Aerospace Engineering Commons^™

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 …

Design For Reliability In Microoptelectromechanical Systems (Moems), Abiodun Abiodun Fasoro

Mechanical and Aerospace Engineering Dissertations - Archive

Microelectromechanical systems (MEMS) is an enabling technology for miniaturization. MEMS consist of micron sized moving mechanical structures and electronics fabricated on a suitable substrate such as silicon. MEMS has found applications in virtually every aspect of human life, ranging from the automobile to the aerospace, and from the telecommunications to the consumer electronic industries. Technology integration has led to several subsets of MEMS e.g. microoptoelectromechanical systems (MOEMS), radio-frequency MEMS (RF MEMS), etc. Together with these added functionalities, by way of technology integration come additional issues and challenges never before experienced by packaging engineers. MEMS and MOEMS package requirements vary widely …

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 …

Incorporation Of Evidences Into An Intelligent Computational Argumentation Network For A Web-Based Collaborative Engineering Design System, Xiaoqing Frank Liu, Ekta Khudkhudia, Ming-Chuan Leu

Computer Science Faculty Research & Creative Works

Conflicts among the stakeholders are unavoidable in the process of collaborative engineering design. Resolution of these conflicts is a challenging task. In our previous research, a web based intelligent collaborative system was developed which provides decision-making support, using computational argumentation techniques. Enhancements were done to this system to incorporate the priorities of the stakeholders and to detect arguments that self conflict. As an effort to make this system more effective and more objective in the process of decision making, we develop a method to assess the effect of evidences in the argumentation network, using Dempster-Shafer theory of evidence and fuzzy …

Educational Outreach In The Arctic Regions?, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Educational Outreach in the Arctic Regions?" from April 24, 2008.

Flight Data Analysis And Simulation Of Wind Effects During Aerial Refueling, Timothy Allen Lewis

Mechanical and Aerospace Engineering Theses - Archive

This thesis presents an analysis of data obtained in an automated aerial refueling test flight conducted with a KC-135 as the tanker and a Learjet 25 as the surrogate receiver UAV. The purpose is to identify the wind induced by the tanker wake and its effect on the receiver aircraft. From the available flight data, a direct computation of the winds experienced by the tanker and receiver is carried out. The mean variation of the receiver wind is compared with the tanker wind when the receiver is at the observation and contact positions. This results in the identification of the …

Closed-Form Development Of A Family Of Higher Order Tetrahedral Elements Through The Fourth Order, Sara Elizabeth Mccaslin

Mechanical and Aerospace Engineering Dissertations - Archive

This research is concerned with the development and implementation of a family of tetrahedral elements through the fourth order. The straight-sided tetrahedral elements are developed in closed-form. This work investigates the efficiency of closed-form implementation of stiffness matrices and error estimators compared to numerical implementation. An additional objective is the compaction of closed-form source-code files which require as little storage space as possible, a more pronounced requirement at high p-levels. For the straight-sided elements through p-level 4, the stiffness matrix, equivalent nodal load vectors, and error estimators (based on nodal averaging) are developed using closed-form equations obtained through the use …

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 …

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 …

Adaptive Control Of Large Amplitude Nonlinear Free Vibrations Of Composite Shallow Shells Using System Identification And Self-Sensing Piezoelectric Actuators, Minseock Park

Mechanical & Aerospace Engineering Theses & Dissertations

A coupled structural-electrical nonlinear modal finite element formulation for anti-symmetrical laminated composite shallow shells with embedded piezoelectric sensors and actuators is presented for the suppression of large-amplitude nonlinear free vibrations. The triangular shallow shell finite element is utilized, which is developed &om an extension of the triangular Mindlin (MIN3) element with the improved shear correction factor. The system equations of motion are first derived in the physical structural-node degrees of freedom (DOF), However, numerical simulation in structural-node DOF is costly in computation due to the large size of system matrices, and the nonlinear terms have to be updated at each …

Uncertainty Assessment Of Aircraft Maintenance Times By Using Evidence Theory And Expert Judgment Elicitation, Huseyin Kudak

Engineering Management & Systems Engineering Theses & Dissertations

The goal of this study is to demonstrate the use of the Dempster-Shafer Theory of evidence as a decision aid to predict aircraft maintenance times during wartime operations using expert judgment elicitation. Increased precision in time estimation enables the jet engine aircraft maintenance facility commander to make more accurate decisions for the Air Force's wartime tactical operations allowing the commander to gain a decisive advantage. A questionnaire was designed to elicit judgments from experts in the Aircraft Maintenance Facility (AMF) to investigate maintenance times of the major failure modes (Ignition, Fuel, and Electrical). Results of the expert judgment elicitation were …

Impact Of Airline Business Models On Fuel Efficiency Of Aircraft Operations In The National Airspace System (Nas), Trisha R. Khetia

Mechanical & Aerospace Engineering Theses & Dissertations

This is a documentation of the research that has been conducted by T. Khetia of the Batten College of Engineering and Technology at Old Dominion University in Norfolk, Virginia. The report summarizes fuel efficiency studies of aircraft operations in the National Airspace System (NAS).

This research was conducted to analyze the Hub-and-Spoke (H&S) system operations in the NAS and how a change in the balance of the H&S system would affect fuel efficiency metrics in the NAS. Several fuel metrics were calculated during the research in order to find out which metric would best represent the desired operation of the …

Tightly Integrating Optical And Inertial Sensors For Navigation Using The Ukf, Sedat Ebcin

Theses and Dissertations

The motivation of this research is to address the benefits of tightly integrating optical and inertial sensors where GNSS signals are not available. The research begins with describing the navigation problem. Then, error and measurement models are presented. Given a set of features, a feature detection and projection algorithm is developed which utilizes inertial measurements to predict vectors in the feature space between images. The unscented Kalman filter is applied to the navigation system using the inertial measurements and feature matches to estimate the navigation trajectory. Finally, the image-aided navigation algorithm is tested using a simulation and an experiment. As …

Houchin, Roy Franklin, Ii, B. 1954 (Sc 1602), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scans (Click on "Additional Files" below) for Manuscripts Small Collection 1602. Typescripts of interviews conducted by Roy Franklin Houchin, II with: Joe Richardson regarding early aviation and the aerospace industry, Douglas Campbell regarding his World War I aerial combat experience, and Bob Ford regarding World War I military uniforms. Includes Houchin family information.

The Concept Design Of A Split Flow Liquid Hydrogen Turbopump, Michael A. Arguello

Theses and Dissertations

An initial design of a split flow liquid hydrogen turbopump for the Dual Expander Aerospike Nozzle (DEAN) upper stage engine was completed. The engine nozzle is an annular aerospike. The engine cycle requires a combustion chamber pressure of 1,740 psia. The DEAN is designed to deliver 57,200 lbf of thrust and 472 seconds of Isp. The turbopump design was completed using a meanline software tool. The design consists of a single piece rotor, with a two-stage pump and radial inflow turbine. The turbopump flow rates are 15.1 and 7.55 lbm/s into the first and second stage, respectively. The first and …

Analysis Of Multi-Layered Materials Under High Velocity Impact Using Cth, Jason K. Lee

Theses and Dissertations

Multi-layer armor containing ceramic and metallic layers has become more common in the past two decades. Typically, ceramics have high compressive strength which combined with their low density make them highly desirable for armor applications. This research effort numerically simulates high velocity impact of cylindrical projectiles on multi-layer metallic and ceramic targets of finite thickness. The impact of the projectile occurs normal to the surface of the target. The projectiles used are made of either S7 tool steel or tungsten. The targets consist of either rolled homogeneous armor, 4340 steel and boron carbide ceramic or rolled homogeneous armor and boron …

Computational Design Of Upperstage Chamber, Aerospike, & Cooling Jacket For Dual-Expander Rocket Engine, David F. Martin Ii

Theses and Dissertations

To increase the performance of the current US satellite launch capability, new rocket designs must be undertaken. One concept that has been around since the 50s but yet to be utilized on a launch platform is the aerospike, or plug nozzle. The aerospike nozzle concept demonstrates globally better performance compared to a conventional bell nozzle, since the expansion of the jet is not bounded by a wall and therefore can adjust to the environment by changing the outer jet boundary. A dual-expander aerospike nozzle (DEAN) rocket concept would exceed the Integrated High Payoff Rocket Propulsion Technology initiative (IHPRPT) phase three …

On-Board Thermal Management Of Waste Heat From A High-Energy Device, Nathan D. Klatt

Theses and Dissertations

The use of on-board high-energy devices such as megawatt lasers and microwave emitters requires aircraft system integration of thermal devices to either rid waste heat or utilize it in other areas of the aircraft. Non-chemical lasers are among the most challenging applications due to the low cooling temperature requirements (67 °F) and high waste heat generation times of order 20 s. (Microwave devices will be cooled at 157.7 °F.) One plan calls for the rapidly generated waste energy to be stored prior to peripheral utilization, with subsequent removal of the heat over a 5-10 minute span. A method is presented …

Optimal Guidance Of A Relay Mav For Isr Support Beyond Line-Of-Sight, John H. Hansen

Theses and Dissertations

This thesis developed guidance laws to optimally position a relay Micro-UAV (MAV) to provide an operator with real-time Intelligence, Surveillance, and Reconnaissance (ISR) by relaying communication and video signals when there is no line-of-sight between the operator at the base and the rover MAV performing the ISR mission. The ISR system consists of two MAVs, the Relay and the Rover, and a Base. The Relay strives to position itself to minimize the radio frequency (RF) power required for maintaining communications between the Rover and the Base, while the Rover performs the ISR mission, which may maximize the required RF power. …

Finite Element Simulation Methods For Dry Sliding Wear, Aaron J. Chmiel

Theses and Dissertations

The Holloman High Speed Test Track is a rocket sled track for testing at hypersonic velocities. However, there are customers that desire to test at even greater velocities. In order to achieve higher velocities there are several phenomena that must be overcome. One important phenomenon is wear of the shoe that holds the sled on the rail. This research is a look at the feasibility of using finite element analysis to predict the wear of the shoe during a test run down the track. Two methods are investigated, one is a macro-scale, incremental method utilizing traditional wear equations from Archard, …

Filtered Rayleigh Scattering Measurements In A Buoyant Flow Field, Steven M. Meents

Theses and Dissertations

Filtered Rayleigh Scattering (FRS) is a non-intrusive, laser-based flow characterization technique that consists of a narrow linewidth laser, a molecular absorption filter, and a high resolution camera behind the filter to record images. Gases of different species have different molecular scattering cross-sections that become apparent as they pass through the interrogating laser light source, and this difference is used to discriminate between the different gaseous components. This study focuses on the behavior of a buoyant helium jet exiting horizontally into ambient air, and more specifically this jet’s tendency to form side lobes that are discharged from the core fluid under …

A Static Aeroelastic Analysis Of A Flexible Wing Mini Unmanned Aerial Vehicle, Nathan A. Pitcher

Theses and Dissertations

The static aeroelastic behavior of the Nighthawk mini unmanned aerial vehicle is examined using a combined experimental and computational approach. Three wings are examined. In order of increasing stiffness they are: a flexible wing, a stiff wing, and a fictitious rigid wing with zero deflection. Photogrammetry is used during wind tunnel testing to measure the average deflected shape of the flexible and stiff wings during flight. The independent variables during wind tunnel tests are angle of attack (ranging from −5.1° through 13.4°) and velocity, which is 20 mph, 30 mph, and 40 mph. Roll angle and yaw angle are control …

Biomimetic Micro Air Vehicle Testing Development And Small Scale Flapping-Wing Analysis, Craig E. Svanberg

Theses and Dissertations

The purpose of this research was to develop testing methods capable of analyzing the performance of a miniature flapping-wing mechanism that can later be adapted to a biomimetic micro air vehicle (MAV). Three small scale flapping mechanisms capable of single plane flapping, flapping with active pitch control, and flapping/pitch with out-of-plane movement were designed using SolidWorks. The flapping-only model was fabricated on an Objet Eden 500V 3-dimensional printer. The flapping mechanism was mounted on an aluminum plate supported by air bearings, and thrust was measured for a variety of conditions. The testing was conducted using wings composed of carbon fiber …

Analyzing Carbohydrate-Based Regenerative Fuel Cells As A Power Source For Unmanned Aerial Vehicles, Olek Wojnar

Theses and Dissertations

Based on current capabilities, we examine the feasibility of creating a carbohydrate-based regenerative fuel cell (CRFC) as the primary power source for unmanned aerial vehicles (UAV) for long endurance missions where station keeping is required. A CRFC power system is based on a closed-loop construct where carbohydrates are generated from zooxanthellae, algae that create excess carbohydrates during photosynthesis. The carbohydrates are then fed to a carbohydrate fuel cell where electric power is generated for the UAV’s propulsion, flight control, payload, and accessory systems. The waste products from the fuel cell are used by the zooxanthellae to create more carbohydrates, therefore …

Minimizing Secular J2 Perturbation Effects On Satellite Formations, Jonathan W. Wright

Theses and Dissertations

The purpose of this thesis is to examine the secular effects of the J₂ oblateness perturbation on close proximity satellites. The main objective is to analyze the deputy’s position and velocity with respect to the chief and adjust the initial conditions of the deputy in an attempt to minimize the secular effects of J₂ perturbations. Previous work has provided a method of obtaining a closed form solution for J₂ invariance with co-planar orbits. Therefore, this work will primarily consider deputy orbits that experience motion outside of the chief’s orbital plane. Upon determining the required initial conditions, the …

Modeling Gps Satellite Orbits Using Kam Tori, Rachel M. Derbis

Theses and Dissertations

Global Positioning System (GPS) satellite orbits are modeled using Kolmogorov, Arnold, Moser (KAM) tori. Precise Global Positioning System satellite locations are analyzed using Fourier transforms to identify the three basis frequencies in an Earth Centered, Earth Fixed (ECEF) rotating reference frame. The three fundamental frequencies are 1) the anomalistic frequency, 2) a combination of earth’s rotational frequency and the nodal regression rate, and 3) the apsidial regression rate. A KAM tori model fit to the satellite data could be used to predict future satellite locations. This model would allow rapid determination with fewer computational requirements than the typical method of …

Thermal Characterization Of A Hall Effect Thruster, Alex M. Bohnert

Theses and Dissertations

The thermal characteristics of a Hall thruster directly influence thruster and spacecraft design. High temperatures affect the magnetic coil capabilities and cause higher insulator erosion rates, influencing both thruster performance and lifetime. The Hall thruster transfers heat through both radiation and conduction, and the spacecraft must handle this additional thermal energy. An infrared camera provides a non-intrusive method to analyze the thermal characteristics of an operational Hall thruster. This thesis contains the thermal analysis of a Busek Co. Inc. 200 W Hall thruster, using a FLIR ThermaCAM SC640 infrared camera. The Space Propulsion Analysis and System Simulator Laboratory at the …

Crew Exploration Vehicle (Cev) Skip Entry Trajectory, Emre Kaya

Theses and Dissertations

This research effort develops a program using MATLAB® to solve the equations of motion for the atmospheric reentry of the Crew Exploration Vehicle (CEV) which is assumed to be in the phase of a lunar return trajectory that could be initiated any time during the mission. The essential reason for this research is to find a solution for the problem of an unplanned lunar return in addition to the normal procedures. Unlike Apollo type missions, the CEV would still be able to land on any preplanned available landing sites without any additional delay. In Apollo type missions, the return phase …

Determination Of Static And Dynamic Stability Derivatives Using Beggar, Michael E. Bartowitz

Theses and Dissertations

The static and dynamic pitch and roll stability derivatives of a finned, axisymmetric missile known as the Basic Finner were examined using a Computational Fluid Dynamics (CFD) approach. Stability derivatives are used to characterize vehicle motion, and knowledge of them is critical to the design of stable uncontrolled vehicles and control systems for controlled vehicles. Using CFD to characterize the motion of new munition designs has the potential to improve overall performance and reduce research and testing costs. The present analysis simulated forced oscillation and free oscillation of the Basic Finner model using the Air Force SEEK EAGLE Office's Beggar …