Engineering Commons^™

Short Duration Missions To Earth Crossing Asteroids, James B. Millar Iii

Theses and Dissertations

My investigation of the Near Earth Object (NEO) catalog has led to identification of numerous short duration, under 40 days, mission opportunities in the future for three different mission types: uncrewed fly-by, uncrewed arrival, and crewed arrival. 2-body propagation techniques were used to model the orbits of various asteroid candidates and the Earth to determine when a close approach would occur. Once the dates were calculated, distance between the bodies was computed to estimate the ∆V to complete the mission. From the mission ∆V values, a possible mission duration was also computed. The values were analyzed to determine the best …

Analysis Of A Modified Equivalent Circuit Model For Lithium-Ion Battery Modules In Cubesats, James J. Liu

Theses and Dissertations

Failure of the electrical power system (EPS) to meet mission requirements is a common problem in nano-size satellites commonly referred to as CubeSats. The motivation for this research stems from the desire to prevent EPS failure through a process of testing and space qualification of components. Utilizing models to predict the behavior of an EPS before it is designed, built, and tested for space can provide critical insight in areas of limitation in performance and survivability. Modeling an entire EPS system is challenging because it requires extensive knowledge of all components and their behavior. This research focuses specifically on the …

An Openeaagles Framework Extension For Hardware-In-The-Loop Swarm Simulation, Derek B. Worth

Theses and Dissertations

Unmanned Aerial Vehicle (UAV) swarm applications, algorithms, and control strategies have experienced steady growth and development over the past 15 years. Yet, to this day, most swarm development efforts have gone untested and thus unimplemented. Cost of aircraft systems, government imposed airspace restrictions, and the lack of adequate modeling and simulation tools are some of the major inhibitors to successful swarm implementation. This thesis examines how the OpenEaagles simulation framework can be extended to bridge this gap. This research aims to utilize Hardware-in-the-Loop (HIL) simulation to provide developers a functional capability to develop and test the behaviors of scalable and …

Comparison Of Radio Frequency Distinct Native Attribute And Matched Filtering Techniques For Device Discrimination And Operation Identification, Barron D. Stone

Theses and Dissertations

The research presented here provides a comparison of classification, verification, and computational time for three techniques used to analyze Unintentional Radio- Frequency (RF) Emissions (URE) from semiconductor devices for the purposes of device discrimination and operation identification. URE from ten MSP430F5529 16-bit microcontrollers were analyzed using: 1) RF Distinct Native Attribute (RFDNA) fingerprints paired with Multiple Discriminant Analysis/Maximum Likelihood (MDA/ML) classification, 2) RF-DNA fingerprints paired with Generalized Relevance Learning Vector Quantized-Improved (GRLVQI) classification, and 3) Time Domain (TD) signals paired with matched filtering. These techniques were considered for potential applications to detect counterfeit/Trojan hardware infiltrating supply chains and to defend …

Neutron Versus Gamma Radiation Effects On Ytterbium-Doped Optical Fibers, Olivia M. Borman

Theses and Dissertations

Multimode ytterbium-doped optical fibers (YDFs) are increasingly utilized in military applications involving fiber lasers and amplifiers. YDFs were irradiated with three different radiation sources (neutron, gamma, and mixed gamma/neutron) in order to determine the independent effects that gamma and neutron radiation have on the fibers. The transmission spectra of the fibers were measured during each irradiation and the spectral shapes and attenuation were compared at similar doses. Comparisons of the spectra showed that gamma radiation results in increased attenuation over the 550-975 nm wavelengths. Fast neutrons were found to contribute to increased attenuation near 500 nm. Neutron radiation also caused …

Lifecycle Cost Evaluation Of Flexible Facility Designs, Trevor P. Ellis

Theses and Dissertations

The purpose of this research is to ascertain the type of facility design, standard, robust, or flexible, that yields the greatest lower lifecycle costs (LCC) savings to the USAF. To this aim, the researcher constructed a Monte Carlo simulation to determine the LCC for flexible, robust, and standard administrative facility designs for thousands of potential facility lifecycles. The simulation also illustrates the circumstances under which each type of design would result in the lowest LCC. The results of this research will show the USAF the importance of focusing on LCC and designing flexible facilities. Standard and robust designs are the …

A Service Oriented Architecture Approach For Global Positioning System Quality Of Service Monitoring, Stuart A. Everson

Theses and Dissertations

This research focuses on the development of a Service Oriented Architecture (SOA) for monitoring the Global Positioning System (GPS) Standard Positioning Service (SPS) in near real time utilizing a Mobile Crowd Sensing (MCS) technique. A unique approach to developing the MCS SOA was developed that utilized both the Depart- ment of Defense Architecture Framework (DoDAF) and the SOA Modeling Language (SoaML) guidance. The combination of these two frameworks resulted in generation of all the architecture products required to evaluate the SOA through the use of Model Based System Engineering (MBSE) techniques. Ultimately this research provides a feasibility analysis for utilization …

Additive Manufacturing Process Parameter Effects On The Mechanical Properties Of Fused Filament Fabrication Nylon, Eric S. Holm

Theses and Dissertations

The purpose of this research was to determine how varying Fused Filament Fabrication (FFF) process parameters affect the mechanical properties of PA6 nylon dog-bone specimens produced on the Mark One 3D Printer. A design of experiment (DOE) was conducted using the factors of layer height and raster angle orientation. The mechanical properties measured in the experiment were tensile modulus, yield stress, percent strain at yield, ultimate tensile strength and percent strain at break. An analysis of variance (ANOVA) was performed to identify which factors were statistically significant in influencing mechanical properties. Results of the ANOVA showed that layer height was …

Unmanned Aerial Vehicle (Uav) Operators’ Workload Reduction: The Effect Of 3d Audio On Operators’ Workload And Performance During Multi-Aircraft Control, Sungbin Kim

Theses and Dissertations

The importance and number of Unmanned Aerial Vehicle (UAV) operations are rapidly growing in both military and civilian applications. This growth has produced significant manpower issues, producing a desire that multiple aircraft are controlled by a single operator as opposed to the current model where one aircraft may require multiple operators. A potential issue is the need for an operator to monitor radio traffic for the call signs of multi-aircraft. An investigation of the use of 3D sound was undertaken to investigate whether an automatic parser, which preselected the spatial location of relevant versus irrelevant call signs, could aid UAV …

The Efficacy Of Implementing A Small, Low-Cost, Real Time Kinematic Gps System Into A Small Unmanned Aerial System Architecture, Kevin J. Hendricks

Theses and Dissertations

Along with the growing uses for small unmanned aerial systems (UAS) within the Department of Defense (DoD), is the utility of small UAS within the civilian market is also increasing. This has led to significant research and development on small UAS subsystems by the commercial market. The focus of this research is characterizing and investigating the application considerations of a small, low-cost real time kinematic (RTK) GPS receiver system. Work was also accomplished to characterize the accuracy and precision of the commonly used GPS receiver subsystem in small UAS to show the increased utility of the RTK GPS system. The …

Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 700°C In Air And In Silicic Acid-Saturated Steam, Matthew W. Piper

Theses and Dissertations

Aircraft structural and engine components are subjected to elevated temperature and steam environments during operation. Turbine blades experience particularly harsh conditions that are approaching the operating temperature limits of current Nickel-based superalloys even with active cooling. Ceramic matrix composites (CMCs), which demonstrate high specific strength and specific stiffness and maintain these properties at elevated temperatures such that active cooling is not required, are prime candidates to replace superalloys as the materials for turbine blades. Ceramic matrix composites are composite materials that consist of a ceramic matrix with fiber reinforcement. This research investigated a silicon carbide (SiC) fiber, Hi-Nicalon™ S, which …

Analysis Of A Near Real-Time Optimal Attitude Control For Satellite Simulators, Ryan M. Patrick

Theses and Dissertations

Dynamic optimization of spacecraft attitude reorientation maneuvers can result in significant savings in attitude determination and control system size, mass, and power. Optimal control theory is generally applied using an open loop trajectory which is vulnerable to disturbances. A closed loop implementation of optimal control has been difficult to achieve due to the computational requirements needed to quickly compute solutions to the optimal control problem. This research focuses on evaluating a near real-time optimal control (RTOC) system for large angle slew maneuvers on the Air Force Institute of Technology's spacecraft simulator called SimSat. A near RTOC algorithm computes optimal control …

Force And Moment Measurements Applicable To A Flexible Weapons System, James B. Sellers

Theses and Dissertations

Continuing the development of the 6-DOF Motion Test Apparatus (MTA) for performing dynamic wind tunnel tests revealed the importance of a capable data acquisition (DAQ) system for collecting and analyzing data. Assembling and testing the DAQ system in conjunction with the MTA, AFIT Low-Speed Wind Tunnel, and a selection of high-performance sensors was the primary focus of this research. Specifically, acquiring time-accurate aerodynamic force and moment measurements on a variety of test models was of high importance. With the established real-time DAQ system hardware, a National Instruments (NI) LabVIEW program was created to acquire data from an ATI Nano25-E force …

Fatigue Behavior Of An Advanced Sic/Sic Composite At 1300° C In Air And Steam, Michael Lee

Theses and Dissertations

The fatigue behavior of an advanced silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite (CMC) was investigated at 1300 ºC in laboratory air and in steam environments. The composite was manufactured using chemical vapor infiltration (CVI). The composite consisted of an oxidation-inhibited matrix, which was comprised of alternating layers of silicon carbide and boron carbide and was reinforced with laminated Hi-Nicalon™ fibers woven in a plain weave. Fiber preforms had pyrolytic carbon fiber coating with boron carbon overlay applied. Two specimen geometries were evaluated, a dog bone and an hourglass geometry. Tensile stress-strain behavior and tensile properties were evaluated at 1300 …

Multi-Trajectory Automatic Ground Collision Avoidance System With Flight Tests (Project Have Escape), John V. Trombetta

Theses and Dissertations

Multi-trajectory automatic collision avoidance techniques for heavy-type aircraft are explored to increase aviation safety procedures and decrease losses due to controlled flight into terrain. Additionally, this research includes flight test results from the United States Test Pilot School’s Test Management Project (TMP) titled Have Emergency Safe Calculated Autonomous Preplanned Exit (ESCAPE). Currently, the heavy aircraft community lacks an automatic collision avoidance system that has proven to save lives in fighter-type aircraft. The tested algorithm includes both a 3-path and a 5-path avoidance technique that is compared to an optimal solution which minimizes aircraft control to avoid terrain. The research utilizes …

Military Applications Of High-Altitude Satellite Orbits In A Multi-Body Dynamical Environment Using Numerical Methods And Dynamical Systems Theory, Meredith M. Wilmer

Theses and Dissertations

The circular restricted three-body problem (CR3BP) is a simplified dynamical model for a satellite under the gravitational influence of both the Earth and the Moon, maintaining closer fidelity to the gravitational environment experienced by a high-altitude Earth-orbiting spacecraft than modeling in the Earth-satellite two-body problem. Resonant orbit arcs are used to determine an initial guess to input into an algorithm that computes a trajectory solution with specific design requirements and constraints. A test case uses this method to compute a lunar fly-by transfer solution requiring less than two-body transfer methods and offers an unusual pathway that adds an unpredictability element …

Minimum-Fuel Trajectory Design In Multiple Dynamical Environments Utilizing Direct Transcription Methods And Particle Swarm Optimization, Alfredo G. Zurita Jr.

Theses and Dissertations

Particle swarm optimization is used to generate an initial guess for designing fuel-optimal trajectories in multiple dynamical environments. Trajectories designed in the vicinity of Earth use continuous or finite low-thrust burning and transfer from an inclined or equatorial circular low-Earth-orbit to a geostationary orbit. In addition, a trajectory from near-Earth to a periodic orbit about the cislunar Lagrange point with minimized impulsive burn costs is designed within a multi-body dynamical environment. Direct transcription is used in conjunction with a nonlinear optimizer to find locally-optimal trajectories given the initial guess. The near-Earth transfers are propagated at low-level thrust where neither the …

Influence Of Coolant Flow Rate Parameters In Scaling Gas Turbine Cooling Effectiveness, Connor J. Wiese

Theses and Dissertations

Film cooling scheme development for use in gas turbine engines often entails the characterization of adiabatic wall temperature distributions in order to determine the driving temperatures for the convective heat transfer processes in the engine. For convenience, adiabatic effectiveness experiments are often performed near room temperature and presumed to scale the engine condition. In order to perform these experiments, researchers elect to match the freestream Reynolds number to that of the engine. When scaling to engine temperatures, however, coolant and freestream fluid properties both change nonlinearly. Therefore the ratio of these properties does not remain constant as the temperature changes. …

An Economic Analysis Of The Transition Of A Contingency Military Installation To An Enduring Status Using Monte Carlo Simulations, Ryan M. Amedee

Theses and Dissertations

The construction of expeditionary bases is central to Department of Defense’s (DoD) responses to contingency operations. Usually expected to be transitory, expeditionary bases are constructed with temporary materials that can be erected quickly. The Global War on Terrorism is entering its fifteenth year and bases within Central Command that were expected to be temporary have provided an enduring presence. The decision to transition a base from temporary to semi-permanent or permanent is difficult, as it requires substantial capital investment for facility construction. This decision is further complicated by unknown mission durations. The DoD has attempted to reduce the decision’s complexity …

Removal Of Perfluorooctanoic Acid From Water Using Primitive, Conventional And Novel Carbonaceous Sorbent Materials, Christopher K. Brown

Theses and Dissertations

Polyfluoroalkyl Substances (PFAS), like perfluorooctanoic acid, have been used for the last 50 years in a wide variety of industrial processes and consumer-based products, including polymer additives, lubricants, fire retardants and suppressants, pesticides, and surfactants (Buck et al. 2015). The Department of Defense (DoD) has used PFAS-based Aqueous Film Forming Foam (AFFF) at fire training facilities and aircraft hangars. AFFF has contaminated approximately 600 sites classified as fire training facilities with PFAS (Huang, 2013).

This study focused on testing the most likely carbonaceous adsorbent compounds to remediate PFAS-contaminated sites on Air Force installations. Batch tests were performed to determine the …

Validation And Improvement Of Reliability Methods For Air Force Building Systems, Patrick A. Deering

Theses and Dissertations

The United States Air Force manages its civil infrastructure resource allocation via a two-dimensional risk model consisting of the consequence of failure and reliability. Air Force civil engineers currently use the BUILDER® Sustainment Management System to estimate and predict reliability at multiple levels within its civil infrastructure systems. Alley (2015) developed and validated a probabilistic model to calculate reliability at the system level. The probabilistic model was found to be a significant improvement over the currently employed BUILDER® model for four major building systems (electrical, HVAC, fire protection, and electrical). This research assessed the performance and accuracy of both the …

Measuring The Effectiveness Of Us Military Humanitarian Construction Projects Through Geospatial Analysis Of Public Opinion In Belize, Arthur Z. Dietrich

Theses and Dissertations

As part of broader US foreign policy efforts the Department of Defense (DoD) increasingly conducts complex operations which focus on efforts to influence local populations. These \hearts and minds" operations often include humanitarian and development construction projects. The wider impact on US foreign policy effort from the US military's participation in projects traditionally conducted by civilian agencies is not well understood. This research examined the effects on local public opinion from two US Air Force led \Operation New Horizons" Humanitarian and Civic Assistance (HCA) missions conducted in the nation of Belize in 2013 and 2014. The study specifically looked for …

Forensic Schedule Analysis Of Construction Delay In Military Projects In The Middle East, James W. Forbes

Theses and Dissertations

This research performs forensic schedule analysis of delay factors that impacted recent large-scale military construction projects in the Middle East. The purpose of this study is to understand the most significant causes of project delay and how AFCEC might improve schedule management performance. The methodologies for analysis are adapted from the Professional Practice Guide to Forensic Schedule Analysis, particularly Method 3.7 Modeled/Additive/Multiple Base, or Time Impacted Analysis—Adjusted. The data is gathered from USACE and AFCEC, consisting of Primavera project schedules and project documents from the Resident Management System database. The project delays from two large-scale projects are apportioned as compensable, …

Non-Linear Optimization Applied To Angle-Of-Arrival Satellite Based Geo-Localization For Biased And Time Drifting Sensors, Daniel E. Levy

Theses and Dissertations

Multiple sensors are used in a variety of geolocation systems. Many use Time Difference of Arrival (TDOA) or Received Signal Strength (RSS) measurements to locate the most likely location of a signal. When an object does not emit a classical RF signal, Angle of Arrival (AOA) measurements become more feasible than TDOA or RSS measurements. AOA measurements can be created from any sensor platform with any sort of camera. When location and attitude knowledge of the sensor passive objects can be tracked. A Non-Linear Optimization (NLO) method for calculating the most likely estimate from AOA measurements has been created in …

A Comparative Analysis Of Ieee 802.15.4 Adapters For Wireless Range Finding, Andrew P. Seitz

Theses and Dissertations

ZigBee wireless networks have become increasingly prevalent over the past decade. Based on the IEEE 802.15.4 low data rate wireless standard, ZigBee offers low-cost mesh connectivity in hospitals, refineries, building automation, and critical infrastructure. This thesis explores two ZigBee Received Signal Strength Indicator (RSSI)-based rangefinding tool sets used for assessing wireless network security: Z-Ranger and Zbfind. Z-Ranger is a new tool set developed herein for the Microchip Zena Wireless Adapter that offers configurable distance estimating parameters and a RSSI resolution of 256 values. Zbfind is an application developed for the Atmel RZUSBstick with no configurable distance estimating parameters and a …

Multi-Cubesat Deployment Strategies: How Different Satellite Deployment Schemes Affect Satellite Separation And Detection For Various Types Of Constellations And Missions, Scott A. Biehl Jr.

Theses and Dissertations

As economics drive an increased demand for small satellites and, consequently, an increase in the number of satellites deployed per launch, different deployment schemes and their effects on satellite dynamics must be well understood. While there are advantages to deploying multiple satellites at once, users may have trouble with tracking, identifying, and communicating with their satellites. This investigation examines the deployment of eight 3U CubeSats, and the resulting relative motion within a constellation. Both the distance between any two satellites within a constellation and the volume of a polygon encompassing a constellation are used to analyze the satellite dynamics within …

Effectiveness Based Design Of A Tactical Tanker Aircraft, Andrew K. Petry

Theses and Dissertations

An approach to drive conceptual aircraft design using mission effectiveness parameters is described and applied to an operational scenario. The scenario includes traditional aircraft refueling tankers and a proposed tactical tanker concept supporting fighter aircraft conducting offensive (OCA) and defensive (DCA) counter air patrols. Traditional conceptual design methodologies were used to generate a baseline design for a tactical tanker aircraft, which was evaluated using a MATLAB-based model to investigate Measures of Effectiveness (MOE). The model holds the traditional tanker and fighter capabilities constant, while varying the tactical tanker's specific fuel consumption, lift-to-drag ratio, fuel payload, mass fraction, and proximity to …

Design And Flight Test Of A Weapons-Cavity Acoustics And Separation Test Bed, Zachary Probst

Theses and Dissertations

Two very important, and often detrimental, phenomena can occur when an open weapons bay, or more generally-a cavity, is exposed to high-velocity flow. First, a shear layer develops over the cavity, leading to large regions of difficult-to-predict flow. Second, dynamic pressure oscillations are generated within the cavity itself. These two issues can combine to have multiple harmful effects on weapons carriage and employment. This provided motivation for flight tests which quantify forces and moments on a store, mounted at various positions in the cavity, for a variety of flight conditions. Specifically, a low-cost, easily reconfigurable test bed for weapons-cavity research …

Investigation Into Active Spanwise Camber Deformation On The Lateral Stability And Roll Control Of The X-56a Compared To Conventional Ailerons, Eric T. Yerly

Theses and Dissertations

"This research compares the stability and roll characteristics of an X-56A using AFRL’s Variable Camber Complaint wing technology to actively change wing camber compared to conventional ailerons deflected at set angles. An analysis of the stability and roll characteristics was modeled using a 3-D vortex lattice theory simulation, and that data was compared to wind tunnel testing to verify and validate the model results. Wind tunnel data was collected using 19 inch 3-D printed scale models with wings fabricated with a pre-determined percentage of camber deformation, as well as models with fixed aileron deflections. The full span model changed camber …

A Time-Variant Value-Focused Methodology For Supporting Pre-Acquisition, Brian K. Scheller

Theses and Dissertations

Military operations are dynamic in nature, as time-dependent requirements or adversary actions can contribute to differing levels of mission performance among systems. Future military operations commonly use multi-criteria decision analysis techniques that rely on value-focused thinking (VFT) to analyze and ultimately rank alternatives during the Analysis of Alternatives phase of the acquisition process. Traditional VFT approaches are not typically employed with the intention of analyzing time-variant performance of alternatives. In this research, a holistic approach towards integrating fundamental practices such as VFT, systems architecture, and modeling and simulation is used to analyze time-dependent data outputs of an alternative’s performance within …