Engineering Commons^™

Effects Of Filament Reinforced Plexiglass Pressure Vessel On Failure Analysis, Faysal A. Kolkailah, Eltahry Elghandour, Luis J. Valenzuela

Aerospace Engineering

This paper presents an investigation into the effect of reinforcing a Plexiglas tube with fiberglass/epoxy threads wound at different angles. This paper shows an experimental analysis approach to find the ultimate failure pressure of these vessels. The properties of the Plexiglas, fiberglass, orientation (wind) angle and the matrix were taken into account to determine their effects on the ultimate failure pressure of the vessels. Mandrels were wound at +/- 75, +/- 65, and +/- 55 deg, and specimen were cut out from each to 19.05 cm long, 7.62 cm inner diameter and outer diameters dependent of the wind angle. The …

The Study Of Empirical Methodology To Observe Damping Characteristics Of Various Laminate Composite Plates, Faysal A. Kolkailah, Eltahry Elghandour, Taikha Oh, Jason Bolosan

Aerospace Engineering

Modifying the stiffness of the structure is usually not a feasible solution to enhancing damping, since changing the stiffiless effects the natural frequency changing and eventually the condition of resonance will be reached. Therefore, one of the recommendatory ways to reduce the response on structural elements is to improve damping characteristics. The objectives of this study are to present empirical methodology to detect damping characteristics of structural elements, and determine the optimal location of sensor to detect structural failure by analyzed data from both experimental and numerical analysis. Using orthotropic composite plates comprised of 977-2 Carbon fiber/IM7 epoxy, the natural …

First Casi/Utias Workshop On Low-Cost Space System: University Of Toronto, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "First CASI/UTIAS Workshop on Low-Cost Space System: University of Toronto" from May 4, 2001.

Cybersecurity Considerations With The Increasing Uses Of Small Unmanned Aircraft Systems (Suas) Or Drones, Matthew Kucharek, Stanley Mierzwa

Center for Cybersecurity

The effort to produce this information resource results from a collaborative effort between the Bergen County Technical Schools (high school), through the advisor Andrea Buccino, and a cybersecurity expert mentor. High school senior members of this learning partnership are provided with an interactive learning experience. They gain an increase and knowledge in a particular area of study while under the topical guidance of a mentor. In this example, the high school senior is pursuing coursework in Aerospace Engineering, and this was combined with the focus of cybersecurity to expand the students’ cross-discipline knowledge. This collaborative work was done virtually, given …

University Of Texas Austin: Stanford Space Systems Program, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "University of Texas Austin: Stanford Space Systems Program" from April 30, 2001.

Visiting Committee Review: Spacecraft Program, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Visiting Committee Review: Spacecraft Program" from April 26, 2001.

Student Space Systems Program At Stanford Univerity: The Aerospace Corporation, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Student Space Systems Program At Stanford Univerity: The Aerospace Corporation" from April 6, 2001.

The Airline Quality Rating 2001, Brent D. Bowen, Dean Headley, Uno Aviation Institute

Faculty Books and Monographs

UNOAI Report 01-2

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, Airline Quality Rating 2001, reflects monthly Airline Quality Rating scores for 2000. AQR scores for the calendar year 2000 are based on 15 elements that focus on airline performance areas important to air travel consumers.

The Airline Quality Rating 2001 is a summary of month-by-month quality ratings for the ten major U.S. airlines operating during 2000. Using the Airline Quality Rating system of weighted averages and monthly performance …

Solving Nonlinear Aeronautical Problems Using The Carleman Linearization Method, Brian William Gaude

Master's Theses - Daytona Beach

Many problems in aeronautics can be described in terms of nonlinear systems of equations. Carleman developed a technique to linearize such equations that could lead to analytical solutions of nonlinear problems. Nonlinear problems are difficult to solve in closed form and therefore the construction of such solutions is usually nontrivial. This thesis will apply the Carleman linearization technique to three model problems: a two-degree of-freedom (2DOF) ballistic trajectory, Blasius' boundary layer, and Van der Pol's equation and evaluate how well the technique can adequately approximate the solutions of these ordinary differential equations.

Optimization Of Flow Quality In The Test Section Of The 30-Inch X 40- Inch Subsonic Tunnel, Ahmed F. Elnenaey

Master's Theses - Daytona Beach

The purpose of this study is to optimize the flow quality inside the 30-inch x 40-inch subsonic wind tunnel. The tunnel is an open circuit with its inlet positioned adjacent to the side door of the lab; forcing the air to make a ninety degrees turn entering the tunnel. The flow suffered from two main deficiencies, high level of turbulence and slightly unsteady flow with a non-uniform velocity distribution across the test section. By utilizing a hot-film anemometer system and a total pressure rake, turbulence and velocity distribution data were obtained. Rounded corners and a turning vane were installed in …

Development And Testing Of A Cfd-Based Optimization System For Axially Symmetric Rocket Nozzles, John-Paul Shebalin

Mechanical & Aerospace Engineering Theses & Dissertations

A software system has been developed to optimize rocket nozzle shapes for maximizing their performance. It has been established in the literature that one can use computer-based optimization with the parabolized Navier-Stokes equations to optimize the dimensions of low Reynolds number rocket nozzles-micronozzles. The Nozzle Optimization System described herein uses the full Navier-Stokes equations to optimize any axially symmetric rocket nozzle for which a converged solution can be obtained.

Four nozzles are optimized using this system-conical and contoured micronozzles and conical and contoured Space Transportation System(STS)-class nozzles. The optimum cone angle (O_cone) for the conical micronozzle was …

On Multifunctional Collaborative Methods In Engineering Science, Jonathan B. Ransom Sr.

Mechanical & Aerospace Engineering Theses & Dissertations

Engineers are challenged to produce better designs in less time and for less cost. Hence, to investigate novel and revolutionary design concepts, accurate, high-fidelity data must be assimilated rapidly into the design, analysis and simulation process. This data assimilation should consider diverse mathematical modeling and multi-discipline interactions necessitated by concepts exploiting advanced materials and structures. Integrated high-fidelity methods with diverse engineering applications provide the enabling technologies to assimilate these high-fidelity, multi-disciplinary data rapidly at an early stage in the design. These integrated methods must be multifunctional, collaborative and applicable to the general field of engineering science and mechanics.

Multifunctional methodologies …

Enhancing Commercial Aircraft Survivability Via Active Venting, Roger L. Veldman

Dissertations

A new technique for enhancing aircraft safety in the event of an on-board explosion was studied. The method under study employs deployable vent panels located on the fuselage which are activated by an array of pressure sensors in the aircraft interior. In the event that an explosion is detected, appropriate vent panels are rapidly released from the aircraft. This approach seeks to provide timely relief of explosive pressures within an aircraft to prevent catastrophic structural failure.

In this study, the approximate time scale of an explosive detonation and the subsequent sensing and electronic processing was determined. Then, the actuation response …

Adaptive And Reconfigurable Flight Control, Yih Shiun Huang

Theses and Dissertations

An indirect adaptive and reconfigurable flight control system is developed. The three-module controller consists of: (1) a system identification module, (2) a parameter estimate smoother, and (3) a proportional and integral compensator for tracking control. Specifically: (1) The identification of a linear discrete-time control system's open-loop gain is addressed. The classical Kalman filter theory for linear control systems is extended and the control system's state and loop gain are jointly estimated on-line. Explicit formulae for the loop gain's estimate and estimation error covariance are derived. The estimate is unbiased and the predicted covariance is reliable. (2) An adaptive smoother is …

Turbine Blade Surface Roughness Effects On Shear Drag And Heat Transfer, Jess W. Drab

Theses and Dissertations

This work used scaled samples of actual turbine blade surfaces to characterize correlations between turbine surface roughness, friction coefficient, and convective heat transfer rate-parameters which affect an engine's efficiency and the blade's lifespan. For erosion/deposits, friction coefficients up to 250 times higher and convective heat transfer coefficients of up to 150 times higher were found when compared to a flat plate baseline. Other roughness types (pitting and fuel deposits) yielded less dramatic results. These results did not follow existing friction coefficient-to-heat transfer coefficient correlations, such as the Reynolds analogy. While these analytical and empirical correlations hold for flat plates, they …

Quality Initiatives In The Air Force Development Of Reusable Launch Vehicles, Charles S. Galbreath

Theses and Dissertations

This thesis identifies useful tools and techniques available to aid the Air Force development of a reusable launch vehicle (RLV). These tools are identified by comparing traits found within the Lean Aerospace Initiative, Six Sigma and systems engineering. While identified specifically for the RLV effort, these tools and techniques will be of use to many development programs. Historical perspectives of both RLV development efforts within the Air Force and origins of modern quality teachings are provided to establish a common foundation of knowledge, upon which, further analysis can be conducted. This thesis, also, summarizes the current RLV effort within the …

Prediction Of Pilot Induced Oscillations (Pio) Due To Activator Rate Limiting Using The Open-Loop Onset Point (Olop) Criterion, Gregory P. Gilbreath

Theses and Dissertations

Rate limiting has been a causal or contributing factor for Pilot Induced Oscillations (PIO). As part of the joint Air Force Institute of Technology/Test Pilot School (AFIT/TPS) program, an examination of the Open-Loop Onset Point (OLOP) criterion, developed by DLR German Aerospace, was conducted to see if it could predict PIO due to rate limiting and to evaluate its potential as a design tool. The criterion was applied to three previous flight test programs involving rate limiting. Findings from this analysis led to the HAVE OLOP flight test which was flown on the NF-16D Variable Stability In-flight Simulator Test Aircraft …

Cooperative Behavior Schemes For Improving The Effectiveness Of Autonomous Wide Area Search Munitions, Daniel P. Gillen

Theses and Dissertations

The problem being addressed is how to best find and engage an unknown number of targets in unknown locations using multiple autonomous wide area search munitions. In this research cooperative behavior is being investigated to improve the overall mission effectiveness. A simulation was used to emulate the behavior of autonomous wide area search munitions and measure their overall expected performance. This code was modified to incorporate the capability for cooperative engagement based on a parameterized decision rule. Using Design of Experiments and Response Surface Methodologies, the simulation was run to achieve optimal decision rule parameters for given scenarios and to …

Analysis Of The Application Of A Triggered Isomer Heat Exchanger As A Replacement For The Combustion Chamber In An Off-The-Shelf Turbojet, Carl R. Hartsfield

Theses and Dissertations

The objective of this research was to evaluate the feasibility of using the triggered decay of a radioactive isomer in a solid-state heat exchanger to power a gas turbine engine. Primary performance measures were stagnation temperature increase and stagnation pressure drop across the heat exchanger. Analysis was performed using commercial software, and explored three types of heat exchanger: concentric tubes, radial fins with constant spacing, and radial fins with constant thickness. All met or exceeded performance of the baseline J-57 turbojet engine at static sea level conditions. A single configuration of heat exchanger, using concentric tubes, was evaluated at typical …

Development And Testing Of A Multiple Filter Approach For Precise Dgps Positioning And Carrier-Phase Ambiguity Resolution, Paul E. Henderson

Theses and Dissertations

The most precise relative positioning obtained using differential GPS depends on accurately determining carrier-phase integer ambiguities. To achieve high precision, many current static and kinematic algorithms use a floating-point solution until enough information becomes available to fix the carrier-phase ambiguities accurately. A mew method is presented that uses a multiple model Kalman filter to resolve the carrier-phase integer ambiguities. This method starts with the floating-point results, yet smoothly and rapidly attains the precision of the correct fixed-integer solution, eliminating the need to decide when to switch from the floating to the fixed-integer solution. This method is based on a theoretically …

A Study Of Linear Vs. Nonlinear Control Techniques For The Reconfiguration Of Satellite Formations, David J. Irvin Jr.

Theses and Dissertations

This thesis investigates several linear and nonlinear feedback control methods for satellite formation reconfigurations and compares them to a near optimal open loop, discrete-time, impulsive maneuver. The reconfigurations are done in terms of a set of relative parameters that define an orbit about the leader satellite (or center reference position if a leader satellite does not exist at the center of the formation). The purpose of the study is two-fold, to compare the control usage of continuous feedback control methods versus a discrete bum method and to determine if nonlinear control techniques offer significant improvement over more conventional linear control …

Desktop Computer Programs For Preliminary Design Of Transonic Compressor Rotors, Brian C. Mcdonald

Theses and Dissertations

A need exist for correlation-based desktop computer programs that predict the flow through transonic compressor rotors with nominal computational time and cost. Modified versions of two desktop computer programs, BOWSHOCK and TRANSROTOR, were used to perform a parametric study on a modem compressor rotor. BOWSHOCK calculates the exit flow properties of a supersonic streamtube through a user-defined compressor rotor. TRANSROTOR calculates flow properties at three stations in a user-defined compressor stage. Modifications to TRANSROTOR included the incorporation of a recently published rotor loss model. Baseline and modified TRANSROTOR versions were run with two modern transonic compressor blades. Results were compared …

Air Vehicle Optimal Trajectories For Radar Exposure Minimization, Michael C. Novy

Theses and Dissertations

This study addresses the problem of analyzing the single vehicle path planning problem for radar exposure minimization. The calculus of Variations and optimal control are applied to formulate the cost function and numerical algorithms are used to solve for the optimal paths. Cost sensitivity to path length is analyzed for flight against one radar; a second radar is then included in the formulation and the optimal path for flight between the radars is found for cases of equal and unequal radar power. The costs of the optimal path, direct path, and Voronoi diagram-generated paths are compared. Results indicate low sensitivity …

Phugoid Damping Control, Nicolas J. Schindeler

Theses and Dissertations

A novel phugoid damping control design methodology is developed, based on the use of wind axes and a point-mass aircraft model. The state variables are air speed, flight path angle, and heading angle, the control variables are thrust setting, angle of attack, bank angle, and sideslip angle, and the command signals are airspeed, flight path angle, and heading angle or heading rate. All the variables and parameters are nondimensionalized. A multivariable set point controller is developed which consists of: (1) a trim calculation-based nonlinear feed-forward control computer; thus, given a commanded new trim state (air speed, flight path angle, and …

Concept Exploration Of An Australian Indigenous Space Launch Capability, Anthony J. Rogers

Theses and Dissertations

This thesis explores the possibility of establishing an Australian indigenous space launch capability through developing and examining an Australian space launch program model. The model is based around launch site location, vehicle design, program duration, and the percentage Australian indigenous input into the program. The model was optimised in an effort maximise the benefits of such a capability, namely political prestige, security and in country technological base, while minimising the program's overall cost.

Computational Investigation Of Aeromechanical Hcf Effects In A Compressor Rotor, Andrew L. White

Theses and Dissertations

High-Cycle Fatigue is a major problem facing the gas turbine industry today. It has been investigated by many researchers, using many different methods. Due to its highly complex nature, designers still do not have adequate tools to accurately predict the onset of high-cycle fatigue. A three-dimensional Navier-Stokes program was used to perform a study of the unsteady aerodynamics on a compressor rotor. The effect of aerodynamic detuning on the forced response of a rotor blade was compared to a baseline tuned rotor case. Detuning consisted of a ten percent decrease in circumferential spacing between alternate pairs of blades. The high-cycle …

Estimation Of Relative Satellite Formation Elements In Near Circular Orbits, Ralph E. Bordner Iii

Theses and Dissertations

Precise relative position determination of satellite formation elements in near circular orbits is the focus of this thesis. A Bayes filter is used for the estimator with the dynamics solution obtained by solving the time periodic, linearized system via Floquet theory. This approach is similar to that of the traditional Clohessy-Wiltshire treatment, however much more of the system's behavior is retained by using a linear, time periodic system. The dynamics model includes all zonal harmonics of the Earth as well as sectoral, tesseral, and air drag perturbations. The filter algorithm was fed three types of simulated measurements: relative Carrier-Phases Differential …

Rigex: Preliminary Design Of A Rigidized Inflatable Get-Away-Special Experiment, John D. Disebastian Iii

Theses and Dissertations

As space structures grow in size and complexity, their weight and cost increase considerably. The use of inflatable and rigidizable structures offers drastic improvements in all areas of spacecraft design. The goal of this experiment is to verify and validate ground testing of inflation and rigidization methods for inflatable space structures. The Rigidized Inflatable Get-Away-Special Experiment is an autonomous, self-contained space shuttle experiment that will inflate and rigidize several structures. After inflation, the experiment will perform a structural analysis by exciting the rigidized structures and collecting vibration data. A systems engineering approach is utilized to make design decisions based on …

Solar Radiation Pressure Modeling Issues For High Altitude Satellites, Dayne G. Cook

Theses and Dissertations

Current satellite orbit propagation techniques employ a solar radiation pressure model that makes simplifying assumptions concerning the satellite and its orbital geometry. Solar radiation pressure, a non-gravitational perturbation, significantly affects satellite motion at high altitudes. The model currently in use by the Air Force for orbit determination includes the following assumptions: a constant cross-sectional area projected to the Sun, cylindrical Earth shadow for eclipse, and specular reflection. In reality, the satellite's cross-sectional area with respect to the Sun constantly changes, the Earth's shadow is conical, and reflection is both specular and diffuse. Additionally, the solar flux received at the Earth …

Modification Of Position And Attitude Determination Of A Test Article Through Photogrammetry To Account For Structural Deformation, Sean A. Krolikowski

Theses and Dissertations

This study improved the current method of position and attitude determination to account for structural deformation of the wind tunnel test article due to aerodynamic loading. To account for deformation, parabolic bending and linear twisting coefficients were added into the Levenberg-Marquardt multi-parameter solver. By accounting for deformation, the accuracy of position and attitude determination was greatly improved. This study also takes a qualitative look at the optimum number of wind tunnel cameras and model targets. Optimal configuration was found to be around 50 targets and 2 cameras offset by 90 degrees.