Engineering Commons^™

The Effect Of Store-To-Store Energy Transfers On The Global Dynamics Of Aircraft, Guilherme Mainieri Eymael

Honors Program: Senior Projects (Public)

This study analyzes the energy transfer mechanisms when nonlinear devices (stores) are attached to a linear model airplane. For that, a reduced-order model (ROM) was derived to simulate the first two flexible modes of vibration of the primary structure (aircraft) with one store in each wing. Each store can either be locked or unlocked. When locked, it only contributes as mass-effect, and when unlocked, it adds nonlinearity to the system. Simulations were then performed with either both stores locked, one store unlocked, or both stores unlocked. It was found that the attachment of nonlinear stores in the ROM changes the …

Gen. Thomas P. Stafford Archive Dedication Program, Southwestern Oklahoma State University

Stafford Archives Dedication Documents

On March 11th, 2022, the Al Harris Library hosted the dedication of the General Thomas P. Stafford Archives.

Unless stated otherwise within this repository collection, all materials are shared under the following Creative Commons license: [Creative Commons Attribution-NonCommercial 4.0 International License].

Influence Of Cold Expansion And Aggressive Environment On Crack Growth In Aa2024-T3, Ken Shishino, Christopher Leirer, Alberto Mello

Publications

This research aims to establish the effect of hole cold expansion on fatigue life of pre-cracked material under aggressive environment. A relationship between crack propagation and secondary crack initiation was established for AA2024-T3 cold worked holes subjected to cyclic loads to determine the impact on fatigue life of joints in presence of saline solution. Galvanic corrosion of a steel fastener/aluminum plate assembly was investigated assuming the presence of cracks in the aluminum plates, whose growth will be monitored in-situ with a digital microscope throughout the fatigue process. The cold expansion treatment improved the fatigue life fourfold under a corrosive environment, …

Humanity’S Journey To The Red Planet, Robinson Raphael

Student Works

Being the fourth planet in our solar system, Mars is half the size of Earth and constitutes a gravity near 0.38 g. Like its fellow terrestrial planets, it has a central core, rocky mantle, and solid crust. Coupled with a thin atmosphere, its surface features are reminiscent of both the Earth and Moon. Given adequate accessibility, Mars has been a hub for scientific exploration. With past and present robotic missions, they have gradually provided information about the Martian environment to help aid future human exploration. For humanity’s first manned mission to the Martian crater, Aram Chaos, a crew of six …

Component Repair Using Additive Manufacturing: Experiments And Thermal Modeling, Lan Li, Xinchang Zhang, Tan Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The objective of this work is to propose an advanced automated damage detection and damage reconstruction algorithm for damaged gear tooth repair. It can automate tool path design and provide precise repair volume detection for complex repair volume. First, models of the damaged and nominal parts were obtained by reverse engineering. Next, the damaged model was aligned with the nominal model. After that, both models were sliced into layers, and a set of parallel and equidistant casting rays was used to intersect with these layers to extract the repair volume. Then the repair tool path was generated and used to …

Aeroelastic Analysis Of Small-Scale Aircraft, Kent Roberts

Master's Theses

The structural design of flight vehicles is a balancing act between maximizing loading capability while minimizing weight. An engineer must consider not only the classical static structural yielding failure of a vehicle, but a variety of ways in which structural deformations can in turn, affect the loading conditions driving those deformations. Lift redistribution, divergence, and flutter are exactly such dynamic aeroelastic phenomena that must be properly characterized during the design of a vehicle; to do otherwise is to risk catastrophe. Relevant within the university context is the design of small-scale aircraft for student projects and of particular consideration, the DBF …

Exploratory Measurement Of Recession Rates Of Low Temperature Ablators Subjected To Mach 6 Flow, Ross H. Kellet

Theses and Dissertations

The high speed/high-temperature effect of heat shield ablation was simulated in the low-enthalpy AFRL Mach 6 Ludwieg Tube using solid dry ice as a low-temperature sublimator. The experiments utilized both 21 half-angle cones and bi-conic models with a 7 ° half-angle leading edge followed by a 26° half-angle base contained within a cryogenic-cooled stainless steel holder. A method of fabricating dry ice test articles was developed using commercially procured dry ice and custom-made aluminum molds. Tests were performed at Mach 6.1 with a stagnation temperature of 490 K and stagnation pressures ranging from 40 - 500 psi. Unit Reynolds number …

Effects Of Cone Tip Changes On Wall-Cooled Hypersonic Boundary Layer Transition And Turbulence, Mathew M. Major

Theses and Dissertations

Boundary layer measurements took place at Air Force Research Lab’s (AFRL) Mach-6 Ludwieg tube hypersonic wind tunnel on a 7-degree half angle spherically blunted nose cone with a 1.5 mm radius to study the effects of a cooled surface on the transition process. Experiments compared uncooled and cooled flow conditions on the blunt-nosed model, and then compared to past data for a sharp-tipped cone of similar geometry. Cooling the surface delayed the onset of transition on the blunt nose model. Combining the effects of nose blunting and cooling further increased transition delay than each acting individually compared to the sharp-tipped …

Manufacturing Of A Ceramic Turbine Rotor For A Compact Jet Engine, Bryan T. Leicht

Theses and Dissertations

The primary goal of this study was to develop a low-cost, timely, scalable manufacturing method that produced a ceramic turbine that can be tested as a drop-in replacement on a JetCat P400 small scale gas turbine engine. This research compared two processes for manufacturing a ceramic turbine utilizing a pour casting method and 3D printing using stereolithography ceramic manufacturing (SLCM). The pour casting method used Silicon Nitride to create a cast turbine using a sacrificial 3D printed mold. The SLCM method evaluated producing an alumina turbine using an ADMATEC Admaflex 300 SLCM printer to directly print a ceramic turbine. This …

Magnetic Anomaly Absolute Positioning For Hypersonic Aircraft, Alexander J. Mcneil

Theses and Dissertations

GPS has proven to be an extremely valuable asset for navigation, and timing. GPS has become the standard navigation system for all applications, but GPS has limitations. GPS is susceptible to jamming, spoofing, and in the case of hypersonic aircraft, is likely unavailable. When an aircraft is traveling at hypersonic speeds, there is a plasma sheath that surrounds the aircraft. This plasma sheath blocks electromagnetic waves, and is therefore responsible for a GPS blackout. GPS unavailability for hypersonic aircraft has prompted the research into the viability of alternate navigation systems for these aircraft. This paper seeks to explore the viability …

Utilization Of Characteristic Modal Analysis For Antenna Design Needed For An Afit Satellite, Scott C. Podlogar

Theses and Dissertations

Antenna design is a pervasive, growing field for electrical engineers. As the number of new materials and techniques increase so too does the demand and requirements pushing forth new innovative ideas. Among these ideas is a leading edge analytic technique called Characteristic Modal Analysis (CMA) originally credited to Garbacz and Turpin. CMA works to break down the current distribution along a structure in a way that can offer great insights into how that structure operates as an antenna. This technique has great merits in post design analytics but it is rarely seen to be integrated into the design process. This …

Surrogate Modeling Of Computational Aerodynamic Responses For A Generic Hypersonic Vehicle, Jacob R. Johanik

Theses and Dissertations

In the field of multidisciplinary hypersonic vehicle design, striking the balance between the accuracy and efficiency of a predictive aerodynamic response model is a significant challenge. In response to this challenge, the objective of this thesis is to evaluate the aerodynamic performance of a Generic Hypersonic Vehicle (GHV) using the technique of surrogate modeling Computational Fluid Dynamic data points across a large range of flight conditions. To accomplish this, the full CFD process was conducted by preparing the vehicle geometry, generating a grid, computing the flow, and post-processing the data. A three-dimensional, quasi-random distribution of 1000 points defined the design …

Thermal Considerations For Film Cooling Materials With Anisotropic Thermal Conductivity, Carol E. Bryant

Theses and Dissertations

Higher performance requirements and reduced core sizes are driving increases in turbine inlet temperature in gas turbine engines, surpassing the melting point of advanced materials. Newer materials, such as composites, are being introduced into the hot sections of gas turbine engines. Components in the hot section use film cooling to prevent melting. One unique aspect of some high-temperature composites is they have a bulk anisotropic thermal conductivity, therefore heat flow differs relative to traditional metallic components. Film cooling designs can be revolutionized by leveraging anisotropy in high-temperature materials. The purpose of this research is to examine thermal considerations for using …

Estimating Atmospheric Turbulence Within A Short Exposure Frame Selection Algorithm, Aaron J. Deluca

Theses and Dissertations

Space is becoming an increasingly crowded domain. As it becomes more congested, the ability to accurately detect and track objects, both natural and man-made, becomes more and more important. Having an accurate space surveillance network allows us to protect our own space assets while also maintaining awareness of foreign space assets and threats to our satellites such as debris and small meteorites. This means that the ability to detect small, dim objects is key to being able to protect our space assets. This thesis will seek to expand on and improve certain existing space object detection techniques and algorithms.

A Decision Analysis Framework To Consider Space Congestion In Orbit Selection, Anthony J. Correale

Theses and Dissertations

Low Earth Orbit (LEO) is becoming more congested, which increases the risk to space missions. Decision makers will need to consider this increase in congestion as an increased risk within their mission engineering process. This thesis proposes a methodology to create and implement a value structure that quantitatively scores a range of orbits based on congestion factors of each orbit and how well each orbit meets mission requirements. This thesis demonstrates this methodology on a set of circular LEO orbits defined by altitude and inclination, and scores this illustrative scenario based on notional mission measures and expected number of encounters …

Uav Positioning Data Determined Via Aruco Tags For Aircraft Surface Inspection, Caleb B. Schmidt

Theses and Dissertations

Aircraft are frequently inspected to ensure that military and civilian safety standards are adhered to. These inspections are performed pre- and post-flight and are currently performed by trained maintenance personnel. This work furthers the automation of aircraft surface inspection by using ArUco tags to determine the position of the UAV during aerial inspections. The ArUco tag based position data was then compared to a highly accurate infrared motion capture system to determine the viability of this for accurate positioning of the vehicle. This work includes flight experiments with two different UAVs to perform a system viability comparison.

Design And Application Of Compact Combustors In Small-Scale Jetcat Engines, Nathan A. Clark

Theses and Dissertations

Ultra-compact combustors (UCC) are an innovative approach to improving overall engine efficiency and thrust-to-weight ratio by reducing the axial length and weight of the engine. Previous efforts looked at integrating a UCC into a small-scale JetCat P90 engine utilizing gaseous propane fuel. The current investigation aimed to utilize the previous compact combustor design and switch fuels to liquid kerosene. Based on the results from testing, a new combustor was designed equipped with a different flame holding mechanism at the larger P400-scale while maintaining a length savings of 20%. Testing of the P400 compact combustors was performed within a newly designed …

Underactuated Attitude Control Of A Cubesat Using Cold Gas Thrusters And Nonlinear Control Methods, Adam S. Cottrell

Theses and Dissertations

Impulsive thrusters on small satellites, such as CubeSats, are typically used for attitude control. However, to become more agile, small CubeSats must also look to propulsion systems utilizing impulsive thrusters, such as cold-gas, for translational maneuvers. The combined thrust vector is often misaligned with the system's center of mass resulting in a disturbance torque. This must be counteracted by either an attitude determination and control system (ADCS), additional thrusters, or a control method to keep the satellite's attitude at or near equilibrium. Nonlinearities generated by the impulsive maneuvers are overcome via control techniques explored in this research to include on-off …

Design Of An Electro-Thermal Nanosatellite Propulsion System, James H. Founds

Theses and Dissertations

This research focused on designing an arcjet system with water as the propellant. Previous research developed a compact, reliable, and safe propellant storage and feed system. The goal is to combine the arcjet with the previous tank to achieve thrust and specific impulse characteristics greater than cold gas or resistojet system. This platform features a 1 U, non-hazardous, and sub-kilowatt powered propulsion system for nanosatellites. A simplified analysis of the design predicts thrust and specific impulse greater than can be achieved by cold gas or resistojet thrusters. Testing resulted in oxidation of the electrodes raising concerns about the longevity of …

Development Of Minimum Delta-V Trajectories To Service Geo Assets From Cislunar Space, Alexander C. Urban

Theses and Dissertations

Orbits around Earth are becoming increasingly congested and contested, posing potential future threats to space assets. Cislunar space may offer an effective solution to these problems by offering storage for servicing and replacement vehicles. This investigation explores how to minimize the dV costs required of a network of service vehicles traveling from cislunar space to GEO using in-situ resource utilization. In this investigation the arc costs of an event-driven generalized multicommodity network flow are generated for creation of a model to be used to develop a dynamic scheduler. High-thrust trajectories between various inclinations of GEO, an Earth-Moon L1 Lyapunov orbit …

Synthetic Aperture Sillouette Imaging For Space Domain Awareness, Lester L. Tuck Iv

Theses and Dissertations

A gap exists in imaging capabilities necessary for Space Domain Awareness, at Geostationary Equatorial Orbit (GEO) distances and beyond. Synthetic Aperture Silhouette Imaging (SASI), which resolves a space object's silhouette with measurements of the diffraction pattern cast by the object's occultation of a distant star, provides a new method that may be used to characterize these satellites. This research analyzes the reconstruction of satellite silhouettes using data from a scaled benchtop experiment to evaluate the distance and resolution limitations of SASI at distances equal to and beyond GEO. Diffraction patterns of two satellite silhouette targets are captured at various scaled …

Characterizing Wake Roll-Up And Vortex Structure For Delta Wing Configuations Featuring Flow Control Devices At Low Reynolds Number, Jeffrey M. Layng

Theses and Dissertations

Various configurations of a cropped delta wing featuring a NACA 0012 wing-section were evaluated experimentally at a Reynolds number of 5.0 x 10⁵ in the Air Force Institute of Technology Low-Speed Wind Tunnel facility. The effects of active flow control (AFC) and passive boundary-layer fences (BLF) were shown to improve high angle of attack delta wing performance. The AFC BLFs were shown to replicate the performance enhancements found in passive BLFs without incurring a drag penalty. An experimental characterization of the wake region is presented to compare the wake roll-up and leading edge vortices for these baseline, passive BLF, …

Differential Game-Based Defensive Architecture Study Employing Ground-Based Interceptors, Stephen T. Zittrouer

Theses and Dissertations

A study of defensive architectures for combating hypersonic glide vehicles (HGVs) via interception with a ground-based interceptor (GBI) is presented. Pursuit-evasion differential games are formulated for numerical simulation of the interception engagements. A one-sided optimal control problem wherein the evader HGV is optimized and the pursuer GBI employs a suboptimal proportional navigation control strategy is solved. The solution space is characterized by varying the pursuer initial velocity advantage relative to the evader. A two-sided optimal control problem in which both players behave optimally is solved via the semi-direct collocation with nonlinear programming (semiDCNLP) method. The resulting state and control trajectories …

Aeroelasticity Of Six Degree-Of-Freedom Satellite Bus Configurations During Terminal Reentry, Jinhee F. Byun

Theses and Dissertations

With disposable equipment on board, the emphasis on structural strength and robust thermal protection system (TPS) pales for a conventional satellite in comparison to reentry capsules, which are specifically designed to withstand the intense aerothermodynamic effects experienced during reentry. In this research, six degree-of-freedom (6DOF) analyses of three distinct non-aerodynamic satellite bus configurations were performed with emphasis on the investigation of their terminal reentry characteristics, and thermal and deceleration loading on the satellite body. Aeroelastic effects on their respective solar panel structures were also analyzed focusing on characterizing bending stress at their attachment/deployment mechanism. It was found that the Terra …

A Proposed Mission Assurance Framework For University Cubesat Programs, Mitchell R. Thomas

Theses and Dissertations

The low cost, small form factor, and use of Commercial-Off-The-Shelf components make CubeSats an ideal platform for university use given their unique constraints. Since 2000, roughly 55% of CubeSats developed by universities fail to meet mission goals. Mission assurance, which is used to increase confidence in mission success, is based around traditional government programs, and does not provide an adequate road map for universities. Leaving them without specific guidance in tailoring mission assurance activities to operate within their constraints. This paper adapts these traditional practices to develop a baseline mission assurance framework for university CubeSat programs.

Investigation Of Mechanical Properties Of Parts Fabricated With Gas- And Water-Atomized 304l Stainless Steel Powder In The Laser Powder Bed Fusion Process, M. Hossein Sehhat, Austin T. Sutton, Chia Hung Hung, Joseph William Newkirk, Ming-Chuan Leu

Materials Science and Engineering Faculty Research & Creative Works

The use of gas-atomized powder as the feedstock material for the laser powder bed fusion (LPBF) process is common in the additive manufacturing (AM) community. Although gas-atomization produces powder with high sphericity, its relatively expensive production cost is a downside for application in AM processes. Water atomization of powder may overcome this limitation due to its low-cost relative to the gas-atomization process. In this work, gas- and water-atomized 304L stainless steel powders were morphologically characterized through scanning electron microscopy (SEM). The water-atomized powder had a wider particle size distribution and exhibited less sphericity. Measuring powder flowability using the Revolution Powder …

Molecular Simulation Of Steady-State Evaporation And Condensation Of Water In Air, Eric Bird, Jesus Gutierrez Plascencia, Pawel Keblinski, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

It Was Shown in Recent Experiments and Molecular Dynamics (MD) Simulations that Schrage Equation Predicts Evaporation and Condensation Rates of Water in the Absence of a Non-Condensable Gas with Good Accuracy. However, It is Not Clear Whether Schrage Equation is Still Accurate or Even Valid for Quantifying Water Evaporation and Condensation Rates in Air. in This Work, We Carry Out MD Simulations to Study Steady-State Evaporation and Condensation of Water at a Planar Water-Air Interface. the Simulation Results Show that the Evaporation and Condensation Fluxes of Water in the Presence of Air Are Still in a Good Agreement with the …

Applied Agile Digital Mission Engineering For Cislunar Space Domain Awareness, Benjamin R. Williams

Theses and Dissertations

In the backdrop of an expansion into cislunar space and a digital transformation, the author synthesizes a methodology from agile system development, DE, ME, and MBSE processes, methods, and tools to develop a basic RA and DT for cislunar SDA mission and system design. The Agile DME methodology is used to conduct basic requirements analysis, develop a concept, understand cislunar physics, study scenario geometries, and perform analyses and the DT implements, executes, and accelerates research by integrating a descriptive tool with analytical and simulation tools. This research demonstrates the value of automated Modeling, Simulation, and Analysis (MSA) work flows and …

Pedagogical Approaches For Facilitating Engineering Leadership Development, Teresa J. Didiano, Annie E. Simpson, David J. Bayless

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This article describes transformative, impactful pedagogical practices that engage students in the process of leadership development. We share practical examples of instructional strategies and facilitation techniques from curricular and co-curricular initiatives.

Coupled Orbit-Attitude Dynamics And Control Of A Cubesat Equipped With A Robotic Manipulator, Charles M. Carr

Theses and Dissertations

This research investigates the utility and expected performance of a robotic servicing CubeSat. The coupled orbit-attitude dynamics of a 6U CubeSat equipped with a four-link serial manipulator are derived. A proportional-integral-derivative controller is implemented to guide the robot through a series of orbital scenarios, including rendezvous and docking following ejection from a chief spacecraft, repositioning the end effector to a desired location, and tracing a desired path with the end effector. Various techniques involving path planning and inverse differential kinematics are leveraged. Simulation results are presented and performance metrics such as settling time, state errors, control use, and system robustness …