Digital Commons Network^™

Reconstructing Spectral Scenes Using Statistical Estimation To Enhance Space Situational Awareness, Travis F. Blake

Theses and Dissertations

A new sensor, the Advanced Electro-Optical System (AEOS) Spectral Imaging Sensor (ASIS) has been developed at the Maui Space Surveillance Complex (MSSC). ASIS is capable of collecting resolved imagery of space objects in 10's-100's of spectral bands while using an adaptive optics system. However, the stringent requirements of collecting ground-based images requires a sensor that induces spectral blurring. Post-processing algorithms to remove this blurring are required to fully exploit these spectral images. This research focuses on developing the reconstruction algorithms, based on proven estimation theories, required to spectrally deblur the images collected from ASIS. Additionally, the research will expand the …

Branch Detonation Of A Pulse Detonation Engine With Flash Vaporized Jp-8, John David Slack

Theses and Dissertations

Pulse Detonation Engines (PDE) operating on liquid hydrocarbon fuels are limited to operating frequencies of 35 Hz due to long ignition times from a low energy ignition sources. This study shows ignition time of JP-8 can be nearly eliminated by igniting a thrust tube using a secondary detonation. A counter flow heat exchanger attached to a thrust tube utilized waste heat from the detonation process to heat JP-8 to supercritical conditions. The fuel flash vaporized when injected into the air stream of the engine. A detonation was produced by a spark in a 5 cm diameter, 1.37 m long tube. …

Neural Network Burst Pressure Prediction In Composite Overwrapped Pressure Vessels From Acoustic Emission Data, Seth-Andrew T. Dion

Master's Theses - Daytona Beach

Composites have grown in importance in the aerospace industry where high specific strength is a priority. Weight reduction in space vehicles is critical because of the exorbitant cost associated with placing objects into space. Major weight savings have been obtained by switching from all metal pressure vessels to composite overwrapped pressure vessels (COPVs). Due to the nature of composites, current nondestructive analysis procedures for COPVs are not adequate for assessing structural integrity. As such, new methods must be developed. Presented herein is one such method.

A method for burst pressure prediction using parametric filtering of acoustic emission (AE) data along …

Coupling Of Fluid & Solid Thermal Models To Correct Heat Flux Measurements Taken On Launch Vehicles, Danielle M. Ford

Master's Theses - Daytona Beach

Knowledge of aerothermally induced convective heat transfer and plume induced radiative heat transfer loads is essential to the design of thermal protection systems (TPS) for launch vehicles. These loads are measured via the cylindrical heat flux gauges that are flush mounted with the outer surface of a launch vehicle and are exposed to the in-flight external thermal and velocity boundary layers as well as thermal radiation. Typically, Schmidt-Boelter gauges measure the incident heat flux based on the one-Dimensional Fourier's law. This instrumentation, when surrounded by low-conductivity insulation, has an exposed surface temperature significantly lower than the insulation. A substantial disturbance …

Application Of Energy Analysis To The Problem Of Propulsion Driven Nutation Instability Of Spin Stabilized Spacecraft, Tina Morina Rice

Masters Theses

Propulsion driven nutation instability in spin stabilized spacecraft was first observed in the late nineteen seventies. It’s often referred to as the PAM-D coning anomaly, as it first occurred in the McDonnell Douglas Payload Assist Module (PAM-D). Propulsion driven nutation instability is a performance degrading phenomenon that occurs in spin-stabilized spacecraft used for the raising of satellite payloads to geosynchronous orbit. It is characterized by a coning (wobbling) motion that grows to a large degree during the final seconds of motor burn. The instability is clearly related to the increased size of the rocket needed to support the increasing …

The Functional Application Of The Propeller Load Curve For Fixed Pitch Propellers, Rebecca Barnett Speas

Masters Theses

This thesis attempts to help the flight test community by using the propeller load curve (also known as prop load) to find brake horsepower (BHP) easily with only a propeller tachometer. This thesis also covers the equation for the propeller load curve.

The flight test was done using a Piper Cherokee 180 equipped with a Lycoming 0-360-A3A engine. The flight test data were collected at University of Tennessee Space Institute (UTSI). This data were then compared to the prop load from the engine manufacturer.

Based on the result of this flight test, using the prop load equation from the Lycoming …

Retrofit Reconfigurable Flight Control System And The F/A-18c, Matthew E. Doyle

Masters Theses

The United States Navy has completed the initial flight test of a Reconfigurable Control Law System (RCLAWS) on the F/A-18C. The purpose of reconfigurable control is to allow for the safe operation of an aircraft that has experienced a sudden change in aircraft dynamics resulting from aircraft damage or flight control effector damage. The RCLAWS utilized during this flight test are novel in that they are designed to augment the production flight control system instead of replacing it. In order to reduce verification and certification requirements, this retrofit reconfigurable methodology supplements pilot commands to compensate for undesirable aircraft dynamics instead …

An Evaluation Of The Ah-64 Night Vision Systems For Use In 21st Century Urban Combat, John Kevin Heinecke

Masters Theses

Currently one of the most arduous and dangerous aviation missions for the military attack helicopter pilot is the night combat mission. The mission entails flight at close proximity to the ground and obstacles such as wires, trees, and buildings in an effort to avoid detection by enemy air defense and insurgent small arms fire. Night flight requires the use of augmented vision systems and enhanced aircraft stability and control systems to allow pilots to effectively see and negotiate those hazards that would otherwise be visible during daylight.

The U.S. Army currently fields two variants of augmented visionics, the Aviator Night …

Investigation Of Knock In Gaseous Fuels In The Presence Of Diluents, Roshan Ashok Rodrigues

Masters Theses

Recent energy security and environmental concerns have prompted growing interest into utilization of alternative fuels such as, natural gas and landfill gas. These gaseous fuels contain significant amount of diluents in the fuel composition, such as carbon dioxide, nitrogen, water vapor and other trace gases, which vary by geographical location. Successful engine operation is limited by a phenomenon called "knock", which occurs due to auto-ignition of the end gas ahead of the flame front, and therefore, needs to be investigated with the utilization of these gaseous fuels.

The present contribution discusses the experimental set-up, procedure and results of the investigation …

System Identification And Parameter Estimation Of The Piper Pa32-301 Saratoga, Catherine Anne Kelly

Masters Theses

The purpose of this project was to estimate the longitudinal stability derivatives of the Piper Saratoga (tail number N22UT), one of the aircraft owned and operated by the University of Tennessee Space Institute (UTSI), using the System Identification Programs for Aircraft, SIDPCAC. After the instrumentation error was reduced by means of a data compatibility analysis, the stability derivatives were estimated using both an output error and an equation error parameter estimation technique.

Following a discussion of the test aircraft and instrumentation and a brief overview of stability derivatives and parameter estimation, the flight test is discussed in detail along with …

Vacuum Chamber Construction And Contamination Study Of A Micro Pulsed Plasma Thruster, Jacob H. Debevec

Theses and Dissertations

The micro pulsed plasma thruster (micro-PPT) is a simple and versatile electric thruster capable of performing multiple missions, from precise attitude control on standard satellites to primary propulsion for nanosatellites. In order to fill this role as both industry and government move toward utilizing smaller satellites, micro-PPTs first need to be thoroughly tested on the ground. This study examines the deposition profile and rate of particle emission from the thruster so that satellite designers understand any potential contamination issues with sensitive instruments and solar panels. Employing a newly assembled vacuum chamber system, four tests were completed with the micro-PPTs, and …

An Exploration Of Several Structural Measurement Techniques For Usage With Functionally Graded Materials, Robert A. Reuter

Theses and Dissertations

Titanium / titanium boride functionally graded 6"x 1"x1" beams were subjected to a four-point beam test in order to critique the value of several measurement techniques. Also, finite element analysis results were compared with experimental values and general observations about the experiment were recorded. Uniform 85% TiB /15% Ti and uniform commercially pure titanium specimens were also subjected to the same loading conditions as a control. Techniques used include digital image correlation, fiber optic strain gauging, strain gauging, and differential infrared thermography techniques. The strain data results were compared with one another and to linear finite element models. It was …

Integrated Conceptual Design Of Joined-Wing Sensor Craft Using Response Surface Models, Josh E. Dittmar

Theses and Dissertations

A multidisciplinary conceptual design and analysis of Boeing's joined-wing SensorCraft has been conducted. This analysis was completed using geometrical optimization, aerodynamic analyses, and response surface methodology on a composite structural model. Phoenix Integration's Model Center was used to integrate the sizing and analysis codes found in Raymer's text, "Aircraft Design: A Conceptual Approach" as well as those from the NASA derived conceptual design tool AirCraft Synthesis (ACSYNT), and a modified Boeing Finite Element Model (FEM). This research demonstrated the utility of integrated low-order models for fast and inexpensive conceptual modeling of unconventional aircraft designs.

An Investigation Of Different Golf Ball Dimple Flow Fields, Walter Robert Michalchuk

Masters Theses

This experimental study evaluated the potential of various golf ball dimple designs to reduce the drag produced by a golf ball in flight. An experimental setup using four dimple models placed between the leading and trailing edges of a wing section was used. A traditional spherical dimple design was used as the baseline to comparatively study and evaluate the results of the other three different designs. This study was performed on scaled dimple geometries in a water channel at realistic Reynolds number. Surface dye flow visualization, pressure measurements and Computational Fluid Dynamics (CFD) were used to evaluate the various designs. …

An Experimental Study Of Incompressible Axisymmetric Cavity Flow With Swirl, Lee Charles Wendell

Masters Theses

A systematic study was performed of the flow phenomena in an axisymmetric cavity. Axial flow Reynolds numbers ranged from 100,000 to 530,000 for cavity L/D range of 0.25 to 1.65. Working medium for this study was water reflecting that only incompressible domain of cavity flow was covered in this study. Previous results of axisymmetric flow investigations were reproduced and extended to lower L/D values, with the modified test article. Introduction of swirl in the cavity flow was studied in detail for its effects on the enhancement or suppression of cavity modes that have been measured.

The axial apparatus tested here …

Outside The Fence,' The Threat To The U.S. Aviation Industry, David Thomas Ramsey

Masters Theses

The purpose of this thesis was to examine the threat to the Aviation Industry from within the United States. The overall investigation starts with one assumption “that there will at some time in the near future be a covert operative group that desires to attack or engage the United States in war on its home land.” The principles of war will be analyzed resulting in covert cell guidance specifically; “economy of force” will require the covert units to be as small as possible to affect as many nodes as possible. Endurance will require the covert team to restrict any tactics …

Design And Optimization Of A Wind Deflector For Round-Nose Md-500 Series Helicopters, James Joseph Wright

Masters Theses

This thesis examines the problem experienced by the numerous rotary wing operators whose operations require flight with personnel seated outside the fuselage or with doors off. This investigation is specific to the round nose configured MD-500 series aircraft due to test aircraft availability and the wide range of missions it conducts worldwide. During cruise flight, personnel exposed to the aircraft slipstream are subjected to high wind loads and extreme wind chill effects, compromising their ability to perform required tasks. External passengers also add to the overall helicopter parasite drag, decreasing its performance as well as interfering with the crew through …

Increasing The Reliability Of General Purpose Bomb Fuzing In Precision Strike Warfare, Mitchell Ralph Conover

Masters Theses

The advent of modern high-precision guided airborne weapons has increased the need for extremely reliable bomb fuzing systems. An electro-mechanical bomb fuzing system is currently used in U.S. Navy and Air Force General Purpose bomb based-weapons to include Joint Direct Attack Munition and Laser Guided Bombs. The demonstrated reliability of that fuzing system in combat operations on average has been less than perfect. The operational commanders have expressed that this is unacceptable since any dud results in coalition forces being held at additional risk because a duded bomb could be utilized as an Improvised Explosive Device by enemy forces. Just …

Forced Resonant Periodic Shock Waves And Mean Pressure Shift In A Closed Tube, Eric James Jacob

Masters Theses

The thesis outlines an experiment done in the oscillation of a closed tube near to its fundamental frequency. A tube with a length of ten feet was oscillated via a piston driven by a DC motor. The pressure waveform and mean pressure was recorded at the end of the tube and the mean pressure was measured at the middle of the tube. When the tube was excited near to its 1^st mode non-linear features such as shock-like waveforms, cascading of energy to higher modes and mean pressure shift were recorded.

These Results are only possible to predict by using …

Installing A Night Vision Imaging System In The Cf-188 Hornet: Compatibility Of Warning And Caution Lights, Andrew John Soundy

Masters Theses

The purpose of this thesis was to investigate the NVIS compatibility of fire warning lights as installed during a NVIS upgrade of the CF-188 Hornet for operation with Generation 3 AN/AVS-9 night vision goggles. Data was gathered and compared to the specifications listed in MIL-STD-3009 to determine suitability of the implemented design. Of particular concern during the execution of this project was the compatibility of fire warning lights for operation in both day-time and night-time conditions with respect to NVIS radiance. The initial design placed the NVIS radiance of cockpit warning lights at a level commensurate with that suggested by …

Compressible Flow In Slab Rocket Motors, Brian A. Maicke

Masters Theses

In this thesis, the compressible flow inside a rectangular, porous channel is considered. A Rayleigh-Janzen perturbation is applied to the inviscid, steady, two-dimensional, isentropic flow equations. Closed form expressions are derived for the main properties of interest. The results of the study are verified via numerical simulation, with laminar and turbulent models, and with available experimental data. The critical point where the flow field reaches sonic conditions is determined analytically. Our analysis captures the steepening of the velocity profiles that has been reported in several studies using either computational or experimental methods. Explicit design criteria are presented to quantify the …

Modelamiento Geométrico De Un Motor De Combustión Interna, Simulación Del Ciclo Dinámico Y Representación Gráfica De La Transferencia De Calor Del Sistema Biela, Pistón, Cigüeñal, Miguel Ángel Gómez Herrera, Míller Mauricio Gómez Parra

Ingeniería en Automatización

No abstract provided.

Optimization Of Active Rendezvous Trajectories By Genetic Algorithms, Marie Emmanuelle Ricour

Master's Theses - Daytona Beach

Trajectory optimization is and will remain a hot topic in the engineering field. Because analytical or exact solutions are often difficult and sometimes impossible to compute, there is a need for alternative and efficient methods. UnderWater Vehicles (UWV) trajectories and rendezvous trajectories of continuous low-thrust spacecraft are examined. One of the methods to solve such problems is the Genetic Algorithm (GA) method. In this work, a GA has been developed using Matlab®. It treats possible solutions to the studied problems as individuals and eventually converges to an optimal or near optimal solution. Genetic Algorithms have been used previously to solve …

Evaluation Of Probabilistic Methodology For Predicting Satellite Tracking Resources, Matthew Lynn Stubbe

Master's Theses - Daytona Beach

This research evaluates a probabilistic methodology for estimating the ability of satellite tracking networks to provide tracking and data acquisition services to large constellations of satellites. This approach, developed by Hagar is evaluated using Monte Carlo simulations of optimal satellite contact scheduling on a tracking network for a certain class of satellites. The actual results of the scheduled Monte Carlo simulations were then compared to the predicted values computed with Hagar's methodology for a range constellation and network sizes. Comparison methods include percent difference, a Wilcoxon signed ranks test and a Mann-Whitney U test.

The Monte Carlo simulations were run …

Lightweight In-Plane Actuated Deformable Mirrors For Space Telescopes, Michael J. Shepherd

Theses and Dissertations

This research focused on lightweight, in-plane actuated, deformable mirrors, with the ultimate goal of developing a 20- meter light gathering aperture for space telescopes. The 0.127 meter diameter deformable mirror small scale testbed was modelled infinite elements using MSC.Nastran software and then used as a basis for a quasi-static controller. Experimental tracking of Zernike tip, tilt, and defocus modes was accomplished. The analytical solutions to plate-membrane and beam-string ordinary differential equations were developed. A simplified approach to modelling the axisymmetric cases was also presented. A novel static control strategy, the Modal Transformation Method, was developed to form Zernike surfaces within …

Dynamics And Control Of Tethered Satellite Formations For The Purpose Of Space-Based Remote Sensing, Kurt A. Vogel

Theses and Dissertations

This dissertation assesses the utility of tethered satellite formations for the space-based remote sensing mission. Energy dissipation is found to have an adverse effect on foundational rigid body (Likins-Pringle) equilibria. It is shown that a continuously earth-facing equilibrium condition for a fixed-length tethered system does not exist since the spin rate required for the proper precession would not be high enough to maintain tether tension. The range of required spin rates for steady-spin motion is numerically defined here, but none of these conditions can meet the continuously earth-facing criteria. Of particular note is the discovery that applying certain rigid body …

Laser Covariance Vibrometry For Unsymmetrical Mode Detection, Michael C. Kobold

Theses and Dissertations

Simulated cross - spectral covariance (CSC) from optical return from simulated surface vibration indicates CW phase modulation may be an appropriate phenomenology for adequate classification of vehicles by structural mode. The nonlinear structural to optical relationship is close to unity, avoiding nulls and high values; optical return contains sufficient spectral ID information necessary for data clustering. The FE model has contact between the homogeneous rolled armor and vehicle hull, a simple multi - layer skin model typical of most vehicles. Most of the high frequency energy moved to lower frequencies. This nonlinearity segments contact vibration modes into two classes: symmetrical …

Modeling Fracture In Z-Pinned Composite Co-Cured Laminates Using Smeared Properties And Cohesive Elements In Dyna3d, Jason K. Freels

Theses and Dissertations

The purpose of the present research was three-fold: 1) gain a more sophisticated understanding of the response of co-cured composite joints with and without through-thickness reinforcement (TTR), 2) compare the behavior of specimens reinforced with various sizes and densities of reinforcement, and 3) use experimental data to verify the existing DYNA3D smeared property model. Double cantilever beam, end-notch flexure and T-section specimens reinforced with 0.011" diameter z-pins at 2% and 4% volume densities were tested to determine the mode I, mode II and mixed mode (I and II) behavior. Results were added to preliminary research in which tests were conducted …

Three Component Velocity Measurements In The Tip Vortex Of A Micro-Air-Vehicle, Hong-Joon Park

Theses and Dissertations

The purpose of this research was to improve the MAV that will be used for battle damage assessment and reconnaissance or local surveillance through the experiments in AFIT wind tunnel. The experiments were performed to investigate the wing displacement and wing tip vortex interaction. To conduct the experiments, telescopic survey tool and tri-axial hot-wire anemometer was utilized. The results indicate that wing tip displacement of the flexible wing was approximately 8 times that of the rigid wing in an unstalled condition and data suggests that flexible wing has a denser core-distribution of velocity within the wing tip vortex and delays …

Scaling Flight Tests Of Unmanned Air Vehicles, Jeevani I. Abeygoonewardene

Theses and Dissertations

Increasing technological advances and research interest in unmanned air vehicles (UAVs), have led to the need for having safe, inexpensive and effective means of experimenting with their fight performance and surveillance capabilities. Work has previously been done in areas of controlling, analyzing, and predicting cooperative and autonomous operations of UAVs and other vehicles. In addition, there are well established guidelines for scaling experiments in fluid mechanics, where geometric, kinematic and dynamic similarity is obtained by formulating problems in terms of non dimensional variables using dimensional analysis. However, little or no work has been done in developing experiments or guidelines for …