Aerospace Engineering Commons^™

Indentation Of A Square Elastomeric Thin Film By A Flat-Ended Cylindrical Punch In The Presence Of Long-Range Intersurface Forces, Bing Feng Ju, Kai-Tak Wan, Kuo Kang Liu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper reports an experimental study of the elastic deformation of a 200 μm thick microfabricated square membrane with sides ranging from 8.5 mm to 15 mm as indented by a fine cylindrical, flat-ended punch with diameter 500 μm in the presence of long-range intersurface forces. an apparatus was constructed to allow simultaneously measurements of the indenter displacement and the applied force. a number of interesting phenomena such as the "jump-into-contact" and the "pull-off" between the membrane and the moving cylinder were observed. a simple theoretical analysis using linear elasticity was adopted to fit the load-displacement curve (compliance) and thus …

Wind Tunnel Investigation Of The Static Stability And Control Effectiveness Of A Rotary Tail In A Portable Uav, Jose R. Rivera Parga

Theses and Dissertations

The Air Force Research Lab, Munitions Directorate, Flight Vehicles Integration Branch (AFRL/MNAV) developed a man-portable, carbon-fiber matrix UAV with a flexible rectangular wing of 24" span and 6" chord, 18.2" length. There is a need for the development of smaller and lighter UAV's to perform certain missions. The objective of this experimental study was to determine the behavior and the aerodynamic characteristics of rotary tails. The bird-inspired rotary tail mechanism studied enabled control of two degrees of freedom and was configured to provide elevator deflection and rotation. Its effects on the static stability and control effectiveness were measured using the …

Real Space Projects For University Student Education, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Real Space Projects for University Student Education" from November 17, 2004.

Stanford University Antarctic Development Programs, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Stanford University Antarctic Development Programs" from October 27, 2004.

Multi Application Survivable Tether: Mast, Eric P. Lee

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Eric P. Lee titled "Multi Application Survivable Tether MAST" from October 19, 2004.

Systems Engineering Education Via Real Life – Hands On Projects, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Systems Engineering Education Via Real Life – Hands on Projects" from October 14, 2004.

2005 Cansat Competition Guide, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A guide titled "2005 CanSat Competition Guide" for the ARLISS Project from October 11, 2004.

Stanford To The Moon, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Stanford to the Moon" on October 2, 2004.

Adaptive Synchronization Of Chaos For Secure Communication, Manish Pantha

Master's Theses - Daytona Beach

The purpose of this thesis is to study the use of adaptive synchronization of chaos for secure communication. Several non-linear models were studied, the one-dimensional logistic map, two-dimensional coupled logistic map, three dimensional Lorenz systems with and without time delay. Numerical simulation using MATLAB was conducted. The Lorenz system with time delay was studied numerically as well as by testing an analog circuit and comparisons was made between them. It has been pointed out in many research papers that for low-dimensional chaotic processes, once intercepted, the information can be readily extracted, so the interest has been directed to higher dimensional …

The Effects Of Gender And Regional Dialect On Performance In Aviation Communication, Erin E. Mccollum

Master's Theses - Daytona Beach

The purpose of this study was to analyze the performance effects of gender and regional dialect on air traffic control statement recall. Sixty-one student volunteers participated in the experiment. Thirty-one participants held a pilot’s license and 30 participants had no flight experience. Each participant listened to one CD with 60 ATC statements each representing a male and female voice and New England, Southern, and General American dialect. Participants were asked to recall exactly what they heard. If the participant could not understand what they heard, they requested a repeat. The participant’s performance was recorded to CD and analyzed. Demographic questionnaires …

Swing-Up And Balancing Nonlinear Control For A Rotational Inverted Pendulum, Jiang Wang

Mechanical & Aerospace Engineering Theses & Dissertations

In this thesis, nonlinear controllers are designed for the swing-up and balance modes of a rotational inverted pendulum, which is a pendulum hinged on a horizontally rotating link. The proposed control algorithms are designed by partial feedback linearization and sliding mode control techniques, for swing-up and balancing respectively. First a mathematical model of the pendulum dynamics is derived, followed by experimental verification. Then the system model is partially linearized, which makes it possible for the system to track a simple desired trajectory with "pump energy" function. Then a swing-up controller is designed. For an under-actuated mechanical system, like the inverted …

2005 Cansat Competition Guide, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A guide created by Professor Bob Twiggs titled "2005 CanSat Competition Guide" from September 7, 2004.

Quantifying Initial Condition And Parametric Uncertainties In A Nonlinear Aeroelastic System With An Efficient Stochastic Algorithm, Daniel R. Millman

Theses and Dissertations

There is a growing interest in understanding how uncertainties in flight conditions and structural parameters affect the character of a limit cycle oscillation (LCO) response, leading to failure of an aeroelastic system. Uncertainty quantification of a stochastic system (parametric uncertainty) with stochastic inputs (initial condition uncertainty) has traditionally been analyzed with Monte Carlo simulations (MCS). Probability density functions (PDF) of the LCO response are obtained from the MCS to estimate the probability of failure. A candidate approach to efficiently estimate the PDF of an LCO response is the stochastic projection method. The objective of this research is to extend the …

Analytical Solution For Low-Thrust Minimum Time Control Of A Satellite Formation, John Sang-Pil Seo

Theses and Dissertations

Satellite formations or distributed satellite systems provide advantages not feasible with single satellites. Efficient operation of this platform requires the use of optimal control of the entire satellite formation. While the optimal control theory is well established, only a very simple dynamical system affords an analytical solution. Any practical optimal control problem solves the resulting two-point boundary value (TPBV) problem numerically. The relative satellite dynamics using Hill's coordinate system and approximations made by Clohessy and Wiltshire, combined with body-fixed thruster control, result in a linearized dynamic system. This dissertation provides the analysis for the minimum time satellite formation control by …

An Analysis Of The Conventional Wire Maintenance Methods And Transition Wire Integrity Programs Utilized In The Aviation Industry., Susan Jeruto Kiptinness

Electronic Theses and Dissertations

Aging aircraft wiring poses a significant threat to both commercial and military aircraft. Recent air disasters involving aging aircraft wiring have made it clear that aging wiring can be catastrophic. Aging of an electrical wiring system can result in loss of critical functions of equipment or loss of information regarding equipment operation. Either result can lead to an electrical failure causing smoke and fire, consequently being a danger to public health and aircraft safety.

Conventional maintenance practices do not effectively manage aging wiring problems. More proactive methods are needed so that aircraft wiring failures can be anticipated and wiring systems …

Modeling And Simulation Research And Instruction At The U.S. Air Force Academy, Russell M. Cummings, Scott A. Morton, Keith Bergeron

Aerospace Engineering

Modeling and simulation has become a driving force within the engineering and science communities as the cost of, and time for, experimentation continues to rise. Some areas of study, such as chemistry and biology, may not even have the ability to fully evaluate certain processes experimentally, making modeling and simulation even more important. The situation has led many areas of research to the necessity of modeling and simulating various processes using computers. In addition, the rise in computational capabilities (the supercomputers of a decade ago are outmoded by the PC clusters of today), has led to a paradigm shift from …

Aeroelastic Analysis Of A Flexible Membrane Wing, Isaac Nguri Wanjohi

Master's Theses - Daytona Beach

The focus of this research proposal is the investigation of the aeroelastic effects of a flexible lift augmentation system (LAS) wing. This research involves characterization of the forced vibration response of a wing appendage used to augment short field take off and landing (STOL) operations.

Although flutter theory is now well understood, the LAS presents the complications of a highly deformable airfoil shape as well as larger structural damping values compared to metal wings.

The proposed research will involve derivation of the equations of motion aided by experimental data from nodal excitation of the wing; stiffness and rigidity modeling from …

Modeling Launch Vehicle Success Using Artificial Neural Networks, Jennifer A. Schuck

Master's Theses - Daytona Beach

Expendable launch vehicles in the United States currently have a reliability of 92%. The failures that do occur cost millions of dollars in spacecraft replacement, lost revenue, and other expenses. These costs are passed on in higher insurance rates and launch vehicle price. If the launch outcome of the launch vehicles could be better predicted, the overall cost of launching payloads into space would decrease. This study used artificial neural networks to model the overall launch outcome of a launch vehicle so that the results of a launch could be predicted. Two neural network architectures--MLP and fuzzy ARTMAP--were trained on …

Stability Analysis Of Jump-Linear Systems Driven By Finite-State Machines With Markovian Inputs, Sudarshan S. Patilkulkarni

Electrical & Computer Engineering Theses & Dissertations

A control system with a fault recovery mechanism in the feedback loop and with faults occurring in a non-deterministic manner can be modeled as a class of hybrid systems, i.e., a dynamical system switched by a finite-state machine or an automaton. When the plant and controller are linear, such a system can be modeled as a jump-linear system driven by a finite-state machine with a random input process. Such fault recovery mechanisms are found in flight control systems and distributed control systems with communication networks. In these critical applications, closed-loop stability of the system in the presence of fault recoveries …

Pilot Performance And Eye Movement Activity With Varying Levels Of Display Integration In A Synthetic Vision Cockpit, Julie Michele Stark

Psychology Theses & Dissertations

The primary goal of the present study was to investigate the effects of display integration in a simulated commercial aircraft cockpit equipped with a synthetic vision display. Combinations of display integration level (low/high), display view (synthetic vision view/traditional display), and workload (low/high) were presented to each participant. Sixteen commercial pilots flew multiple approaches under IMC conditions in a moderate fidelity fixed-base part-task simulator. Pilot performance data, visual activity, mental workload, and self-report situation awareness were measured.

Congruent with the Proximity Compatibility Principle, the more integrated display facilitated superior performance on integrative tasks (lateral and vertical path maintenance), whereas a less …

Uncertainty Propagation And Robust Design In Cfd Using Sensitivity Derivatives, Michele M. Putko

Mechanical & Aerospace Engineering Theses & Dissertations

This study investigates and demonstrates a methodology for uncertainty propagation and robust design in Computational Fluid Dynamics (CFD). Efficient calculation of both first- and second-order sensitivity derivatives is requisite in the proposed methodology. In this study, first- and second-order sensitivity derivatives of code output with respect to code input are obtained through an efficient incremental iterative approach.

An approximate statistical moment method for uncertainty propagation is first demonstrated on a quasi one-dimensional (1-D) Euler CFD code. This method is then extended to a two-dimensional (2-D) subsonic inviscid model airfoil problem. In each application, given statistically independent, random, normally distributed input …

United States Antartic Program: Aws-Amrc-Amps Annual Joint Meeting, Kathie Hill

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Kathie Hill titled "United States Antartic Program: AWS-AMRC-AMPS Annual Joint Meeting" from June 4, 2004.

Status Report On The Antarctic Meteorological Research Centermay 2003 To May 2004, Matthew A. Lazzara, Charles R. Stearns, Linda M. Keller, Jessica A. Staude

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Matthew A. Lazzara, Shelley L. Knuth, Charles R. Stearns, Linda M. Keller, and Jessica A. Staude titled "Status Report on the Antarctic Meteorological Research CenterMay 2003 to May 2004" from June 8, 2004.

Mcmurdo Station Fog Climatology: 1973-1998, Matthew A. Lazzara

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "McMurdo Station Fog Climatology:1973-1998" from June 8, 2004.

Meteorological Satellite Status Report: A Sample Of Key Developments, Matthew A. Lazzara

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Matthew A. Lazzara  titled "Meteorological Satellite Status Report: A Sample of Key Developments" June 8, 2004.

Antarctic Automatic Weather Station (Aaws), Antarctic Mesoscale Prediction System (Amps), And Antarctic Meteorological Research Center (Amrc): Joint Annual Meeting, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled  "Antarctic Automatic Weather Station (AAWS), Antarctic Mesoscale Prediction System (AMPS), and Antarctic Meteorological Research Center (AMRC) Joint Annual Meeting" from June 8, 2004.

Plans For 2004/2005 Mcmurdo Based Operations, John Cassano, Thomas R. Parish

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Joh Cassano and Thomas R. Parish titled "Plans for 2004/2005 Mcmurdo Based Operations" from June 7, 2004.

Aerodynamic Analysis Of Lattice Grid Fins In Transonic Flow, Karl S. Orthner

Theses and Dissertations

Lattice grid fins have been studied for missile tail control for several years. A lattice grid fin can be described as an unconventional missile control surface comprised of an outer frame supported by an inner lattice grid of lifting surfaces. This unconventional fin design offers favorable lift characteristics at high angle of attack as well as almost zero hinge moments allowing the use of small and light actuators. In addition, they promise good storability for potential tube-launched and internal carriage dispenser-launched applications. The drawback for the lattice grid fins is the high drag and potentially poor radar cross section performance …

Detached Eddy Simulation Analysis Of Pak-B Low Pressure Turbine Blade, Kyle Malone

Theses and Dissertations

Two cases were computationally investigated using the detached eddy simulation (DES) turbulence model: an unmodified Pak-B blade and a Pak-B blade with a dimple located at 65% of axial chord. Both cases were created so that they simulated an infinite span with an infinite number of dimples. The cases were run for an inlet Reynolds number of 25,000. The computed results were used to resolve the location of separation and reattachment, visualize the streamlines for the dimpled case, build velocity magnitude contour and vector plots, and map the thickness of the boundary layer. The results were then compared to previous …

Magnetogasdynamic Flow Acceleration In A Scramjet Nozzle, Brian H. Harrington

Theses and Dissertations

The effect of magnetogasdynamic (MGD) interactions on flow acceleration and thrust in a scramjet accelerator/nozzle are examined numerically at a free-stream flight condition of Mach 8. The parameters of conductivity pattern and load factor are varied in both inviscid and viscous flow regimes with the intent of increasing axial force exerted on the flow through a scramjet accelerator. The numerical code solves the Navier-Stokes equations with additional source terms for the MGD forces and energy interactions. An accelerating Lorentz force is applied to the flow resulting from a constant magnetic field and an electric field produced by two continuous side …