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Aerospace Engineering Commons™

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Faculty Publications

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Articles 91 - 120 of 125

Full-Text Articles in Aerospace Engineering

Aerodynamic Modeling Of Nrel 5-Mw Wind Turbine For Nonlinear Control System Design: A Case Study Based On Real-Time Nonlinear Receding Horizon Control, Pedro A. Galvani, Fei Sun, Kamran Turkoglu Jan 2016

Aerodynamic Modeling Of Nrel 5-Mw Wind Turbine For Nonlinear Control System Design: A Case Study Based On Real-Time Nonlinear Receding Horizon Control, Pedro A. Galvani, Fei Sun, Kamran Turkoglu

Faculty Publications

The work presented in this paper has two major aspects: (i) investigation of a simple, yet efficient model of the NREL (National Renewable Energy Laboratory) 5-MW reference wind turbine; (ii) nonlinear control system development through a real-time nonlinear receding horizon control methodology with application to wind turbine control dynamics. In this paper, the results of our simple wind turbine model and a real-time nonlinear control system implementation are shown in comparison with conventional control methods. For this purpose, the wind turbine control problem is converted into an optimization problem and is directly solved by the nonlinear backwards sweep Riccati method …

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Constructal Alkaline Membrane Fuel Cell (Amfc) Design, E. M. Sommer, J. V. C. Vargas, Lauber De Souza Martins, J. C. Ordonez Jan 2016

Constructal Alkaline Membrane Fuel Cell (Amfc) Design, E. M. Sommer, J. V. C. Vargas, Lauber De Souza Martins, J. C. Ordonez

Faculty Publications

This paper introduces a structured procedure to optimize the internal structure (relative sizes, spacing) and external shape (aspect ratios) of a single alkaline membrane fuel cell so that net power is maximized. The optimization of flow geometry is conducted for the smallest (elemental) level of a fuel cell stack, i.e., the single alkaline membrane fuel cell, which is modeled as a unidirectional flow system. The polarization curve, total and net power, and efficiency are obtained as functions of temperature, pressure, electrolyte solution concentration (KOH), geometry and operating parameters. The optimization is subjected to fixed total volume. There are two levels …

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Space Separatism: Degree Of Differentiation, Luke R. Stover, Alan A. Johnson Nov 2014

Space Separatism: Degree Of Differentiation, Luke R. Stover, Alan A. Johnson

Faculty Publications

Space is so important that the DOD recognizes it as one of five domains in which US forces operate (the other four are land, sea, air, and information). In 2001 Secretary of Defense Donald Rumsfeld designated the Department of the Air Force (DAF) the “Executive Agent for Space for the DOD.” Given the national importance of space activities, the formation of a separate space force has been a topic of persistent discussion in academic and doctrinal circles ever since the United States first entered the space age. Proponents of a separate force argue that because space is an inherently unique …

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Modeling The Thermosphere As A Driven-Dissipative Thermodynamic System, William R. Frey, C. S. Lin, Matthew B. Garvin, Ariel O. Acebal Apr 2014

Modeling The Thermosphere As A Driven-Dissipative Thermodynamic System, William R. Frey, C. S. Lin, Matthew B. Garvin, Ariel O. Acebal

Faculty Publications

Thermospheric density impacts satellite position and lifetime through atmospheric drag. More accurate specification of thermospheric temperature, a key input to current models such as the High Accuracy Satellite Drag Model, can decrease model density errors. This paper improves the model of Burke et al. (2009) to model thermospheric temperatures using the magnetospheric convective electric field as a driver. In better alignment with Air Force satellite tracking operations, we model the arithmetic mean temperature, T 1/2, defined by the Jacchia (1977) model as the mean of the daytime maximum and nighttime minimum exospheric temperatures occurring in opposite hemispheres at a …

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Statistics Based Modeling Of Wind Speed And Wind Direction In Real Time Optimal Guidance Strategies Via Ornstein-Uhlenbeck Stochastic Processes, Kamran Turkoglu Feb 2014

Statistics Based Modeling Of Wind Speed And Wind Direction In Real Time Optimal Guidance Strategies Via Ornstein-Uhlenbeck Stochastic Processes, Kamran Turkoglu

Faculty Publications

No abstract provided.

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Guided Wave-Based J-Integral Estimation For Dynamic Stress Intensity Factors Using 3d Scanning Laser Doppler Vibrometry, J. Ayers, Christopher Todd Owen, Eric D. Swenson, Anindya Ghoshal, V. Weiss Jan 2013

Guided Wave-Based J-Integral Estimation For Dynamic Stress Intensity Factors Using 3d Scanning Laser Doppler Vibrometry, J. Ayers, Christopher Todd Owen, Eric D. Swenson, Anindya Ghoshal, V. Weiss

Faculty Publications

The application of guided waves to interrogate remote areas of structural components has been researched extensively in characterizing damage. However, there exists a sparsity of work in using piezoelectric transducer-generated guided waves as a method of assessing stress intensity factors (SIF). This quantitative information enables accurate estimation of the remaining life of metallic structures exhibiting cracks, such as military and commercial transport vehicles. The proposed full wavefield approach, based on 3D laser vibrometry and piezoelectric transducer-generated guided waves, provides a practical means for estimation of dynamic stress intensity factors (DSIF) through local strain energy mapping via the J-integral. Strain energies …

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Wind Loading On Trees Integrated With A Building Envelope, Aly Mousaad Aly, Alberto Zasso, Girma Bitsuamlak, Alberto Nicola Longarini, Arindam Gam Chowdhury Jan 2013

Wind Loading On Trees Integrated With A Building Envelope, Aly Mousaad Aly, Alberto Zasso, Girma Bitsuamlak, Alberto Nicola Longarini, Arindam Gam Chowdhury

Faculty Publications

With the sustainability movement, vegetated building envelopes are gaining more popularity. This requires special wind effect investigations, both from sustainability and resiliency perspectives. The current paper focuses on wind load estimation on small- and full-scale trees used as part of green roofs and balconies. Small-scale wind load assessment was carried out using wind tunnel testing in a global-effect study to understand the interference effects from surrounding structures. Full-scale trees were investigated at a large open-jet facility in a local-effect study to investigate the wind-tree interaction. The effect of Reynolds number combined with shape change on the overall loads measured at …

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Solid-Fuel Regression Rate Modeling For Hybrid Rockets, Francesca Favaro, W. Sirignano, M. Manzoni, L. Deluca Jan 2013

Solid-Fuel Regression Rate Modeling For Hybrid Rockets, Francesca Favaro, W. Sirignano, M. Manzoni, L. Deluca

Faculty Publications

The regression rate of the solid fuel is a primary parameter in the performance analysis for a hybrid rocket. Many studies in the past few years have theoretically claimed, or experimentally shown, a dependence of the regression rate on the chamber total pressure. Such behavior is generally traced back to the presence of oxygen below the flame zone and of heterogeneous reactions occurring at the surface and affecting the pyrolysis law. An experimental program was performed at the Space Propulsion Laboratory of the Politecnico di Milano showing, within the explored operating conditions and the associated uncertainty bands, a neutral trend …

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Empirically Bounding Of Space Booms With Tape Spring Hinges, Alan L. Jennings, Jonathan T. Black, Chris Allen Nov 2012

Empirically Bounding Of Space Booms With Tape Spring Hinges, Alan L. Jennings, Jonathan T. Black, Chris Allen

Faculty Publications

Self-deploying structures seek to provide a compact launch package for large, lightweight satellite booms. One self-deploying method is a foldable tape spring. This paper examines the large scale behavior of a boom attached by a tape spring hinge during mock deployments. A boom attached by tape spring to a rigid stand was released and the boom bounced up to 60° before coming to rest (as opposed to snap-through behavior). These large amplitude bounces can cause the boom to collide with sensors, other booms or arrays causing damage or preventing full deployment. Results show the first bounce of deployment is nearly …

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Defining, Teaching, And Assessing Engineering Design Skills, Nikos J. Mourtos Jan 2012

Defining, Teaching, And Assessing Engineering Design Skills, Nikos J. Mourtos

Faculty Publications

The paper discusses a systematic approach for defining, teaching, and assessing engineering design skills. Although the examples presented in the paper are from the field of aerospace engineering, the principles apply to engineering design in general. What makes the teaching of engineering design particularly challenging is that the necessary skills and attributes are both technical and non-technical and come from the cognitive as well as the affective domains. Each set of skills requires a different approach to teach and assess. Implementing a variety of approaches for a number of years at SJSU has shown that it is just as necessary …

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Aerospike Rockets For Increased Space Launch Capability, Carl R. Hartsfield, Richard D. Branam, Joshua N. Hall, Joseph R. Simmons Iii Jul 2011

Aerospike Rockets For Increased Space Launch Capability, Carl R. Hartsfield, Richard D. Branam, Joshua N. Hall, Joseph R. Simmons Iii

Faculty Publications

The US Department of Defense (DOD) increasingly depends on space assets for everyday operations. Precision navigation; communications; and intelligence, surveillance, and reconnaissance satellites are highly leveraged space assets. The launch vehicles that place these satellites in orbit are a major limitation of current space systems. If higher-performing launch vehicles were available, many satellites could accommodate additional capabilities, whether in terms of more sensor channels, types of payloads, electrical power, or propellant for orbital maneuvering and station keeping.

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A Taskable Space Vehicle: Realizing Cost Savings By Combining Orbital And Suborbital Flight, Thomas Co, Jonathan T. Black Jul 2011

A Taskable Space Vehicle: Realizing Cost Savings By Combining Orbital And Suborbital Flight, Thomas Co, Jonathan T. Black

Faculty Publications

The use of space gives the United States distinct advantages in any battlefield environment, but the high cost of space operations increasingly jeopardizes those advantages. Although the United States pioneered much of the current space technology, declining budgets for space research, development, and operations leave our legacy systems vulnerable to adversaries around the world. Other nations formerly incapable of space exploitation are quickly learning to counter US space technologies at surprisingly low costs. In order to reduce the expense of deploying and maintaining a robust space capability, the Department of Defense (DOD) must change the status quo in space operations …

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Precision Position, Navigation, And Timing Without The Global Positioning System, Kenneth A. Fisher, John F. Raquet Jul 2011

Precision Position, Navigation, And Timing Without The Global Positioning System, Kenneth A. Fisher, John F. Raquet

Faculty Publications

The NAVSTAR Global Positioning System GPS has revolutionized modern warfare. Since 2005 almost all US precision-guided munitions have used GPS targeting data. Consequently, weapons delivery systems are able to strike enemy targets with precision, often resulting in little or no collateral damage. Furthermore, nearly all military assets, including aircraft, tanks, ships, missiles, mortar rounds, cargo boxes, and dismounted Soldiers rely on the accurate position determination that GPS provides. For military users of this system, two main limitations emerge. First, the system relies on line of sight that is, the satellites must be in view of the receiver s antenna so …

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X-Hale: Designing The Atmospheric Surveillance Platforms Of The Future, Christopher M. Shearer Jul 2011

X-Hale: Designing The Atmospheric Surveillance Platforms Of The Future, Christopher M. Shearer

Faculty Publications

Imagine the benefits that battlefield commanders or intelligence analysts could derive from an airborne surveillance platform that would carry a 500-pound payload, operate above the range of small arms fire, remain on station for weeks or even years, cost much less than a satellite, and relocate around the globe to a new region of interest within a couple of weeks. Realizing this concept, known as a high-altitude, long-endurance HALE aircraft, is a 10-to-15-year goal of researchers at the Air Force Institute of Technology AFIT. In order to reach this goal, those researchers are following a developmental path similar to the …

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Challenges Students Face When Solving Open - Ended Problems, Nikos J. Mourtos Jan 2010

Challenges Students Face When Solving Open - Ended Problems, Nikos J. Mourtos

Faculty Publications

Several core aerospace engineering courses at SJSU have been re-designed in an effort to help students develop problem-solving skills. This re-design includes (a) explicit definition of skills and attributes students need to develop to become capable problem-solvers, (b) inclusion of open-ended problems in each of several key, junior-level, core courses, (c) coaching students in the use of Wood’s Problem-Solving Methodology, and (d) development of rubrics to evaluate student performance at each step of this methodology. The paper discusses the application of this process and, in particular, it presents an assessment of student performance in two courses: fluid mechanics and aerodynamics. …

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Application Of Systems Engineering To Rapid Prototyping For Close Air Support, John M. Colombi, Richard G. Cobb Oct 2009

Application Of Systems Engineering To Rapid Prototyping For Close Air Support, John M. Colombi, Richard G. Cobb

Faculty Publications

Twenty-first century military operations have brought forth many new challenges for the Armed Forces of the United States. One such challenge is with new operating environments, where current systems are not always effective. While it is desirable to apply a systems engineering approach to best meet critical user needs, there may be a misconception that systems engineering requires a lengthy and detailed process not nimble enough for a rapid prototyping effort. This article describes how a classic systems engineering methodology was successfully tailored to the rapid development of potential material solutions to meet a critical operational need. Key observations are …

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Maximizing Warfighter Capability Using Surveyed Necessity Measurement: Application To The Usaf F-15c Fleet, John M. Colombi, David R. Jacques, Dennis D. Strouble Dec 2008

Maximizing Warfighter Capability Using Surveyed Necessity Measurement: Application To The Usaf F-15c Fleet, John M. Colombi, David R. Jacques, Dennis D. Strouble

Faculty Publications

Within the Department of Defense, with changing missions to counter dynamic and asymmetrical threats, the acquisition workforce strives to maximize capability for joint warfighting. How acquisition professionals measure and select capability improvements for the nation’s weapon systems is a perpetual challenge, made even more complex with constrained defense budgets. This study identifies a method for determining which upgrades should be purchased (production) for which aircraft in the F- 15C fleet by optimizing a capability proxy measure. Each upgrade’s “necessity” for a given mission area was obtained by conducting a survey of over 250 experienced F-15C pilots. The solution presented in …

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Adaptive Quaternion Control Of A Miniature Tailsitter Uav, Nathan B. Knoebel, Timothy W. Mclain Jun 2008

Adaptive Quaternion Control Of A Miniature Tailsitter Uav, Nathan B. Knoebel, Timothy W. Mclain

Faculty Publications

The miniature tailsitter is a unique aircraft with inherent advantages over typical unmanned aerial vehicles. With the capabilities of both hover and level flight, these small, portable systems can produce efficient maneuvers for enhanced surveillance and autonomy with little threat to surroundings and the system itself. Such vehicles create control challenges due to the two different flight regimes. These challenges are addressed with a computationally efficient adaptive quaternion control algorithm. A backstepping method for model cancellation and consistent tracking of reference model attitude dynamics is derived. This is used in conjunction with a regularized data-weighting recursive least-squares algorithm for the …

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Pid Parameter Optimization Of An Uav Longitudinal Flight Control System, Kamran Turkoglu, Ugur Ozdemir, Melike Nikbay, Elbrous Jafarov Jan 2008

Pid Parameter Optimization Of An Uav Longitudinal Flight Control System, Kamran Turkoglu, Ugur Ozdemir, Melike Nikbay, Elbrous Jafarov

Faculty Publications

In this paper, an automatic control system design based on Integral Squared Error (ISE) parameter optimization technique has been implemented on longitudinal flight dynamics of an UAV. It has been aimed to minimize the error function between the reference signal and the output of the plant. In the following parts, objective function has been defined with respect to error dynamics. An unconstrained optimization problem has been solved analytically by using necessary and sufficient conditions of optimality, optimum PID parameters have been obtained and implemented in control system dynamics.

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Contingency Planning And An Air Force Space Command Information System, Kaylin Freedman, Michael R. Grimaila Apr 2006

Contingency Planning And An Air Force Space Command Information System, Kaylin Freedman, Michael R. Grimaila

Faculty Publications

No abstract provided.

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Managing The Integration Of Space And Information Operations, Daniel F. Gottrich, Michael R. Grimaila Apr 2006

Managing The Integration Of Space And Information Operations, Daniel F. Gottrich, Michael R. Grimaila

Faculty Publications

No abstract provided.

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A Sustainable, Systematic Process For Continuous Program Improvement, Nikos J. Mourtos Jan 2006

A Sustainable, Systematic Process For Continuous Program Improvement, Nikos J. Mourtos

Faculty Publications

The USA Accreditation Board for Engineering and Technology (ABET) adopted recently a new set of criteria for evaluating engineering programmes. One of these (criterion 3) refers to programme outcomes and assessment. In this article, the author describes the design and implementation of a sustainable, systematic process for defining and assessing programme outcomes. This process involves analysing each outcome into elements, defining a set of attributes for each element, selecting outcome indicators and performance targets, and developing special rubrics for an accurate assessment of student skills. The author also describes a systematic way of addressing specific programme outcomes through course and …

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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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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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Open-Ended Problem-Solving Skills In Thermal-Fluids Engineering, Nikos J. Mourtos, Nicole Dejong-Okamoto, Jinny Rhee Jan 2004

Open-Ended Problem-Solving Skills In Thermal-Fluids Engineering, Nikos J. Mourtos, Nicole Dejong-Okamoto, Jinny Rhee

Faculty Publications

Problem-solving skills have always been important in many professions. However, ABET EC 2000 recently placed a new focus on these skills in engineering education with outcome 3e, which states that engineering graduates must have an ability to identify, formulate and solve engineering problems. Problem-solving is defined as a process used to obtain a best answer to an unknown or a decision that is subject to some constraints. Problem-solving is not the same as textbook exercise solving, which is very common in engineering curricula. In the article, the authors first define engineering problem-solving and, in particular, what it means to identify …

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From Learning To Talk To Learning Engineering; Drawing Connections Across The Disciplines, Nikos J. Mourtos Jan 2003

From Learning To Talk To Learning Engineering; Drawing Connections Across The Disciplines, Nikos J. Mourtos

Faculty Publications

This paper introduces eight so-called conditions of learning (immersion, demonstration, engagement, expectations, responsibility, approximation, employment and response), which have been previously established for the learning of literacy. It is stipulated that these conditions are universal in nature; in other words, they must be present for any learning to occur. When these conditions are met, students learn more efficiently and are able to enjoy and appreciate their subject matter. The article discusses briefly how these conditions were established and their relevance in the study of engineering. More importantly, the article also presents examples of how these conditions can be satisfied in …

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Propagation Of Detonation Waves In Tubes Split From A Pde Thrust Tube, August J. Rolling, Paul I. King, Fred R. Schauer Jul 2002

Propagation Of Detonation Waves In Tubes Split From A Pde Thrust Tube, August J. Rolling, Paul I. King, Fred R. Schauer

Faculty Publications

A Pulse Detonation Engine (PDE) combusts a fuel air mixture through detonation. Existing designs require spark plugs in each separate thrust tube to ignite premixed reactants. A single thrust tube could require the spark plug to fire hundreds of times per second for long durations. This paper reports on the use of a continuously propagating detonation wave as both a thrust producer and a single ignition source for a multi-tube system. The goal was to minimize ignition complexity and increase reliability by limiting the number of ignition sources. The work includes a systematic investigation of single tube geometric effects on …

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Introducing Cooperative Learning Through A Faculty Instructional Development Program, Nikos J. Mourtos, Emily L. Allen Oct 2001

Introducing Cooperative Learning Through A Faculty Instructional Development Program, Nikos J. Mourtos, Emily L. Allen

Faculty Publications

Cooperative Learning was officially introduced in the College of Engineering at San Jose State University in 1995 with a two-day workshop. The Faculty Instructional Development Program in the college maintains interest in the subjsect and provides support for instructors who use Cooperative Learning, through workshops and informal discussions (Conversations on Teaching). This paper discusses the effectiveness of the program in introducing, promoting, and implementing Cooperative Learning among the faculty and students in the college of engineering. A variety of performance criteria have been used in this assessment, some faculty-centered and some student-centered. The results indicate that although a relatively small …

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Unmanned Research Vehicle (Urv): Development, Implementation, & Flight Test Of A Mimo Digital Flight Control System Designed Using Quantitative Feedback Theory, Constantine H. Houpis, Steven J. Rasmussen Apr 2000

Unmanned Research Vehicle (Urv): Development, Implementation, & Flight Test Of A Mimo Digital Flight Control System Designed Using Quantitative Feedback Theory, Constantine H. Houpis, Steven J. Rasmussen

Faculty Publications

The Quantitative Feedback Theory (QFT) design technique, which has the ability to bridge the gap between theory and the real-world control design problem, is utilized in the design of a MIMO digital flight control system for an unmanned research vehicle (URV) that is presented in this paper. The design illustrates how the real-world knowledge of the plant to be controlled and the desired performance specifications can be utilized in trying to achieve a successful robust design for a nonlinear control problem. This paper presents some of the issues involved in developing, implementing, and flight testing a flight control system (FCS) …

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A Five-Year Development Plan For The California Aviation Database, H.-S. Jacob Tsao Jun 1999

A Five-Year Development Plan For The California Aviation Database, H.-S. Jacob Tsao

Faculty Publications

The California Aviation Database (CAvD) project was suggested by Caltrans Aeronautics Program to fulfill a need of the planners involved in aviation system planning and programming activities to locate and access aviation data and information in an efficient and comprehensive way. CAvD is being implemented in the form of an Internet website and is currently intended as a five-year project. However, the development can be accelerated, and the duration will depend on the available resources. CAvD is a joint project between the National Center of Excellence for Aviation Operations Research (NEXTOR) and the California Department of Transportation (Caltrans). Its primary …

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