Engineering Commons^™

A Pipeline Analog-To-Digital Converter For A Plasma Impedance Probe, Mohamad A. El Hamoui

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Space instrumentation technology is an essential tool for rocket and satellite research, and is expected to become popular in commercial and military operations in fields such as radar, imaging, and communications. These instruments are traditionally implemented on printed circuit boards using discrete general-purpose Analog-to-Digital Converter (ADC) devices and other components. A large circuit board is not convenient for use in micro-satellite deployments, where the total payload volume is limited to roughly one cubic foot. Because micro-satellites represent a fast growing trend in satellite research and development, there is motivation to explore miniaturized custom application-specific integrated circuit (ASIC) designs to reduce …

Design Of A "Figure-8" Spherical Motion Flapping Wing For Miniature Uav's, Zohaib Parvaiz Rehmat

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hummingbirds and some insects exhibit a Figure-8 motion, which allows them to undergo variety of maneuvers including hovering. It is therefore desirable to have flapping wing miniature air vehicles (FWMAV) that can replicate this unique wing motion. In this research, a design of a flapping wing for FWMAV that can mimic Figure-8 motion using a spherical four bar mechanism is presented. To produce Figure-8 motion, the wing is attached to the coupler point of the spherical four bar mechanism and driven by a DC servo motor. For verification of the design, a prototype of the wing and mechanism is fabricated …

Development Of A New Mixed Mode I-Ii-Iii Delamination Toughness Test, Ruben Hortensius

Renée Crown University Honors Thesis Projects - All

Optimal use of laminated composite materials can only be achieved if its most common failure mechanisms are well understood. One of the most common modes of failure in laminates is delamination, or the separation of adjacent material layers. Therefore, there is a need to be able to predict a laminated composite’s resistance to delamination growth due to the complex real-world application loadings that it may experience. These complex loadings are made up of three primary modes of delamination growth, known as modes I, II, and III. Test fixtures for a new mixed mode I-II-III delamination toughness test were designed, built, …

Terrain-Relative And Beacon-Relative Navigation For Lunar Powered Descent And Landing, Daniel Porter Christensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As NASA prepares to return humans to the moon and establish a long-term presence on the surface, technologies must be developed to access previously unvisited terrain regardless of the condition. Among these technologies is a guidance, navigation and control (GNC) system capable of safely and precisely delivering a spacecraft, whether manned or robotic, to a predetermined landing area. This thesis presents detailed research of both terrain-relative navigation using a terrain-scanning instrument and beacon-relative radiometric navigation using beacons in lunar orbit or on the surface of the moon. The models for these sensors are developed along with a baseline sensor suite …

A Flight Simulation Study Of The Simultaneous Non-Interfering Aircraft Approach, Brian H. Reel

Master's Theses

Using a new implementation of a NASA flight simulation of the Quiet Short-Haul Research Aircraft, autopilots were designed to be capable of flying both straight in (ILS) approaches, and circling (SNI) approaches. A standard glideslope coupler was sufficient for most conditions, but a standard Proportional-Integral-Derivative (PID) based localizer tracker was not sufficient for maintaining a lateral track on the SNI course. To track the SNI course, a feed-forward system, using GPS steering provided much better results.

NASA and the FAA embrace the concept of a Simultaneous, Non-Interfering (SNI) approach as a way to increase airport throughput while reducing the noise …

Comparison And Design Of Simplified General Perturbation Models (Sgp4) And Code For Nasa Johnson Space Center, Orbital Debris Program Office, Nicholas Z. Miura

Master's Theses

This graduate project compares legacy simplified general perturbation model (SGP4) code developed by NASA Johnson Space Center, Orbital Debris Program Office, to a recent public release of SGP4 code by David Vallado. The legacy code is a subroutine in a larger program named PREDICT, which is used to predict the location of orbital debris in GEO. Direct comparison of the codes showed that the new code yields better results for GEO objects, which are more accurate by orders of magnitude (error in meters rather than kilometers). The public release of SGP4 also provides effective results for LEO and MEO objects …

Design And Control Considerations For A Skid-To-Turn Unmanned Aerial Vehicle, Tanner Austin Sims

Master's Theses

The use of Unmanned Aerial Vehicles (UAVs) are rapidly expanding and taking on new roles in the military. In the area of training and targeting vehicles, control systems are expanding the functionality of UAVs beyond their initially designed purpose. Aeromech Engineering’s NXT UAV is a high speed target drone that is intended to simulate a small aircraft threat. However, in the interest of increasing functionality, enabling NXT to accomplish wings level skidding turns provides the basis for a UAV that can simulate a threat from a missile. Research was conducted to investigate the aerodynamic and performance characteristics of a winged …

Design And Fabrication Of A Small Prototype Airframe Structure, Kimberly Lynn Clark

UNLV Theses, Dissertations, Professional Papers, and Capstones

This project called for a first-generation prototype aircraft with hovering capabilities that was lightweight. The focus of this study was to design a small low-cost prototype composite airframe that meets specified requirements, analyze structures using finite element analysis and mechanical testing, and construct a prototype using proven composite manufacturing techniques. One fuselage, one wing, and several engine nacelles were designed and fabricated. Several design and fabrication methods and materials were analyzed, with focus given to the nacelles, and recommendations were provided for the manufacture of the first generation airframe based on time, weight, and cost.

Turn Constrained Path Planning Problems, Victor M. Roman

UNLV Theses, Dissertations, Professional Papers, and Capstones

We consider the problem of constructing multiple disjoint paths connecting a source point s to a target point t in a geometric graph. We require that the paths do not have any sharp turn angles. We present a review of turn constrained path planning algorithms and also algorithms for constructing disjoint paths. We then combine these techniques and present an O(nlogn) time algorithm for constructing a pair of edge disjoint turn constrained paths connecting two nodes in a planar geometric graph. We also consider the development of a turn constrained shortest path map in the presence of …

Influence Of Structural Flexibility On Flapping Wing Propulsion, Aaron M. Mcclung

Theses and Dissertations

The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at 288 degrees C. The experimental program was designed to explore the influence of strain rate on tensile loading, unloading, and strain recovery behaviors. In addition, the effect of the prior strain rate on the relaxation response of the material, as well as on the creep behavior following strain controlled loading were examined. The experimental data were modeled with the Viscoplasticity Based on Overstress (VBO) theory. A systematic procedure for determining model parameters was developed and the model was employed to predict the response of the …

Smallsats, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "SmallSats" from April 30 2009.

Satellite Earth Observation And Surveillance Payloads, Rainer Sandau

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Rainer Sandau titled "Satellite Earth observation and surveillance payloads" from April 9, 2009.

Distributed Satellite Systems For Earth Observation And Surveillance, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Rainer Sandau titled "Distributed satellite systems for Earth observation and surveillance" from April 7, 2009.

A Technology Survey Of Emergency Recovery And Flight Termination Systems For Uas, Richard Stansbury, Wesley Tanis, Timothy Wilson

Publications

For safe flight in the National Airspace System (NAS), either under the current interim rules or under anticipated longer-term regulatory guidelines facilitating unmanned aircraft system (UAS) access to the NAS, the UAS must incorporate technologies and flight procedures to ensure that neither people nor property in the air, on the ground, or on or in the water are endangered by the failure of an onboard component, by inappropriate unmanned aircraft (UA) response to pilot commands, or by inadvertent entry by the UA into prohibited airspace. The aircraft must be equipped with emergency recovery (ER) procedures and technologies that ensure that …

Miniaturization Techniques To Realize Very Small Satellites, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Miniaturization Techniques to Realize Very Small Satellites" from April 6, 2009.

Aircraft Landing Operations On Contaminated Runways, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Subsystem Realization Actuators And Sensors For Satellite Attitude Control For Very Small Satellites, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Subsystem Realization Actuators and Sensors for Satellite Attitude Control for very Small Satellites" from April 1, 2009.

(U) Cubesat Experiments (Qb X), Patrick Bournes, Dave Williamson

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Patrick Bournes and Dave Williamson titled "(U) CubeSat Experiments (Qb X)" from April of 2009.

The Effect Of The Fastener Of Different Configuration Composite Panels On Failure Analysis, Robert Austin

Master's Theses

This study presents the effect of the stacking sequence and fiber orientation on a composite sandwich panel subjected to static in-plane bolt loading. Six plates were constructed with laminates of unidirectional carbon fiber and cross ply weaves of fiberglass. The orientations that were examined included 0, +/- 45, and 90 degrees. Half of the plates had fiberglass lamina on the outside of the laminate while the other three plates had the carbon fiber on the outside. Experimental and analytical tests were performed to determine the best orientations and stacking sequence.

For the numerical analysis, plates with fibers oriented at +/- …

Shielding Effectiveness Of Superalloy, Aluminum, And Mumetal Shielding Tapes, Cindy Suit Cheung

Master's Theses

Using MIL-HDBK-419A, MATLAB and Nomographs, Shielding Effectiveness for the Magnetic Field, Electric Field, and Plane Wave were calculated over a frequency range from 10 Hz to 1 GHz. The three shielding tapes used included superalloy, aluminum, and mumetal. Calculations for Shielding Effectiveness involve the computation of Absorption Loss, Reflection Loss, and Re-Reflection Correction Factor. From the outcome of the calculations, it was suitable to conclude that all three metals fulfill the 40 dB Shielding Effectiveness requirements for SGEMP fields for frequencies greater or equal to 1 MHz. Accordingly, all three shielding tapes provide at least 40 dB of shielding to …

Multiscale Modeling Of Impact On Heterogeneous Viscoelastic Solids With Evolving Microcracks, Flavio V. Souza

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Multiscale computational techniques play a major role in solving problems related to viscoelastic composite materials due to the complexities inherent to these materials. In the present work, a numerical procedure for multiscale modeling of impact on heterogeneous viscoelastic solids containing evolving microcracks is proposed in which the (global scale) homogenized viscoelastic incremental constitutive equations have the same form as the local scale viscoelastic incremental constitutive equations, but the homogenized tangent constitutive tensor and the homogenized incremental history dependent stress tensor depend on the amount of damage accumulated at the local scale. Furthermore, the developed technique allows the computation of the …

Mitigating Crack Propagation In A Highly Maneuverable Flight Vehicle Using Life Extending Control Logic, Mohamed Mostafa Yousef Bassyouny Elshabasy

Mechanical & Aerospace Engineering Theses & Dissertations

In this research, life extending control logic is proposed to reduce the cost of treating the aging problem of military aircraft structures and to avoid catastrophic failures and fatal accidents due to undetected cracks in the airframe components. The life extending control logic is based on load tailoring to facilitate a desired stress sequence that prolongs the structural life of the cracked airframe components by exploiting certain nonlinear crack retardation phenomena. The load is tailored to include infrequent injections of a single-cycle overload or a single-cycle overload and underload. These irregular loadings have an anti-intuitive but beneficial effect, which has …

Multidisciplinary Design Optimization For Sonic Boom Mitigation, Isik A. Ozcer

Mechanical & Aerospace Engineering Theses & Dissertations

Automated, parallelized, time-efficient surface definition and grid generation and flow simulation methods are developed for sharp and accurate sonic boom signal computation in three dimensions in the near and mid-field of an aircraft using Euler/Full-Potential unstructured/structured computational fluid dynamics. The full-potential mid-field sonic boom prediction code is an accurate and efficient solver featuring automated grid generation, grid adaptation and shock fitting, and parallel processing. This program quickly marches the solution using a single nonlinear equation for large distances that cannot be covered with Euler solvers due to large memory and long computational time requirements. The solver takes into account variations …

Numerical Study Of Confined Flow Past An Airfoil Injector With A Planar Jet, Omar A. Alabbasi

Mechanical & Aerospace Engineering Theses & Dissertations

Vortex shedding from an airfoil injector in a channel is investigated by using a numerical solution for unsteady, two-dimensional, Navier-Stokes Equations. A second-order implicit finite-volume scheme is employed to solve the equations. The effect on vortex shedding of a planar jet injected from the rear of the injector is studied. The effect of the jet velocity on the vortex shedding and its drag and lift coefficients are also studied at different blockage ratios and Reynolds numbers for laminar flow. Initial results to validate previous numerical simulations are performed on a square cylinder with and without a planar jet. Good agreement …

Characterization Of Microwave Cavity Discharges In A Supersonic Flow, Dareth Janette Drake

Physics Theses & Dissertations

A partially ionized gas is referred to as either a plasma or a discharge depending on the degree of ionization. The term discharge is usually applied to a weakly ionized gas, i.e. mostly neutrals, where as a plasma usually has a larger degree of ionization. To characterize a discharge the plasma parameters, such as the rotational temperature, vibrational temperature, and electron density, must be determined. Detailed characterization of supersonic flowing discharges is important to many applications in aerospace and aerodynamics. One application is the use of plasma-assisted hydrogen combustion devices to aid in supersonic combustion. In conditions close to the …

A Compact Lidar For Aircraft Ozone Atmospheric Measurements, Joel A. Marcia

Electrical & Computer Engineering Theses & Dissertations

Researchers and the general public have expressed great concern over how human activities exacerbate pollution's deteriorating impact upon the environment. Effects such as global warming, air quality and ozone layer depletion are but a few examples that can have a dramatic effect on the quality of life worldwide.

A compact lidar system for the purpose of aircraft ozone atmospheric measurements was tested and evaluated. This system will eventually be deployed for aircraft-based, and possibly unpiloted atmospheric vehicle (UAV), ozone and aerosol measurements to improve our understanding of ozone production and transport. Each of the major subsystems was characterized and from …

Microgravity Experiments For The Iss, Justin Koeln, Jan Sojka

Posters

The Get Away Special (GAS) team is a microgravity research team known for leading Utah State University to the impressive distinction of flying more experiments in space than any other university in the world. The following experiments were designed by the GAS team after receiving the opportunity to develop and experiment to be performed by a Space Flight Participant aboard the International Space Station (ISS).

Low-Cost Missions At The Space Flight Laboratory, Robert E. Zee

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Robert E. Zee titled "Low-Cost Missions at the Space Flight Laboratory" from March 24, 2009.

Fuel Composition And Performance Analysis Of Endothermically Heated Fuels For Pulse Detonation Engines, Christopher A. Stevens

Theses and Dissertations

Waste heat from a pulse detonation engine (PDE) was extracted via concentric, counter flow heat exchangers to produce supercritical pyrolytic conditions for JP-7 and JP-8 fuels. A sampling system and method was utilized to collect samples of reacted fuel to be extracted during steady state operation. Samples were collected over a range of heat exchanger exit temperatures from 820 K (1016° F) to 940 K (1232 degrees F) and for two sets of heat exchangers, one set coated with zeolite catalyst and one set left uncoated. Variation in fuel mass flow rate required the calculation of heat addition as an …

An Experimental Investigation Studying The Influence Of Dimples On A Film Cooled Turbine Blade Leading Edge, Paul G. Frisinger

Theses and Dissertations

An investigation was conducted to examine the effect of a row of cylindrical surface dimples in reducing the heat load on a turbine blade leading edge model. The models consisted of a foam cylindrical leading edge with a flat afterbody fabricated from Plexiglass. A single coolant hole was located 21.5 degree from the leading edge, angled 20 degree to the surface and 90 degree from the streamwise direction. The leading edge diameter to hole diameter ratio was D/d = 18.7. A row of seven dimples was placed upstream of one of the coolant holes. Infrared thermography techniques were used to …