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Aerospace Engineering

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2005

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Flightlines, Vol. 13, No. 1, Jeffrey A. Johnson Oct 2005

Flightlines, Vol. 13, No. 1, Jeffrey A. Johnson

Flightlines Newsletter

No abstract provided.

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Repeatable Nanostructures In Dielectrics By Femtosecond Laser Pulse Trains, Lan Jiang, Hai-Lung Tsai Oct 2005

Repeatable Nanostructures In Dielectrics By Femtosecond Laser Pulse Trains, Lan Jiang, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using the plasma model recent developed by the authors, this study predicts the existence of a constant ablation-depth zone with respect to fluence in femtosecond laser ablation of dielectrics, which has also been observed experimentally. It is found that the value of the constant ablation depth is significantly decreased by the pulse train technology. Repeatable nanostructures can be achieved with the parameters in the constant ablation-depth zone of a femtosecond pulse train, even when the laser system is subject to fluctuations in fluences.

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Adaptive Control Of A Projectile Fin Using Piezoelectric Elastic Beam, Smitha Mani, Sahjendra N. Singh, Surya Kiran Parimi, Woosoon Yim, Mohamed B. Trabia Aug 2005

Adaptive Control Of A Projectile Fin Using Piezoelectric Elastic Beam, Smitha Mani, Sahjendra N. Singh, Surya Kiran Parimi, Woosoon Yim, Mohamed B. Trabia

Mechanical Engineering Faculty Research

No abstract provided.

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Variable Structure Control Of Unsteady Nonlinear Aeroelastic System, With Partial State Information, Sushma Gujjula, Sahjendra N. Singh Aug 2005

Variable Structure Control Of Unsteady Nonlinear Aeroelastic System, With Partial State Information, Sushma Gujjula, Sahjendra N. Singh

Electrical & Computer Engineering Faculty Research

This paper treats the question of control of a two-degree-of-freedom unsteady aeroelastic system with partial state information in the presence of uncertainties. The chosen model describes the plunge and pitch motion of a wing and a single trailing-edge control surface is utilized for the purpose of control. Based on the Lyapunov approach, a variable structure control law is derived. For the control law derivation, the system is treated as the interconnection of two subsystems in which the subsystem associated with the unsteady aerodynamics is input-to-state stable. The stability property of this subsystem is exploited to generate a dominating signal for …

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Optimization Of Waiting Time At Toll Plazas, Arvind Kumar Busam Jul 2005

Optimization Of Waiting Time At Toll Plazas, Arvind Kumar Busam

FIU Electronic Theses and Dissertations

Toll plazas have several toll payment types such as manual, automatic coin machines, electronic and mixed lanes. In places with high traffic flow, the presence of toll plaza causes a lot of traffic congestion; this creates a bottleneck for the traffic flow, unless the correct mix of payment types is in operation. The objective of this research is to determine the optimal lane configuration for the mix of the methods of payment so that the waiting time in the queue at the toll plaza is minimized. A queuing model representing the toll plaza system and a nonlinear integer program have …

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Introduction To Product Design And Innovation: A Cross Disciplinary Mini Curriculum, Patricia Backer, Seth Bates Jun 2005

Introduction To Product Design And Innovation: A Cross Disciplinary Mini Curriculum, Patricia Backer, Seth Bates

Faculty Publications

For the past two years, faculty at San Jose State University (SJSU) have implemented a three- semester minicurriculum in Product Design and Manufacturing. The project follows the Project- Based Learning (PBL) model and is central to the Certificate Program in Product Design in the Mechanical Engineering Department, the Manufacturing Systems concentration in the Department of Aviation and Technology, and the Industrial Design Program in the School of Art and Design. Students in the three courses in the minicurriculum face design challenges while being instructed about the constraints of manufacturability. In each course, students develop three to four products. All products …

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Technology And You: Working With The Aerospace Industry To Enhance Engineering Education, Russell M. Cummings, John H. Mcmasters Jun 2005

Technology And You: Working With The Aerospace Industry To Enhance Engineering Education, Russell M. Cummings, John H. Mcmasters

Aerospace Engineering

While many engineers in the aerospace engineering profession know that interacting with students is a good idea, few of them know how to do it. Certainly some engineers are asked on occasion to give lectures at various university club meetings, and some are even heavily involved in interacting with students working on various design projects, but the average engineer has little or no interaction with students over the course of their career. A number of companies, including Boeing, have created technical interest groups to encourage mentoring and sharing of corporate knowledge throughout the company. These efforts have been met with …

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Hierarchical Optimal Force-Position-Contour Control Of Machining Processes. Part Ii. Illustrative Example, Yan Tang, Robert G. Landers, S. N. Balakrishnan Jun 2005

Hierarchical Optimal Force-Position-Contour Control Of Machining Processes. Part Ii. Illustrative Example, Yan Tang, Robert G. Landers, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

There has been a tremendous amount of research in machine tool servomechanism control, contour control, and machining force control; however, to date these technologies have not been tightly integrated. This paper develops a hierarchical optimal control methodology for the simultaneous regulation of servomechanism positions, contour error, and machining forces. The contour error and machining force process reside in the top level of the hierarchy where the goals are to 1) drive the contour error to zero to maximize quality and 2) maintain a constant cutting force to maximize productivity. These goals are systematically propagated to the bottom level, via aggregation …

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Hierarchical Optimal Force-Position-Contour Control Of Machining Processes. Part I. Controller Methodology, Yan Tang, Robert G. Landers, S. N. Balakrishnan Jun 2005

Hierarchical Optimal Force-Position-Contour Control Of Machining Processes. Part I. Controller Methodology, Yan Tang, Robert G. Landers, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

There has been a tremendous amount of research in machine tool servomechanism control, contour control, and machining force control; however, to date these technologies have not been tightly integrated. This paper develops a hierarchical optimal control methodology for the simultaneous regulation of servomechanism positions, contour error, and machining forces. The contour error and machining force process reside in the top level of the hierarchy where the goals are to 1) drive the contour error to zero to maximize quality and 2) maintain a constant cutting force to maximize productivity. These goals are systematically propagated to the bottom level, via aggregation …

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Flightlines, Vol. 12, No. 2, Jeffrey A. Johnson Apr 2005

Flightlines, Vol. 12, No. 2, Jeffrey A. Johnson

Flightlines Newsletter

No abstract provided.

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Modelling And Validation Of A Propellant Mixer For Controller Design, Hanz Richter, Enrique Barbieri, Fernando Figueroa Nasa Stennis Space Center Feb 2005

Modelling And Validation Of A Propellant Mixer For Controller Design, Hanz Richter, Enrique Barbieri, Fernando Figueroa Nasa Stennis Space Center

Mechanical Engineering Faculty Publications

A mixing chamber used in rocket engine testing at the NASA Stennis Space Center is modelled by a system of two nonlinear ordinary differential equations. The mixer is used to condition the thermodynamic properties of cryogenic liquid propellant by controlled injection of the same substance in the gaseous phase. The three inputs of the mixer are the positions of the valves regulating the liquid and gas flows at the inlets, and the position of the exit valve regulating the flow of conditioned propellant. Mixer operation during a test requires the regulation of its internal pressure, exit mass flow, and exit …

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Experimental Verification Of The Aerodynamics Of Stream Thrust Probes, Robert S. Hiers Iii, James R. Sirbaugh, Capt Barrett T. Mccann, Russell M. Cummings, Cadet Laura S. Luft, Cadet Dimitrios P. Grillos Jan 2005

Experimental Verification Of The Aerodynamics Of Stream Thrust Probes, Robert S. Hiers Iii, James R. Sirbaugh, Capt Barrett T. Mccann, Russell M. Cummings, Cadet Laura S. Luft, Cadet Dimitrios P. Grillos

Aerospace Engineering

Determining the local stream thrust (a vector quantity) from a measured pitot pressure (a scalar quantity) requires either knowledge of the flow direction or a probe shape that compensates for flow direction. This compensation ideally would make the measured pressure directly proportional to the component of momentum along the probe axis. The flow angle sensitivity required to resolve this component of momentum was previously determined theoretically. A proposed probe nose shape was analyzed using computational fluid dynamics (CFD) and was found to produce a flow angle sensitivity close to the required sensitivity. In the current work, the proposed nose shape …

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Des Turbulence Modeling On The C-130 Comparison Between Computational And Experimental Results, Malcom P. Claus, Scott A. Morton, Russell M. Cummings, Yannick Bury Jan 2005

Des Turbulence Modeling On The C-130 Comparison Between Computational And Experimental Results, Malcom P. Claus, Scott A. Morton, Russell M. Cummings, Yannick Bury

Aerospace Engineering

This paper represents the results from the initial phase of a research program to determine the flow characteristics of the C-130 Hercules transport aircraft. The initial phase of the program consists of evaluation and comparison of the flow-field obtained from flow visualization methods. Specifically CFD (Computational Fluid Dynamics) results are compared with experimental Hot Wire results produced by wind tunnel tests on the C-130 in clean configuration. This paper outlines the results to date and provides a description of further work. The CFD element of this research features the use of Detached Eddy Simulation (DES) in order to extend its …

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Computational Aerodynamics Goes To School: A Course In Cfd For Undergraduate Students, Russell M. Cummings, Scott A. Morton Jan 2005

Computational Aerodynamics Goes To School: A Course In Cfd For Undergraduate Students, Russell M. Cummings, Scott A. Morton

Aerospace Engineering

As aerodynamics education has evolved over the past decades, a slow transition from important analytic methods to increasingly powerful computational methods has taken place. While a basic understanding of theoretical aerodynamics should always be included in coursework, the realities of modern design practices make the usefulness of the traditional approach less and less practical. A new undergraduate course in computational aerodynamics has been developed that attempts to give students experience with the modern computational tools of aerodynamics, primarily from an applications perspective. While introducing students to the important computational topics of accuracy and stability, the course stresses the practical tools …

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Deformation Of Unstructured Viscous Grids, Denis B. Kholodar, Scott A. Morton, Russell M. Cummings Jan 2005

Deformation Of Unstructured Viscous Grids, Denis B. Kholodar, Scott A. Morton, Russell M. Cummings

Aerospace Engineering

A mesh deformation algorithm for unstructured grids is presented. It is designed for high Reynolds number flow problems. Such grids are employed in aerodynamic and aeroelastic studies of wings or complete aircraft configurations in flows where the viscous effects are important. Given a surface deformation, the method efficiently recalculates new locations of high aspect ratio cells that make up the viscous layers of the grid and then deforms the inviscid part of the grid using an established method based on a torsional spring analogy technique. Results are presented for monitoring the deterioration of the quality of the grid during subsequent …

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Robust Control Techniques For State Tracking In The Presence Of Variable Time Delays, Jarrett Goodell, Marc Compere, Miguel Simon, Wilford Smith, Ronnie Wright, Mark Brudnak Jan 2005

Robust Control Techniques For State Tracking In The Presence Of Variable Time Delays, Jarrett Goodell, Marc Compere, Miguel Simon, Wilford Smith, Ronnie Wright, Mark Brudnak

Publications

In this paper, a distributed driver-in-the-Ioop and hardware-in-the-Ioop simulator is described with a driver on a motion simulator at the U.S. Army TARDEC Ground Vehicle Simulation Laboratory (GVSL). Realistic power system response is achieved by linking the driver in the GVSL with a full-sized hybrid electric power system located 2,450 miles away at the TARDEC Power and Energy Systems Integration Laboratory (P&E SIL), which is developed and maintained by Science Applications International Corporation (SAIC). The goal is to close the loop between the GVSL and P&E SIL over the Internet to provide a realistic driving experience in addition to realistic …

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Neural Network Control Of A Parallel Hybrid-Electric Propulsion System For A Small Unmanned Aerial Vehicle, Frederick G. Harmon Jan 2005

Neural Network Control Of A Parallel Hybrid-Electric Propulsion System For A Small Unmanned Aerial Vehicle, Frederick G. Harmon

Engineering and Computer Science Faculty Publications

No abstract provided.

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United States Air Force Posture Statement 2005, U.S. Air Force Jan 2005

United States Air Force Posture Statement 2005, U.S. Air Force

U.S. Air Force Research

Today's security environment is characterized by change and ambiguity. The future will include a variety of challenges, including the risk of catastrophic attacks on the homeland and possibly of disruptive technological breakthroughs by our adversaries.

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Decision Support For The Career Field Selection Process At The Us Air Force Academy, Andrew P. Armacost, James K. Lowe Jan 2005

Decision Support For The Career Field Selection Process At The Us Air Force Academy, Andrew P. Armacost, James K. Lowe

U.S. Air Force Research

Each year, the US Air Force Academy graduates nearly 1000 young men and women. To support the decision of which cadets will be classified into which career fields, we describe a linear programming formulation with appealing computational properties that enable it as the core of a decision support tool. We explore methods for measuring and balancing cadets' class standing, Air Force career field requirements, and cadets' career field preferences in the context of this model. Our computational experiments demonstrate the improvement of this method over previous classification approaches, yielding more than 10% increase in the number of cadets assigned to …

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Laboratory Evaluation Of Colored Light As An Attractant For Female Aedes Aegypti, Aedes Albopictus, Anopheles Quadrimaculatus, And Culex Nigripalpus, Douglas A. Burkett, Jerry F. Butler Jan 2005

Laboratory Evaluation Of Colored Light As An Attractant For Female Aedes Aegypti, Aedes Albopictus, Anopheles Quadrimaculatus, And Culex Nigripalpus, Douglas A. Burkett, Jerry F. Butler

U.S. Air Force Research

Mosquito feeding activity was monitored in an electronic apparatus (visualometer), having ten ports, illuminated from below with narrow bandwidths of light (700, 650, 600, 550, 500, 450, 400, or 350 nm). Responses of adult female Aedes albopictus Skuse, Ae. aegypti (L.), Anopheles quadrimaculatus, Say and Culex nigripalpus Theobald to feeding stations (blood containers) over each light port. No-light and broad spectrum white light were used as controls. Color preferences were based on electronic detection of feeding times. Aedes aegypti showed no significant feeding preferences over any of the colors. Conversely, Ae. albopictus, An. quadrimaculatus, and Cx. nigripalpus showed …

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Performance Of A New Cfd Flow Solver Using A Hybrid Programming Paradigm, M. J. Berger, M. J. Aftosmis, D. D. Mashall, S. M. Murman Jan 2005

Performance Of A New Cfd Flow Solver Using A Hybrid Programming Paradigm, M. J. Berger, M. J. Aftosmis, D. D. Mashall, S. M. Murman

Aerospace Engineering

This paper presents several algorithmic innovations and a hybrid programming style that lead to highly scalable performance using shared memory for a new computational fluid dynamics flow solver. This hybrid model is then converted to a strict message-passing implementation, and performance results for the two are compared. Results show that using this hybrid approach our OpenMP implementation is actually marginally faster than the MPI version, with parallel speedups of up to 599 out of 640 using OpenMP and 486 with MPI.

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Incorporating The Impact Of Engineering Solutions On Society Into Technical Engineering Courses, Nicole Dejong-Okamoto, Jinny Rhee, Nikos J. Mourtos Jan 2005

Incorporating The Impact Of Engineering Solutions On Society Into Technical Engineering Courses, Nicole Dejong-Okamoto, Jinny Rhee, Nikos J. Mourtos

Faculty Publications

In the era of market and workforce globalisation, engineers need a solid understanding of the impact that their products have locally, as well as globally. This is why the US Accreditation Board for Engineering and Technology (ABET) recently put a new spin on this requirement in engineering education. Specifically, outcome 3h of Engineering Criteria 2000 states that engineering graduates must have the broad education to understand the impact of engineering solutions in a global/ societal context. This outcome may be one of the most difficult to achieve, since it requires not only a strong technical understanding, but also an informed …

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Analysis And Modeling Of Information Flow And Distributed Expertise In Space-Related Operations, Barrett S. Caldwell Jan 2005

Analysis And Modeling Of Information Flow And Distributed Expertise In Space-Related Operations, Barrett S. Caldwell

School of Industrial Engineering Faculty Publications

Evolving space operations requirements and mission planning for long-duration expeditions require detailed examinationsand evaluations of information flow dynamics, knowledge-sharing processes, and information technology use in distributedexpert networks. This paper describes the work conducted with flight controllers in the Mission Control Center (MCC) ofNASA’s Johnson Space Center. This MCC work describes the behavior of experts in a distributed supervisory coordinationframework, which extends supervisory control/command and control models of human task performance. Findings from thiswork are helping to develop analysis techniques, information architectures, and system simulation capabilities for knowledgesharing in an expert community. These findings are being applied to improve knowledge-sharing processes …

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Model Predictive Control Of A Parafoil And Payload System, Nathan Slegers, Mark Costello Jan 2005

Model Predictive Control Of A Parafoil And Payload System, Nathan Slegers, Mark Costello

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

No abstract provided.

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An Existing Global Heptane Mechanism Augmented With Diffusive Transport, Michael R. Foster, Howard Pearlman Jan 2005

An Existing Global Heptane Mechanism Augmented With Diffusive Transport, Michael R. Foster, Howard Pearlman

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

The couplings between diffusive transport and the temperature and species concentration distributions associated with low and intermediate temperature heptane oxidation are explored using an existing four-step heptane mechanism, tuned for elevated pressures. The energy and species concentration equations are augmented with diffusive fluxes for heat and species and solved numerically in a one-dimensional domain. The ignition delay times are also tabulated and compared with the zero-dimensional data reported in the literature.

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Modeling And Control Of Re-Entry Heat Transfer Problem Using Neural Networks, Katie Grantham, Radhakant Padhi, S. N. Balakrishnan, Dwight C. Look Jan 2005

Modeling And Control Of Re-Entry Heat Transfer Problem Using Neural Networks, Katie Grantham, Radhakant Padhi, S. N. Balakrishnan, Dwight C. Look

Engineering Management and Systems Engineering Faculty Research & Creative Works

A nonlinear optimal re-entry temperature control problem is solved using single network adaptive critic (SNAC) technique. The nonlinear model developed and used accounts for conduction, convection and radiation at high temperature, represents the dynamics of heat transfer in a cooling fin for an object re-entering the earth's atmosphere. Simulation results demonstrate that the control synthesis technique presented is very effective in obtaining a desired temperature profile over a wide envelope of initial temperature distribution.

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Stochastic Optimal Control With Neural Networks And Application To A Retailer Inventory Problem, Zhongwu Huang, Xiaohua Wang, S. N. Balakrishnan Jan 2005

Stochastic Optimal Control With Neural Networks And Application To A Retailer Inventory Problem, Zhongwu Huang, Xiaohua Wang, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Overwhelming computational requirements of classical dynamic programming algorithms render them inapplicable to most practical stochastic problems. To overcome this problem a neural network based Dynamic Programming (DP) approach is described in this study. The cost function which is critical in a dynamic programming formulation is approximated by a neural network according to some designed weight-update rule based on Temporal Difference(TD)learning. A Lyapunov based theory is developed to guarantee an upper error bound between the output of the cost neural network and the true cost. We illustrate this approach through a retailer inventory problem.

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The U.S. Air Force Remotely Piloted Aircraft And Unmanned Aerial Vehicle Strategic Vision, U.S. Air Force Jan 2005

The U.S. Air Force Remotely Piloted Aircraft And Unmanned Aerial Vehicle Strategic Vision, U.S. Air Force

U.S. Air Force Research

The U.S. Air Force Remotely Piloted Aircraft and Unmanned Aerial Vehicle Strategic Vision (hereafter referred to as The Strategic Vision) examines the future role of Air Force remotely piloted aircraft (RPAs) and unmanned aerial vehicles (UAVs) and their integration with other Air Force and joint systems. The Strategic Vision is presented in five sections.

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Sample Preparation And Characterization Of Artificially Aged Aircraft Coatings For Microstructural Analysis, Lisa M. Farrier, Stephen A. Szaruga Jan 2005

Sample Preparation And Characterization Of Artificially Aged Aircraft Coatings For Microstructural Analysis, Lisa M. Farrier, Stephen A. Szaruga

U.S. Air Force Research

The paper describes a method for metallographic preparation of artificially aged aircraft coatings. In order to better understand the in-service performance and identify degradation mechanisms of an aircraft coating, complete characterization of the microstructure is essential. This paper discusses metallographic sample preparation and subsequent microscopy techniques (light optical microscopy, scanning electron microscopy) for characterization of a standard polyurethane aircraft coating system. The preparation method has proven to produce good, consistent results on a wide range of laboratory-produced simulated environmental exposures.

The military specification coating system under study (MIL-PRF-85285C and MIL-PRF-23377G) degrades severely after accelerated weathering. Typical degradation includes deterioration of …

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Improving Pilot Mental Workload Classification Through Feature Exploitation And Combination: A Feasibility Study, Jeremy B. Noel, Kenneth W. Bauer, Jr., Jeffrey W. Lanning Jan 2005

Improving Pilot Mental Workload Classification Through Feature Exploitation And Combination: A Feasibility Study, Jeremy B. Noel, Kenneth W. Bauer, Jr., Jeffrey W. Lanning

U.S. Air Force Research

Predicting high pilot mental workload is important to the United States Air Force because lives and aircraft have been lost due to errors made during periods of flight associated with mental overload and task saturation. Current research efforts use psychophysiological measures such as electroencephalography (EEG), cardiac, ocular, and respiration measures in an attempt to identify and predict mental workload levels. Existing classification methods successfully classify pilot mental workload using flight data for a single pilot on a given day, but are unsuccessful across different pilots and/or days. We demonstrate a small subset of combined and calibrated psychophysiological features collected from …

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