Aerospace Engineering Commons^™

Tiny Satellites For Stem, Carlos G. Niederstrasser

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Carlos G. Niederstrasser titled "Tiny Satellites for STEM" from July 13, 2012.

Efficient Airframe Management Using In-Situ Structural Health Monitoring, Mark M. Derriso, M. S. Leonard, Martin P. Desimio, Steven E. Olson

Student Publications

The United States Air Force utilizes the Aircraft Structural Integrity Program (ASIP) to service and maintain its airframes. This schedule-based maintenance approach works well for ensuring system integrity; however, it is very costly, labor-intensive, and it reduces system availability. As a result, the Air Force intends to transition to a process that services aircraft based on their actual condition instead of the presumptive schedule-based approach. Structural health monitoring (SHM) technologies are being investigated to enable such real-time state awareness and decision-making. This paper provides a brief review of ASIP and the required inspections to investigate structural fatigue. The current ASIP …

Potential Significance Of Photoexcited No2 On Global Air Quality With The Nmmb/Bsc Chemical Transport Model, O. Jorba, D. Dabdub, Christopher S. Blaszczak-Boxe, C. Pérez, Z. Janjic, J. M. Baldasano, M. Spada, A. Badia, M. Gonçalves

Publications and Research

Atmospheric chemists have recently focused on the relevance of the NO2* + H2O → OH + HONO reaction to local air quality. This chemistry has been considered not relevant for the troposphere from known reaction rates until nowadays. New experiments suggested a rate constant of 1.7 × 10−13 cm3 molecule−1 s−1, which is an order of magnitude faster than the previously estimated upper limit of 1.2 × 10−14 cm3 molecule−1 s−1, determined by Crowley and Carl (1997). Using the new global model, NMMB/BSC Chemical Transport Model (NMMB/BSC-CTM), simulations are presented that assess the potential significance of this chemistry on global …

Merrill-Cazier Library Gas Exhibition, Betty Rozum, Andrew Wesolek, Pamela N. Martin

Education and Outreach

This exhibition, presented in the Merrill-Cazier Library, captured the history and accomplishments of the GAS program. Click the download button to see a PowerPoint presentation featuring images and text from the exhibition.

Hot-Wire Anemometer For The Boundary Layer Data System, William D. Neumeister

Master's Theses

Hot-wire anemometry has been routinely employed for laboratory measurements of turbulence for decades. This thesis presents a hot-wire anemometer suitable for use with the Boundary Layer Data System (BLDS). BLDS provides a unique platform for in- flight measurements because of its small, self-contained, robust design and flexible architecture. Addition of a hot-wire anemometer would provide BLDS with a sensor that could directly measure flow velocity fluctuations caused by turbulence. Hot-wires are commonly operated in constant-temperature mode for high frequency response, but require a carefully tuned bridge. The constant-voltage anemometer (CVA) uses a simple op-amp circuit to improve frequency response over …

Extended Pcr Rules For Dynamic Frames, Florentin Smarandache, Jean Dezert

Branch Mathematics and Statistics Faculty and Staff Publications

In most of classical fusion problems modeled from belief functions, the frame of discernment is considered as static. This means that the set of elements in the frame and the underlying integrity constraints of the frame are fixed forever and they do not change with time. In some applications, like in target tracking for example, the use of such invariant frame is not very appropriate because it can truly change with time. So it is necessary to adapt the Proportional Conflict Redistribution fusion rules (PCR5 and PCR6) for working with dynamical frames. In this paper, we propose an extension of …

Response Surface Optimization Of Electron Beam Freeform Fabrication Depositions Using Design Of Experiments, Patricia A. Quigley

Engineering Management & Systems Engineering Theses & Dissertations

The Electron Beam Freeform Fabrication (EBF³ ) System is a material depositing, layer additive technique that produces three dimensional (3D) parts out of a wide range of metals in high vacuum, using an electron beam and wire feedstock. Screening deposition trials on a titanium alloy, Ti-6Al-4V, at the National Aeronautics Space Administration (NASA) revealed selective vaporization of the aluminum content of linear prototypes when subjected to chemical analysis. In this study, the aluminum content, bead height and bead width output responses were analyzed from a systematic study of the effects that the interactions of the EBF³ processing parameters …

Measurement System Characterization In The Presence Of Measurement Errors, Sean A. Como

Mechanical & Aerospace Engineering Theses & Dissertations

In the calibration of a measurement system, data are collected in order to estimate a mathematical model between one or more factors of interest and a response. Ordinary least squares is a method employed to estimate the regression coefficients in the model. The method assumes that the factors are known without error; yet, it is implicitly known that the factors contain some uncertainty. In the literature, this uncertainty is known as measurement error. The measurement error affects both the estimates of the model coefficients and the prediction, or residual, errors. There are some methods, such as orthogonal least squares, that …

Modeling, Identification, Validation And Control Of A Hybrid Maglev Ball System, Ahmed Elhussein E. Mekky

Mechanical & Aerospace Engineering Theses & Dissertations

In this thesis, the electrodynamics of a single axis hybrid electromagnetic suspension Maglev system was modeled and validated by applying it to a single axis hybrid maglev ball experiment. By exploring its linearized model, it was shown that the single axis hybrid Maglev ball has inherently unstable dynamics. Three control scenarios were explored based on the linearized model; (1) Proportional, Deferential (PD) control, (2) Proportional, Deferential, Integral (PID) and (3) PID controller with pre-filtering. This thesis has shown that a PID controller with a pre-filtering technique can stabilize such a system and provide a well-controlled response.

A parametric system identification …

The Influence Of Non-Equilibrium Pressure On Rotating Flows, Irfan Rashid Zardadkhan

Mechanical & Aerospace Engineering Theses & Dissertations

This study was undertaken to investigate the influence of pressure relaxation on steady, incompressible flows with strong streamline curvature. In the early part of this dissertation research, the significance of non-equilibrium pressure forces in controlling the structure of a steady, two dimensional axial vortex was demonstrated. In order to extend the study of pressure relaxation influences on more complex rotating flows, this dissertation has examined other rotating flow features that can be associated with hurricanes, tornadoes and dust devils. To model these flows, modified boundary layer equations were developed for a fluid column rotating near a solid plane including the …

The Effects Of Familiarity And Persuasion On Risk Assessment, Casey L. Smith

Doctoral Dissertations and Master's Theses

Cognitive biases influence decisions and the analyses of risk. They are often derived from two separate processes: bias based on familiarity (familiarity bias) and bias as the result of influences from outside sources (persuasion bias). Research suggests that familiarity-based bias may lead to acceptance of an activity's drawbacks and a leniency of its risks.

In addition, research has tried to measure and analyze different types of biases individually, but few have compared the interactions of more than one bias at once. Because different biases may derive from different mental phenomena it is important to tease out the distinctions, and observe …

A Design Of Experiments Approach To Visor Drag Reduction On Heavy Vehicles Using Wind Tunnel Testing, Adam Golembeski

Mechanical & Aerospace Engineering Theses & Dissertations

Drag reduction on a scale wind tunnel model of a tractor and partial trailer was used as a case study to investigate the use of Designed Experiments. Specifically, the drag reduction benefits of replacing a tractor sunvisor with an airfoil shaped sunvisor were investigated. The airfoil-shaped sunvisor was theorized to generate thrust in the direction of travel thus reducing the net drag force. The drag force was measured using a load cell integrated into the tractor-trailer model. The experimental factors were the angle of attack, the horizontal position relative to the surface of the tractor body, the yaw angle and …

A Multi-Objective Differential Evolution Algorithm For Engineering Design Optimization, Shantanu S. Muluk

Mechanical & Aerospace Engineering Theses & Dissertations

The current research investigation focuses on the development of a multi-objective global optimizer based on the differential evolution algorithm. A rotationally invariant version of the original differential evolution algorithm is adopted as the core component of the optimization procedure. The optimizer is applied to a number of multi-objective problems: constrained problems, problems of high dimensionality, and problems with non-convex Pareto fronts.

The effectiveness of the proposed optimization framework in real engineering design problems is demonstrated by carrying out an aerodynamic shape optimization of wind turbine airfoils. The investigation focuses on both thin and thick airfoils. The produced Pareto-optimal airfoil shapes …

Transient Turbine Engine Modeling With Hardware-In-The-Loop Power Extraction, Michael W. Corbett, Peter T. Lamm, Philip R. Owen, S. Danny Phillips, Mark J. Blackwelder, J. Timothy Alt, John M. Mcnichols, Michael A. Boyd, Mitch Wolff

Mechanical and Materials Engineering Faculty Publications

Increasingly high aircraft power demands require that the interactions between an aircraft’s electrical subsystem and the engine subsystem be considered in dynamic, systemlevel tests. Traditionally, system-level dynamics have only been captured in completely assembled aircraft systems. Component-level or subsystem-level optimization is no longer appropriate because highly interdependent dynamics between subsystems only become apparent during system-level analysis. In an effort to reduce the high cost of testing integrated power and propulsion systems in an altitude-simulating wind tunnel, alternatives such as modeling and simulation are considered. Synchronizing and coupling simulations of vastly different time scales is possible, but the resulting system simulation …

Unsteady Specific Work And Isentropic Efficiency Of A Radial Turbine Driven By Pulsed Detonations, Kurt P. Rouser

Theses and Dissertations

There has been longstanding government and industry interest in pressure-gain combustion for use in Brayton cycle based engines. Theoretically, pressure-gain combustion allows heat addition with reduced entropy loss. The pulsed detonation combustor (PDC) is a device that can provide such pressure-gain combustion and possibly replace typical steady deflagration combustors. The PDC is inherently unsteady, however, and comparisons with conventional steady deflagration combustors must be based upon time-integrated performance variables. In this study, the radial turbine of a Garrett automotive turbocharger was coupled directly to and driven, full admission, by a PDC in experiments fueled by hydrogen or ethylene. Data included …

Electric Aircraft Propulsion System, Austin J. Doupe

Aerospace Engineering

This report specifies the purpose, assembly, operation, and data collection of a testing apparatus to characterize small electric aircraft propulsion systems designed for commercial use. This apparatus was constructed with the goal of determining overall system characteristics and efficiencies. The apparatus was pushed to a safety limit as deemed by advisor John Dunning and the results of the experiment were an output power of 3.2kW (25% of max rated power) and a system efficiency of 58.6%, both of which occurred at 2200 RPM. Currently the apparatus needs improvement. It should have an upgraded structure to mount to (instead of the …

High-Fidelity Low-Thrust Trajectory Determination Research And Analysis, Tyler Hill

Aerospace Engineering

This document discusses a numerical analysis method for low thrust trajectory propagation known as the proximity quotient or Q-Law. The process uses a Lyapunov feedback control law developed by Petropoulos^[1] to propagate trajectories of spacecraft by minimizing the user defined function at the target orbit. A simplified propagator is created from the core mechanics of this method in MATLAB and tested in several user defined cases to demonstrate its capabilities. Several anomalies arose in test cases where variations in eccentricity, inclination, right ascension of the ascending node, and argument of perigee were specified. Solutions to these anomalies are discussed …

Low Cost Vacuum Chamber Design For Electromagnetic Railgun Operation, Andrew W. Bothwell, David J. Foster

Aerospace Engineering

This report describes the design and fabrication of a low cost vacuum chamber capable of supporting the operation of an electromagnetic railgun. This would be used to simulate the impact of high velocity impacts in space. The vacuum chamber was constructed out of 10in diameter 10ft PVC pipe with a Wye fitting for viewing impacts during testing. The chamber was designed to accommodate a 6.5in X 6.5in X 60in railgun. The vacuum chamber feedthroughs were designed to be able to carry 1-2Mamps at 8kV to the railgun. The vacuum chamber is capable of reaching 50 Torr and remaining under 100 …

Interstellar Mission To Gliese 581, Brock Schmalzel, Brian Tsoi

Aerospace Engineering

This report details a conceptual design for a one-way, interstellar mission, based upon assumed technological advances over the next few hundred years. It addresses the unique challenges associated with an interstellar mission, looking at both developed and theoretical technologies. This report looks specifically at propulsion systems required to reach an exoplanet. In addition, the power, communication, and orbital trajectories are analyzed to see the differences and technological advancements necessary for future missions and the proposed interstellar mission. The destination for the interstellar mission in Gliese 581, a star system located 20.3 light years away and has 5 known planets and …

Accelerating Lambert's Problem On The Gpu In Matlab, Nathan Parrish

Aerospace Engineering

The challenges and benefits of using the GPU to compute solutions to Lambert’s Problem are discussed. Three algorithms (Universal Variables, Gooding’s algorithm, and Izzo’s algorithm) were adapted for GPU computation directly within MATLAB. The robustness of each algorithm was considered, along with the speed at which it could be computed on each of three computers. All algorithms used were found to be completely robust. Computation time was measured for computation within a for-loop, a parfor-loop, and a call to the MATLAB command ‘arrayfun’ with gpuArray-type inputs. Then, a Universal Variables Lambert’s solver was written in CUDA and compiled for use …