Aerospace Engineering Commons^™

Multi-Element Airfoil Optimization Using Computational Fluid Dynamics, Mustafa Kubilay Ictuzer

Mechanical & Aerospace Engineering Theses & Dissertations

High-lift systems are frequently used on commercial transport aircrafts to obtain low speed performance, in terms of take-off and landing field lengths and approach speed. To maximize the take-off and landing performance within the critical restrictions required by the new generation transport wing designs, enhanced high-lift technologies are needed. Moreover, the economic realities faced by the airlines require a design that is mechanically simple and effective. These facts lead us to the optimization of the high lift systems.

Optimizing a high-lift system improves an aircraft's take-off and landing performance. The weight of the system, the advantages and the disadvantages all …

Follow Up Nucleate Boiling On-Flight Experiment, Andrew Fassmann

Presentations

No abstract provided.

Compression Testing Of Composite Laminated Foam Under Thermal Loading And With Central Holes, Dominic Surano, Jonathan Russo, Daniel Leighton

Aerospace Engineering

A study was conducted to investigate the effect of heat on composite sandwich plates, fabricated with the vacuum resin infusion process, with center holes of varying diameters. The study involved conventional notched specimens and notched specimens with shear keys, both of which were subjected to monotonic inplane compression loading. Hole diameter was be varied from one to four inches in one inch increments. Loading rate was applied using the Instron machine at one millimeter per minute. The diameter of the shear key around the holes varied from one inch to four inches in one inch increments. The specimens were placed …

Validation Of A Novel Approach To Solving Multibody Systems Using Hamilton's Weak Principle, Ashton D. Hainge

Theses and Dissertations

A novel approach for formulating and solving for the dynamic response of multibody systems has been developed using Hamilton’s Law of Varying Action as its unifying principle. In order to assure that the associated computer program is sufficiently robust when applied across a wide range of dynamic systems, the program must be verified and validated. The purpose of the research was to perform the verification and validation of the program. Results from the program were compared with closed-form and numerical solutions of simple systems, such as a simple pendulum and a rotating pendulum. The accuracy of the program for complex …

Back-Pressure Effect On Shock-Train Location In A Scramjet Engine Isolator, Richard I. Paek

Theses and Dissertations

The isolator of the scramjet decelerates the incoming high Mach flow to a lower Mach number and stabilizes the flow before it enters the combustor. Because of the unsteady combustion phenomenon and inconsistent completeness of the combustion, pressures within the combustor can vary drastically. These pressure variations can propagate forward and affect the flow field in the isolator - worst case unstarting the inlet. In this research, the shock train location versus the back-pressure is examined experimentally. The back-pressure is artificially created by symmetric (top & bottom) ramps that can close the flow area. Raising/lowering ramps result in higher/lower back-pressure. …

Thrust And Performance Study Of Micro Pulsed Plasma, Jeremy J. Selstrom

Theses and Dissertations

This research is focused on several areas of the μPPT performance. An important idea studied is the effect of lifetime use on the performance. The thruster is fired for a simulated lifetime of use to see if there is an impact on the thrust of the thruster later in life. Also vital is the efficiency of the thruster. A μPPT performing at max efficiency will ionize all ablated material; however, we know that not to be the case. In this research the effort is made to collect these non-ionized particles in order to measure their mass post-test. With this collected …

Global Navigation Satellite System Software Defined Radio, Jason M. Mcginthy

Theses and Dissertations

The GNSS world is quickly growing. The United States’ GPS, the European Union’s Galileo, China’s Compass, and Russia’s GLONASS systems are all developing or modernizing their signals, and there will soon be more navigation satellites in space than ever before. The goal of this research was to develop an initial capability for an AFIT GNSS software receiver. This software receiver is intended to be used for research purposes at the Advanced Navigation Technology (ANT) Center. First a GPS-only software receiver was built. It successfully acquired, tracked, and provided reasonable position estimates. Next, the receiver was successfully modified to acquire and …

Minimizing Losses In A Space Laser Power Beaming System, Charlie T. Bellows

Theses and Dissertations

A mathematical model is developed to track the amount of power delivered in a wireless laser power beaming system. In a wireless system the power proceeds through several different stages before being delivered to a payload for use. Each of these stages results in power losses that are thoroughly examined and modeled, allowing for the calculation of the likely amount of power delivered. Adjusting variable factors within the model allows for the optimization of the system for a specific task. The model shows that an optimized wireless power transfer system can deliver enough power to meet the space experiment objectives. …

Development Of A Remotely Operated Autonomous Satellite Tracking System, Michael E. Graff

Theses and Dissertations

AFIT is currently developing a capability to remotely and autonomously track LEO satellites using commercial telescopes. Currently, the system is capable of open-loop tracking based on Two-Line Element sets (TLEs) downloaded from NORAD’s space object catalog. The ability to actively track using a closed-loop control system would allow tracking of satellites which deviated from the published TLEs along with providing some information about the object’s new orbital elements. To accomplish closed-loop tracking, the object is imaged by a digital camera connected to a wide field-of-view (WFOV) spotting scope. Software was developed to provide azimuth and elevation inputs in order to …

Consideration Of Wear Rates At High Velocity, Chad S. Hale

Theses and Dissertations

The development of the research presented here is one in which high velocity relative sliding motion between two bodies in contact has been considered. The experimental results of a VascoMax 300 maraging steel slipper sliding on an AISI 1080 steel rail during a January 2008 sled test mission were considered for the determination of high velocity wear rates. The numerical model, based on a metallographic study of a test slipper, contained all of the physical features present in order to adequately characterize high velocity wear rates. Two-dimensional, plane strain models have been implemented in the explicit finite element code, ABAQUS. …

Fatigue Behavior Of An Advanced Sic/Sic Composite With An Oxidation Inhibited Matrix At 1200°C In Air And In Steam, Jacob Delapasse

Theses and Dissertations

The fatigue behavior of an advanced Silicon Carbide/Silicon Carbide (SiC/SiC) ceramic matrix composite (CMC) with oxidation inhibited matrix was investigated at 1200˚C in laboratory air and in steam environments. The composite consisted of an oxidation inhibited SiC matrix reinforced with Hi-Nicalon fibers coated with pyrolytic carbon (PyC) with a boron carbide overlay woven into eight-harness-satin (8HS) weave plies. Tensile stress-strain behavior and tensile properties were evaluated at 1200˚C. Tension-tension fatigue tests were conducted in both laboratory air and in steam at 1200˚C at frequencies of 0.1 Hz, 1.0 Hz, and 10 Hz. The tension-tension fatigue tests had a ratio of …

Performance Of A Small Internal Combustion Engine Using N-Heptane And Iso-Octane, Cary W. Wilson

Theses and Dissertations

With the sustained interest in Unmanned Aircraft Systems (UAS) and Micro Air Vehicles (MAV), the military services have a real need for vehicles powered by an internal combustion (IC) engine that can run efficiently on heavy hydrocarbon fuels, especially JP-8 due to established logistics. This thesis concerns the results of running a two horsepower, 4-stroke, spark-ignition engine (FUJI BF34-EI) with both iso-Octane and n-Heptane. Results include the knocking characteristic of this engine with n-Heptane, a comparison of the brake specific fuel consumption (BSFC) of the two fuels in a factory delivered engine configuration with a 17x10 APC propeller loading, a …

Simulation And Application Of Gpops For Trajectory Optimization And Mission Planning Tool, Danielle E. Yaple

Theses and Dissertations

Rapid trajectory generation is crucial to prompt global warfare. To meet the USAF’s objective of Persistent and Responsive Precision Engagement, a rapid mission planning tool is required. This research creates the framework for the mission planning tool and provides a sample optimal trajectory which is solved using the GPOPS software package. GPOPS employs a Gaussian pseudospectral method to solve the non-linear equations of motion with both end conditions and path constraints. By simultaneously solving the entire trajectory based on an initial guess and small number of nodes, this method is ideal for generating rapid solutions. The sample case is a …

Monocular Vision Localization Using A Gimbaled Laser Range Sensor, Don J. Yates

Theses and Dissertations

There have been great advances in recent years in the area of indoor navigation. Many of these new navigation systems rely on digital images to aid an inertial navigation estimates. The Air Force Institute of Technology (AFIT) has been conducting research in this area for a number of years. The image-aiding techniques are centered around tracking stationary features in order to improve inertial navigation estimates. Previous research has used stereo vision systems or terrain constraints with monocular systems to estimate feature locations. While these methods have shown good results, they do have drawbacks. First, as unmanned exploration vehicles become smaller …

Assembly, Integration, And Test Methods For Operationally Responsive Space Satellites, Lisa A. Baghal

Theses and Dissertations

Current government and industry standards in spacecraft testing result in an Assembly, Integration, and Test (AIT) timeline greater than six months. These standards will not support the vision of Operationally Responsive Space (ORS) to deploy a satellite within six days to fill an urgent need. Using the Air Force Research Laboratory’s Plug-and-Play Satellite (PnPSat), multiple Rapid AIT trials were conducted. By exercising the AIT process with various spacecraft configurations and personnel, methods for reducing or modifying traditional testing regimen were investigated.

Gravity Gradiometry And Map Matching: An Aid To Aircraft Inertial Navigation Systems, Anthony J. Degregoria

Theses and Dissertations

Inertial navigation systems (INS) offer passive, all-weather, and undeniable navigation information, which military customers often view as especially appealing strengths. Unfortunately, Airmen and engineers still struggle with INS’s drifting position errors, and navigation aids generally detract from INS’s strengths. At this year’s Air, Space, and Cyberspace in the 21st Century Conference, the Chief of Staff of the Air Force identified the Global Positioning System (GPS) as a widely-known and exploitable vulnerability, saying that it’s critical the Joint force reduce GPS dependence. Recent advances provide an opportunity for gravity gradient instruments (GGI), which measure spatial derivatives of the gravity vector, to …

Effectsof Prior Aging At 260 °C In Argon On Inelastic Deformation Behavior Of Pmr-15 Polymer At 260 °C: Experiment And Modeling, Bradley K. Diedrick

Theses and Dissertations

The purpose of this research was to investigate the inelastic deformation behavior of PMR-15 neat resin, a high-temperature polymer, at 260 °C. The experimental program was designed to explore the influence of strain rate on loading and unloading behaviors. In addition, the effect of prior strain rate on creep, relaxation, and recovery responses was evaluated. The material exhibits positive, nonlinear strain rate sensitivity in monotonic loading. Early failures occur before fully establishing inelastic flow. The creep, relaxation, and recovery responses are significantly influenced by prior strain rate. The experimental results suggest the behavior of PMR-15 at 260 °C can be …

Analysis Of Hybrid-Electric Propulsion System Designs For Small Unmanned Aircraft Systems, Ryan M. Hiserote

Theses and Dissertations

Currently fielded electric-powered small unmanned aircraft systems (UAS) lack the endurance desired by warfighters, while their internal combustion engine (ICE) driven counterparts generate mission compromising acoustic and thermal signatures. Parallel hybrid-electric propulsion systems would meet the military’s needs by combining the advantages of hydrocarbon and electric power systems. Three distinct parallel hybrid-electric system designs, each with three unique battery discharging profiles, were analyzed and compared using a constrained static optimization formulation based upon traditional aircraft design equations. Each system combined an ICE sized for cruise speed with an electric motor sized for endurance speed. The nine hybrid variations were compared …

Experiments With Geometric Non-Linear Coupling For Analytical Validation, Jonathan D. Boston

Theses and Dissertations

This study was focused on obtaining accurate experimental data for the validation of the geometrically exact beam theory from a series of experiments in which high quality surface shape and deflection data was collected. Many previous experiments have experienced issues with data collection or test articles which the researchers were unable to overcome. The test program was performed in two stages: qualification and joined-wing. The qualification stage validated the experimental procedures on simple 72 in long aluminum beams with 8 in x 0.5 in cross-sections. The joined-wing stage was the primary experiment focused on obtaining quality data for use in …

Particle Size Control For Piv Seeding Using Dry Ice, Brian T. Love

Theses and Dissertations

Particle image velocimetry (PIV) has been carried out using solid carbon dioxide (CO₂) particles as the seed material to continue the development of clean seeding for use in large-scale, closed-circuit tunnels. Testing occurred in two wind tunnels at subsonic and supersonic speeds using dry ice particles generated by allowing liquefied CO₂ to expand from a small diameter injector tube through a larger diameter shroud tube. The particles were injected into the plenum and discrete solid particles, suitable for PIV measurements, were present in the test section. Data on particle size were first collected using a Malvern particle …