Aerospace Engineering Commons^™

Application Of Kalman Filtering To Real-Time Flight Regime Recognition Algorithms In A Helicopter Health And Usage Monitoring System, Rachel Elizabeth Rajnicek

Master's Theses - Daytona Beach

The purpose of this study is the application of Kalman filters to real-time Flight Regime Recognition (FRR) algorithms to identify the regime flown and observe transitions between flight regimes. Rotor fault identification, a technique that is somewhat similar to flight regime recognition, successfully used Kalman filters to determine fault types and damage locations. Recently developed FRR algorithms successfully applied Hidden Markov Models, which are similar to Kalman filters. The selected regime set for this study derives from a study performed by Bell Helicopter Textron, Inc. The selected parameter set for this study is modified from the Schweizer 300 Flight Test …

Using Ansys Workbench Computer Environment In Turbomachinery Design Process, Patricia Lynn Bowlds

Master's Theses - Daytona Beach

The main focus of designing turbomachinery is to analyze and optimize the aerodynamic efficiency and structural integrity of the machine. The preferred way to perform aerodynamic and structural analysis is to connect the analyses and shorten the analysis time as much as possible. ANSYS, Inc. provides a comprehensive approach to model fluid structure interaction phenomenon in turbomachinery within the ANSYS Workbench environment. This environment combines a number of software components that conduct blade design, fluid dynamic and structural analyses, and pre- and post-processing including mesh generation and overall performance estimation.

The focus of this study is to apply the ANSYS …

An Investigation Of Classical Panel Stiffener Buckling Methods For Modern Airframe Applications, Ryan Timothy Holt

Master's Theses - Daytona Beach

Classical methods for buckling assessment of aircraft panels reinforced by bulb-stiffened flanges differ regarding symmetric versus asymmetric cross-sections. The present research addresses a number of classical derivations of methods with a focus on the work of Dwight Windenburg as published in "The Elastic Stability of Tee Stiffeners" and the expansion of his work to asymmetric sections by E. F Bruhn in Analysis and Design of Aerospace Vehicle Structures. Vagueness in the relevance of geometric symmetry of the bulb exists between Windenburg's plate theory approach, and the accepted industry standard applications defined in the methods of Bruhn. The results presented trace …

Development Of Automatic Cfd Grid Generation For The Design Of The Preliminary Wing Sweep Schedule For The Gulfstream Quiet Supersonic Jet, Ali Kazeneh

Master's Theses - Daytona Beach

The wing sweep schedule for the Gulfstream Quiet Supersonic Jet (wing and body) was investigated using CFD analysis methods. The use of automating the gridding procedure allowed for numerous cases to be investigated. The examination of the drag polar for different Mach cases indicated the optimum corresponding wing sweep position. The study results revealed that for the Mach 0.85 case, the wings should remain at the forward most pivoted position (Ʌ=25°). The Mach 1.1 case indicted that the wings should be in the fully swept back position (Ʌ=60°). The majority of the wing sweep transition occurs from Mach 0.85 to …

Development, Verification, And Future Applications Of A 3-Dof Entry And Descent Simulation Tool, Shaun Deacon

Master's Theses - Daytona Beach

With any space related mission, the unknown effects are often some of the most important design considerations. These effects must be accounted for in some fashion, and often lead to mission elements being centered around gathering information on the unknown.

It is the purpose of this research to develop and test a tool for simulation of entry, descent, and landing, (EDL) and to present a brief analysis of possible dispersion patterns related to autonomous radiosonde deployment on the surface of Mars.

The EDL simulation tool is written in Matlab. The aerodynamic information used by the tool is obtained with the …

Implementation Of A Low Cost Micro Electro Mechanical Systems Inertial Navigation Solution, Charles Njenga

Master's Theses - Daytona Beach

The purpose of this study is to develop a low cost navigation solution for General Aviation (GA) aircraft and flight testing aircraft. This low cost solution uses a Global Positioning System (GPS) coupled with an Inertial Navigation Solution (INS) to provide a more accurate, stable navigation solution that can be acceptable for aircraft navigation. Lab VIEW was utilized to perform data acquisition and computation. LabVIEW was the backbone software to perform real time computation. MATLAB ® Simulink ® was used to plot graphs for final analysis of the code. A software Kalman Filter was utilized to provide signal stability and …

Wing Optimization Technique Based On Vortex Lattice Theory, Santiago Pinzon

Master's Theses - Daytona Beach

An integrated aerodynamic optimization technique based on vortex lattice theory is being proposed. The technique in this work will aim at optimizing the geometric parameters of a general wing with NACA 65-210 airfoil sections under a low speed aerodynamic regime. This will be completed by performing an aerodynamic analysis based on vortex lattice theory with the objective of satisfying a performance index function. This function will seek to optimize the high lift-to-drag ratio of the wing at cruise velocity, while maximizing theoretical cruise range and minimizing wing weight. The optimization method has been developed using MATLAB and the focus of …

Attitude Determination Using Imaging Lidar, Camille Decoust

Master's Theses - Daytona Beach

The purpose of this study is to determine the attitude of an out of control object using a new technology called lidar (Light Ranging and Detection). As the number of spacecraft continues to grow, it is paramount to introduce a new type of autonomous on-orbit satellite inspection and repair involving docking. Traditional space vision technology is based on video systems. This method is limited by the necessity of operating when the target is illuminated by the sunlight or using its own source of illumination. The use of laser imaging technology offers an elegant solution to these challenges. This approach allows …

A Cfd Investigation Of Axisymmetric Microthruster Nozzles For Use On Nano-Satellites, Michael R. O'Gara

Master's Theses - Daytona Beach

The performance of microthruster nozzles (^ 0.1 N thrust) depending on nozzle contour, propellant and surroundings, destined for use in nanosatellite missions, is investigated via a numerical approach using the Wind-US flow solver. An experimental apparatus designed to measure microthruster performance in atmospheric or vacuum conditions used to aid numerical simulations is also presented. Comparing the numerical and experimental results show an approximate 25% drop in efficiency for unknown reasons. An evaluation of favorable nozzle contours suggested by previous researchers is conducted, and the results demonstrate the need for a more rigorous treatment of the nozzle flow at the exit …

A Computational Method For Flow Separation Detection And Control For Axial Compressor Airfoils, Chang Jun Meang

Master's Theses - Daytona Beach

Conducting full annulus experiments on multistage compressors is costly and time consuming due to the complexity of the experimental processes. To reduce complexity, Computational Fluid Dynamics (CFD) methods are applied to turbomachinery and other applications in recent analysis of such cases. CFD methods are widely used within the aerospace industry and are increasingly demonstrating their reliability. For axial compressors, it is known that highly staggered compressor stators will increase the aerodynamic loading on the stator, which directly relates to the compressor stall and efficiency. In this work, compressor stators stagger angle is increased 4 ° to induce separation on the …

Assessment Of The Thermal Improvements Awarded By Horseshoe Vortex Elimination On A Turbine Stator Blade In Computational Fluid Dynamics And Conjugate Heat Transfer, Laurent Lachmann

Master's Theses - Daytona Beach

The present work looks at an advanced turbine stator blade design and evaluates its thermal performance relative to a standard design. A new turbine stator blade is designed to eliminate the horseshoe vortex appearing at the leading edge. The new design is characterized by an extension of the leading edge at the hub and at the tip of about 30% of chord. By comparing this new design to an ordinary one (featuring straight leading edge), the present thesis verifies the horseshoe vortex elimination, and compares the thermal attributes of the fluid. The fluid is three-dimensional, viscous and turbulent. The analysis …

Study Of Contra-Rotating Coaxial Rotors In Hover: A Performance Model Based On Blade Element Theory Including Swirl Velocity, Florent Lucas

Master's Theses - Daytona Beach

The purpose of this study is to create a simple model to evaluate the performance of a counter-rotating coaxial rotor system. As it is based on the blade element theory, it could be used as a design tool where the engineer can modify all parameters - rotor radius, blade pitch distribution, tip velocity, rotor spacing, number of blades, blade chord, and airfoil's shape through its lift coefficient versus angle of attack slope. Different blade pitch distributions are tried and are assessed based on the power required to hover at the same weight. Also, the impact of the swirl velocity induced …

The Effects Of Foreign Accent And Language On Reaction Time And Accuracy In An Air Traffic Control Task, Rosabelle Suarez

Master's Theses - Daytona Beach

The present study examines the effect of foreign accent interference with the ability to execute commands presented in speech format. The objective of this study was to demonstrate that a foreign accent influences performance. Participants were between 18 and 40 years of age. Half of the participants were native speakers of Spanish who began learning English as a second language via the classroom setting. The other half were native English-speaking with little or no exposure to the Spanish language. The experimental design was similar to an aviation scenario where participants listened to simulated ATC procedural commands and execute them on …

Microthruster Experimental Analysis, Amy Denise Richards

Master's Theses - Daytona Beach

The purpose of this study was to design an experimental apparatus that could accurately test and measure the thrust efficiency of conical shaped microthrusters with varying divergence half angles. The experimental apparatus measured the thrust of micronozzles for various feed pressures in vacuum (to duplicate in space operation) as well as ambient. Calibration experiments confirmed the force measurement accuracy of the setup while gas thrust experiments were used to help determine the most efficient divergence half angle. Thrust results were compared to findings from two separate scientific studies that sought to optimize microthruster nozzles using CFD software.

Prediction Of Fatigue Life In 7075-T6 Aluminum From Neural Network Analysis Of Acoustic Emission Data, Nicholas S. Spivey

Master's Theses - Daytona Beach

Through the use of an acoustic emission (AE) data acquisition system, a Kohonen self-organizing map, and a back-propagation neural network, AE data from 7075-T6 aluminum specimens were used to classify failure mechanisms and predict the number of fatigue cycles to failure. AE waveforms were captured from 40 notched tensile specimens during the low-cycle fatiguing process. A Kohonen self-organizing map and initial data filters were used to classify the data into two distinct failure mechanisms, plane strain and plane stress fracture, plus a third less prevalent mechanism. These results were employed to construct a back-propagation neural network to predict the number …

Fabrication And Compressive Behavior Of Corrugated Aramid-Epoxy Cellular Solids, Jeffrey Arthur Schneider

Master's Theses - Daytona Beach

Cellular solids are materials whose base material does not always occupy the entire solid fraction available. A number of cellular solids can provide blast protection and absorb impact energy, but few perform well resisting blunt object (ballistic) penetration. In this thesis, a method is proposed for fabricating cellular solids from aramid-epoxy composites that can absorb impact energy and resist blunt object penetration. The aramid-epoxy samples were fabricated using wet-layup techniques, with two different styles of Kevlar 49 woven fabric in a variety of orientations. Test sample density ranged from 0.08 0.23 g/cm3. Different lamination orientations, assembly techniques, and bonding adhesives …

Investigation Of Magnetic Field Profile Effects In Hall Thrusters, Oren Kornberg

Master's Theses - Daytona Beach

The purpose of this study was to show the relationship of different magnetic field profiles to the acceleration region length of a Hall thruster. The general transport equations were simplified and solved using a one-dimensional analysis. Some of the model assumptions include quasineutrality, Maxwellian electrons, and negligible thruster wall effects. The solved equation kept magnetic field as an input to the model for the analysis. The magnetic field was altered by changing the shape through the thruster, while keeping the maximum point fixed, and by shifting the profile, while keeping the shape fixed. Results indicate a strong correlation between the …

Control System Design And Simulation Of Spacecraft Formations Via Virtual Formation Approach, Pavan Donepudi

Master's Theses - Daytona Beach

The problem of formation control of multiple spacecraft using the virtual structure approach is studied. The thesis first summarizes the progress made in the area of spacecraft formation control and then provides an overview of the virtual structure method. Modifying earlier established control design techniques, new feedback laws are constructed to control both the rotational and translational motion of a group of spacecraft. Several computer simulations are performed to illustrate the effectiveness of the modified control laws. The ephemeris and attitude data files generated via Matlab are exported to Satellite Tool Kit (STK) to create 3D animations. Various formation scenarios …

Validation Of Conjugate Heat-Transfer Capability For Water- Cooled High-Speed Flows, Bruno R. Fletcher

Master's Theses - Daytona Beach

A FORTRAN conduction/convection heat transfer module named FOGO (meaning fire in Portuguese) has been developed to perform the conjugate heat transfer analyses with existing flow solvers. In this work, FOGO is coupled with TBD and WIND-US flow solvers. WIND-US is a well validated flow solver developed by NASA, AEDC, and Boeing. TBD is a new flow solver developed at ERAU. TBD is verified for laminar stagnation point heat transfer prediction and turbulent flowfield protection. The FOGO module is verified against an exact solution for transient one-dimensional heat flow in a semi-infinite solid

The coupled TBD-FOGO and WIND-FOGO conjugate heat-transfer solvers …

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 …

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 …

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 …

An Investigation Of The Dynamic Effects Of Flap Deflection On The Aerodynamic Characteristics Of An Airplane Wing Using Computational Fluid Dynamics, Alexander Moerchel

Master's Theses - Daytona Beach

Flaps are used to increase an airplane's lift and to adjust its stability and maneuverability. This study shows an application of STAR-CD, a commercial computational fluid dynamics (CFD) software, to an investigation of the dynamic effects of flap deflection on the lift, drag and moment coefficients, as well as on the location of the center of pressure. For this study, a plain flap was modeled with a moving mesh and was attached to a NACA 0012 airfoil and a wing of a general aviation aircraft for a 2D and 3D investigation, respectively. In addition, the flap deflection rates were varied …

Theoretical Analysis Of Transpiration Cooling Of A Liquid Rocket Thrust Chamber Wall, Philip A. Davis

Master's Theses - Daytona Beach

Transpiration cooling is a process that could reduce the overall weight of the cooling system of an actively cooled thrust chamber wall of a liquid rocket engine by up to 50% when compared to other active cooling techniques, increasing the thrust to weight ratio of the rocket engine. In this thesis, mathematical models and computer codes were developed for simulating the flow of a coolant and the transport phenomena in a transpiration cooled thrust chamber wall of a liquid rocket engine by treating the coolant in two ways: as an incompressible fluid and as a compressible fluid in local thermal …

Parameter Estimation Of Spacecraft Fuel Slosh Using Pendulum Analogs, Keith L. Schlee

Master's Theses - Daytona Beach

The nutation (wobble) of a spinning spacecraft in the presence of energy dissipation is a well-known problem in dynamics and is of particular concern for space missions. Its rate of growth is characterized by the Nutation Time Constant (NTC). For analytical prediction of the NTC, fuel slosh is often modeled using simple mechanical analogs such as pendulums or rigid rotors coupled to the spacecraft. Identifying model parameter values which adequately represent the sloshing dynamics is the most important step in obtaining a good NTC estimate. Currently, the identification of the model parameters is a laborious trial-and-error process in which the …

Filtering Of Acoustic Emission Data Through Principal Frequency Component Extraction, Justin O. Karl

Master's Theses - Daytona Beach

Rapid editing of acoustic emission (AE) data is required in order to make real-time acoustic emission flaw growth systems a viable testing method for materials and setups that contain noisy signals. It was hypothesized that extracting major frequency components from the acoustic emission signal would therefore provide a representative acoustic signature of the major waveforms occurring due to defect growth This research has verified that the aforementioned filtering technique does, in fact, extract a representative signal from the composite and metal specimens utilized herein These findings were verified both through visual analysis of the data as well as the low …

Impact Simulation And Analysis Of Sandwich Structures, Daewon Kim

Master's Theses - Daytona Beach

Impact damage on aircraft and spacecraft can be a severe problem that may cause catastrophic results. Several aerospace structures have been used to resist or absorb energy in the occasion of impact. Among these, a sandwich structure has advantages with high stiffness, strength to weight ratio, and its relatively cheap cost. However, finding the impact structural response of a sandwich structure, by performing experiments, has disadvantages. First, impact is a complex problem with a multi-parameter nature and many factors should be considered. Secondly, it is a destructive test and the test subject may be damaged during the test. On the …

Dynamics Of Nonlinear Diffusion Processes, Dustin A. Sipka

Master's Theses - Daytona Beach

The purpose of this thesis is to analyze nonlinear diffusion processes. In particular, some of the results arrived at by Newman and Sagan in their 1981 paper "Galactic Civilizations: Population Dynamics and Interstellar Diffusion," will be reproduced by different means. First, a thorough analysis of the linear diffusion equation will be performed in order to test a numerical algorithm that can solve the nonlinear diffusion equation and look at the processes of interest with sufficient accuracy. Once the algorithm is tested and shows good resolution it is used to solve the nonlinear equation. The post processing is then done to …

Design Optimization Of The First Stage Fan Blade Of A Low Bypass Turbofan Engine, Troy James Ramnath

Master's Theses - Daytona Beach

A procedure for solving for and analyzing the aerodynamics, thermodynamics, and blade geometry across the first stage rotor blade under an extreme set of conditions, while altering several design parameters, has been developed and applied. The conditions for which the analyses have been developed were designed for the use of, but not exclusively limited to the application of, military aircraft at altitude. The approach consists of solving for specific key performance parameters across the first stage rotor and analyzing their trends due to the effect of varying other parameters, such as the axial velocity at the rotor's trailing edge, circumferential …