Aerospace Engineering Commons^™

An Investigation Of High-Speed Consolidation And Repair Of Carbon Fiber - Epoxy Composites Through Ultrasonic Welding, David A. Hoskins

LSU Master's Theses

Adhesive repair of carbon fiber composite structures is commonly done on damaged structures to extend the service life. This method requires careful preparation of the damaged surface with intricate steps to ensure good bonding between the repair patch and the parent structure by means of an adhesive film. As with many forms of composite manufacturing, it is required to perform vacuum bagging, debulking, and a heated cure depending on the resin. All these steps make the repair process costly and time consuming.

In this present work, an alternative method of repair is investigated which explores the experimental feasibility of using …

A Co-Optimal Coverage Path Planning Method For Aerial Scanning Of Complex Structures, Zhexiong Shang, Justin Bradley, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

The utilization of unmanned aerial vehicles (UAVs) in survey and inspection of civil infrastructure has been growing rapidly. However, computationally efficient solvers that find optimal flight paths while ensuring high-quality data acquisition of the complete 3D structure remains a difficult problem. Existing solvers typically prioritize efficient flight paths, or coverage, or reducing computational complexity of the algorithm – but these objectives are not co-optimized holistically. In this work we introduce a co-optimal coverage path planning (CCPP) method that simultaneously co-optimizes the UAV path, the quality of the captured images, and reducing computational complexity of the solver all while adhering to …

Sustainable Aviation Fuels Approval Streamlining: Auxiliary Power Unit Lean Blowout Testing, Erin E. Peiffer, Joshua S. Heyne, Meredith Colket

Mechanical and Aerospace Engineering Faculty Publications

An underpinning hindrance in the market penetration of sustainable aviation fuel is the approval process for alternative jet fuels. One solution to this is to develop low-cost screening tools that can be implemented earlier in the approval process. Auxiliary power unit combustors historically show the most sensitivity to physical and volatile fuel properties, making it a useful tool in assessing potential alternative jet fuel effects at test conditions representative of operability stability limits. It is hypothesized that these observations can be explained via timescale analysis considering fuel droplet breakup and evaporation, combustor mixing, and chemical reactivity timescales on the progression …

Development Of Cislunar Space Logistics Networks For Satellite Constellation Support Using Event-Driven Generalized Multi-Commodity Network Flows, Alexander R. Collins

Theses and Dissertations

As space becomes an increasingly congested domain, the risk of damage to satellite constellations is increasing. In response, there is an increasing need for capabilities for unmanned repair, refueling, and reconstitution (R3) of those constellations. Cislunar orbits offer a promising storage and low-cost transfer solution for on-orbit service vehicles and replacement satellites to leverage those capabilities. This research makes use of mixed-integer linear programming-based logistics models to determine the situations in which a cislunar mission architecture would offer a cost-effective alternative to Earth-based R3. The network models presented in this research make use of the latest developments in Event-Driven Generalized …

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …

Transport Phenomena In The Knudsen Layer Near An Evaporating Surface, Eric Bird, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using the Combination of the Kinetic Theory of Gases (KTG), Boltzmann Transport Equation (BTE), and Molecular Dynamics (MD) Simulations, We Study the Transport Phenomena in the Knudsen Layer Near a Planar Evaporating Surface. the MD Simulation is First Used to Validate the Assumption Regarding the Anisotropic Velocity Distribution of Vapor Molecules in the Knudsen Layer. based on This Assumption, We Use the KTG to Formulate the Temperature and Density of Vapor at the Evaporating Surface as a Function of the Evaporation Rate and the Mass Accommodation Coefficient (MAC), and We Use These Vapor Properties as the Boundary Conditions to Find …

Gelatine Cavity Dynamics Of High-Speed Sphere Impact, Akihito Kiyama, Mohammad M. Mansoor, Nathan B. Spiers, Yoshiyuki Tagawa, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

We investigate the impact and penetration of a solid sphere passing through gelatine at various impact speeds up to 143.2 m s^-1 Tests were performed with several concentrations of gelatine. Impacts for low elastic Froude number Fr_e a ratio between inertia and gelatine elasticity, resulted in rebound. Higher Fr_e values resulted in penetration, forming cavities with prominent surface textures. The overall shape of the cavities resembles those observed in water-entry experiments, yet they appear in a different order with respect to increasing inertia: rebound, quasi-seal, deep-seal, shallow-seal and surface-seal. Remarkably, similar to the We – Bo phase …

Unmanned Aircraft System (Uas) Technology And Applications In Agriculture, Samuel C. Hassler, Fulya Baysal-Gurel

Agricultural and Environmental Sciences Faculty Research

Numerous sensors have been developed over time for precision agriculture; though, only recently have these sensors been incorporated into the new realm of unmanned aircraft systems (UAS). This UAS technology has allowed for a more integrated and optimized approach to various farming tasks such as field mapping, plant stress detection, biomass estimation, weed management, inventory counting, and chemical spraying, among others. These systems can be highly specialized depending on the particular goals of the researcher or farmer, yet many aspects of UAS are similar. All systems require an underlying platform—or unmanned aerial vehicle (UAV)—and one or more peripherals and sensing …

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …

Modeling And Testing Powerplant Subsystems Of A Solar Uas, Luke J. Bughman

Master's Theses

In order to accurately conduct the preliminary and detailed design of solar powered Unmanned Aerial Systems (UAS), it is necessary to have a thorough understanding of the systems involved. In particular, it is desirable to have mathematical models and analysis tools describing the energy income and expenditure of the vehicle. Solar energy income models may include available solar irradiance, photovoltaic array power output, and maximum power point tracker efficiency. Energy expenditure models include battery charging and discharging characteristics, propulsion system efficiency, and aerodynamic efficiency. In this thesis, a series of mathematical models were developed that characterize the performance of these …

Risk Mitigation For Low Latitude Ground-Based Augmentation System (Gbas) Precision Approach Operations, Richard Walter Cole

Doctoral Dissertations and Master's Theses

The ground-based augmentation system (GBAS) is a safety-critical system consisting of the hardware and software that augments the Global Positioning System (GPS) to provide precision approach and landing capability and is one of the navigational cornerstones of the International Civil Aviation Organization's (ICAO) global transition to space-based technologies. In low latitude regions, where the space-based augmentation system (SBAS) cannot provide adequate precision approach service due to large system errors induced by ionospheric delays, GBAS is the best option to provide the primary navigation function for the modernized global air traffic system. The purpose of the study was to identify patterns …

Dear Neil Armstrong: Letters To The First Man From All Mankind, James R. Hansen

Purdue University Press Book Previews

In the years between the historic first moon landing by Apollo 11 on July 20, 1969, and his death at age 82 on August 25, 2012, Neil Armstrong received hundreds of thousands of cards and letters from all over the world, congratulating him, praising him, requesting pictures and autographs, and asking him what must have seemed to him to be limitless—and occasionally intrusive—questions. Of course, all the famous astronauts received fan mail, but the sheer volume Armstrong had to deal with for more than four decades after his moon landing was staggering.

Today, the preponderance of those letters—some 75,000 of …

Possible Detection Of Low Energy Solar Neutrons Using Boron Based Materials, Nicole Benker, Elena Echeverria, Robert Olesen, Brant E. Kananen, John W. Mcclory, Yaroslav V. Burak, Volodymyr T. Adamiv, Ihor M. Teslyuk, George Glenn Peterson, Ben Bradley, Ethiyal R. Wilson, James C. Petrosky, Bin Dong, Jeffry Kelber, Jennifer Hamblin, Jaques Doumani, Peter A. Dowben, Alex Enders

Faculty Publications

Solar neutrons have been detected aboard the International Space Station (ISS), using lithium tetraborate and boron carbide detector elements. We find that evidence of a solar neutron flux, as detected in a neutron calorimeter following subtraction of the proton background, with an energy of about 2 to 4 MeV. This solar neutron flux is likely no more than 250 to 375 neutrons cm⁻²sec⁻¹, with a lower bound of 50–75 neutrons cm⁻²sec⁻¹ at one au.

Extension Of A Penalty Method For Numerically Solving Constrained Multibody Dynamic Problems, Troy Newhart

Mechanical & Aerospace Engineering Theses & Dissertations

Numerical analysis of constrained static and multibody dynamic systems has become an integral part of engineering analysis with the continued improvements in technology and software availability. Many methods currently exist for numerically solving constrained static and dynamic systems. The applicability of a penalty method for constrained static solutions is observed in many academic texts and papers. The appeal for using a penalty method in statics pertains to its ease of implementation, computational suitability, and accuracy. This thesis extends a static penalty method for use with constrained multibody dynamics to observe if the penalty method’s benefits are similar for a dynamics …

Design Of The 21-Meter Network Monitor And Control System For Deep Space Network Cross Support, Sarah E. Wilczewski

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science Morehead State University in Partial Fulfillment of the Requirements for the Degree Master of Science by Sarah E. Wilczewski on September 26, 2019.

Experimental And Numerical Analysis Of Quasi-Static Deformation Mechanisms Of Additively Manufactured Lattice Structures, Behzad Bahrami Babamiri

Von Braun Symposium Student Posters

No abstract provided.

Seeded Hydrogen In Nuclear Thermal Propulsion (Ntp) Engines, Daria Nikitaeva

Von Braun Symposium Student Posters

No abstract provided.

Evaluation Of Varying Surface Finishes On Thin-Walled Blown Powdered Deposition Inconel 625, Noah Naden, Giancarlo Puerto, Judy Schneider

Von Braun Symposium Student Posters

No abstract provided.

Characterization Of A Pulse-Recharge Circuit For Puff, Nathan Schilling

Von Braun Symposium Student Posters

No abstract provided.

Design And Development Of An Autonomous Return Vehicle, Sean Widmier, An Nguyen, Colin Oberthur, Sean Mitchell, Fred Snopl

Von Braun Symposium Student Posters

No abstract provided.

A Test-Bed For Measuring Uas Servo Reliability, Abdelrahman Elsaid, Daniel Kwasi Adjekum, John Nordlie, Fatima El Jamiy

Aviation Faculty Publications

Extant literature suggests minimal research on the reliability of Commercial off-the-shelf (COTS) components used in fabricating non-military Unmanned Aerial System (UAS). Stochastic failures of components during operational cycles over time poses a safety hazard to flight operations. The purpose of the study was to critically assess the operational performance standards (reliability) of a laboratory designed UAS component test-bed operated using real-world data collected from a Boeing Scan Eagle^® UAS aileron servo unit via a flight data recorder. The study hypothesized that the test-bed’s reliability, in terms of a measured encoder output of commanded servo positions, will not be significantly …

Aircraft Hydraulic Systems - Fundamentals, Nihad E. Daidzic

Aviation Department Publications

Aircraft hydraulic systems are essential non-propulsive power systems. Hydraulic power systems are used to power major functional aircraft systems, such as flight controls (primary and secondary), friction braking, nose gear steering, thrust-reversers, operating heavy cargo doors, etc.

Wind Tunnel Measurements And Data Analysis Tutorial, Nihad E. Daidzic

Aviation Department Publications

This tutorial gives details on processing of raw aerodynamic data measured directly in the wind tunnel on airfoils and wings. Also procedures and equations from the lab report are given and demonstrated how to compute geometric characteristics of wings/airfoils and air data. All numeric results are typically rounded to five significant digits.

Development Of A Tailored Flight Test Approach For Small Unmanned Aircraft Systems, Neil A. Wolfe

Master's Theses

This document contains the details of a study conducted to determine an effective performance flight test approach specifically for small Unmanned Aircraft Systems (sUAS). This was done by taking proven procedures and documentation from the FAA and the Air Force for manned aircraft and tailoring them specifically for use with sUAS flight test programs. A ‘sUAS Flight Testing Handbook’ was created from the proceedings to aid commercial organizations and recreational developers conducting sUAS research without access to flight test experience. A performance flight test program was conducted with the AeroVironment RQ-20 Puma sUAS using the developed approach to verify that …

A Comparison Of Crushing Parameters Of Graphite Composite Thin-Walled Cylinders Cured In Low And High Pressures, Trenton John Matson

Master's Theses

Out-of-Autoclave (OoA) processes for manufacturing aerospace-grade parts needs to be better understood to further the development and success of industries that are manufacturing reusable launch vehicles, military and commercial aircraft, and spacecraft. Overcoming the performance limitations associated with OoA, also known as low-pressure prepreg curing, methods (void count, energy absorption, etc.) will help decrease the costs associated with aerospace composite manufacturing and the negative environmental effects correlated with high-pressure composite curing methods. Experimental, theoretical, and numerical approaches are used to explore both low and high-pressure curing cycles and how the two different processes affect final cured parts. Quasi-static uniaxial compression …

Cubesat Astronomy Mission Modeling Using The Horizon Simulation Framework, Alexander W. Johnson

Master's Theses

The CubeSat Astronomy Network is a proposed system of multiple CubeSat spacecraft capable of performing follow-up observations of astronomical targets of interest. The system is intended to serve as a space-borne platform that can complement existing systems utilized for astronomical research by undergraduate and high school students. Much research and development work has been performed to develop model-based system engineering methodologies and products for CubeSat missions, including the Horizon Simulation Framework. The Horizon Simulation Framework enables the development of system models using the Extended Markup Language (XML), and its simulation program can generate system simulations over model-specified timespans. System requirements …