Aerospace Engineering Commons^™

Modeling, Dynamics And Control Of Spacecraft Relative Motion In A Perturbed Keplerian Orbit, Mohamed Okasha, Brett Newman

Mechanical & Aerospace Engineering Faculty Publications

The dynamics of relative motion in a perturbed orbital environment are exploited based on Gauss' and Cowell's variational equations. The inertial coordinate frame and relative coordinate frame (Hill frame) are used, and a linear high fidelity model is developed to describe the relative motion. This model takes into account the primary gravitational and atmospheric drag perturbations. Then, this model is used in the design of a navigation, guidance, and control system of a chaser vehicle to approach towards and to depart from a target vehicle in proximity operations. Relative navigation uses an extended Kalman filter based on this relative model …

A Comparison Of Combined Overlap Block Fuzzy Cognitive Maps (Cobfcm) And Combined Overlap Block Neutrosophic Cognitive Map (Cobncm) In Finding The Hidden Patterns And Indeterminacies In Psychological Causal Models: Case Study Of Adhd, Hojjatollah Farahani, Florentin Smarandache, Lihshing Leigh Wang

Branch Mathematics and Statistics Faculty and Staff Publications

In spite of researchers’ concerns to find causalities, reviewing the literature of psychological studies one may argue that the classical statistical methods applied in order to find causalities are unable to find uncertainty and indeterminacies of the relationships between concepts.

In this paper, we introduce two methods to find effective solutions by identifying “hidden” patterns in the patients’ cognitive maps. Combined Overlap Block Fuzzy Cognitive Map (COBFCM) and Combined Overlap Block Neutrosophic Map (COBNCM) are effective when the number of concepts can be grouped and are large in numbers. In the first section, we introduce COBFCM, COBNCM, their applications, and …

Adaptive Double Chain Quantum Genetic Algorithm For Constrained Optimization Problems, Kong Haipeng, Li Ni, Yuzhong Shen

Computational Modeling & Simulation Engineering Faculty Publications

Optimization problems are often highly constrained and evolutionary algorithms (EAs) are effective methods to tackle this kind of problems. To further improve search efficiency and convergence rate of EAs, this paper presents an adaptive double chain quantum genetic algorithm (ADCQGA) for solving constrained optimization problems. ADCQGA makes use of double-individuals to represent solutions that are classified as feasible and infeasible solutions. Fitness (or evaluation) functions are defined for both types of solutions. Based on the fitness function, three types of step evolution (SE) are defined and utilized for judging evolutionary individuals. An adaptive rotation is proposed and used to facilitate …

Acoustic Emission Characteristics Of Damage Accumulation In Kevlar® 49 Composites, Eduardo Andrade

Open Access Theses & Dissertations

Acoustic emission (AE) data attained during tensile testing of epoxy impregnated Kevlar® 49 (K/Ep) composite strands were reduced and analyzed to monitor progressive damage accumulation during the approach to tensile failure. The K/Ep material tested in this study was chosen due to its similarity to the material-of-construction used in composite overwrapped pressure vessels (COPVs) used on the NASA Space Shuttle Orbiter. Insight into the progressive microstructural degradation of K/Ep strands was gained by monitoring AE event rate and energy. Source location based on energy attenuation and arrival time data was used to differentiate between significant AE attributable to microstructural damage …

Damage Characteristics In 3d Stitched Composites With Various Stitch Parameters Under In-Plane Tension, Arief Yudhanto, Gilles Lubineau, Isaac Aguilar Ventura, Naoyuki Watanabe, Yutaka Iwahori, Hikaru Hoshi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Three-dimensional (3D) reinforcement by stitching is effective in improving the impact resistance of composites. Stitching, however, adversely affects the composite's in-plane mechanical responses, and alters its damage mechanisms due to stitch-induced irregularities. We experimentally investigate the effect of two important stitch parameters, stitch density and thread diameter, on the damage characteristics of 3D stitched multidirectional composites under in-plane tension using X-ray radiography, X-ray micro-computed tomography and digital image correlation (DIC). Our study shows that composites stitched with thicker thread exhibit improved tensile strength due to effective hindrance of edge-delamination. We also found that stitch thread affects damage behaviors. A higher …

Magnus Effect In Duct Flow, Cameron W. Clarke, Jesse S. Batko, Kenneth W. Smith Jr.

Williams Honors College, Honors Research Projects

The following research paper details the preliminary research carried out by this team. The project was originally conceived to determine if Magnus Lift could be utilized in an unconventional way to assist rockets during takeoff. Several conceptual designs were proposed, but the idea was scrapped when it became apparent that the team would not be able to generate the desired lift without inducing significant amounts of drag and additional weight on a rocket. Instead, the team focused on researching an interesting topic that hasn’t been previously explored: Magnus lift on a cylinder within a duct. An experimental procedure that could …

Design Of The Structural And Propulsion Systems For The 2015 University Of Akron Rocket Team, Kyle W. Dehoff, Nicholas J. Hrusch

Williams Honors College, Honors Research Projects

No abstract provided.

Electric Field Modification Of A Diffusion Flame With Variable Electrode Geometry, Zachary Pinz

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Design Of A High Intensity Turbulent Combustion System, Mohammad Arif Hossain

Open Access Theses & Dissertations

In order to design next generation gas turbine combustor and rocket engines, a systematic study of flame structure at high intensity turbulent flow is necessary. The fundamental study of turbulent premixed combustion has been a major research concern for decades. The work is focused on the design and development of a high intensity turbulent combustion system which can be operated at compressible (0.3 < M < 0.5), preheated (T0=500K) and premixed conditions in order to investigate the 'Thickened Flame' regime. An air-methane mixture has been used as the fuel for this study. An optically accessible backward-facing step stabilized combustor has been designed for a maximum operating pressure of 6 bar. A grid has been introduced with different blockage ratios (BR = 54%, 61% & 67%) in order to generate turbulence inside the combustor for the experiment. Optical access is provided via quartz windows on three sides of the combustion chamber. Finite Element Analysis (FEA) is done in order to verify the structural integrity of the combustor at rated conditions. In order to increase the inlet temperature of the air, a heating section was designed to use commercially available in-line heaters. Separate cooling subsystems have been designed for chamber cooling and exhaust cooling. The LabVIEW software interface has been selected as the control mechanism for the experimental setup. A 10 kHz Time Resolved Particle Image Velocimetry (TR-PIV) system and a 3 kHz Planer Laser Induced Fluorescence (PLIF) system have been integrated with the system in order to diagnose the flow field and the flame respectively. The primary understanding of the flow field inside the combustor was achieved through the use of Detached Eddy Simulation (DES) by using commercially available software package ANSYS FLUENT. Preliminary validation is done by 10 kHz TR-PIV technique. Both qualitative and quantitative analysis have been done for CFD and experiment. Major flow parameters such as average velocity, fluctuation of velocity, kinetic energy, and turbulent intensity have been calculated for two distinct Reynolds number (Re = 815 & 3500). PIV results are compared with CFD results which show significant agreement with each other.

Planar Laser Induced Fluorescence Experiments And Modeling Study Of Jets In Crossflow At Various Injection Angles, Luke Thompson

Electronic Theses and Dissertations

Planar Laser Induced Fluorescence (PLIF) with acetone seeding was applied to measure the scalar fields of an axisymmetric freejet and an inclined jet-in-crossflow as applicable to film cooling. From the scalar fields, jet-mixing and trajectory characteristics were obtained. In order to validate the technique, the canonical example of a nonreacting freejet of Reynolds Numbers 900-9000 was investigated. Desired structural characteristics were observed and showed strong agreement with computational modeling. After validating the technique with the axisymmetric jet, the jet-in-crossflow was tested with various velocity ratios and jet injection angles. Results indicated the degree of wall separation for different injection angles …

Microgravity Testing Of A Phase Change Reference On The International Space Station, T. Shane Topham, Gail E. Bingham, Harri Latvakoski, Igor Podolski, Vladimir S. Sychev, Andre Burdakin

Space Dynamics Laboratory Publications

Orbital sensors to monitor global climate change during the next decade require low drift rates for onboard thermometry, which is currently unattainable without on-orbit recalibration. Phase change materials (PCM), such as those that make up the ITS-90 standard, are seen as the most reliable references on the ground and could be good candidates for orbital recalibration. Space Dynamics Lab (SDL) has been developing miniaturized phase change references capable of deployment on an orbital blackbody for nearly a decade. To determine if and how microgravity will affect the phase transitions, SDL conducted experiments with ITS-90 standard material (gallium, Ga) on the …

Buckling Instability Of Crown Sealing, J. O. Marston, Mohammad M. Mansoor, Tadd T. Truscott, S. T. Thoroddsen

Mechanical and Aerospace Engineering Faculty Publications

Despite the scholarly fascination with water entry of spheres for well over a century,¹ we present a new observation, namely, the crown-buckling instability. This instability is characterized by striations appearing near the top of the crown walls just prior to the surface seal, as shown in Fig. 1(a). The crown wall collapses inward due to the pressure differential across the wall created by the moving air in the wake of the sphere and surface tension within the crown. Since the rate of collapse is faster than that at which fluid drains out from the neck region, fluid collects into …

High Regression Rate Hybrid Rocket Fuel Grains With Helical Port Structures, Stephen A. Whitmore, Sean D. Walker, Daniel P. Merkley, Mansour Sobbi

Mechanical and Aerospace Engineering Faculty Publications

Results froma development campaign, where modern additive manufacturing methods are used to fabricate hybrid rocket fuel grains with embedded helical ports, are presented. The fuel grains were constructed from acrlyonitrile butadiene styrene using commercially available three-dimensional printer feedstockmaterial.Gaseous oxygen is used as the oxidizer for this test campaign.When compared to cylindrical fuel ports, significant increases in fuel regression rates were observed, and these increases in regression rate diminished with time as the helical fuel port burns to become progressivelymore cylindrical. Comparisons to the helical pipe flow skin friction correlation developed by Mishra and Gupta indicate that increased skin friction only …

Matryoshka Cavity, Randy Craig Hurd, T. Fanning, Zhao Pan, C. Maybey, Kyle G. Bodily, Kip Schafer Hacking, Nathan B. Spiers, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

When a water droplet impacts a free surface with sufficient velocity, the momentum transfer results in the formation of a hemispherical cavity expanding radially from the point of impact.¹ This cavity continues to expand until the kinetic energy is completely converted to potential energy (Fig. 1(a)).² Pumphrey and Elmore equated the potential energy of this subsurface cavity with the kinetic energy of the impacting droplet, concluding that the magnitude of the cavity radius is proportional to impact velocity and droplet diameter.³

Uncertainty Estimates And Prediction Interval Development For Internal Strain Gage Balance Calibration Systems, Kenneth G. Toro

Mechanical & Aerospace Engineering Theses & Dissertations

Currently, there is a lack of the use of mathematically rigorous methods to evaluate the performance of multivariate force measurement systems. The specific problem addressed in the research stems from the practical issues faced by test engineers when wind tunnel models with internal strain gage balances are readied for test. Check loads are applied and the question that needs to be answered is whether or not the balance is reading within acceptable limits. These systems tend to be difficult to characterize uncertainty, primarily due to their multivariate nature, but also due to the desire for an estimate on the explanatory …

Cubesat Wakes In The Earth’S Ionosphere, Robert M. Albarran Ii

Doctoral Dissertations and Master's Theses

Space exploration is currently being revolutionized by the advent of the CubeSat: 10cm cubed satellites that typically deploy in constellations for less than $100,000. Spacecraft instrumentation design must be redefined to abide by the compact CubeSat payload. Furthermore, the CubeSat dimension must be considered with respect to characteristic length scales of the space plasma environment, namely, the Debye length. Although spacecraft-plasma interactions- surface charging, plasma sheaths and wakes- have been well-studied for larger satellites, they are less understood for CubeSats.

The Dynamic Ionosphere CubeSat Experiment (DICE) is a 1.5U CubeSat which recently ended its mission. DICE carried two fixed-bias Langmuir …

Ultra-Fast, Autonomous, Reconfigurable Communication System, Paul Bupe Jr

College of Graduate Studies: Theses & Dissertations

The recent years have witnessed an increase in natural disasters in which the destruction of essential communication infrastructure has significantly affected the number of casualties. In 2005, Hurricane Katrina in the United States resulted in over 1,900 deaths, three million land-line phones disconnections, and more than 2000 cell sites going out of service. This incident highlighted an urgent need for a quick-deployment, efficient communication network for emergency relief purposes. In this research, a fully autonomous system to deploy Unmanned Aerial Vehicles (UAVs) as the first phase disaster recovery communication network for wide-area relief is presented. As part of this system, …

Analysis Of Ion Emitting Jet Structures During Ionic Liquid Electrospraying, Shawn W. Miller

Doctoral Dissertations

"The ionic liquid [Bmim][DCA] is a propellant candidate for a standalone electrospray thruster or a dual-mode propulsion system. Characterization of positive polarity ions produced by [Bmim][DCA] capillary emitters with a nominal extraction voltage of 2.0 kV within a quadrupole and time-of-flight mass spectrometers is presented along with the predictions of propulsion performance. Flow rates from 0.05 to 2.18 nL/s are used to investigate the impact variations in the flow parameter have on the electrospray plume. The retarding potential analysis reveals ions emitted from the capillary are formed below the emitter potential of 500 eV. Angular distributions indicate broadening of both …

Advancements In Uncertainty Quantification With Stochastic Expansions Applied To Supersonic And Hypersonic Flows, Thomas Kelsey West Iv

Doctoral Dissertations

"The primary objective of this study was to develop improved methodologies for efficient and accurate uncertainty quantification with stochastic expansions and apply them to problems in supersonic and hypersonic flows. Methods introduced included approaches for efficient dimension reduction, sensitivity analysis, and sparse approximations. These methods and procedures were demonstrated on multiple stochastic models of hypersonic, planetary entry flows, which included high-fidelity, computational fluid dynamics models of radiative heating on the surface of hypersonic inflatable aerodynamic decelerators during Mars and Titan entry. For these stochastic problems, construction of an accurate surrogate model was achieved with as few as 10% of the …

Investigation Of Robust Optimization And Evidence Theory With Stochastic Expansions For Aerospace Applications Under Mixed Uncertainty, Harsheel R. Shah

Doctoral Dissertations

One of the primary objectives of this research is to develop a method to model and propagate mixed (aleatory and epistemic) uncertainty in aerospace simulations using DSTE. In order to avoid excessive computational cost associated with large scale applications and the evaluation of Dempster Shafer structures, stochastic expansions are implemented for efficient UQ. The mixed UQ with DSTE approach was demonstrated on an analytical example and high fidelity computational fluid dynamics (CFD) study of transonic flow over a RAE 2822 airfoil.

Another objective is to devise a DSTE based performance assessment framework through the use of quantification of margins and …

Pulsed Inductive Plasma Studies By Spectroscopy And Internal Probe Methods, Warner C. Meeks

Doctoral Dissertations

The broad effort of the Missouri Plasmoid Experiment is to elucidate the energy conversion processes in a pulsed inductive discharge due to the presence of plasma. The test article is a 440 to 490 kHz theta-pinch (or solenoidal) geometry coil with a stored energy of around 80 joules. In this work experimental hydrogen, helium, argon and xenon data at back-fill pressures of 10 to 100 mTorr (1.3 to 133.3 Pa) are obtained and interpreted. Spectral and internal probe studies were performed on MPX Mk.I and Mk.II devices, respectively. IR spectra were acquired in the Mk.I device for argon and xenon. …

Optimization Based Control Design Techniques For Distributed Parameter Systems, Manoj Kumar

Doctoral Dissertations

"The study presents optimization based control design techniques for the systems that are governed by partial differential equations. A control technique is developed for systems that are actuated at the boundary. The principles of dynamic inversion and constrained optimization theory are used to formulate a feedback controller. This control technique is demonstrated for heat equations and thermal convection loops. This technique is extended to address a practical issue of parameter uncertainty in a class of systems. An estimator is defined for unknown parameters in the system. The Lyapunov stability theory is used to derive an update law of these parameters. …

Development Of Ionic Liquid Multi-Mode Spacecraft Micropropulsion Systems, Steven Paul Berg

Doctoral Dissertations

"This dissertation presents work on development of multi-mode specific spacecraft propulsion systems. Specifically, this work attempts to realize a single propellant capable of both chemical monopropellant and electric electrospray rocket propulsion, develop methods to characterize multi-mode propulsion system performance, and realize a system capable of both monopropellant and electrospray propulsion for a small spacecraft. Selection criteria for ionic liquid propellants capable of both monopropellant and electrospray propulsion are developed. These are based on desired physical properties and performance considering use in both propulsive modes. From these insights, a monopropellant mixture of 1-ethyl-3-methylimidazolium ethyl sulfate and hydroxylammonium nitrate is selected and …

Quantum Inspired Algorithms For Learning And Control Of Stochastic Systems, Karthikeyan Rajagopal

Doctoral Dissertations

"Motivated by the limitations of the current reinforcement learning and optimal control techniques, this dissertation proposes quantum theory inspired algorithms for learning and control of both single-agent and multi-agent stochastic systems.

A common problem encountered in traditional reinforcement learning techniques is the exploration-exploitation trade-off. To address the above issue an action selection procedure inspired by a quantum search algorithm called Grover's iteration is developed. This procedure does not require an explicit design parameter to specify the relative frequency of explorative/exploitative actions.

The second part of this dissertation extends the powerful adaptive critic design methodology to solve finite horizon stochastic optimal …

Use Of Anaerobic Adhesive For Prevailing Torque Locking Feature On Threaded Product, Alan Hernandez

USF Tampa Graduate Theses and Dissertations

The purpose of this research is to determine if anaerobic adhesive can be used as a prevailing torque locking feature. Maintaining preload in critical joints is the usual standard that anaerobic adhesives are held to in aerospace and other industry. To test if anaerobic adhesive can be used as a prevailing torque locking feature a test procedure was developed and implemented to measure the removal torque of threaded fasteners after an allotted cure time. In total, 191 threaded fasteners of different material and coatings were tested in the unseated and seated states with various strengths and varieties of anaerobic adhesive. …

Use Of Single Stage Model Rockets To Teach Some Engineering Principles And Practices To First Year Engineering And Engineering Technology Students, Hüseyin Sarper, Linda Vahala

Electrical & Computer Engineering Faculty Publications

Model rocketry has been called miniature astronautics; a technology in miniature, a hobby, a sport, a technological recreation, an educational tool, and it is all of these things. This paper will describe student projects using model rockets and engines to learn engineering principles for launching rockets and determining the apogee. Model rocketry is a powerful tool for instructors who wish to incorporate science, technology, engineering, and mathematics into a fun, engaging, and challenging activity for first year engineering students. The apogee can be determined using four distinct methods: trigonometry using hand held angle measuring tools, onboard altimeter devices, analytical calculations …