Aerospace Engineering Commons^™

Robust Image-Based Visual Servo Control Of An Uncertain Missile Airframe, Murat Tunca Aygun

Doctoral Dissertations and Master's Theses

A nonlinear vision-based guidance law is presented for a missile-target scenario in the presence of model uncertainty and unknown target evasive maneuvers. To ease the readability of this thesis, detailed explanations of any relevant mathematical tools are provided, including stability definitions, the procedure of Lyapunov-based stability analysis, sliding mode control fundamentals, basics on visual servo control, and other basic nonlinear control tools. To develop the vision-based guidance law, projective geometric relationships are utilized to combine the image kinematics with the missile dynamics in an integrated visual dynamic system. The guidance law is designed using an image-based visual servo control method …

Investigation Into The Effects Of Wire Mesh On Tensile And Impact Properties Of Fiber Metal Laminates, Shivani A. Rudradat

Doctoral Dissertations and Master's Theses

An investigational study was conducted into the tensile and impact behavior of Fiber Metal Laminates by combining 5052 alumintrm mesh or2024-T3 aluminum sheets,2.47 N (8.9 oz) or 6.67 N (24 az) ShieldStand^® S fiberglass, and Hysol EA 9313 epoxy. Testing was performed under the guidelines of ASTM D3039-00 utilizing an lnstron 8802 Servohydraulic Materials Testing Instrument for tensile tests and ASTM D3763-06 utilizing an Inston 9250 HV Dynatup Impulse Impact Testing System for impact tests. Samples were strained at arate of 2 mrn/min for tensile tests and impacted with enetgies of 10 to 40 J in l0 J increments …

Molecular Dynamics Model Of Carbon Nanotubes In Epon 862/Detda Polymer, Guttormur Arnar Ingvason

Doctoral Dissertations and Master's Theses

The aerospace industry is interested in increasing the strength while reducing the weight of carbon fiber composite materials. Adding single walled carbon nanotubes (SWCNT) to a polymer matrix can achieve that goal by improving delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential to represent the interactions between the atoms of the polymer and the SWCNT. This …

Flying The U-2, Art Saboski

ERAU Prescott Aviation History Program

Learn what it was like to fly the famous U-2, one of history’s most secretive aircraft, from a pilot who has done just that. Art Saboski spent most of his Air Force career flying the U-2; commanding U-2 organizations as well as planning and conducting reconnaissance/intelligence operations. He will give his unique perspectives on the high altitude aircraft, its history, development and current uses today.

Mapping Automotive Like Controls To A General Aviation Aircraft, Christopher G. Carvalho

Doctoral Dissertations and Master's Theses

The purpose of this thesis was to develop fly-by-wire control laws enabling a general aviation aircraft to be flown with automotive controls, i.e. a steering wheel and gas/brake pedals. There was a six speed shifter used to change the flight mode of the aircraft. This essentially allows the pilot to have control over different aspects of the flight profile such as climb/descend or cruise. A highway in the sky was used to aid in the navigation since it is not intuitive to people without flight experience how to navigate from the sky or when to climb and descend.

Many believe …

Preliminary Design Of Blade And Disc Fixing For Aerospace Application Using Multi-Disciplinary Approach, Abdulhalim Twahir

Doctoral Dissertations and Master's Theses

The preliminary design phase of a turbine rotor has an important impact on the architecture of a new engine definition, as it sets the technical envelope of the product to be designed. Additionally, preliminary design cycle times are increasingly critical in capturing business opportunities in an ever competitive environment. Improving the accuracy of the preliminary design (pre-detailed design) is also necessary as not only does it significantly reduce the overall development of an engine, but also because any mistakes made at this stage can be extremely hard to rectify.

Previously, typical pre-detail fixing design cycle time was greater due to …

Observability And Confidence Of Stability And Control Derivatives Determined In Real Time, Alfonso Noriega

Doctoral Dissertations and Master's Theses

Stability and control derivatives of an aircraft were estimated from real flight test data in real time. A higher language block diagram library was developed for this purpose. Parameter identification techniques and requirements were used to detect and rate maneuvers present in the data. These ratings were used to blend newly calculated derivatives with previously known values by means of a Kalman filter. The Kalman filter output was used to identify the health of control surfaces actuators. Statistical and measured data were used to predict the probability that an actuator failure has occurred at any given time during the flight. …

Investigation Of Grid Adaptation To Reduce Computational Efforts For A 2-D Hydrogen-Fueled Dual-Mode Scramjet, Kam Keong Foo

Doctoral Dissertations and Master's Theses

A two-dimensional dual-mode scramjet flowpath is developed and evaluated using the ANSYS Fluent density-based flow solver with various computational grids. Results are obtained for fuel-off, fuel-on non-reacting, and fuel-on reacting cases at different equivalence ratios. A one-step global chemical kinetics hydrogen-air model is used in conjunction with the eddy-dissipation model. Coarse, medium and fine computational grids are used to evaluate grid sensitivity and to investigate a lack of grid independence. Different grid adaptation strategies are performed on the coarse grid in an attempt to emulate the solutions obtained from the finer grids. The goal of this study is to investigate …

Attitude Dynamics Of Debris Resulting From Upper Stage Fragmentation In Low Earth Orbit, Killian Marie

Doctoral Dissertations and Master's Theses

This thesis addresses the analysis of the attitude dynamics of pieces of space debris that could result from the fragmentation of a spent upper stage in low Earth orbit (LEO).

Up to now only whole objects of axisymmetric shape have been studied with the purpose of estimating their tumbling rates in LEO. Three shapes have been considered to be representative for the purpose of the study: a thin plate, a monocoque shell, an half conical shell and a spherical shell, and it has been assumed that they are fabricated from aluminum alloy. The motion of conducting body in a magnetic …

Multi-Stage Axial Compressor With Counter-Rotation, Vinod Gehlot, Magdy S. Attia, Divyam Garg

Publications

A multi-stage axial compressor incorporating a counter-rota­tional movement is provided with a series of rotors mounted along and driven by a driveshaft, and a geared counter-rotat­ing outer casing. A planetary gear system is assembled along a static casing, which can be assembled as a forward or aft casing for the compressor. The bearings of the planetary gear system typically will be aligned concentrically with a center rotor drum assembly mounted along the single driveshaft. The counter-rotating drum assembly will be assembled over the rotor drum assembly and will be engaged by the forward and aft casings so as to provide …

Fluid-Structure Interaction And Multidisciplinary Design Analysis Optimization Of Composite Wind Turbine Blade, Naishadh G. Vasjaliya

Doctoral Dissertations and Master's Theses

A multidisciplinary design analysis optimization (MDAO) process is defined for a composite wind turbine blade to optimize its aerodynamic and structural performance by developing a fluid-structural interaction (FSI) system. The objectives are to maximize aerodynamic efficiency and structural robustness while reducing blade mass and total cost. In the previous research, a MDO process of a composite wind turbine blade has been pioneered as an effective process to develop structurally optimized blade design. Present MDAO process is defined in conjunction with structural and aerodynamic performance of the blade which is divided into three steps and the design variables considered are related …

Computing Radiation Exchange, Jonathan L. Nutzati Fontaine

Doctoral Dissertations and Master's Theses

A computational tool to simulate thermal radiation between surfaces is developed. The output is verified against cases for which the analytical solutions are available. The tool can be used as a stand-alone program, or as an interactive module for CFD. In such an application the module would augment other heat transfer boundary conditions. The tool is demonstrated by post-processing surface temperature field data from a supersonic CFD calculation. The result is a net thermal radiation surface data field - the black body radiative effluxes as functions of temperature, less the integrated influxes multiplied by their geometric view factors from other …

The Effects Of Angle-Of-Attack Indication On Aircraft Control In The Event Of An Airspeed Indicator Malfunction, Claas Tido Boesser

Doctoral Dissertations and Master's Theses

Analysis of accident data by the Federal Aviation Administration, the National Transportation Safety Board, and other sources show that loss of control is the leading cause of aircraft accidents. Further evaluation of the data indicates that the majority of loss of control accidents are caused by the aircraft stalling. In response to these data, the Federal Aviation Administration and the General Aviation Joint Steering Committee emphasize the importance of stall and angle-of-attack awareness during flight. The high-profile crash of Air France Flight 447, in which pilots failed to recover from a self-induced stall, reinforced concerns over the need for improved …

The Effects Of Sensor Performance As Modeled By Signal Detection Theory On The Performance Of Reinforcement Learning In A Target Acquisition Task, Nate Quirion

Doctoral Dissertations and Master's Theses

Unmanned Aerial Systems (UASs) today are fulfilling more roles than ever before. There is a general push to have these systems feature more advanced autonomous capabilities in the near future. To achieve autonomous behavior requires some unique approaches to control and decision making. More advanced versions of these approaches are able to adapt their own behavior and examine their past experiences to increase their future mission performance. To achieve adaptive behavior and decision making capabilities this study used Reinforcement Learning algorithms. In this research the effects of sensor performance, as modeled through Signal Detection Theory (SDT), on the ability of …

Linear Model Estimation Of Nonlinear Systems Using Least-Squares Algorithm5, Alireza Rahrooh, Walter W. Buchanan, Remzi Seker

Publications

This paper presents utilizes Least-Squares Algorithm to obtain more accurate linear models of nonlinear systems using parameter estimation. This approach generates an optimal linear model which is valid over a wide range of trajectories and converges to the desired steady-state value with no errors unlike the existing techniques. The proposed technique is very efficient and does not require storing the data. Therefore, it can easily be used and implemented with limited resources for undergraduate curriculum especially in underdeveloped countries. Most available techniques for linearization of nonlinear system are only valid about the operating point; furthermore, the knowledge of the operating …

The Application Of Advanced Composites For The Construction Of Commercial Transport Aircraft, Mark D. Severson

Graduate Student Works

This individual Capstone project examined and evaluated current industry methods of testing, certification, and maintenance of advanced composite materials for the construction of commercial transport aircraft and the FAA regulations governing their use. The project critically compared and contrasted existing FAA standards and regulations governing the testing, certification, and maintenance of advanced composites for commercial transport aircraft structural applications with current industry practices to determine whether there were any areas of conflict between the two in order to accept or reject that current testing, certification, and maintenance procedures for advanced composites used in primary and secondary commercial transport aircraft structures …

Investigation Of A Lagrangian-Point Propellant Depot Rendezvous Approach For An Interplanetary Mission To Mars, Joshua W. Ehrlich

Doctoral Dissertations and Master's Theses

This thesis investigates the feasibility of a refueling station for a beyond Earth orbit (BEO) mission. The propellant depot is located at the L₂ -Lagrangian point within the Earth-Moon system. This investigation determines if a refueling mission will reduce propulsive energy requirements necessary for Earth departure of a BEO-vehicle to achieve an interplanetary transfer to Mars. Furthermore, this research presents a trade study which identifies approximate total requirements for a direct and rendezvous mission to Mars as well as the necessary fuel masses to complete each approach. This analysis provides conclusive information in determining the benefits in utilizing a …

Hydrodynamic Impact Analysis And Testing Of An Unmanned Aerial Vehicle, Isabel Bird

Doctoral Dissertations and Master's Theses

Analysis and testing have been conducted to assess the feasibility of a small UAV that can be landed in the water and recovered for continued use. Water landings may be desirable in a number of situations, for example when testing UAVs outside of the territorial waters of the US to avoid violating FAA regulations. Water landings may also be desirable when conducting surveillance missions in marine environments. Although the goal in landing is to have the UAV lightly set down on the water, rough seas or gusty winds may result in a nose-in landing where the UAV essentially impacts the …

Design Considerations And Requirements For In-Flight Refueling Of Unmanned Vehicles, Ian R. Mcandrew, Kenneth Witcher

Publications

The need to refuel in-flight has become a significant part of military strategy for air forces to work at further distances from safe shores. The use of Unmanned Vehicles is increasing and expected to be the principal part of military deployment. This paper will address the concepts and requirements for applying refueling unmanned vehicles in a military context for supporting fixed and rotor aircraft. Design aspects of human factors in the process are considered, reviewed and solutions proposed to allow for the first generation of designs to be developed. Furthermore, the practical and operational limitations will be addressed as part …

Orbital Debris Removal Technologies: A Hybrid Electrodynamic Tether And Ion Beam Shepherd Satellite Design For Fuel Efficient Contactless Debris Removal, Jorn Mumme

Doctoral Dissertations and Master's Theses

Space debris poses a serious threat to humanities efforts at space exploration as well as the expanding uses for earth-orbiting satellites. This thesis investigates the proposed technologies for the debris's removal both large and small. Focus is applied to the large debris removal technologies since the small size category is dominated by the ORION laser system. Furthermore, the large debris objects pose the most destructive threat upon impact to satellites. Electrodynamic tethers (EDT) as well as their control strategies, ion-beam shepherds (IBS), and tradition thruster methods are investigated for effectiveness and feasibility. Hybrid combinations of these technologies are investigated in …

Pilots For Space Tourism, Robert A. Goehlich, Jay K. Anderson, Nathan N. Harrold, Joseph A. Bemis, Mike T. Nettleingham, Joshua M. Cobin, Bradley R. Zimmerman, Ben L. Avni, Michael D. Gonyea, Nicholas Y. Ilchena

Aeronautics, Graduate Studies - Worldwide

This article sheds light on the key player needed for any space tourism adventure: the pilot who flies the spacecraft. The paper addresses the potential benefits of including a pilot at the controls when designing a space tourism spacecraft. It examines the basic qualifications and advanced skills required of space tourism pilots and discusses key training requirements for selected pilots and space pilots’ pay and benefits. In addition, the research concludes that, just as the pioneers of passenger transport in aviation entertained and captured the interest of their passengers, the space pilot should have the skills of a tour guide.

Incorporating Industry Needs Into The Development Of An Undergraduate Degree In Commercial Space Operations, Yash Bipinchandra Mehta

Doctoral Dissertations and Master's Theses

The rapid expansion of the commercial space industry, not unlike the aviation industry in the early 20^th century, has left the industry facing unique challenges. As companies continue to expand, the need for a well-trained workforce becomes critical. The needed workforce must be specifically educated to enter the commercial space industry at graduation. To have a successful industry, a workforce must be trained in skills that meet the industry's needs. In that regard, this study consisted of a survey of leaders in the commercial space industry to identify the different skill-sets sought by the industry. The results of the …

An Investigation To Advance The Technology Readiness Level Of The Centaur Derived On-Orbit Propellant Storage And Transfer System, Nathan L. Silvernail

Doctoral Dissertations and Master's Theses

This research was carried out in collaboration with the United Launch Alliance (ULA), to advance an innovative Centaur-based on-orbit propellant storage and transfer system that takes advantage of rotational settling to simplify Fluid Management (FM), specifically enabling settled fluid transfer between two tanks and settled pressure control. This research consists of two specific objectives: (1) technique and process validation and (2) computational model development. In order to raise the Technology Readiness Level (TRL) of this technology, the corresponding FM techniques and processes must be validated in a series of experimental tests, including: laboratory/ground testing, microgravity flight testing, suborbital flight testing, …

Investigation Of Pulse Detonation Engines; Theory, Design And Analysis, Jeff Vizcaino

Doctoral Dissertations and Master's Theses

Detonation and constant volume combustion has been known to the scientific community for some time but only recently has active research been done into its applications. Detonation based engines have received much attention in the last two decades because of its simple design and potential benefits to the aerospace industry. It is then the goal of this study to provide a background into detonation theory and application and establish the basis for future detonation based research at Embry-Riddle Aeronautical University. In this paper we will discuss the experimental aspects of building, testing, and analysis of a pulsed detonation tube …

Measuring Acoustic Attenuation Of Polymer Materials Using Drop Ball Test, Yi Zhang

Doctoral Dissertations and Master's Theses

Polymers are often used for vibration damping and energy absorption. The effect of a material in reducing the strength of sound waves traveling through it is called acoustic attenuation. In the past, attenuation has mostly been evaluated in the MHz frequency range, using a pulse generator and transmitting transducer as the wave source. However, most real acoustic activities occur at frequencies up to a few hundred kHz. Here, a simple drop ball mechanism is used to generate acoustic source waves in the kHz range, and the attenuation capacities of several solid materials are measured. The recorded waveforms substantially differ between …

Estimation Of Real-Time Runway Surface Contamination Using Flight Data Recorder Parameters, Donovan C. Curry

Doctoral Dissertations and Master's Theses

Within this research effort, the development of an analytic process for friction coefficient estimation is presented. Under static equilibrium, the sum of forces and moments acting on the aircraft, in the aircraft body coordinate system, while on the ground at any instant is equal to zero. Under this premise the longitudinal, lateral and normal forces due to landing are calculated along with the individual deceleration components existent when an aircraft comes to a rest during ground roll. In order to validate this hypothesis a six degree of freedom aircraft model had to be created and landing tests had to be …

A Preliminary Study Of Acoustic Prediction Technology Based On Detached Eddy Simulations For Supersonic Jets Impinging On Flat Plates, Yuvraj Dewan

Doctoral Dissertations and Master's Theses

An application of an existing industry tool to study supersonic jets impinging on at plates is shown. This industry tool is the commercially available CFD package ANSYS FLUENT. The supersonic jet studied is perfectly expanded with a Mach number of 1.5, and it impinges on a flat surface 4 nozzle throat diameters from the jet exit. All turbulence modeling is done using a hybrid RANS/LES technique known as Delayed Detached Eddy Simulation (DDES). A transient solution is calculated using the pressure-based coupled solver formulation with the second-order bounded central-upwind spatial discretization and second-order implicit time marching scheme. Flow features like …

New Peril + Old Promises = Bad Results, Paul Eschenfelder

Paul F. Eschenfelder

No abstract provided.

Validation Of Proposed Metrics For Two-Body Abrasion Scratch Test Analysis Standards: In Principle, Any Scratch Can Be Analyzed By This Method, Kenneth W. Street, Ryan L. Kobrick, David M. Klaus

Publications

Abrasion of mechanical components and fabrics by soil on Earth is typically minimized by the effects of atmosphere and water. Potentially abrasive particles lose sharp and pointed geometrical features through erosion. In environments where such erosion does not exist, such as the vacuum of the Moon, particles retain sharp geometries associated with fracturing of their parent particles by micrometeorite impacts. The relationship between hardness of the abrasive and that of the material being abraded is well understood, such that the abrasive ability of a material can be estimated as a function of the ratio of the hardness of the two …

Numerical Modeling Of Anti-Icing Using An Array Of Heated Synthetic Jets, Nikisha Maria Nagappan

Doctoral Dissertations and Master's Theses

A novel approach to icing control using an array of thermally activated synthetic jet actuators (SJAs) embedded in a wedge surface subject to a super-cooled flow is investigated numerically. The effects of SJA actuation with and without jet heating on ice accretion are studied using the FENSAP-ICE software. It is shown that the heated actuating SJAs can lead to a significant reduction in the amount of ice accreted on the surface. Additional parametric studies on several icing and SJA parameters are analyzed for their influence on the amount of ice accretion.