Aerospace Engineering Commons^™

Developing A Robust Balance For Wingsuit Aerodynamic Research, Timothy A. Sestak

Aviation / Aeronautics / Aerospace International Research Conference

Research on wingsuit aerodynamics requires specialized wind tunnel equipment. There is the potential for the relatively large ram-air inflated fabric airfoils being examined to flap and oscillate uncontrolled in the wind tunnel airflow. This chaotic combination of motion and forces could damage the fragile precision balances currently used. Due to the relatively recent development of wingsuit flight as an active sport, there is very little background literature on wingsuit aerodynamics, wingsuit testing, and the equipment and sensors required. A new balance design, able to accurately measure and record basic lift and drag forces while also being able to withstand the …

Human Factors Considerations In Autonomous Lethal Unmanned Aerial Systems, Kristine Kiernan

Aviation / Aeronautics / Aerospace International Research Conference

The United States military is committed to the development of complete autonomy in unmanned vehicles, including armed unmanned aerial systems (UAS). The design and deployment of autonomous lethal UAS raises ethical issues that have implications for human factors. System design, procedures, and training will be impacted by the advent of autonomous lethal UAS. This paper will define relevant vocabulary, review the literature on robot ethics as it applies to the military setting, discuss various perspectives in the research community, address levels of UAS autonomy, and discuss implications for operator training, responsibility, and human-machine interaction. Familiarity with these ethical issues and …

Insights Into Uas Accidents And Incidents, Robert Joslin

Aviation / Aeronautics / Aerospace International Research Conference

The proliferation and extension of unmanned aircraft systems from military to civil and public use applications has rapidly outpaced the safety analysis that is normally associated with the introduction of a new and novel aircraft. Insights into the types of anomalous events associated with accidents and incidents involving civil and public use unmanned aircraft systems operating in the National Airspace System were derived from an information synthesis of archival publically available reports from the FAA Preliminary Reports of Unmanned Aircraft System Accidents and Incidents database, as recorded in the Aviation Safety Information and Analysis Sharing system. The vast majority of …

Effect Of A Dc Preionization Source On Energy Deposition In A Pulsed Inductive Plasma, Ryan A. Pahl, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Time-Resolved Argon Theta-Pinch Plasma Properties By Line Ratio Method With Collisional-Radiative Model, Warner C. Meeks, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

A Low-Cost, Software Defined, Ground-Based Radio Frequency Beacon Receiver (Rfbr) For Measuring Ionosphere Tec And Amplitude And Phase Scintillation, Jacob Gunther, Chad Fish, Charles Swenson, Tim Neilsen, Brent Haslem, Bryan Hansen, Kelby Davis, Steve Higley, Todd Parris, Don Thompson, Charles Rino, Keith Groves

Space Dynamics Laboratory Publications

By monitoring the effects of the ionosphere on multiple space originating radio frequency (RF) beacons, characterizing parameters can be derived which can then be ingested into global assimilative models to improve ionospheric specification and to estimate ionosphere-induced degradation of communication and navigation signals across the electromagnetic spectrum. This paper describes the requirements, design and construction of a ground-based beacon receiver for measuring total electron concentration and amplitude and phase scintillation of the ionosphere. The design achieves very low cost by using the latest in commercial RF and software defined radio technology. The receiver can simultaneously observe three tones spanning ultra-high …

Aerodynamic Testing And Development Of Sunswift Eve, Simon Ambrose, Graham Doig

Aerospace Engineering

The current understanding of the aerodynamic performance of Sunswift’s solar-electric race car eVe is limited, despite the design and manufacture of the vehicle in 2012-13. This paper describes an investigation into the aerodynamic behaviour of the vehicle and details the successive design and development of drag minimisation strategies. A study of the ex­ternal airflow around the vehicle was undertaken through a computational fluid dynamics analysis, with validation offered through the results of real-world track testing. Particular reference is made to the Sunswift team’s successful long-range electric vehicle land speed record attempt on 23 July 2014. A predicted 10% reduction in …

Numerical Investigation On Charring Ablator Geometric Effects: Study Of Stardust Sample Return Capsule Heat Shield, Haoyue Weng, Alexandre Martin

Mechanical Engineering Faculty Publications

Sample geometry is very influential in small charring ablative articles where 1D assumption might not be accurate. In heat shield design, 1D is often assumed since the nose radius is much larger than the thickness of charring. Whether the 1D assumption is valid for the heat shield is unknown. Therefore, the geometric effects of Stardust sample return capsule heat shield are numerically studied using a material response program. The developed computer program models material charring, conductive heat transfer, surface energy balance, pyrolysis gas transport and orthotropic material properties in 3D Cartesian coordinates. Simulation results show that the centerline temperatures predicted …

A Multi-Scale Based Model For Composite Materials With Embedded Pzt Filaments For Energy Harvesting, A.E. El-Etriby, M.E. Abdel-Meguid, K.M. Shalan, Tarek Hatem, Yehia Bahei-El-Din

Centre for Advanced Materials

Ambient vibrations are major source of wasted energy, exploiting properly such vibration can be converted to valuable energy and harvested to power up devices, i.e. electronic devices. Accordingly, energy harvesting using smart structures with active piezoelectric ceramics has gained wide interest over the past few years as a method for converting such wasted energy. This paper provides numerical and experimental analysis of piezoelectric fiber based composites for energy harvesting applications proposing a multi-scale modeling approach coupled with experimental verification. The multi-scale approach suggested predicting the behavior of piezoelectric fiber-based composites use micromechanical model based on Transformation Field Analysis (TFA) to …

Intelligent Control Of Miniature Holonomic Vertical Take-Off And Landing Robot, Mohammad A. Jaradata, Mohamed Al-Fandia, Omar Alkhatiba, Yousef Sardahi

All Engineering Faculty Research

This paper discusses the development of a fuzzy based controller for miniaturized unmanned aerial vehicle (UAV).This controller is designed to control the center-of-gravity (CoG) in a new configuration of coaxial miniaturized flying robot (MFR). The idea is to shift the CoG by controlling two pendulums located in perpendicular directions; each pendulum ends with a small mass. A key feature of this work is that the control algorithm represents the original nonlinear function that describes the dynamics of the proposed system. The controller model incorporates two cascaded subsystems: PD and PI fuzzy logic controllers. These two controllers regulate the attitude and …

Identification Of Geostationary Satellites Using Polarization Data From Unresolved Images, Andy Speicher

Electronic Theses and Dissertations

In order to protect critical military and commercial space assets, the United States Space Surveillance Network must have the ability to positively identify and characterize all space objects. Unfortunately, positive identification and characterization of space objects is a manual and labor intensive process today since even large telescopes cannot provide resolved images of most space objects. Since resolved images of geosynchronous satellites are not technically feasible with current technology, another method of distinguishing space objects was explored that exploits the polarization signature from unresolved images.

The objective of this study was to collect and analyze visible-spectrum polarization data from unresolved …

The Milton Lehman Papers, Milton Lehman

Finding Aids

Milton Lehman (1917-1966) was a free-lance writer, contributing about 250 articles to national magazines such as Saturday Evening Post, Life, Reader’s Digest, McCall’s, Look, The York Times, and other periodicals, books and newspapers. He wrote a biography of Robert H. Goddard that was published in 1963. He was helped throughout the seven year writing process by Esther C. Goddard, Goddard’s wife, who supplied him with transcripts of Goddard’s notes, notebooks, diaries, reports and correspondence and with photographs of his work as well as her own recollections. Lehman interviewed people from all parts of Goddard’s life; his childhood, schooling, early Clark …

Cavity Ignition In Supersonic Flow By Spark Discharge And Pulse Detonation, Timothy M. Ombrello, Campbell D. Carter, Chung-Jen Tam, Kuang-Yu Hsu

United States Air Force: Publications

Ignition of an ethylene fueled cavity in a supersonic flow was achieved through the application of two energy deposition techniques: a spark discharge and pulse detonator (PD). High-frequency shadowgraph and chemiluminescence imaging showed that the spark discharge ignition was passive with the ignition kernel and ensuing flame propagation following the cavity flowfield. The PD produced a high-pressure and temperature exhaust that allowed for ignition at lower tunnel temperatures and pressures than the spark discharge, but also caused significant disruption to the cavity flowfield dynamics. Under certain cavity fueling conditions a multiple regime ignition process occurred with the PD that led …

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 …

Three-Dimensional Indeterminate Impacts In Legged Robotic Locomotion, Abhishek Chatterjee

Mechanical and Aerospace Engineering Theses - Archive

Legged robotic systems undergo a large number of impacts during walking or running tasks. These impacts occur over the surface of contact between the feet and the ground. If a rigid body assumption is held, these impacts can be analyzed by selecting a certain number of points on the impacting bodies. A minimum of three points are required for analyzing a surface contact on a plane. However, using a minimum number of points for analyzing surface impact would require an additional analysis for appropriately selecting these points. On the other hand, if a large number of evenly distributed impact points …

Biomechanical Analysis Of The Cornea To Improve Post Surgical Outcomes Through Finite Element Analysis, Salman Nasir Khan

Mechanical and Aerospace Engineering Dissertations - Archive

Vision deterioration is a major healthcare concern. It is estimated that one in three persons develops some form of vision reducing eye disease by the age of 65 and these numbers are expected to increase. Deterioration in visual acuity is due to ocular diseases that change the shape or clarity of the cornea. Health/shape of the cornea is extremely important as it determines the refractive power of the eye.This work studies ocular surgeries from a mechanical/structural engineering perspective. It begins by discussing laser in-situ keratomileusis (LASIK) surgery and explains the role of lasers in modifying the corneal shape to improve …

Design Of Cooling And Ventilation Of Telecommunication Shelter At High Altitude, Palak Patel

Mechanical and Aerospace Engineering Theses - Archive

Telecommunication shelters house information technology (IT), networking, power, and cooling equipment such as racks, power cabinets, batteries, fans, etc. For reliable operation of the IT and networking equipment, shelters need to satisfy or exceed minimum environmental guidelines for all equipment they contain. These guidelines typically contain specified operational temperature, maximum gaseous and particular contaminant levels. In this work, cooling and ventilation needs of a telecommunication shelter at an altitude of 9,678 feet are studied by modeling the system and simulating various operational and weather scenarios using FloVENT 10.1, a computational fluid dynamics (CFD) tool. The shelter contains two compartments: the …

Experimental And Computatonal Analysis Of The Effect Of Pcb Layer Copper Thickness And Prepreg Layer Stiffness On Solder Joint Reliability, Sanjay Mahesan Revathi

Mechanical and Aerospace Engineering Theses - Archive

The emphasis of this study is to find out how the solder joints of the BGA package are affected with change in the stack up PCB layer copper thickness and the prepeg layer stiffness. In general the effect of the PCB layer thickness is to increase the stress and strain range and to decrease the thermal fatigue life. Basically a PCB consists of different layers with different material properties (Eg: Cu, FR4 etc.).In this paper we deal with the PCB with 1-6-1 configuration (6 core layers and 1 prepeg layer on the top and bottom). A Prepeg is a fiber …

Study Of Hotspot Cooling For Integrated Circuits Using Electrowetting On Dielectric Digital Microfluidic System, Govindraj Shreyas Bindiganavale

Mechanical and Aerospace Engineering Dissertations - Archive

Thermal management in electronics is an ever-growing challenge which needs constant innovations to regulate hotspots in integrated circuits for safe operation within its Thermal Design Power (TDP) envelope. As the number of transistors increase due to advancements in photolithography to enable die shrink, portable electronics are on the rise and so is the demand for microscale cooling systems because conventional cooling components like heat sinks, heat pipes and fans are not capable of meeting design requirements for cooling solutions. In addition to the benefits enjoyed by microscale cooling systems like compact and lightweight design along with simple operation, electrowetting on …

Accurate Three-Dimensional Characterization Of The Nonlinear Material Constitutive Properties For Laminated Composite Materials, Julia Elaine Cline

Mechanical and Aerospace Engineering Dissertations - Archive

Accurate and efficient full three-dimensional characterization of mechanical properties of composite materials, including stress-strain curves and strength characteristics, is essential for understanding complex deformation and failure mechanisms of composites and optimizing material qualification efforts. Non-contact full-field deformation measurement techniques such as digital image correlation (DIC) allowing for assessment of all surface strain components on the entire specimen surface, enable simpler experimental setups and material specimen designs for more efficient and accurate material characterization. This work presents a new method enabling simultaneous assessment of the shear stress-strain curves in all three principal material planes. The method uses a small rectangular plate …