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- Additive manufacturing; Convective heat transfer; Surface roughness; Computational fluid dynamics; Discrete Element Roughness Method (1)
- Aerosol dynamics; Ventilation effects; Pathogen transmission; Computational fluid dynamics; Social distancing (1)
- Alumina coatings; Lunar exploration; Wear resistance; Mechanical properties; Surface energy (1)
- Bio-inspired propulsion; Numerical modeling; Fluid dynamics; Undulating mechanisms; Efficiency metrics (1)
- Blisk dynamics; Mistuning characterization; Vibration localization; Modal assurance criterion; Engine-order forcing (1)
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- Boron carbide; Mechanical properties; Neutron absorption; Spark Plasma Sintering; Fracture toughness (1)
- CMAS infiltration; Residual stress; High temperature coatings; Raman spectroscopy; Turbine engines (1)
- Carbon nanotubes; Piezoresistivity; Viscoelasticity; Nanocomposites; Strain sensing (1)
- Coaxial rotors; Wing design; Computational fluid dynamics; Aerodynamic performance; Flight conditions (1)
- Combustion liner; Sand ingestion; Cooling geometries; Particulate deposition; Aerospace maintenance (1)
- Composite booms; Eccentric loading; Finite element analysis; Buckling behavior; Solar sails (1)
- Computational fluid dynamics; Aerodynamic heating; Hypersonic flow; Shock layer; Drag reduction (1)
- Computational fluid dynamics; Aerodynamic quantification; Control volume techniques; Fluid momentum; Energy components (1)
- Coupled Radial Basis Functions; Nonlinear optimal control; Numerical methods; Shape parameter optimization; Boundary value problems (1)
- Deployable drones; Aerodynamic design; Computational Fluid Dynamics; Propeller testing; Aerodynamic modeling (1)
- Deployable structures; Propeller blade; Snap through buckling; Structural architecture; Computational analysis (1)
- Detonation combustion; Liquid RP-2; Rocket propulsion; Thrust measurement; Spray dynamics (1)
- Detonation dynamics; Carbon black; Hydrogen-air mixtures; Stagnation pressure; Combustion efficiency (1)
- Detonation engine; Propulsion technology; Fuel injection; Thermodynamic efficiency; Experimental research (1)
- Detonation interaction; Liquid fuel combustion; Shock wave analysis; Fuel droplet ignition; Aerospace propulsion (1)
- Detonation transition; Flame acceleration; Turbulence effects; High-speed diagnostics; Compressibility (1)
- Detonation tube; Liquid fuel droplets; Experimental validation; Pressure measurements; Laser spectroscopy (1)
- Detonation wave properties; Mode transition instability; Rotating detonation engine; Combustion instabilities; Operating conditions (1)
- Droplet breakup; Detonation wave; RP-2 fuel; Shadowgraphy; Explosion dynamics (1)
- Droplet breakup; Hypersonic vehicles; Viscoelastic fluids; Multi-scale modeling; Viral transmission (1)
- Elliptical fairing; Bluff body; Numerical modeling; Aerodynamic optimization; Wake effects (1)
- Flow-induced vibration; Fluid-structure interaction; Experimental investigation; Numerical modeling; Vibration characteristics (1)
- Forward osmosis; Polyelectrolyte membranes; Spacecraft wastewater; Nanofiltration; Water reclamation (1)
- Functionally graded materials; Additive manufacturing; Sandwich structures; Mechanical characterization; Flexural stiffness (1)
- Hybrid models; Recurrent neural networks; Fatigue crack growth; Data-driven kernels; Numerical integration (1)
Articles 31 - 60 of 66
Full-Text Articles in Aerospace Engineering
On Liquid Rotating Detonation Rocket Engines Characterization And Performance, Vidhan Malik
On Liquid Rotating Detonation Rocket Engines Characterization And Performance, Vidhan Malik
Electronic Theses and Dissertations, 2020-2023
The current research investigates a next-generation method of combustion called detonations for propulsive applications which has support from the Combustion Services Branch at the Air Force Research Laboratory (AFRL) of the Rocket Propulsion Division. The overall initiative seeks to explore the viability of detonation-based systems to augment or replace current rocket propulsion methods in the coming five years. The present work progresses this vision by providing proof of a liquid RP-2 based Rotating Detonation Rocket Engine (RDRE) as well as the fundamentals associated with the physics involved to further the understanding of the phenomenon and its potential uses. Phase one …
A Unified Tool For Adaptive Collocation Techniques Applied To Solving Optimal Control Problems, Bethany Kelly
A Unified Tool For Adaptive Collocation Techniques Applied To Solving Optimal Control Problems, Bethany Kelly
Electronic Theses and Dissertations, 2020-2023
In this work, a user-friendly MATLAB tool is introduced to solve nonlinear optimal control problems by applying collocation techniques using Coupled Radial Basis Functions (CRBFs). CRBFs are a new class of Radial Basis Functions combined with a conical spline r^5, which provides the advantage of insensitivity to the shape parameter while maintaining accuracy and robustness. To solve optimal control problems, software tools are often employed to implement numerical methods and apply advanced techniques to solving differential equations. Although several commercial software tools exist for solving optimal control problems, such as ICLOCS2, GPOPS, and DIDO, there are no options available that …
The Breakup Of Rp-2 Liquid Fuel Droplets In A Detonation Field, Daniel Dyson
The Breakup Of Rp-2 Liquid Fuel Droplets In A Detonation Field, Daniel Dyson
Electronic Theses and Dissertations, 2020-2023
Experimentally obtained droplet breakup patterns are presented for RP-2 liquid fuel droplets in the environment behind a detonation wave. To the best of our knowledge, this data is the first of its kind to examine the fundamental interactions between detonation waves and an individual fuel droplet. The experiments presented here are expected to support the ongoing effort of creating accurate models of droplet breakup in a variety of environments, which in turn will lead to enhanced predictions of rotating detonation engine performance, improved safety considerations for facilities operating in hazardous conditions, and new knowledge in energetics, hypersonics, and explosion dynamics …
Broadband Investigation Of The Pyrolysis Of Propane Using A Mir Optical Parametric Oscillator, Robert Greene
Broadband Investigation Of The Pyrolysis Of Propane Using A Mir Optical Parametric Oscillator, Robert Greene
Electronic Theses and Dissertations, 2020-2023
The chemistry of propane continues to play a pivotal role in today's power production technologies. As reliance on natural gas expands as greener cleaner fuels are sought throughout the world, especially as countries are attempting to transition away from traditional coal and crude-oil fired plants towards solar, wind, and hydro-electric sources. Natural gas, often seen as a bridge fuel between these two competing ends, has been in the recent past and for the foreseeable future will continue to play an important role in the energy sector. Among the components of natural gas, propane plays a key role in the chemistry …
Autoignition Delay Time Measurements And Chemical Kinetic Modeling Of Hydrogen/Ammonia/Natural Gas Mixtures, Jessica Baker
Autoignition Delay Time Measurements And Chemical Kinetic Modeling Of Hydrogen/Ammonia/Natural Gas Mixtures, Jessica Baker
Electronic Theses and Dissertations, 2020-2023
In recent years, hydrogen-carrying compounds have accrued interest as an alternative to traditional fossil fuels due to their function as zero-emission fuels. As such, there is interest in investigating hydrogen-carrying compounds to improve understanding of the fuels' characteristics for use in high pressure systems. In the current study, the oxidation of ammonia/natural gas/hydrogen mixtures was carried out to study CO formation profiles as well as the ignition delay times behind reflected shock waves in order to refine chemical kinetic models. Experiments were carried out in the University of Central Florida's shock tube facility by utilizing chemiluminescence to obtain OH* emission …
Shock Tube And Gas Dynamic Design Considerations And Implementation For Extended Test Times, Jacklyn Higgs
Shock Tube And Gas Dynamic Design Considerations And Implementation For Extended Test Times, Jacklyn Higgs
Electronic Theses and Dissertations, 2020-2023
A new shock tube test section has been designed and manufactured for the purpose of increasing the test time and expanding the applications of the shock tube for a multitude of ongoing and future projects. One purpose for the test section extension is to allow for flow visualization of droplets impacted by a shock wave for the interaction of hypersonic vehicles and atmospheric disturbances. Another purpose is to measure behind the incident shock to capture the chemical kinetics for a high-altitude environment and low-pressure, high-temperature space applications. This new test section contains 24 round optical ports for laser spectroscopy for …
Investigating The Effect Of Cmas Infiltration On Residual Stress Of High Temperature Ceramic Coatings For Turbine Engines Using 3d Confocal Raman Spectroscopy, Zachary Stein
Electronic Theses and Dissertations, 2020-2023
Calcium-magnesium-aluminosilicates (CMAS), such as sand or volcanic ash, are ingested by aircraft jet engines during operation. CMAS then becomes molten while traveling through the combustor of the engine before depositing onto turbine blades within the turbine section of the engine. The molten CMAS melt infiltrates and interacts with the high temperature ceramic coated turbine blades. This infiltration increases coating stiffness and promotes coating phase destabilization, encouraging micro-crack formation and increasing the risk of spallation. Thermomechanical effects from CMAS infiltration were mapped over time with confocal Raman spectroscopy. The residual stresses within infiltrated 7YSZ EB-PVD coatings were captured with microscale resolution. …
Studying The Electrostatic Effects On The Dynamics Of Charged Lunar Dust Via Discrete Element Method, Hao Wang
Studying The Electrostatic Effects On The Dynamics Of Charged Lunar Dust Via Discrete Element Method, Hao Wang
Electronic Theses and Dissertations, 2020-2023
Dust problems raise significant concerns in planetary surface exploration. The unusual behavior of the dust particles that surround the vehicle after engine cutoff has the potential to have more of an influence on surface systems than the high velocity lunar rocket plume ejecta in the landing process. A prevailing hypothesis attributes the levitation and transport of dust particles on the surface of airless bodies to the electrostatic effects and electric field. However, there is no accurate model considering the inter-particle electrostatic interactions, especially when the particles are charged by plume. This dissertation aims to understand the behavior of charged lunar …
Exploration Of Shock-Droplet Ignition And Combustion, John Patten
Exploration Of Shock-Droplet Ignition And Combustion, John Patten
Electronic Theses and Dissertations, 2020-2023
Liquid fuels are desirable in aerospace applications due to their higher energy density when compared to gaseous fuels. With the advent of detonation-based engines, it is necessary to characterize and analyze how liquid fuel interacts with detonation waves as well as shocks to ignite. While liquid fuel sprays have been proven to successfully aid and sustain detonations, the physical mechanism by which the individual liquid droplets accomplish this is yet to be understood. Such knowledge allows for more predictable detonation properties, which in turn can let detonation-based engines be sustained more easily. This research seeks to quantify and characterize interactions …
Quantification Of The Aerodynamic Drivers Of A Deployable Propeller, David Malyszek
Quantification Of The Aerodynamic Drivers Of A Deployable Propeller, David Malyszek
Electronic Theses and Dissertations, 2020-2023
With the use deployable drones becoming more common research into their improvement is necessary. Deployable drones that are launched from tubes have size limits on the diameter of the propeller during launch and storage. The purpose of this research is to develop deployable propeller blades for practical uses, such as tube launched propeller driven drones and easier to transport wind turbine blades. A deployable propeller will allow for the utilization of larger propellers when a large non-deployable blade isn't an option. Because deployable propellers need to fold, the deployable propeller blades were designed to be hollow and with a slit …
Aerodynamic Characterization Of An Elliptical Fairing In The Wake Of A Bluff Body, Luis Amaya
Aerodynamic Characterization Of An Elliptical Fairing In The Wake Of A Bluff Body, Luis Amaya
Electronic Theses and Dissertations, 2020-2023
Aerodynamic optimization is a key step in designing planes, cars, and even buildings. Numerical modeling is used to automate the optimization process and can use different methods to iterate through designs. In this process, consideration of the starting design is paramount as a poor choice can use up computational time and effort. Often, these designs are made with the intention of being out in the open, for which studies on shape variations in freestream situations abound. However, for the case where an object must be placed in the wake of another, there is little research. The study presented here aims …
Modeling And Experimentation Of Buckling Of Composite Deployable Booms Under Bending, Christopher D. Rehberg
Modeling And Experimentation Of Buckling Of Composite Deployable Booms Under Bending, Christopher D. Rehberg
Electronic Theses and Dissertations, 2020-2023
This thesis presents experimental and finite element analysis results of eccentrically loaded carbon-fiber composite booms that can deploy solar sails. Using the collapsible tubular mast design along with the geometry from the upcoming Advance Composite Solar Sail System mission, short composite booms segments were manufactured for testing. New clamps were also designed to allow a column bending test to achieve eccentric loading. As buckling through eccentric loading has not previously seen much research, the geometry and composite layups were simplified to allow for ease of manufacturing and verification. The work presented here shows that a finite element simulation, using a …
Energy Based Diagnostics Of Cfd: Revealing New Insights To Complex Aerodynamics, George Loubimov
Energy Based Diagnostics Of Cfd: Revealing New Insights To Complex Aerodynamics, George Loubimov
Electronic Theses and Dissertations, 2020-2023
This thesis documents a new approach to assess the aerodynamics of complex fluid dynamic systems using modern assessment methods associated with computational fluid dynamics (CFD). The method is developed to extract novel and additional insight in the context of a higher-fidelity modeling tool. Although the methods are based on classical control volume techniques balancing fluid momentum and energy, the approach uses the detailed data provided by CFD to expand on it. Classical methods typically use a fixing control volume defined at simple control surfaces, whereas this assessment method utilizes CFD to provide complex integrals on the control surfaces and uses …
Investigation Into Wedge Turbulator Effects In High Aspect Ratio Cooling Channels, Daniel Garcia
Investigation Into Wedge Turbulator Effects In High Aspect Ratio Cooling Channels, Daniel Garcia
Electronic Theses and Dissertations, 2020-2023
With reusability being a novel design parameter for liquid rocket engines (LRE), the need to lower internal wall temperatures for an increased engine longevity is a desired outcome. One of the mechanisms that has been effectively implemented is the use of high aspect ratio cooling channels (HARCC) to promote fin-like effects from internal cooling channel sidewalls. In the gas turbine industry, the use of wedge turbulators has gained recognition for its heat augmentation properties with relatively low pressure drop penalty. In an ideal case, LRE's could adopt the wedge turbulator cooling technique to enhance the benefits of HARCC with minimal …
On Mode Transition Phenomenon And Operating Conditions In Rotating Detonation Rocket Engines, Taha Rezzag-Lebza
On Mode Transition Phenomenon And Operating Conditions In Rotating Detonation Rocket Engines, Taha Rezzag-Lebza
Electronic Theses and Dissertations, 2020-2023
The work presented herein consist of first studying the instantaneous properties of the detonation waves in a rotating detonation rocket engine by tracking each individual wave and recording its position, velocity, and peak intensity as it travels around the annulus. Results for a steady portion of a test performed on a rotating detonation rocket engine show that the wave properties exhibit oscillatory behavior. Results obtained from the rotating detonation rocket engine show that the properties are highly dependent on the azimuthal position. In an attempt to understanding the cause of such a behavior, similar investigations were performed on an air-breathing …
Creasing Of Polyimide Thin Film For Use In Solar Sails, Andrew Allen
Creasing Of Polyimide Thin Film For Use In Solar Sails, Andrew Allen
Electronic Theses and Dissertations, 2020-2023
Polymer thin membranes are used in a variety of deployable structures that require large areas and compact stowage. Packaging membrane structures often involves creasing the membrane along predefined fold lines to enforce the desired kinematics under folding action. Inducing permanent deformation by folding to a high curvature is a common method to create creases, particularly in the design of solar sails. The distinct mechanical characteristics at the crease regions have a profound effect on the subsequent deployment and tensioning of the membrane structures. The mechanical and geometric properties at the crease are related to the crease formation process, but the …
Computational Studies For Extending Understanding Of Complex Droplet Breakup Mechanisms, Caroline Anderson
Computational Studies For Extending Understanding Of Complex Droplet Breakup Mechanisms, Caroline Anderson
Electronic Theses and Dissertations, 2020-2023
Conventional methods of classifying droplet breakup are evaluated in the context of unique variation in environmental and droplet fluid conditions. Most characterization is developed for subsonic speeds and Newtonian fluids, so this study extends understanding on how these forms change to a span of applications outside these conditions. Presented examples include the impact effects on hypersonic vehicles travelling through precipitation, where even smallest of rain drops at such speeds can cause damage. Before the droplet even reaches the vehicle, it interacts with the detached bow shock that leads it. Another example of exceptional recent concern is risk of viral transmission …
Optimization Of A Wing Supporting A Coaxial Rotor For Multiple Flight Conditions, Tadd Yeager
Optimization Of A Wing Supporting A Coaxial Rotor For Multiple Flight Conditions, Tadd Yeager
Electronic Theses and Dissertations, 2020-2023
Rotor-powered drones continue to grow in popularity in private and government sectors. The use of these drones in challenging environments and in high stakes applications calls for a certain level of robustness and redundancy. Often, these drones are equipped with sets of paired coaxial rotors, which not only improve the performance of the vehicle, but also ensure that a failure of one motor does not constitute the failure of the whole vehicle. Some applications such as extraterrestrial exploration, which use these coaxial rotors, can benefit from a wing shaped rotor arm to reduce drag and increase lift, extending mission lifetime. …
Development Of Multi-Scale Characterization Techniques For Stress Corrosion Cracking Of Aerospace Alloys, Nicholas Reed
Development Of Multi-Scale Characterization Techniques For Stress Corrosion Cracking Of Aerospace Alloys, Nicholas Reed
Electronic Theses and Dissertations, 2020-2023
Corrosion presents an inherent challenge in the safe and effective use of metallic aerospace structures for extended periods of time. Progress in the fundamental understanding of corrosion initiation and propagation under stress requires a multi-scale approach that leverages experiments to develop predictive models. Although there exists a large amount of research results tracking the corrosive processes of anodic dissolution and hydrogen embrittlement, the amount of available data and modeling of the micro-scale initiation of corrosion is sparse. This work leverages a suite of characterization techniques to systematically analyze an aerospace grade aluminum alloy AA7075-T6, providing important multi-scale data for correlation …
Solid Materia And Multiphase Detonations Wave Dynamics In A Rotating Detonation Engine, Ian Dunn
Solid Materia And Multiphase Detonations Wave Dynamics In A Rotating Detonation Engine, Ian Dunn
Electronic Theses and Dissertations, 2020-2023
Coal dust explosions can be hazardous; however, they can also generate a significant rise in stagnation pressure if adequately harnessed. Rotating detonation engine combustors seek to take advantage of the stagnation pressure rise phenomenon in a more sustained and controlled manner via confinement to a physical annulus, leading to increased overall thermodynamic efficiency. This investigation presents an analysis of detonations fueled by Carbon Black, a solid particulate consisting of virtually pure carbon molecules and lean Hydrogen-Air mixtures. As was previously realized with the addition of Carbon Black, an increase of operability limits and detonation velocities over that of a pure …
Numerical Modeling Of Shockwave Initiated Combustion Of A Hydrogen-Oxygen Mixture Within A Shock Tube, Reed Forehand
Numerical Modeling Of Shockwave Initiated Combustion Of A Hydrogen-Oxygen Mixture Within A Shock Tube, Reed Forehand
Electronic Theses and Dissertations, 2020-2023
Shock tubes are as close to an ideal reactor as most modern experiments can attain to examine chemical kinetics. As reaction temperatures drop, homogeneous combustion within a shock tube begins to exhibit inhomogeneous modes, which in a typical Hydrogen-Oxygen system are ex- pressed as deflagration to detonation transition. Experimental results of such a system in the Uni- versity of Central Florida's low-pressure shock tube have been collected through end and side-wall imaging to analyze flame structure and chemical kinetics. The purpose of this work is to con- duct a baselining of these results using both chemical and computational fluid dynamics …
Simulating Ejecta Blown Off The Lunar Surface Due To Landing Spacecraft Using The Mercury N-Body Integrator, Isabel Rivera
Simulating Ejecta Blown Off The Lunar Surface Due To Landing Spacecraft Using The Mercury N-Body Integrator, Isabel Rivera
Electronic Theses and Dissertations, 2020-2023
The experiences of the Apollo lunar landings revealed the danger lunar dust can pose to surrounding hardware, outposts, and orbiting spacecraft. Future lunar missions such as the Artemis program will require more information about the trajectories of ejecta blown by landers to protect orbiting spacecraft such as the Lunar Gateway. In this paper, we simulate lunar lander ejecta trajectories using the Mercury N-body integrator. We placed cones of test particles on the Moon at the North Pole, South Pole, and Equator with various ejection speeds and angles. The results show that particles ejected at speeds near the Moon's escape velocity …
Inertial Orbit Estimation Using Multiple Space Based Observers: A New Measurement Model, James Hippelheuser
Inertial Orbit Estimation Using Multiple Space Based Observers: A New Measurement Model, James Hippelheuser
Electronic Theses and Dissertations, 2020-2023
Presented within this work is a new method for inertial orbit estimation of an object, either known or unknown, adaptable to a network of low-cost observation satellites. The observation satellites would only require a monocular camera for line of sight measurements. Using the line of sight measurements of each observer, a pair of orthogonal geometric planes that intersect both the observation satellite and the target are created. The intersection of the two planes in the inertial frame defines the new measurement model that is implemented with multiple observation nodes. Total system observability is analyzed and the instantaneous (per node) observability …
Operability And Wave Characterization Of Hydrogen And Oxygen Fed Rotating Detonation Rocket Engine, Robert Burke
Operability And Wave Characterization Of Hydrogen And Oxygen Fed Rotating Detonation Rocket Engine, Robert Burke
Electronic Theses and Dissertations, 2020-2023
Recently, novel experimental evidence of continuous rotating detonations for gaseous H2/O2 propellants with a rotating detonation rocket engine (RDRE) was attained on the 3-inch Air Force Research Laboratory (AFRL) Distribution A RDRE, with the fuel and oxidizer injectors modified for H2/O2 gas propellants. Evident in previous experiments, detonation instabilities arising from upstream deflagration, from recirculation zones, and from insufficient gas mixing challenged resolution of detonation wave behavior from back-end imaging with the available optical equipment. Images were often over-illuminated from both the high amount of deflagration in the plume and the higher density of detonation waves in the annulus coupled …
Piezospectroscopic Sensing Systems - Multi-Scale And In-Situ Sensing Technology For Structural Integrity, Remelisa Esteves
Piezospectroscopic Sensing Systems - Multi-Scale And In-Situ Sensing Technology For Structural Integrity, Remelisa Esteves
Electronic Theses and Dissertations, 2020-2023
The aerospace industry relies on nondestructive evaluation (NDE) to ensure aircraft safety and will benefit from methods that allow for early damage detection. Photoluminescence piezospectroscopy (PS) has demonstrated stress and damage sensing of substrates when coupled with alpha-alumina nanoparticles in a polymer matrix applied as a sensor coating. Alpha phase alumina exhibits photoluminescent spectral emission lines (R-lines) that shift due to changes in the stress state of the alumina. The coatings' capability for sensing early subsurface damage suggests the potential for implementing stress sensing paint for integrity monitoring of aircraft structures. To achieve a viable stress sensing coating that can …
Dynamic Modeling And Simulation Of A Power Plant Steam Condenser On The Siemens Sppa-T3000 Platform, Mohammad Odeh
Dynamic Modeling And Simulation Of A Power Plant Steam Condenser On The Siemens Sppa-T3000 Platform, Mohammad Odeh
Electronic Theses and Dissertations, 2020-2023
With rapidly increasing computational power, modeling and simulation of complex systems is gradually becoming the norm for evaluating and predicting performance. This research focuses on modeling and simulating thermodynamic behavior of condensers within Combined Cycle Power Plants. This is particularly useful for power generation companies as this allows a wide range of operating conditions to be simulated and characterized without risking damage or the need to shut down the power plant, all of which results in losing revenue in the process. Moreover, being able to observe the thermodynamic evolution of the system provides useful insight into efficiency and response to …
A Study Into Validating A Coupled Method Of Characteristics And Direct Simulation Monte Carlo Method Against Empirical Data, Andrew Brown
A Study Into Validating A Coupled Method Of Characteristics And Direct Simulation Monte Carlo Method Against Empirical Data, Andrew Brown
Electronic Theses and Dissertations, 2020-2023
The following will outline the methodology and results of validating a coupled Method of Characteristics (MOC) and Direct Simulation Monte Carlo (DSMC) method. This research focused specifically on modeling plume impingement, induced by Reaction Control System (RCS) thrusters that flew on the National Aeronautics and Space Administration's (NASA's) space shuttle Discovery. For each simulation, the continuum portion of the RCS thruster was simulated using MOC for solving hyperbolic Partial Differential Equations (PDEs) and computed with the NASA code, Reacting and Multi-phase Program (RAMP). The solution was then implemented as a starting condition into the NASA DSMC code, Direct Simulation and …
Design And Visual Servo Control Of A Mechanical Gripper For Autonomous Strawberry Harvesting, Jonah Mapes
Design And Visual Servo Control Of A Mechanical Gripper For Autonomous Strawberry Harvesting, Jonah Mapes
Electronic Theses and Dissertations, 2020-2023
With rising labor costs and high consumer demand, economic conditions are becoming increasingly favorable for mechanization in the strawberry industry. However, virtually all strawberry crops are still picked by hand because the harvesting process is very challenging to automate, and strawberries are susceptible to bruising. For these reasons, the development of a harvester which can avoid damaging the fruit is of interest. Conventional designs for robotic grippers are less than ideal, as precise positioning or force feedback capabilities are required to reduce the risk of bruising. As an alternative, a novel "camera-in-hand" gripper design is presented which effectively avoids bruising …
Mechanical Properties Of Boron Carbide (B4c), Ruslan Kuliiev
Mechanical Properties Of Boron Carbide (B4c), Ruslan Kuliiev
Electronic Theses and Dissertations, 2020-2023
Boron carbide (B4C) is one of the most important opaque boride ceramics that has high hardness and Young's modulus that along with low density lead to a significant resistance to ballistic impact and, thus, B4C is broadly used as a protective material. B4C has also high neutron capturing cross section; therefore, it is used as control rods and neutron absorption shielding in nuclear reactors. In this work thermal, electrical and mechanical properties of dense B4C ceramics (99%) sintered using Spark Plasma Sintering (SPS) were investigated. The Young's modulus of B4C measured by three different techniques – IE, RUS, and nanoindentation …
Experimentation And Simulation Of Pulsed Eddy Current Thermography Of Subsurface Aircraft Corrosive Defects, Johnathan Hernandez
Experimentation And Simulation Of Pulsed Eddy Current Thermography Of Subsurface Aircraft Corrosive Defects, Johnathan Hernandez
Electronic Theses and Dissertations, 2020-2023
During the life cycle of aircraft, external structures are under constant attack from environmental degradation in the form of corrosion. Corrosive defects consist of multiple types of surface and subsurface damage that are often undetectable due to surface coatings or insulation leading to loss in structural integrity. Non-destructive techniques for corrosion detection typically require the removal of paint. Detection of corrosion under insulation (CUI) is highly valuable for cost and time effectiveness. Although techniques have been developed for detection of CUI, not many of these satisfy the criteria for portability and hangar operation. To address this, multiple techniques were investigated …