Development Of Virtual Simulation For Evaluation Of Robotic Assistive Environment,
2021
University of Texas at Arlington
Development Of Virtual Simulation For Evaluation Of Robotic Assistive Environment, Shubham Raosaheb Gunjal
Mechanical and Aerospace Engineering Theses - Archive
Robotics research in virtual simulation has the advantage of reduced testing time, verification of algorithms on different systems before implementation, and cost-saving. Today’s simulation softwares are capable of providing the physics of the simulation such as torque requirements of the joints which aid in the selection of appropriate hardware. In this research, Webots, an open-source physics-based simulation, and visualization software is evaluated and then used to study and evaluate the performance of two robotic systems for a robotic assistive environment for persons with upper limb disabilities. This includes a wheelchair, a table with objects, and two robotic arms attached to …
Investigating A Finite Element Model Updating Methodology For Characterizing Mechanical Properties Of Ncf Composites,
2021
University of Texas at Arlington
Investigating A Finite Element Model Updating Methodology For Characterizing Mechanical Properties Of Ncf Composites, Pasworn Chanchai
Mechanical and Aerospace Engineering Theses - Archive
Composite materials have been a key breakthrough in developing aircraft structures. Their superior strength and stiffness-to-density ratio, which are unmatched by no other materials, allow engineers to create high strength and ultra-lightweight aircraft structures. Recently, non-Crimp Fabric (NCF) composites have emerged as attractive alternatives to traditional autoclave pre-impregnated composites allowing for lower production costs, better handling and improved shelf life while maintaining excellent in-plane mechanical properties compared to other types of textile composites. NCF out-of-plane mechanical properties can also be enhanced by stitching a high tensile strength yarn throughout their entire laminate thickness, improving the resistance to delamination. However, stitch-reinforced …
Characterization And Enhancement Of Mechanical Properties In Thermoplastic Fff Parts Using In-Situ Annealing,
2021
University of Texas at Arlington
Characterization And Enhancement Of Mechanical Properties In Thermoplastic Fff Parts Using In-Situ Annealing, Rhugdhrivya Rane
Mechanical and Aerospace Engineering Dissertations - Archive
Fused filament fabrication is one of the most common and widely used additive manufacturing techniques. Owing to its ease of use, availability and cheap feedstock it provides a significant advantage over other AM techniques. But these advantages are overshadowed by the fact that FFF parts show high anisotropy and reduced mechanical properties as compared to conventional manufacturing techniques. Literature review of previous research works show multiple approaches to enhance the mechanical properties of FFF parts but each of these techniques have limitations to either the geometries that can be printed or involve complex expensive setups. In one such technique a …
Shape Modeling, Attitude Estimation, And Classification Of Artificial Resident Space Objects (Rso) Using Photometric Light Curves,
2021
University of Texas at Arlington
Shape Modeling, Attitude Estimation, And Classification Of Artificial Resident Space Objects (Rso) Using Photometric Light Curves, Katiyayni Balachandran
Mechanical and Aerospace Engineering Dissertations - Archive
Light curve inversion (LCI) has proven valuable in using photometric measurements to optimize various physical parameters of a resident space object (RSO) such as rotational period about its own spin axis, pole orientation and others. Other characteristics such as shape and size are dependent on the surface brightness. To accurately determine size, shape, spin rate, or attitude information of an unresolved resident space object, photometry is required to capture the relatively rapid changes in brightness that these objects can exhibit. LCI has been developed significantly for asteroids, although not fool-proof for artificial RSOs. Satellites and space debris, unlike asteroids, are …
Theoretical And Experimental Analysis And Optimization Of Thermal Conduction In Electrochemical And Latent Heat Energy Storage Systems,
2021
University of Texas at Arlington
Theoretical And Experimental Analysis And Optimization Of Thermal Conduction In Electrochemical And Latent Heat Energy Storage Systems, Amirhossein Mostafavi
Mechanical and Aerospace Engineering Dissertations - Archive
Phase change materials (PCMs) are used commonly for energy storage purposes. Thermal energy can be stored in a PCM with a variety of configurations such as PCM slabs, cartesian and cylindrical finned systems. Heat transfer in PCM storage systems can be from a heat transfer fluid (HTF) or a heat source at constant temperature to adjacent PCM. The rate of heat transfer is limited by thermal properties. Fin insertion can improve the heat transfer inside the PCM. Chapters 2 and 3 derive and solve the governing energy equations to determine the transient temperature distribution in the PCM due to the …
Rotor Performance Model (Rpm),
2021
University of Texas at Arlington
Rotor Performance Model (Rpm), Chadwick Scott Balfantz
Mechanical and Aerospace Engineering Theses - Archive
Rotorcraft performance modeling is of high interest with multiple industry codes in existence, many of which are high-fidelity and are comprehensive in the analyses that are achievable. Along with the high-fidelity and the comprehensive nature of the industry codes comes an equally high level of complexity in the inputs required to extract meaningful results. The ever-increasing fidelity in the existing codes creates a need for an analysis code that is built to be highly flexible, designed from the top down and implemented from the bottom up in a structured format. The Rotor Performance Model (RPM) was developed to provide high-fidelity …
Development Of An Anisotropic Thermal Stress Model For A Low-Erosion Hybrid Rocket Nozzle System,
2021
Utah State University
Development Of An Anisotropic Thermal Stress Model For A Low-Erosion Hybrid Rocket Nozzle System, Judson C. Stephens
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Hybrid rockets are rockets which employ a solid fuel grain with a liquid oxidizer. Hybrids have many promising potential applications, however they also have a few drawbacks. Of interest to this research is the increased rate of nozzle erosion inherent to hybrid rockets. In order to address this issue, a low-erosion nozzle is proposed and evaluated.
Interior Point Optimization Of Low-Thrust Spacecraft Trajectories,
2021
California Polytechnic State University, San Luis Obispo
Interior Point Optimization Of Low-Thrust Spacecraft Trajectories, Jordan D. Frederiksen
Master's Theses
Low-thrust interplanetary spacecraft trajectory optimization poses a uniquely difficult problem to solve because of the inherent nonlinearities of the dynamics and constraints as well as the large size of the search space of possible solutions. Tools currently exist that optimize low-thrust interplanetary trajectories, but these tools are rarely openly available to the public, and when they are available they require multiple interfaces between multiple different packages. The goal of this work is to present a new piece of low-thrust interplanetary spacecraft trajectory optimization software that is open-source and entirely self-contained so that more people can have access to the ability …
Plasma-Based Water Purification For Crewed Space Missions: Laboratory Experimental Comparisons For On-Board Applicability,
2021
University of Alabama in Huntsville
Plasma-Based Water Purification For Crewed Space Missions: Laboratory Experimental Comparisons For On-Board Applicability, Ryan P. Gott, Sydney D. Miller, Josie C. Hodges, Kunning G. Xu
PRC-Affiliated Research
Low-temperature, atmospheric pressure plasma presents a new, inexpensive, and environmentally friendly method of water purification. For long duration crewed space missions, a novel water purification system that does not rely on consumable filters and chemicals would be desirable. Plasma systems provide a viable option for these missions, but their operation and designs need to be optimized and compared to existing technology. For this application, gas and power usage are key limiting factors. In this work, water contaminated with methylene blue is purified with plasma. The rate of purification, gas flow usage, and power consumption are compared for multiple devices. A …
Plasma-Based Water Purification For Crewed Space Missions: Laboratory Experimental Comparisons For On-Board Applicability,
2021
University of Alabama in Huntsville
Plasma-Based Water Purification For Crewed Space Missions: Laboratory Experimental Comparisons For On-Board Applicability, Ryan P. Gott, Sydney D. Miller, Josie C. Hodges, Kunning G. Xu
PRC-Affiliated Research
Low-temperature, atmospheric pressure plasma presents a new, inexpensive, and environmentally friendly method of water purification. For long duration crewed space missions, a novel water purification system that does not rely on consumable filters and chemicals would be desirable. Plasma systems provide a viable option for these missions, but their operation and designs need to be optimized and compared to existing technology. For this application, gas and power usage are key limiting factors. In this work, water contaminated with methylene blue is purified with plasma. The rate of purification, gas flow usage, and power consumption are compared for multiple devices. A …
Multilateration Index.,
2021
University of Louisville
Multilateration Index., Chip Lynch
Electronic Theses and Dissertations
We present an alternative method for pre-processing and storing point data, particularly for Geospatial points, by storing multilateration distances to fixed points rather than coordinates such as Latitude and Longitude. We explore the use of this data to improve query performance for some distance related queries such as nearest neighbor and query-within-radius (i.e. “find all points in a set P within distance d of query point q”). Further, we discuss the problem of “Network Adequacy” common to medical and communications businesses, to analyze questions such as “are at least 90% of patients living within 50 miles of a covered emergency …
Object Classication, Detection And State Estimation Using Yolo V3 Deep Neural Network And Sensor Fusion Of Stereo Camera And Lidar,
2021
University of Texas at Arlington
Object Classication, Detection And State Estimation Using Yolo V3 Deep Neural Network And Sensor Fusion Of Stereo Camera And Lidar, Kamalkumar Bharatkumar Mehta
Mechanical and Aerospace Engineering Theses - Archive
Real-time object classification, localization, and detection with region-based convolution neural network (R-CNN) require high computational power, or it consumes a tremendous amount of time with the use of the available onboard computer system. Therefore, either of those ways is not practical in real-time object detection. In contrast, the YOLO-v3 network, which stands for you only look once, that uses the YOLO algorithm seems to be practical in live object classification, localization, and detection, since the YOLO algorithm seems to work faster than the sliding window algorithm used by R-CNN. Sensor fusion in this context requires estimation and association of information …
Background Flow Influence On Impulsive Jet-Driven Micro Droplet Dispersal,
2021
Embry-Riddle Aeronautical University
Background Flow Influence On Impulsive Jet-Driven Micro Droplet Dispersal, Vaishak Thiruvenkitam
Doctoral Dissertations and Master's Theses
Accurately predicting the airborne spread of infectious diseases is crucial in controlling the COVID19 pandemic today. Studies have shown the spread of expiratory droplets depends on ambient thermodynamic conditions and flow properties of the jet emitted by the activity. However, the droplet spread in conditions of background flow is not yet comprehensively understood. This study uses the Eulerian-Lagrangian model with k−ω turbulence modelling to simulate spread of particles and study the factors affecting it in a closed environment with a background flow. Respiratory activities are modeled as a non-isothermal jet of air with droplets suspended in them in a predetermined …
Active Control Of Coherent Structures In An Axisymmetric Jet,
2021
Embry-Riddle Aeronautical University
Active Control Of Coherent Structures In An Axisymmetric Jet, Michael Marques Goncalves
Doctoral Dissertations and Master's Theses
The primary objective of this work is to develop high-fidelity simulation model for jet noise control predictions and quantify the sound reduction when an external source frequency mode excitation is imposed on the jet flow. Whereas passive approaches using mixing devices, such as chevrons, have been shown to reduce low-frequency noise in jet engines, such approaches incur a performance penalty since they result in a reduced thrust. To avoid a performance penalty in reducing jet noise, the current work investigates a open-loop active noise control (ANC) system that utilizes a unsteady microjet actuator on the nozzle lip in the downstream …
Shape Optimization Of A Sandwich Composite Plate With Low-Velocity Impact Loading And Effect Of Finite Difference Sensitivity Analysis,
2021
Embry-Riddle Aeronautical University
Shape Optimization Of A Sandwich Composite Plate With Low-Velocity Impact Loading And Effect Of Finite Difference Sensitivity Analysis, Utsav Shah
Doctoral Dissertations and Master's Theses
The structural design of spacesuits is essential in an advancing future of both Lunar and Martian space exploration. A typical spacesuit is made of sandwich composite material and designed to withstand various pressure and loading conditions while also considering the safety and comfort of the astronauts. One of the critical load cases in spacesuit design is a low-velocity impact (LVI) which may occur due to tool drop and other similar scenarios. The objectives of this work were (a) to create a finite element (FE) model of a component of a spacesuit, (b) validation of the FE model through experiments, (c) …
Design, Development, And Testing Of Research Payloads On Various Suborbital Flight-Test Platforms,
2021
Embry-Riddle Aeronautical University
Design, Development, And Testing Of Research Payloads On Various Suborbital Flight-Test Platforms, Vijay Vishal Duraisamy
Doctoral Dissertations and Master's Theses
With recent advances in the commercial space industry, suborbital payload launches have become more common and accessible to researchers actively seeking solutions for problems involving prolonged space travel and future missions to Moon and Mars. Suborbital payload missions compared to orbital launches are less expensive and offer faster turnaround times; however, the novelty of this domain provides unique challenges. This multidisciplinary research effort aims to tackle some of these challenges by detailing the design, development, and testing techniques followed in the successful launch and recovery of payload experiments in currently active and upcoming suborbital launch vehicles. The research methodology involves …
Durability And Damage Analysis Of Hybrid Multiscale Composites,
2021
Embry-Riddle Aeronautical University
Durability And Damage Analysis Of Hybrid Multiscale Composites, Suma Ayyagari
Doctoral Dissertations and Master's Theses
In this dissertation, an effort was carried out to enhance the mechanical performance of fiber reinforced composites (FRPs) by modification of the fibers’ surface morphologies. The effects of various surface alterations of a plain-woven carbon fiber fabric surface, on the fiber/epoxy interface were investigated. The alterations were mostly achieved by growing different nanofillers like zinc oxide nanorods (ZnO NR), carbon nanotubes (CNTs), and metal organic frameworks (MOFs) on the fiber surface. While the growth techniques for ZnO NR and CNTs place restrictions on the size of the fabricated composites, MOFs route is uniform, affordable, and can be readily scaled up …
A Reduced-Order Model Bi-Modal Excitation Of A Supersonic Planar Jet,
2021
Embry-Riddle Aeronautical University
A Reduced-Order Model Bi-Modal Excitation Of A Supersonic Planar Jet, Benjamin Malczewski
Doctoral Dissertations and Master's Theses
This work analytically and numerically examines the effects of bi-modal excitation on a Mach 1.5 heated planar jet. Starting with the Navier-Stokes equations, triple decomposition is applied to the flow components. A reduced order model is derived, turning the Navier-Stokes partial differential equations into a set of coupled ordinary differential equations, relating the momentum thickness and amplitudes of a fundamental and subharmonic mode to the streamwise location along the jet. Computational fluid dynamics data from the minor plane of a Mach 1.5 heated rectangular jet is used to verify a hyperbolic tangent profile for the mean flow at various streamwise …
Envelope Analysis Of Speed-Controlled Evtol Urban Air Mobility Vehicles,
2021
Embry-Riddle Aeronautical University
Envelope Analysis Of Speed-Controlled Evtol Urban Air Mobility Vehicles, David J. Thompson
Doctoral Dissertations and Master's Theses
There are many vehicles being developed which rely on electrically driven propellers/rotors for both control and propulsion. Based on these vehicles, it is hypothesized that there exists a size limit for speed-controlled propellers/rotors in terms of propeller/rotor diameter. To investigate this, a scaling method was created to allow for a vehicle to be created without being based on a specific mission or passenger/cargo requirement. Relationships were developed to size both the physical vehicle and the weight of the vehicle based on the propeller/rotor diameter. A simulation of a quadcopter was created for the vehicle and scaled with both propeller/rotor diameter …
Flight Trajectory Prediction For Aeronautical Communications.,
2021
University of Louisville
Flight Trajectory Prediction For Aeronautical Communications., Nathan T Schimpf
Electronic Theses and Dissertations
The development of future technologies for the National Airspace System (NAS) will be reliant on a new communications infrastructure capable of managing a limited spectrum among aircraft and ground systems. Emerging approaches to this spectrum allocation task mostly consider machine learning techniques reliant on aircraft and Air Traffic Control (ATC) sector data. Much of this data, however, is not directly available. This thesis considers the development of two such data products: the 4D trajectory (latitude, longitude, altitude, and time) of aircraft, and the anticipated airspace utilization and communication demand within an ATC sector. Data predictions are treated as a time …
