Aerospace Engineering Commons^™

Volterra Series Approximation For Multi-Degree Of Freedom, Multi-Input, Multi-Output, Aircraft Dynamics, Alexander J. Chen

Mechanical & Aerospace Engineering Theses & Dissertations

An analytical model of a second order system is extended from a single-axis framework, to a multi-axis, multi-degree of freedom framework for a multiple input, multiple output system. This mathematical model is built from the variational approach of the Volterra series representation of nonlinear systems. The new representation describes the second order, oscillatory natural modes of a system, and shows how to organize the Volterra terms in intuitive ways. The constructed mathematical model aims to establish an organization of the Volterra kernels to allow for analytical cause and effect type analysis on system behavior.

To demonstrate the accuracy of the …

Case Study: Cooling Channels For Material Testing Applications Using Laser Powder Bed Fusion, Benjamin M. Doane, Ryan P. O'Hara, K. Liu, Carl R. Hartsfield

Faculty Publications

Additive Manufacturing continues to gain a reputation as a key technology that will have a major impact on all aspects of mechanical engineering. The United States Air Force’s (USAF) Air Force Institute of Technology (AFIT), based in Dayton, Ohio, has expanded its AM-focused education and R&D capabilities with the purchase of a Laser Powder Bed Fusion system from Germany’s Concept Laser.

Design And Implementation Of An Artificial Neural Network Controller For Quadrotor Flight In Confined Environment, Ahmed Mekky

Mechanical & Aerospace Engineering Theses & Dissertations

Quadrotors offer practical solutions for many applications, such as emergency rescue, surveillance, military operations, videography and many more. For this reason, they have recently attracted the attention of research and industry. Even though they have been intensively studied, quadrotors still suffer from some challenges that limit their use, such as trajectory measurement, attitude estimation, obstacle avoidance, safety precautions, and land cybersecurity. One major problem is flying in a confined environment, such as closed buildings and tunnels, where the aerodynamics around the quadrotor are affected by close proximity objects, which result in tracking performance deterioration, and sometimes instability. To address this …

Development Of A Static Aeroelastic Database Using Nastran Sol 144 For Aircraft Flight Loads Analysis From Conceptual Design Through Flight Test, Ryan M. Haughey

Theses and Dissertations

This paper describes a method for predicting aircraft aerodynamic and inertial loading on a structural finite element model, (FEM) based on static aeroelastic coefficients. These coefficients are computed via interpolated spline methods within NASTRAN Solution 144 (static aeroelastic solution) and the “TRIM” module to connect the doublet-lattice model (DLM) and the structural finite element model for a coupled solution. The database is created by selecting key breakpoints where linear interpolation techniques can be utilized to develop and predict static aeroelastic coefficients for the prediction of any aircraft state for a given transient solution. This method is applicable from conceptual design …

Experimental Investigation Of A New Spiral Wingtip, Naseeb Ahmed Siddiqui, Mohammed Aldheeb, Waqar Asrar, Erwin Sulaeman

International Journal of Aviation, Aeronautics, and Aerospace

Experiments on the relative merits and demerits of slotted wingtips mimicking a bird’s primary feathers have been performed. The real emargination length of feather tips, their flexibility and curved shapes during cruise are considered in the present study. The experiments were performed at a Reynolds number of 3.7 x 10⁵ on a symmetric flat plate half wing of aspect ratio 3. Lift, drag and pitching moments were measured using a six component aerodynamic balance. Four different shapes inspired by bird primary feathers have been analysed. The rigid curved tip performed the best increasing the L/D ratio by 20%. This …

Nanosatellite Space Experiment, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A report written by Professor Bob Twiggs titled "Nanosatellite Space Experiment" from March 30, 2018.

Task 10: Research An Alternative Instructional Design Model, Steven Hampton, Jan G. Neal, Luis A. Ramirez, Dustin R. Talkington, Jma Solutions, Inc.

Publications

Under authority of the Federal Aviation Administration (FAA), the Center of Excellence (COE) Technical Training Human Performance (TTHP) Task 10 research team has prepared a comprehensive technical report and an executive summary for the Air Traffic Organization (ATO) concerning the instructional development (ID) of occupational education and training for Air Traffic (AT) controllers and Technical Operations (TO) technicians. Research included:

• Front-end analysis of available FAA courses and government furnished information (GFI), including course-development documentation and associated guidance, policies, and regulations.

• Structured and semi-structured data-gathering techniques in cooperation with Instructional Systems Specialists (ISS), ISS Managers, and Requirements personnel.

• …

The Challenges Of Processing Kite Aerial Photography Imagery With Modern Photogrammetry Techniques, Jeremy W. Aber, Tyler A. Babb

International Journal of Aviation, Aeronautics, and Aerospace

Kite Aerial Photography (KAP) is a traditional method of collecting small-format aerial photography used for work in a variety of fields. This research explored techniques for processing KAP imagery with a focus on some of the challenges specific to photo processing. The performance of multiple automated image compositing programs was compared using a common set of 29 images. Those packages that were based on a photogrammetry approach outperformed the non-photogrammetric software, and generated similar levels of quality to one another. While all three photogrammetric packages produced satisfactory output, each had unique challenges.

Manufacturing Process Simulation – On Its Way To Industrial Application, Dennis Otten, Tobias A. Weber, Jan-Christoph Arent

International Journal of Aviation, Aeronautics, and Aerospace

Manufacturing process simulation (MPS) has become more and more important for aviation and the automobile industry. A highly competitive market requires the use of high performance metals and composite materials in combination with reduced manufacturing cost and time as well as a minimization of the time to market for a new product. However, the use of such materials is expensive and requires sophisticated manufacturing processes. An experience based process and tooling design followed by a lengthy trial-and-error optimization is just not contemporary anymore. Instead, a tooling design process aided by simulation is used more often. This paper provides an overview …

Wall-Modeled Large Eddy Simulation Of A Three-Dimensional Shock-Boundary Layer Interaction, Nicholas J. Marco

Theses and Dissertations

The direct simulation of turbulent flows is prohibitive at high Reynolds numbers; thus, methods such as RANS and LES are used. However, these methods still require a large number of cells near a solid boundary. To circumvent this issue, a Wall-Modeled Large Eddy Simulation (WM-LES) can be used. Of interest is how these wall models perform in comparison to a Wall-Resolved Large Eddy Simulation (WR-LES) and experimental results of a shock turbulent boundary layer interactions (STBLI) and specifically, whether equilibrium wall models are sufficient to resolve the oscillatory and hence non-equilibrium nature of these flows or whether a non-equilibrium model …

Integrity Monitoring For Automated Aerial Refueling: A Stereo Vision Approach, Thomas R. Stuart

Theses and Dissertations

Unmanned aerial vehicles (UAVs) increasingly require the capability to y autonomously in close formation including to facilitate automated aerial refueling (AAR). The availability of relative navigation measurements and navigation integrity are essential to autonomous relative navigation. Due to the potential non-availability of the global positioning system (GPS) during military operations, it is highly desirable that relative navigation can be accomplished without the use of GPS. This paper develops two algorithms designed to provide relative navigation measurements solely from a stereo image pair. These algorithms were developed and analyzed in the context of AAR using a stereo camera system modeling that …

Military Application Of Aerial Photogrammetry Mapping Assisted By Small Unmanned Air Vehicles, Kijun Lee

Theses and Dissertations

This research investigated the practical military applications of the photogrammetric methods using remote sensing assisted by small unmanned aerial vehicles (SUAVs). The research explored the feasibility of UAV aerial mapping in terms of the specific military purposes, focusing on the geolocational and measurement accuracy of the digital models, and image processing time. The research method involved experimental flight tests using low-cost Commercial off-the-shelf (COTS) components, sensors and image processing tools to study key features of the method required in military like location accuracy, time estimation, and measurement capability. Based on the results of the data analysis, two military applications are …

Stabilized Rpa Flight In Building Proximity Operations, Michael M. Kaniut

Theses and Dissertations

The thesis seeks a solution to the requirement for a highly reliable and capable Unmanned Air Vehicle (UAV) to support a wide array of missions and applications that require close proximity flight to structures. The scope of the project includes the drafting of a concept of operations (CONOPs) describing how the mission requirements might be met using the sensor, operators, and air vehicle described here in. The demonstration of the wall-following section of that CONOPs is performed by cart testing a custom algorithm and evaluating its ability to react to its environment. Finally, a flight test was performed to characterize …

Tensile Properties And Fatigue Behavior Of Geopolymer Matrix Composites With Carbon Fiber Reinforcement At Elevated Temperature, Steffan M.L. Wilcox

Theses and Dissertations

The tensile stress-strain and tension-tension fatigue of geopolymer matrix composites reinforced with 0/90 carbon fibers was investigated at 23 and 300°C in laboratory air. Geopolymers are inorganic polymeric materials composed of alumina, silica, and alkali metal oxides. Because geopolymers are synthesized as a fluid mixture or particles and liquid, they can be cast into a desired shape, and cured at only slightly elevated temperatures. The relative ease of synthesis and low processing temperatures make geopolymers an attractive choice as a matrix material for composite materials. Geopolymers also offer resistance to heat and oxidizing environments. Currently, geopolymer matrix composites are being …

Behavior Flexibility For Autonomous Unmanned Aerial Systems, Taylor B. Bodin

Theses and Dissertations

Autonomous unmanned aerial systems (UAS) could supplement and eventually subsume a substantial portion of the mission set currently executed by remote pilots, making UAS more robust, responsive, and numerous than permitted by teleoperation alone. Unfortunately, the development of robust autonomous systems is difficult, costly, and time-consuming. Furthermore, the resulting systems often make little reuse of proven software components and offer limited adaptability for new tasks. This work presents a development platform for UAS which promotes behavioral flexibility. The platform incorporates the Unified Behavior Framework (a modular, extensible autonomy framework), the Robotic Operating System (a RSF), and PX4 (an open- source …

Human Optimization And Performance Enhancement In Flight Via Real-Time Biofeedback (Project Have Hope), Michael S. Fritts

Theses and Dissertations

A four-phase, chronological, and build-up approach was implemented that commenced with basic hardware testing in a centrifuge and culminated in flights augmented by real-time biofeedback displays. A prototype Portable Electrocardiogram Unit (PECGU) was designed and proven to accurately measure heart rate (HR) and display percent heart rate reserve (%HRR). Results showed that %HRR was not a sole predictor of cognitive state. Cognitive responses indicated some correlation with %HRR, but were influenced by environment (centrifuge vs. flight). Subjective perceived exertion levels did not show statistically significant changes during test with biofeedback. A G-tracking task was evaluated during centrifuge and flight tests. …

Creep Of Nextel 720/A Ceramic Matrix Composite With Laser Drilled Effusion Holes At 1200°C In Air And In Steam, Savannah N. Minor

Theses and Dissertations

Creep behavior of an oxide-oxide ceramic matrix composite (CMC) containing an array of effusion holes was investigated at 1200⁰C in air and in steam. The composite (N720/A) consisted of a porous alumina matrix reinforced with alumina-mullite NextelTM 720 fibers. Test specimens had an array of 17 effusion holes with 0.5-mm diameter. The effusion holes were drilled through the specimen thickness normal to the specimen surface using a CO2 laser. Effect of the effusion holes on tensile properties was evaluated tension tests to failure at 1200°C in air. Creep of specimens with effusion holes at 1200°C was studied for creep stresses …

Design And Testing Of An Additively Manufactured Cubesat Structural Bus, Karson A. Roberts

Theses and Dissertations

Recent innovations in additive manufacturing and design capabilities have opened the door for more opportunities to integrate multiple functions into a structural de- sign. Specifically, 3D printing through advanced laser powder bed fusion of metal powder allows for the development and integration of advanced structures that were previously unachievable. The demonstration of these techniques on a small satellite results in a structural bus consisting of various external and internal features, increasing its functionality and capabilities beyond simply providing structural support. 3D printing a multi-functional CubeSat bus with these integrated features such as internal lattices and wiring tabs demonstrates a new …

Parameter Study Of An Orbital Debris Defender Using Two Team, Three Player Differential Game Theory, David F. Spendel

Theses and Dissertations

The United States Air Force and other national agencies rely on numerous space assets to project their doctrine. However, space is becoming an increasingly congested, contested, and competitive environment. A common risk mitigation strategy for the orbit debris problem is either performing evasive maneuvers, or placing additional shielding on the satellite before launch. Current risk mitigation strategies have significant consequences to satellite operators and may not produce sufficient risk mitigation. This research poses that an orbital debris defender, which would defend the primary satellite from orbital debris, may be a more effective risk mitigation strategy. By assuming the worst case …

An Exploration Of Error-Correcting Codes For Use In Noise-Prone Satellite Environments, Min W. Kang

Theses and Dissertations

Satellites are crucial for the modern world to function properly as they provide Global Navigation Satellite System (GNSS) and global communication. However, the data that is stored on these satellites can be corrupted by the radiation found in space, and its bits can be improperly flipped. In the past, Forward Error Correction (FEC) algorithms were selected based on their strength and implemented to correct these bit flips back to their original values. This thesis seeks to determine if the strength of the FEC algorithms Reed Solomon (RS) code and Reed Solomon Product Code (RSPC) directly translates to their effectiveness. These …