Aerospace Engineering Commons^™

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 …

Characterizing Noise Trends Of The Cross-Track Infrared Sounder (Cris), Bryce Walker, Mark Esplin, Ben Esplin, Deron Scott

Space Dynamics Laboratory Publications

Outline

• CrIS Summary

• Noise characterization process

• Noise trending results

• Recent Changes

• Conclusions

Dcgs: Image Processing, Screening, & Product Distribution Solution, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

SCALABLE, CROSS-PLATFORM SOLUTION FOR NEAR REAL-TIME IMAGE PROCESSING, SCREENING, & PRODUCT DISTRIBUTION

SDL provides the Distributed Common Ground System (DCGS) community with a powerful image processing, screening, and product distribution solution by combining a ground station with the VANTAGE™ tactical intelligence software suite and the Sky Lynx data link interface hardware. This system's cost-effectiveness is achieved through the use of flexible and robust hardware configurations that enable the customer to scale the system to their DCGS program needs.

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 …

Evaporative Vapor Deposition For Depositing 2d Materials, Kevin Gleason

Electronic Theses and Dissertations

The development of a new deposition technique called evaporative vapor deposition (EVD) is reported, allowing deposition and formation of atomically-thin, large area materials on arbitrary substrates. This work focuses on the highly popular monolayer material – graphene oxide (GO). A droplet of a GO solution is formed on a heated polymer substrate, and maintained at steady-state evaporation (all droplet parameters are held constant over time). The polymer substrate is laser patterned to control the droplet's contact line dynamics and the droplet's contact angle is maintained using a computer controlled syringe pump. A room temperature silicon wafer is translated through the …

Deposition Thickness Modeling And Parameter Identification For Spray Assisted Vacuum Filtration Process In Additive Manufacturing, August Mark

Electronic Theses and Dissertations

To enhance mechanical and/or electrical properties of composite materials used in additive manufacturing, nanoparticles are often time deposited to form nanocomposite layers. To customize the mechanical and/or electrical properties, the thickness of such nanocomposite layers must be precisely controlled. A thickness model of filter cakes created through a spray assisted vacuum filtration is presented in this paper, to enable the development of advanced thickness controllers. The mass transfer dynamics in the spray atomization and vacuum filtration are studied for the mass of solid particles and mass of water in differential areas, and then the thickness of a filter cake is …

Cacti- And Shorebirds-Inspired Transports Of Liquid Drops And Two Related Fog Collectors, Xin Heng

Mechanical and Aerospace Engineering Dissertations - Archive

Motivated by what has been used in cacti and shorebirds to directionally manipulate water drops, we have explored two approaches to guide the movement of liquid drops. Based on these approaches, in addition to separating oil from its mixture with water, we have further developed two fog collectors. The first fog collector has a configuration similar to its counterpart in a cactus. This collector includes a large ZnO wire and an array of small ZnO wires that are branched on the large wire. All these wires have conical shapes, whose diameters gradually increase from the tip to the root of …

Compact Deployable Antenna For Cubesat Units, Sarah Bolton, Dominic Doty, Peter Rivera

Mechanical Engineering

CubeSats are an appealing platform for space exploration due to their low build and launch costs. Due to their small size, communication rates are often severely limited, preventing missions beyond low earth orbit. A low cost, high gain, high frequency antenna is needed to extend the capabilities of CubeSats.

The goal of the project was to design and build an axisymmetric parabolic antenna that could be deployed from a 10cm x 10cm x 15cm (1.5U) volume and operate at Ka band frequencies. The design selected consisted of an expanding perimeter truss supporting a tensioned mesh reflector. The perimeter truss was …

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 …

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 …

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. …

Adaptive Control For Autonomous Navigation Of Mobile Robots Considering Time Delay And Uncertainty, Stephen Kofi Armah

Dissertations

Autonomous control of mobile robots has attracted considerable attention of researchers in the areas of robotics and autonomous systems during the past decades. One of the goals in the field of mobile robotics is development of platforms that robustly operate in given, partially unknown, or unpredictable environments and offer desired services to humans. Autonomous mobile robots need to be equipped with effective, robust and/or adaptive, navigation control systems. In spite of enormous reported work on autonomous navigation control systems for mobile robots, achieving the goal above is still an open problem. Robustness and reliability of the controlled system can always …

Topology Optimization For Thin Walled Structures Utilizing Simp Method By Additive Manufacturing Using Optimized Conditions, Sajith Anantharaman

Mechanical and Aerospace Engineering Theses - Archive

The objective of this research is to manufacture topology optimized structure by additive manufacturing. Topology Optimization is a method of structural optimization which gives the optimum material distribution in a design domain. This material distribution is then manufactured by additive manufacturing. Additive manufacturing can manufacture complex shapes quite easily since it works by layer-by-layer. This is an on-going field of research and not many optimization algorithms make use of the advantages of additive manufacturing. Numerous researches are done in the field of optimization which are directed towards Homogenization and Solid Isotropic material with Penalization (SIMP). But most of the methods …

Autoignition Behavior Of Synthetic Alternative Jet Fuels: An Examination Of Chemical Composition Effects On Ignition Delays At Low To Intermediate Temperatures, Daniel Valco, Gerald Gentz, Casey Allen, Meredith Colket, Tim Edwards, Sandeep Gowdagiri, Matthew A. Oehlschlaeger, Elisa Toulson, Tonghun Lee

United States Air Force: Publications

The autoignition characteristics of military aviation fuels (JP-5 and JP-8), proposed camelina-derived hydroprocessed renewable jet fuel replacements (HRJ-8 and HRJ-5), Fischer–Tropsch fuels (Shell and Sasol), three Sasol isoparaffinic solvents, as well as 50/50 volumetric blends of the alternative fuels with the conventional fuels are examined. Experiments were conducted in a rapid compression machine and shock tube at compressed temperatures of 625 K ≤ Tc ≤ 1000 K, a compressed pressure of 20 bar, and under stoichiometric and lean conditions. Several implicit properties of the alternative fuels prompted a study of the influence of chemical composition on autoignition, including the influence …

Absorption Properties Of Type-Ii Inas/Inassb Superlattices Measured By Spectroscopic Ellipsometry, P T. Webster, N A. Riordan, S Liu, E H. Steenbergen, R A. Synowicki, Y H. Zhang, S R. Johnson

United States Air Force: Publications

Strain-balanced InAs/InAsSb superlattices offer access to the mid- to long-wavelength infrared region with what is essentially a ternary material system at the GaSb lattice constant. The absorption coefficients of InAs/InAsSb superlattices grown by molecular beam epitaxy on (100)-oriented GaSb substrates are measured at room temperature over the 30 to 800 meV photon energy range using spectroscopic ellipsometry, and the miniband structure of each superlattice is calculated using a Kronig-Penney model. The InAs/InAsSb conduction band offset is used as a fitting parameter to align the calculated superlattice ground state transition energy to the measured absorption onset at room temperature and to …

Discrete-Time Neural Network Based State Observer With Neural Network Based Control Formulation For A Class Of Systems With Unmatched Uncertainties, Jason Michael Stumfoll

Masters Theses

"An observer is a dynamic system that estimates the state variables of another system using noisy measurements, either to estimate unmeasurable states, or to improve the accuracy of the state measurements. The Modified State Observer (MSO) is a technique that uses a standard observer structure modified to include a neural network to estimate system states as well as system uncertainty. It has been used in orbit uncertainty estimation and atmospheric reentry uncertainty estimation problems to correctly estimate unmodeled system dynamics. A form of the MSO has been used to control a nonlinear electrohydraulic system with parameter uncertainty using a simplified …

Parameter Determination And Experimental Validation Of A Wire Feed Additive Manufacturing Model, Kannan Suresh Kumar

Masters Theses

“Laser metal deposition is an additive manufacturing method with great scope and robustness. The wire fed additive manufacturing method has great opportunities in space applications and other zero gravity manufacturing processes. Process parameters play an important role in controlling the complex phenomenon and obtaining an ideal manufactured part. These parameters can be efficiently determined using simulation tools which are highly essential in visualizing real world experiments, therefore saving time and experimental costs. The objective of this study is to develop a transient 3D model of laser aided wire feed metal deposition which realizes the heat transfer and fluid flow behavior …

Hybrid Manufacturing Process Of SicF/Sic Composite Using Preceramic Polymer, Robert Raymond Meinders

Masters Theses

"Continuous fiber-reinforced silicon carbide (SiC_f/SiC) ceramic composites have been increasingly used due to their high temperature strength and graceful failure mechanisms. A disadvantage is the high cost and lengthy production processes that are required to develop these materials. Polymer infiltration and pyrolysis (PIP) is one of the most attractive fabrication processes for composites due to shape flexibility, mass production and relatively low cost; however, the quality of material obtained by this method has been considered insufficient due to the microstructure defects of the material obtained. This study investigated a hybrid of multiple polymer manufacturing processes to maximize quality …

Adjoint-Based Airfoil Shape Optimization In Transonic Flow, Joe-Ray Gramanzini

Masters Theses

"The primary focus of this work is efficient aerodynamic shape optimization in transonic flow. Adjoint-based optimization techniques are employed on airfoil sections and evaluated in terms of computational accuracy as well as efficiency. This study examines two test cases proposed by the AIAA Aerodynamic Design Optimization Discussion Group. The first is a two-dimensional, transonic, inviscid, non-lifting optimization of a Modified-NACA 0012 airfoil. The second is a two-dimensional, transonic, viscous optimization problem using a RAE 2822 airfoil. The FUN3D CFD code of NASA Langley Research Center is used as the ow solver for the gradient-based optimization cases. Two shape parameterization techniques …

Uncertainty Quantification Of Turbulence Model Closure Coefficients For Transonic Wall-Bounded Flows, John Anthony Schaefer

Masters Theses

"The goal of this work was to quantify the uncertainty and sensitivity of commonly used turbulence models in Reynolds-Averaged Navier-Stokes codes due to uncertainty in the values of closure coefficients for transonic, wall-bounded flows and to rank the contribution of each coefficient to uncertainty in various output flow quantities of interest. Specifically, uncertainty quantification of turbulence model closure coefficients was performed for transonic flow over an axisymmetric bump at zero degrees angle of attack and the RAE 2822 transonic airfoil at a lift coefficient of 0.744. Three turbulence models were considered: the Spalart-Allmaras Model, Wilcox (2006) k-ω Model, and the …

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 …

Diffusion And Elastoplastic Analyses Of Polycrystalline Magnesium For Solid State Hydrogen Storage Application, Amey Mathakari

Mechanical and Aerospace Engineering Theses - Archive

Solid state hydrogen storage can be an effective way of storing hydrogen as an energy source for mobile applications. The advantage includes high energy density, low setup cost, safe operation, abundance of metal hydrides, low maintenance, etc. Magnesium is one of the potential metals for the application. However, sluggish desorption kinetics of magnesium requiring relatively high operation temperature has hindered its practical realization. In the present study, an attempt is made to analyze effects of grain boundary on diffusion and diffusion induced stresses in polycrystalline magnesium. Grain boundaries in nanostructured magnesium can undergo severe plastic deformations during the hydrogen insertion …

Simulation And Performance Analysis Of Ejector Nozzle In A Low-Bypass Turbofan Engine Using Npss, Hatim Soeb Rangwala

Mechanical and Aerospace Engineering Theses - Archive

Nozzles for propulsive applications in airbreathing engines have long been studied to augment thrust and reduce the size of the engine. They are critical elements of the engine as they convert the internal energy into kinetic energy, thereby producing thrust. Fixed-geometry nozzles are operated optimally only at a particular set of flight conditions and are not efficient at off-design conditions. To improve off-design performance, variable geometry nozzles can be utilized which require complex mechanisms that ultimately increase weight and susceptibility to failure. Ejector nozzles provide variable geometry capability via aerodynamically varying the effective area ratios of the core and bypass …

Assessing Interlaminar Shear Stress-Strain Curves In Tape Composites Based On The Flat-Plate Torsion Method, Gary Steven Grohman

Mechanical and Aerospace Engineering Theses - Archive

Composites are attractive for structural applications in the aerospace industry for their high strength to weight ratio, stiffness, and low density. The development and implementation of composite structures has grown rapidly through the aerospace industry exceeding our ability to characterize the material properties due to costly and time consuming test methods. The ability to fully characterize the nonlinear stress-strain relationship in the 1-3 and 2-3 principal planes up to the point of failure is extremely important for predicting failures in composites. The principal directions for composites are the fiber direction, transverse direction, and the thru thickness direction, commonly referred to …

Heat Removal Analysis Using Ntu Microscopic Theory And Experimental Fluid Testing Of Radaitors, Pumps And Fans For The Thermal Management System Of Formula Sae Electric Racecar, Shahzad Shahrukh Bulsara

Mechanical and Aerospace Engineering Theses - Archive

Formula SAE at UT Arlington has always been building well engineered race cars, further being one of the top teams in The United States. However, an electric race car being first in the fleet, cooling of electric motors played a vital role. The thermal system being significantly different from combustion cars, consists of a lower heat application. It is always favorable to maintain electronics as close to ambient temperature as compared to its counter hydro-mechanical engines. To attain the objective, a complete thermal & fluid analysis was carried out using the NTU method/ microscopic theory and experimental results associated towards …

Icao Aviation System Block Upgrades: A Method For Identifying Training Needs, Rebecca K. Lutte

Aviation Institute Faculty Publications

Since the mid-1970s, air traffic growth has expanded two-fold once every fifteen years (ICAO, 2013). The ICAO Global Air Navigation Plan (GANP) is a roadmap to achieve a “vision of an integrated, harmonized, and globally interoperable air traffic management (ATM) system” (ICAO, 2012, p. 1). A component of the GANP is the Aviation System Block Upgrades (ASBU), a framework for achieving that vision. A collaborative approach led by ICAO between public and private organizations and member states resulted in the development of the ASBU framework. However, obstacles exist for successful implementation. One area of concern is the need for training …

Analysis Of Thin-Walled Cylindrical Composite Shell Structures Subject To Axial And Bending Loads: Concept Development, Analytical Modeling And Experimental Verification, Sthanu Mahadev

Mechanical and Aerospace Engineering Dissertations - Archive

Several studies have focused on the modeling and response characterization of composite structural members, with particular emphasis on thin-walled cylindrical composite shells. This class of shell configurations is explored to determine their mechanical response in primary aerospace structural members. The present work is focused on formulating a modified composite shell theory prognosis methodology for investigating the structural response of thin-walled cylindrical shell type composite configurations under axial and bending loads, respectively. The prime motivation to develop this theory arises from its capability to generate simple yet accurate closed-form analytical results that can efficiently charecterize cylindrical composite shell constructions. This work …

Design Of Next Generation Antenna Mounts In Telecommunication Towers With Low Effective Projected Area, Ruben Gregory Puthota Dominic Savio

Mechanical and Aerospace Engineering Theses - Archive

Design of new antenna mount with low effective projected area (EPA) and high load carrying capacity for telecommunication towers is the purpose of this thesis. The main aim is to reduce the EPA of the mount against the wind pressure direction at the desired elevation from ground by reducing the mount frame structure parts compared to the previous mount designs used in the market. The model in itself has to withstand its dead weight, operator’s weight along with five antenna-radio units. The new model has been designed with a single horizontal frame and four supporting structure for EPA reduction and …

Characterization Of Flapping Wing Aerodynamics And Flight Dynamics Analysis Using Computational Methods, Alok Ashok Rege

Mechanical and Aerospace Engineering Dissertations - Archive

Insect flight comes with a lot of intricacies that cannot be explained by conventional aerodynamics. Even with their small-size, insects have the ability to generate the required aerodynamic forces using high frequency flapping motion of their wings to perform different maneuvers. The maneuverability obtained by these flyers using flapping motion belies the classical aerodynamics theory and calls for a new approach to study this highly unsteady aerodynamics. Research is on to find new ways to realize the flight capabilities of these insects and engineer a micro-flyer which would have various applications, ranging from autonomous pollination of crop fields and oil …

Comprehensive Design Analysis Of Thick Fr-4 Qfn Assemblies For Enhanced Board Level Reliability, Abhishek Nitin Deshpande

Mechanical and Aerospace Engineering Theses - Archive

Quad Flat No-lead package (QFN) is one of the most cutting-edge technologies emerged in the market, exhibiting high performance and efficiency with unparalleled cost effectiveness. QFN, a leadless package, is an ideal choice for applications where size, weight thermal and electrical characteristics are critical, particularly in mobile and handheld devices. Applications like automotive, defense and high current circuits require the package to be mounted on thick printed circuit boards (PCB). But using thick PCBs (>3mm) is detrimental to the package reliability. The motivation of this work is to understand the effect of several package parameters affecting reliability and optimize …