abrasive particles lose sharp and pointed geometrical features through erosion. In environments where such erosion does not exist, such as the vacuum of the Moon, particles retain sharp geometries associated with fracturing of their parent particles by micrometeorite impacts. The relationship between hardness of the abrasive and that of the material being abraded is well understood, such that the abrasive ability of a material can be estimated as a function of the ratio of the hardness of the two …

Numerical Modeling Of Anti-Icing Using An Array Of Heated Synthetic Jets, Nikisha Maria Nagappan

Doctoral Dissertations and Master's Theses

A novel approach to icing control using an array of thermally activated synthetic jet actuators (SJAs) embedded in a wedge surface subject to a super-cooled flow is investigated numerically. The effects of SJA actuation with and without jet heating on ice accretion are studied using the FENSAP-ICE software. It is shown that the heated actuating SJAs can lead to a significant reduction in the amount of ice accreted on the surface. Additional parametric studies on several icing and SJA parameters are analyzed for their influence on the amount of ice accretion.

Assessing Safety Culture Within A Flight Training Organization, David Freiwald, Carolina Lenz-Anderson, Erik Baker

Applied Aviation Sciences - Daytona Beach

This study was prompted by a string of aircraft hull losses experienced by a multinational, multi-campus flight training organization. A mixed methods study was conducted to study the attitudes and perceptions of the operations and management staff at this flight training organization through the use of a survey instrument previously existing and adapted, in order to ensure validity, and interviews with key staff members. Confirmatory factor analysis was performed to identify underlying constructs in the perceptions and attitudes of the staff in order to identify beliefs that may signify a flight training organization is at risk. An analysis was conducted …

Development Of A Master Of Software Assurance Reference Curriculum, Andrew J. Kornecki, James Mcdonald, Julia H. Allen, Mark Ardis, Nancy Mead, Richard Linger, Thomas B. Hilburn

Department of Electrical Engineering and Computer Science - Daytona Beach

The Next Generation Air Traffic Management system (NextGen) is a blueprint of the future National Airspace System. Supporting NextGen is a nation-wide Aviation Simulation Network (ASN), which allows integration of a variety of real-time simulations to facilitate development and validation of the NextGen software by simulating a wide range of operational scenarios. The ASN system is an environment, including both simulated and human-in-the-loop real-life components (pilots and air traffic controllers).Real Time Distributed Simulation (RTDS) developed at Embry-Riddle Aeronautical University, a suite of applications providing low and medium fidelity en-route simulation capabilities, is one of the simulations contributing to the ASN. …

Fault Tree Analysis For Safety/Security Verification In Aviation Software, Andrew J. Kornecki, Mingye Liu

Department of Electrical Engineering and Computer Science - Daytona Beach

The Next Generation Air Traffic Management system (NextGen) is a blueprint of the future National Airspace System. Supporting NextGen is a nation-wide Aviation Simulation Network (ASN), which allows integration of a variety of real-time simulations to facilitate development and validation of the NextGen software by simulating a wide range of operational scenarios. The ASN system is an environment, including both simulated and human-in-the-loop real-life components (pilots and air traffic controllers).Real Time Distributed Simulation (RTDS) developed at Embry-Riddle Aeronautical University, a suite of applications providing low and medium fidelity en-route simulation capabilities, is one of the simulations contributing to the ASN. …

The Potential Costs To The Dod Of Not Preparing For The Nextgen Nas Overhaul: Lessons Learned From Rvsm, Casey Richardson

Graduate Student Works

In order to facilitate a significant overhaul of the civilian National Airspace System (NAS), the Federal Aviation Administration (FAA) has partnered with many federal agencies, such as the departments of Transportation (DOT), Defense (DoD), Homeland Security (DHS), and Commerce (DOC) and the National Aeronautics & Space Administration (NASA) through a consolidated Joint Planning and Development Office (JPDO) that was established by Congress in 2003 in the VISION 100 – Century of Aviation Reauthorization Act (JPDO, 2012). The JPDO has proposed replacing the old NAS structure of primarily ground-based navigation with robust satellite-enabled air traffic procedures and to supplement ground-based air …

Heteroclinic And Homoclinic Connections Between The Sun-Earth Triangular Points And Quasi-Satellite Orbits For Solar Observations, Pedro J. Llanos, Gerald R. Hintz, Martin W. Lo, James K. Miller

Publications

Investigation of new orbit geometries exhibits a very attractive behavior for a spacecraft to monitor space weather coming from the Sun. Several orbit transfer mechanisms are analyzed as potential alternatives to monitor solar activity such as a sub-solar orbit or quasi-satellite orbit and short and long heteroclinic and homoclinic connections between the triangular points L4 and L5 and the collinear point L3 of the CRTBP (circular restricted three-body problem) in the Sun-Earth system. These trajectories could serve as channels through where material can be transported from L5 to L3 by performing small maneuvers at the departure of the Trojan orbit. …

Robust Control Methods For Nonlinear Systems With Uncertain Dynamics And Unknown Control Direction, Chau T. Ton

Doctoral Dissertations and Master's Theses

Robust nonlinear control design strategies using sliding mode control (SMC) and integral SMC (ISMC) are developed, which are capable of achieving reliable and accurate tracking control for systems containing dynamic uncertainty, unmodeled disturbances, and actuator anomalies that result in an unknown and time-varying control direction. In order to ease readability of this dissertation, detailed explanations of the relevant mathematical tools is provided, including stability denitions, Lyapunov-based stability analysis methods, SMC and ISMC fundamentals, and other basic nonlinear control tools. The contributions of the dissertation are three novel control algorithms for three different classes of nonlinear systems: single-input multiple output (SIMO) …

Payload Charging Events In The Mesosphere And Their Impact On Langmuir Type Electric Probes, T. A. Bekkeng, Aroh Barjatya, U. P. Hoppe, A. Pedersen, J. I. Moen, M. Friedrich, M. Rapp

Publications

Three sounding rockets were launched from Andøya Rocket Range in the ECOMA campaign in December 2010. The aim was to study the evolution of meteoric smoke particles during a major meteor shower. Of the various instruments onboard the rocket payload, this paper presents the data from a multi-Needle Langmuir Probe (m-NLP) and a charged dust detector. The payload floating potential, as observed using the m-NLP instrument, shows charging events on two of the three flights. These charging events cannot be explained using a simple charging model, and have implications towards the use of fixed bias Langmuir probes on sounding rockets …

Nonlinear Control For Dual Quaternion Systems, William D. Price

Doctoral Dissertations and Master's Theses

The motion of rigid bodies includes three degrees of freedom (DOF) for rotation, generally referred to as roll, pitch and yaw, and 3 DOF for translation, generally described as motion along the x, y and z axis, for a total of 6 DOF. Many complex mechanical systems exhibit this type of motion, with constraints, such as complex humanoid robotic systems, multiple ground vehicles, unmanned aerial vehicles (UAVs), multiple spacecraft vehicles, and even quantum mechanical systems. These motions historically have been analyzed independently, with separate control algorithms being developed for rotation and translation. The goal of this research is to study …

Dynamics And Control Of Higher-Order Nonholonomic Systems, Jaime Rubio HerváS

Doctoral Dissertations and Master's Theses

A theoretical framework is established for the control of higher-order nonholonomic systems, defined as systems that satisfy higher-order nonintegrable constraints. A model for such systems is developed in terms of differential-algebraic equations defined on a higher-order tangent bundle. A number of control-theoretic properties such as nonintegrability, controllability, and stabilizability are presented. Higher-order nonholonomic systems are shown to be strongly accessible and, under certain conditions, small time locally controllable at any equilibrium. There are important examples of higher-order nonholonomic systems that are asymptotically stabilizable via smooth feedback, including space vehicles with multiple slosh modes and Prismatic-Prismatic-Revolute (PPR) robots moving open liquid …

Novel Airframe Design For The Dual-Aircraft Atmospheric Platform Flight Concept, Eric Michael Mckee

Doctoral Dissertations and Master's Theses

A high-altitude, long-endurance unmanned aerial airframe was designed for the innovative Dual-Aircraft Atmospheric Platform flight concept that exploits stratospheric wind velocity gradients to remain aloft indefinitely. Classical aircraft preliminary design techniques and high-fidelity tools were used to establish a baseline configuration.

Performance characteristics of numerous airfoil profiles were evaluated with two-dimensional flow software in an effort to determine the best-candidate airfoil for the unique application. Vortex-Lattice method tools were used to investigate the sensitivity of three-dimensional design parameters upon overall vehicle aerodynamic performance and determine both static and dynamic stability characteristics of the airframe. Performance capabilities of the finalized airframe …

Implementation Of Microwave Transmissions For Rocket Exhaust Plume Diagnostics, Nicholas George Coutu

Doctoral Dissertations and Master's Theses

Rocket-launched vehicles produce a trail of exhaust that contains ions, free electrons, and soot. The exhaust plume increases the effective conductor length of the rocket. A conductor in the presence of an electric field (e.g. near the electric charge stored within a cloud) can channel an electric discharge. The electrical conductivity of the exhaust plume is related to its concentration of free electrons. The risk of a lightning strike in-flight is a function of both the conductivity of the body and its effective length. This paper presents an approach that relates the electron number density of the exhaust plume to …

A Gap Analysis Of Meteorological Requirements For Commercial Space Operators, Nicholas J. Stapleton

Doctoral Dissertations and Master's Theses

Commercial space companies will soon be the primary method of launching people and supplies into orbit. Among the critical aspects of space launches are the meteorological concerns. Laws and regulations pertaining to meteorological considerations have been created to ensure the safety of the space industry and those living around spaceports; but, are they adequate? Perhaps the commercial space industry can turn to the commercial aviation industry to help answer that question. Throughout its history, the aviation industry has dealt with lessons learned from mishaps due to failures in understanding the significance of weather impacts on operations. Using lessons from the …

Strain Rate And Orientation Dependencies Of The Strength Of Single Crystalline Copper Under Compression, Virginie Dupont, Timothy C. Germann

Aerospace Engineering - Daytona Beach

Molecular dynamics (MD) simulations are used to model the compression under uniaxial strain of copper single crystals of different orientations at various temperatures and strain rates. Uniaxial strain is used because of the close resemblance of the resulting stress state with the one behind a shock front, while allowing a control of parameters such as strain rate and temperature to better understand the behavior under complex dynamic shock conditions. Our simulations show that for most orientations, the yield strength of the sample is increased with increasing strain rate. This yield strength is also dependent on the orientation of the sample, …

Structural Damage Classification Using Support Vector Machines, Xiang Li

Doctoral Dissertations and Master's Theses

In this research, a methodology to classify crack and corrosion metallic damages using a time-frequency representation method and support vector machines is investigated. Piezoelectric ceramic actuators are utilized to generate guided wave signals on a set of aluminum beam coupons with different damage features, such as types, locations, and thicknesses. The short-time Fourier transform is applied to analyze the measured signals. For damage classification, the spectrograms obtained from finite element models are employed to train a two-class support vector machine learning classifier. The classifier is able to correctly classify different types of damages based upon the measured signals collected from …

Neural Network Fatigue Life Prediction In Steel I-Beams Using Mathematically Modeled Acoustic Emission Data, Prathikshen Nambiar Selvadorai

Doctoral Dissertations and Master's Theses

The purpose of this research is to predict fatigue cracking in metal beams using mathematically modeled acoustic emission (AE) data. The AE data was collected from nine samples of steel I-beam that were subjected to three-point bending caused by cyclic loading. The data gathered during these tests were filtered in order to remove long duration hits, multiple hit data, and obvious outliers. Based on the duration, energy, amplitude, and average frequency of the AE hits, the filtered data were classified into the various failure mechanisms of metals using NeuralWorks® Professional II/Plus software based self-organizing map (SOM) neural network. The parameters …

Acoustic Emission Signal Classification For Gearbox Failure Detection, Jun Shishino

Doctoral Dissertations and Master's Theses

The purpose of this research is to develop a methodology and technique to determine the optimal number of clusters in acoustic emission (AE) data obtained from a ground test stand of a rotating H-60 helicopter tail gearbox by using mathematical algorithms and visual inspection. Signs of fatigue crack growth were observed from the AE signals acquired from the result of the optimal number of clusters in a data set. Previous researches have determined the number of clusters by visually inspecting the AE plots from number of iterations. This research is focused on finding the optimal number of clusters in the …

A (Declassified) History Of Military Drones, Stephen Rayleigh

ERAU Prescott Aviation History Program

Unmanned Aerial Vehicles or drones, are said to be the newest technology of contemporary warfare, but the military's use of drones spans the last 100 years. Hear the riveting story of the numerous secret UAV programs around the world, starting with the Sperry Aerial Torpedo Project in 1918 (consulted by Orville Wright), the German cruise missile program, American remote controlled bombers in WWII, the Firebee recon drone used in Vietnam, Israel's highly successful UAV program, and finally the coming of age of UAV's in Operation Desert Storm.

The Effects Of Familiarity And Persuasion On Risk Assessment, Casey L. Smith

Doctoral Dissertations and Master's Theses

Cognitive biases influence decisions and the analyses of risk. They are often derived from two separate processes: bias based on familiarity (familiarity bias) and bias as the result of influences from outside sources (persuasion bias). Research suggests that familiarity-based bias may lead to acceptance of an activity's drawbacks and a leniency of its risks.

In addition, research has tried to measure and analyze different types of biases individually, but few have compared the interactions of more than one bias at once. Because different biases may derive from different mental phenomena it is important to tease out the distinctions, and observe …

An Experimental Investigation Of Glare And Restructured Fiber Metal Laminates, Adelina Vanessa Benedict

Doctoral Dissertations and Master's Theses

Fiber Metal Laminates (FMLs) are a group of materials fabricated by bonding glass/epoxy layers within metal layers. This class of materials can provide good mechanical properties, as well as weight savings. An FML known as Glass Laminate Aluminum Reinforced Epoxy (GLARE) was studied. An experimental investigation comprising of microscopy and tensile testing was carried out using different grades of GLARE. Microscopy revealed the construction details of GLARE, while tensile testing provided means of measuring and analyzing its stress-strain responses. Next, different metal surface pretreatment methods were explored. These included sandblasting, Phosphoric Acid Anodizing (PAA), and AC-130 Sol-Gel treatment. Woven S-2 …

Spacecraft And Propulsion Technician Error, Daniel Clyde Schultz

Doctoral Dissertations and Master's Theses

Commercial aviation and commercial space similarly launch, fly, and land passenger vehicles. Unlike aviation, the U.S. government has not established maintenance policies for commercial space. This study conducted a mixed methods review of 610 U.S. space launches from 1984 through 2011, which included 31 failures. An analysis of the failure causal factors showed that human error accounted for 76% of those failures, which included workmanship error accounting for 29% of the failures. With the imminent future of commercial space travel, the increased potential for the loss of human life demands that changes be made to the standardized procedures, training, and …

Asteroid Retrieval Feasibility Study, John Brophy, Fred Culick, Louis Friedman, Pedro Llanos, Et Al.

Publications

This report describes the results of a study sponsored by the Keck Institute for Space Studies (KISS) to investigate the feasibility of identifying, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the vicinity of the Earth by the middle of the next decade. The KISS study was performed by people from Ames Research Center, Glenn Research Center, Goddard Space Flight Center, Jet Propulsion Laboratory, Johnson Space Center, Langley Research Center, the California Institute of Technology, Carnegie Mellon, Harvard University, the Naval Postgraduate School, University of California at Los Angeles, University of California at Santa Cruz, University of Southern …

High-Fidelity Modeling Of Airfoil Interaction With Upstream Turbulence, Jacob Brodnick

Doctoral Dissertations and Master's Theses

To supplement past research on low speed unsteady airfoil responses to upstream disturbances, this work proposes and investigates a method to generate a turbulent momentum source to be convected downstream and interact with an SD7003 airfoil in a high-fidelity numerical simulation. A perturbation velocity field is generated from a summation of Fourier harmonics and applied to the forcing function in the momentum terms of the Navier Stokes Equations. The result is a three-dimensional, divergence-free, convected turbulent gust with applied statistical parameters. A parametric study has been done in 2D and 3D comparing the resultant flow fields and airfoil interactions for …

The Development Of A Force Balance For Testing Micro Aerial Vehicles, Michael Christopher King

Doctoral Dissertations and Master's Theses

The purpose of this work was to create a six degree of freedom balance that could produce meaningful data for micro aerial vehicles. Research was conducted to investigate the common balance configurations, and the strengths and weaknesses of each configuration were used to select the most appropriate design. The limitations of available fabrication facilities, the desired level of performance and the end user of the balance were all considered to finalize the design. The balance and data acquisition system were fabricated over a period of several months, and unforeseen design issues were handled forthwith. Rigorous calibration and testing processes were …