Aerospace Engineering Commons^™

Prioritizing Satellite Payload Selection Via Optimization, Benjamin S. Kallemyn

Theses and Dissertations

This thesis develops optimization models for prioritizing payloads for inclusion on satellite buses with volume, power, weight and budget constraints. The first model considers a single satellite launch for which the budget is uncertain and constellation requirements are not considered. Subsequently, we include constellation requirements and provide a more enhanced model. Both single-launch models provide a prioritized list of payloads to include on the launch before the budget is realized. The single-launch models are subsequently extended to a sequence of multiple launches in two cases, both of which incorporate an explicit dependence on the constellation composition at each launch epoch. …

Exploring Effective Methods For Simulating Damaged Structures With Geometric Variation: Toward Intelligent Failure Detection, Daniel A. Mcadams, David Comella, Irem Y. Tumer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Inaccuracies in the modeling assumptions about the distributional characteristics of the monitored signatures have been shown to cause frequent false positives in vehicle monitoring systems for high-risk aerospace applications. to enable the development of robust fault detection methods, this work explores the deterministic as well as variational characteristics of failure signatures. Specifically, we explore the combined impact of crack damage and manufacturing variation on the vibrational characteristics of beams. the transverse vibration and associated eigenfrequencies of the beams are considered. Two different approaches are used to model beam vibrations with and without crack damage. the first approach uses a finite …

Multifrequency Eddy Current Inspection Of Corrosion In Clad Aluminum Riveted Lap Joints And Its Effect On Fatigue Life, Shridhar Natarajan, Anthony Chukwujekwu Okafor

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented.

Optimal Control Of A Circulare Satellite Formation Subject To Gravitational Perturbations, Jason L. Baldwin

Theses and Dissertations

Satellite formations, otherwise known in the space community as satellite clusters or distributed satellite systems, have been studied extensively over the last 10 to 15 years. For use in remote sensing applications, formations consisting of smaller, simpler satellites provide numerous advantages over individual satellites. The image resolution capabilities of small-satellite formations constitute a significant technological leap in the ability to synthesize critical information. This research utilizes the nonlinear satellite dynamics, including gravitational perturbations, to search for the optimal fuel cost for maintaining a circular formation. The system dynamics were developed in an earth-centered inertial coordinate frame using the methods of …

Black Rock Planet: The Next Two Challenges, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Black Rock Planet: The Next Two Challenges" from February 22, 2007.

Soldier/Hardware-In-The-Loop Simulation-Based Combat Vehicle Duty Cycle Measurement: Duty Cycle Experiment 2, Mark Brudnak, Mike Pozolo, Victor Paul, Syed Mohammad, Marc Compere, Et Al.

Publications

This paper describes a human-in-the-loop motion-based simulator interfaced to hybrid-electric power system hardware both of which were used to measure the duty cycle of a combat vehicle in a virtual simulation environment. The project discussed is a greatly expanded follow-on to the experiment published in [1]. This paper is written in the context of [1] and therefore highlights the enhancements. The most prominent of these enhancements is the integration (in real-time) of the Power & Electric System Integration Lab (P&E SIL) with a motion base simulator by means of a “long haul” connection over the Internet (a geographical distance of …

F- 16xl Unsteady Simulations For The Cawapi Facet Of Rto Task Group Avt- 113, Scott A. Morton, David R. Mcdaniel, Russell M. Cummings

Aerospace Engineering

This work represents the USAF Academy portion of a culmination of three years of cooperative research in the Cranked Arrow Wing Aerodynamics International (CAWAPI) RTO Task Group, AVT-113. The objective of the group was to compute high resolution CFD simulations of a subset of the conditions created in the CAWAP flight test program managed by NASA Langley researchers and others. Seven flight conditions were chosen with four of them at symmetric conditions of medium to high angle of attack and subsonic Mach numbers, one symmetric condition at a transonic low angle of attack condition, and two conditions at medium angle …

Circulation Control And Its Application To Extreme Short Take-Off And Landing Vehicles, Julianna B. De La Montanya, David D. Marshall

Aerospace Engineering

Circulation Control is a high-lift method discovered in 1935 when Henry Coanda accidentally stumbled upon the technology. Research was conducted in the 1970‘s and 1980‘s to develop this technique, but the idea fell out of vogue until recently. Energy is introduced into the flow field by means of a jet ejected tangentially from a slot located near the trailing edge of the airfoil; thus changing the effective chamber of the airfoil and increasing lift. Extreme Short Take-Off and Landing (ESTOL) vehicles can use this technology to alleviate today‘s congested airports by reutilizing the small runways that are currently unexploited due …

The Role Of Error In The Conceptual Design Of A Transport Aircraft, Robert A. Mcdonald

Aerospace Engineering

A fidelity trade environment was demonstrated by using it to simulate a decision making process for a transport aircraft. This scenario was not possible without the fidelity trade environment. The role of system feedback and coupling in error stability was also investigated.
A sensitivity approach which relies on the system sensitivity matrix was used to rapidly approximate the propagation of error through the complex system. In verification tests, the sensitivity approach provided approximate results substantially similar to a Monte Carlo approach that was many orders of magnitude more expensive. The rapid sensitivity approach to modeling error propagation enabled the responsive …

The Happy Accidents Of Teaching Aircraft Design, David W. Hall, Russell M. Cummings

Aerospace Engineering

The aircraft design curriculum at Cal Poly has grown and evolved over the past decades to include a full year of senior aircraft design and an introductory aircraft design course in the sophomore year. The combination of sophomore and senior aircraft design courses has created the circumstance where a “cult” of aircraft design has developed. The curriculum is producing students who are enthusiastic and motivated education, as well as being competent designers after they graduate. A number of “happy accidents” has led to this fortunate situation, including: allowing the sophomores to perform a full aircraft design, having the sophomores work …

Wing-Nacelle Assembly Multidisciplinary Performance Optimization, Yevgeniy M. Gisin, David D. Marshall

Aerospace Engineering

The paper analyzes the aerodynamics benefits of above-wing mounting of turbofan engines and performs a trade-off study of the structural limitations with this mounting method. This research is based on the US Patent #6,308,913, aiming to quantify the actual benefit derived from the drag reduction measure described in the patent. The paper focuses on the analysis of a turbofan engine, which when installed above an aircraft’s wing creates a flow field optimized to reduce the overall drag experienced by the wing nacelle assembly. This installation is designed to reduce wave drag during transonic cruise and therefore the wing-nacelle geometry was …

Comparison Of Des And Urans For Unsteady Vortical Flows Over Delta Wings, L. A. Shiavetta, K. J. Badcock, Russell M. Cummings

Aerospace Engineering

The unsteady behaviour of delta wing vortical flows is still a subject which is a challenge for numerical methods, such as computational fluid dynamics. New approaches to turbulence modelling, such as detached eddy simulation (DES) have been proposed which allow for greater accuracy of the numerical predictions. However, this increase in accuracy comes with a considerable increase in computational expense compared to traditional turbulence modelling. This investigation considers the use of both DES and unsteady Reynolds averaged Navier-Stokes (URANS) turbulence methods in the prediction of unsteady vortical flows. Calculations using DES are initially considered for two test cases and the …

Variable Structure Observer For Control Bias On Unmanned Air Vehicles, Nathan Slegers, Mark Costello

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

No abstract provided.

Cool Flame Propagation Speeds, Michael R. Foster, Howard Pearlman

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Cool flames are studied at reduced-gravity in a closed, unstirred, spherical reactor to minimize complexities associated with natural convection. Under such conditions, transport is controlled by diffusive fluxes and the flames are observed to propagate radially outward from the center of the reactor toward the wall. Intensified video records are obtained and analyzed to determine the flame radius as a function of time for different vessel temperatures (593–623 K) and initial pressures (55.2–81.4 kPa) using an equimolar (Ø = 5) propane-oxygen premixture. Polynomial-fits are applied to the data and differentiated to determine the cool flame propagation speeds. In nearly …

Electrical Control Of The Thermodiffusive Instability In Premixed Propane–Air Flames, D. L. Wisman, S. D. Marcum, B. N. Ganguly

United States Air Force: Publications

This work focuses upon the effects of DC electric fields on the stability of downward propagating atmospheric pressure premixed propane–air flames under experimental conditions that provide close coupling of the electric field to the flame. With the appropriate electrode geometry, modest applied voltages are shown to drive a stable conical flame first into a wrinkled-laminar flamelet geometry, and then further toward either a highly unstable distributed flamelet regime or a collective oscillation of the flame front. Applied potentials up through +5 kV over a 40-mm gap encompassing the flame front have been used to force the above transition sequence in …

Use Of Dynamic Incidence Angle For Glide Slope Control Of Autonomous Parafoils, Nathan Slegers, Eric Beyer, Mark Costello

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Strickly speaking, most autonomous parafoil and payload aircraft possess only lateral control, achieved by right and left parafoil brake deflection. An innovative new technique to achieve direct longitudinal control through dynamic incidence angle changes is reported. Addition of this extra control channel requires simple rigging changes and an additional servo actuator. The ability of dynamic incidence angle to alter the glide slope of a parafoil and payload aircraft is demonstrated through a flight test program with a micro parafoil system. Results from the flight test program are synthesized and integrated into a 6 degree-of-freedom simulation. The simulation model is subsequently …

Mechanical Characterization Of Spherical Hydrogels: Contact Diameter Measurement, Joshua Bunch

Opportunities for Undergraduate Research Experience Program (OURE)

In an effort to develop new ophthalmic treatments revolving around the ocular lens, the mechanical characteristics of natural ocular lenses and synthetic models must be determined and compared. One mechanical characteristic that is necessary when making comparisons is the variation of contact circle diameter or contact area with varying strains. A method was used in this experiment to measure the varying contact circle diameter of spherical hydrogels at strains up to 15%. This method could be used to estimate the varying contact diameter of other similar materials such as natural ocular lenses if the precision of the method is improved. …

Parallel Machine Tool Development, Adam Bunton

Opportunities for Undergraduate Research Experience Program (OURE)

The work done during this OURE centered on the parallel machining center that is under development by a research group led by Dr. R. Landers. The specific tasks associated with this research involved the design of several parts, documentation of the processes for assembly and operation, procurement of some materials and stock parts, and involvement with experiments with the machine tool. These various aspects are outlined in the following report, with emphasis on the design of components.

The Effects Of Charging By Ultraviolet Light On Granular Lunar Simulant In A Microgravity Environment, Sydney J. Chamberlin, Troy Munro, Sarah Isert, Tracy Garin Savage

Reports and Proposals

No abstract provided.

Concepts For The Nanosat- 5 Satellite Design Competition, Sunil C. Aggarwal

Opportunities for Undergraduate Research Experience Program (OURE)

This paper presents feasible small space satellite missions which are of interest to the U.S. Air Force and can be used to get selected and win the NANOSAT-5 satellite design competition. Some thought on which of these missions can be used by the University of Missouri-Rolla to successfully take part in the competition have also been presented.

United States Air Force Posture Statement 2007, U.S. Air Force

United States Air Force: Publications

Our 2007 Posture Statement articulates the major elements required to fulfill our mission. It reaffirms our commitment to focus our energies on the Global War on Terror; to develop and care for our Airmen and their families; and to recapitalize and modernize our aging aircraft, spacecraft and equipment.

The Complete Management Of Extremity Vascular Injury In A Local Population: A Wartime Report From The 332nd Expeditionary Medical Group/Air Force Theater Hospital, Balad Air Base, Iraq, Michael A. Peck, W. Darrin Clouse, Mitchell W. Cox, Andrew N. Bowser, Jonathan L. Eliason, Donald H. Jenkins, David L. Smith, Todd E. Rasmussen

United States Air Force: Publications

Background: Although the management of vascular injury in coalition forces during Operation Iraqi Freedom has been described, there are no reports on the in-theater treatment of wartime vascular injury in the local population. This study reports the complete management of extremity vascular injury in a local wartime population and illustrates the unique aspects of this cohort and management strategy.

Methods: From September 1, 2004, to August 31, 2006, all vascular injuries treated at the Air Force Theater Hospital (AFTH) in Balad, Iraq, were registered. Those in non-coalition troops were identified and retrospectively reviewed.

Results: During the study …

Impact Of Phlebotomine Sand Flies On U.S. Military Operations At Tallil Air Base, Iraq: 3. Evaluation Of Surveillance Devices For The Collection Of Adult Sand Flies, Douglas A. Burkett, Ronald Knight, James A. Dennett, Van Sherwood, Edgar Rowton, Russell E. Coleman

United States Air Force: Publications

We evaluated the effectiveness of commercially available light traps and sticky traps baited with chemical light sticks for the collection of phlebotomine sand flies. Evaluations were conducted at Tallil Air Base, Iraq, in 2003. In an initial study, a Centers for Disease Control and Prevention (CDC)-style trap with UV bulb collected significantly more sand flies than did an up-draft CDC trap, a standard down-draft CDC trap (STD-CDC), or a sticky strap with a green chemical light stick. In a subsequent study, we found that the addition of chemical light sticks to sticky traps resulted in a significant increase in the …

Control System Design And Simulation Of Spacecraft Formations Via Virtual Formation Approach, Pavan Donepudi

Master's Theses - Daytona Beach

The problem of formation control of multiple spacecraft using the virtual structure approach is studied. The thesis first summarizes the progress made in the area of spacecraft formation control and then provides an overview of the virtual structure method. Modifying earlier established control design techniques, new feedback laws are constructed to control both the rotational and translational motion of a group of spacecraft. Several computer simulations are performed to illustrate the effectiveness of the modified control laws. The ephemeris and attitude data files generated via Matlab are exported to Satellite Tool Kit (STK) to create 3D animations. Various formation scenarios …

Shock-Tube Investigation Of Ignition Delay Times Of Blends Of Methane And Ethane With Oxygen, Brian Christopher Walker

Electronic Theses and Dissertations

The combustion behavior of methane and ethane is important to the study of natural gas and other alternative fuels that are comprised primarily of these two basic hydrocarbons. Understanding the transition from methane-dominated ignition kinetics to ethane-dominated kinetics for increasing levels of ethane is also of fundamental interest toward the understanding of hydrocarbon chemical kinetics. Much research has been conducted on the two fuels individually, but experimental data of the combustion of blends of methane and ethane is limited to ratios that recreate typical natural gas compositions (up to ~20% ethane molar concentration). The goal of this study was to …

An Algorithm For Determining Satellite Attitude By Comparing Physical Feature Models To Edges Detected In Satellite Or Ground-Based Telescope Imagery, Eric Brian Reinhart

Electronic Theses and Dissertations

This thesis discusses the development and performance of an algorithm created to calculate satellite attitude based on the comparison of satellite "physical feature" models to information derived from edge detection performed on imagery of the satellite. The quality of this imagery could range from the very clear, close-up imagery that may come from an unmanned satellite servicing mission to the faint, unclear imagery that may come from a ground-based telescope investigating a satellite anomaly. Satellite "physical feature" models describe where an edge is likely to appear in an image. These are usually defined by physical edges on the structure of …

Mechanical Fastener Pull-Out In Recycled Plastic Lumber, Ryan Dusheke

Opportunities for Undergraduate Research Experience Program (OURE)

The purpose of this paper is to present test results for the examination of mechanical fastener pull-out in plastic lumber. The testing was performed on both 1 Od galvanized steel nails, nominally 3" long and 0.148" in diameter, and No. 10 flathead low-carbon steel screws, nominally I" long. l "x6" Trimax plastic lumber, produced by US Plastic Lumber, was used for all testing. Tests were performed in each of the three sides of the boards. To evaluate the performance of the materials in varying conditions, testing was performed at -20°f, room temperature, and 125°f.

Simple Penning Ion Source For Laboratory Research And Development Applications, Joshua L. Rovey, Brandon P. Ruzic, Thomas J. Houlahan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A simple Penning ion generator (PIG) that can be easily fabricated with simple machining skills and standard laboratory accessories is described. The PIG source uses an iron cathode body, samarium cobalt permanent magnet, stainless steel anode, and iron cathode faceplate to generate a plasma discharge that yields a continuous 1 mA beam of positively charged hydrogen ions at 1 mTorr of pressure. This operating condition requires 5.4 kV and 32.4 W of power. Operation with helium is similar to hydrogen. The ion source is being designed and investigated for use in a sealed-tube neutron generator; however, this ion source is …

Validation Of Conjugate Heat-Transfer Capability For Water- Cooled High-Speed Flows, Bruno R. Fletcher

Master's Theses - Daytona Beach

A FORTRAN conduction/convection heat transfer module named FOGO (meaning fire in Portuguese) has been developed to perform the conjugate heat transfer analyses with existing flow solvers. In this work, FOGO is coupled with TBD and WIND-US flow solvers. WIND-US is a well validated flow solver developed by NASA, AEDC, and Boeing. TBD is a new flow solver developed at ERAU. TBD is verified for laminar stagnation point heat transfer prediction and turbulent flowfield protection. The FOGO module is verified against an exact solution for transient one-dimensional heat flow in a semi-infinite solid

The coupled TBD-FOGO and WIND-FOGO conjugate heat-transfer solvers …

Modeling Redox-Based Magnetohydrodynamics In Three-Dimensional Microfluidic Channels, Hussameddine S. Kabbani, Aihua Wang, Xiaobing Luo, Shizhi Qian

Mechanical Engineering Faculty Research

RedOx-based magnetohydrodynamic MHD[1] flows in three-dimensional microfluidic channels are investigated theoretically with a coupled mathematical model consisting of the Nernst-Planck equations for the concentrations of ionic species, the local electroneutrality condition for the electric potential, and the Navier-Stokes equations for the flow field. A potential difference is externally applied across two planar electrodes positioned along the opposing walls of a microchannel that is filled with a dilute RedOx electrolyte solution, and a Faradaic current transmitted through the solution results. The entire device is positioned under a magnetic field which can be provided by either a permanent magnet or an electromagnet. …