Aerospace Engineering Commons^™

Design, Development, And Testing Of A Conformal Power Control Interface For Thrust Vectoring Aircraft, David Rozovski

Open Access Dissertations

Over the last five years, a new power control inceptor for tiltrotor aircraft, known as the Rotational Throttle Interface (RTI) was designed and built. Prior to the RTI, no tiltrotor inceptor had been able to simultaneously indicate both the direction and magnitude of thrust conformally. The purpose of the RTI is to provide an interface that maps to the intended vehicle response throughout ALL ranges of operation. Doing so is expected to reduce confusion that may have contributed to several tiltrotor accidents

Two tests were conducted with the RTI, one at the NASA Vertical Motion Simulator, and one at Canada's …

Spacecraft Orbit Design In The Circular Restricted Three-Body Problem Using Higher-Dimensional Poincaré Maps, Christopher D. Geisel

Open Access Dissertations

Strategies for designing three-dimensional spacecraft trajectories in a multi-body dynamical environment are investigated using four-dimensional Poincaré maps. Unlike the planar circular restricted three-body problem, where a two-dimensional map provides a simplified view of a portion of the vast and often chaotic design space, the spatial problem requires a four-dimensional map to achieve an equivalent perspective. Such higher-dimensional maps present a visualization challenge. Furthermore, a spacecraft in the spatial problem can exhibit fundamentally more diverse and complex behavior than in the planar problem. A novel approach to four-dimensional-map-based design in the spatial circular restricted three-body problem is developed and applied to …

Solution To Certain Problems In The Failure Of Composite Structures, Jonathan Goodsell

Open Access Dissertations

The present work contains the solution of two problems in composite structures. In the first, an approximate elasticity solution for prediction of the displacement, stress and strain fields within the m-layer, symmetric and balanced angle-ply composite laminate of finite-width subjected anticlastic bending deformation is developed. The solution is shown to recover classical laminated plate theory predictions at interior regions of the laminate and thereby illustrates the boundary layer character of this interlaminar phenomenon. The results exhibit the anticipated response in congruence with the solutions for uniform axial extension and uniform temperature change, where divergence of the interlaminar shearing stress is …

Applicability Of Continuum Fracture Mechanics In Atomistic Systems, Shao-Huan Cheng

Open Access Dissertations

By quantitating the amplitude of the unbounded stress, the continuum fracture mechanics defines the stress intensity factor K to characterize the stress and displacement fields in the vicinity of the crack tip, thereby developing the relation between the stress singularity and surface energy (energy release rate G). This G-K relation, assigning physical meaning to the stress intensity factor, makes these two fracture parameters widely used in predicting the onset of crack propagation. However, due to the discrete nature of the atomistic structures without stress singularity, there might be discrepancy between the failure prediction and the reality of nanostructured materials. Defining …

Mapping Automotive Like Controls To A General Aviation Aircraft, Christopher G. Carvalho

Doctoral Dissertations and Master's Theses

The purpose of this thesis was to develop fly-by-wire control laws enabling a general aviation aircraft to be flown with automotive controls, i.e. a steering wheel and gas/brake pedals. There was a six speed shifter used to change the flight mode of the aircraft. This essentially allows the pilot to have control over different aspects of the flight profile such as climb/descend or cruise. A highway in the sky was used to aid in the navigation since it is not intuitive to people without flight experience how to navigate from the sky or when to climb and descend.

Many believe …

Investigation Of Grid Adaptation To Reduce Computational Efforts For A 2-D Hydrogen-Fueled Dual-Mode Scramjet, Kam Keong Foo

Doctoral Dissertations and Master's Theses

A two-dimensional dual-mode scramjet flowpath is developed and evaluated using the ANSYS Fluent density-based flow solver with various computational grids. Results are obtained for fuel-off, fuel-on non-reacting, and fuel-on reacting cases at different equivalence ratios. A one-step global chemical kinetics hydrogen-air model is used in conjunction with the eddy-dissipation model. Coarse, medium and fine computational grids are used to evaluate grid sensitivity and to investigate a lack of grid independence. Different grid adaptation strategies are performed on the coarse grid in an attempt to emulate the solutions obtained from the finer grids. The goal of this study is to investigate …

Attitude Dynamics Of Debris Resulting From Upper Stage Fragmentation In Low Earth Orbit, Killian Marie

Doctoral Dissertations and Master's Theses

This thesis addresses the analysis of the attitude dynamics of pieces of space debris that could result from the fragmentation of a spent upper stage in low Earth orbit (LEO).

Up to now only whole objects of axisymmetric shape have been studied with the purpose of estimating their tumbling rates in LEO. Three shapes have been considered to be representative for the purpose of the study: a thin plate, a monocoque shell, an half conical shell and a spherical shell, and it has been assumed that they are fabricated from aluminum alloy. The motion of conducting body in a magnetic …

Observability And Confidence Of Stability And Control Derivatives Determined In Real Time, Alfonso Noriega

Doctoral Dissertations and Master's Theses

Stability and control derivatives of an aircraft were estimated from real flight test data in real time. A higher language block diagram library was developed for this purpose. Parameter identification techniques and requirements were used to detect and rate maneuvers present in the data. These ratings were used to blend newly calculated derivatives with previously known values by means of a Kalman filter. The Kalman filter output was used to identify the health of control surfaces actuators. Statistical and measured data were used to predict the probability that an actuator failure has occurred at any given time during the flight. …

Preliminary Design Of Blade And Disc Fixing For Aerospace Application Using Multi-Disciplinary Approach, Abdulhalim Twahir

Doctoral Dissertations and Master's Theses

The preliminary design phase of a turbine rotor has an important impact on the architecture of a new engine definition, as it sets the technical envelope of the product to be designed. Additionally, preliminary design cycle times are increasingly critical in capturing business opportunities in an ever competitive environment. Improving the accuracy of the preliminary design (pre-detailed design) is also necessary as not only does it significantly reduce the overall development of an engine, but also because any mistakes made at this stage can be extremely hard to rectify.

Previously, typical pre-detail fixing design cycle time was greater due to …

Examination Of Micromotion-Induced Transient Effects Of Brain Tissue Interfaced With A Neural Probe, Michael A. Polanco

Mechanical & Aerospace Engineering Theses & Dissertations

Neural probes are utilized to obtain information regarding the activity of brain cells for neural stimulation. The functional longevity of a probe is dependent upon its ability to minimize injury risk during insertion and the recording period in vivo, which could be related to micromotion-related strain between the probe and surrounding tissue. A series of finite element analyses were conducted using the nonlinear transient dynamic code LSDYNA (LSTC, Livermore, CA) to study the strain induced within the brain in an area around a neural probe. A variety of displacement pulses were input into the brain, first where a high magnitude, …

New Test Capabilities For The 0.3-Meter Transonic Cryogenic Wind Tunnel, Ben D. Phillips

Mechanical & Aerospace Engineering Theses & Dissertations

The small-scale, cryogenic, and high pressure characteristics of the 0.3-Meter Transonic Cryogenic Tunnel provide a unique, high-Reynolds number research capability. However, the facility is currently restricted by its reliance on a two-dimensional adaptive wall test section coupled with an inadequate facility control system. Access to the test section is restricted, the walls require excess time for convergence and are mechanically constrained by a wall jacking system that degrades under cyclic cryogenic operations, and the tunnel requires excessive time to reach the set point, particularly at low Mach numbers. As a result, productivity and operational efficiency are limited, leading to expensive …

An Investigation Of Unsteady, In-Cylinder Flows Of A Mock-Up Internal Combustion Engine Using Particle Image Velocimetry, David Schleeper

Mechanical & Aerospace Engineering Theses & Dissertations

Particle Image Velocimetry is frequently used in fluid mechanics and aerodynamics research to provide accurate, quantitative information on the instantaneous structure of a variety of flow fields. This technique provides a nonintrusive means of capturing vital, whole-field details of internal and external flows, such as vortex size and strength, not usually possible through other flow investigation techniques. Due to practical difficulties, the utilization of this method for the study of combustion chamber flow within an internal combustion engine is still relatively uncommon. This study used a TSI Particle Image Velocimetry system to identify two-dimensional flow patterns and velocities on a …

Space Radiation Environment - Space Systems Engineering Sse 120, Fall 2013, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

Lecture preview on "Space Radiation Environment" created by Professor Bob Twiggs on September 24, 2013.

Space Radiation Environment: Sse 120 By Richard Mcneil, Richard Mcneil

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation delivered by Richard McNeil on "Space Radiation Environment" on September 24, 2013.

Cosmic Perspective: Where Is Space, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Bob Twigg on September 19, 2013, related to the "Cosmic Perspective."

Compression Properties And Damage Mechanisms Of Stitched Carbon/Epoxy Composites, Arief Yudhanto, Naoyuki Watanabe, Yutaka Iwahori, Hikaru Hoshi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The effect of stitching on compression properties and damage mechanisms of carbon/epoxy composites is experimentally investigated. The waviness angle of load-bearing tows is also measured in both in-plane and out-of-plane directions, and a correlation is made between compression strength and the waviness angle. It is found that stitching generally reduces the compression strength of carbon/epoxy composites of up to 16%. The average compression strength has a stronger correlation with the in-plane waviness angle rather than the out-of-plane one. A comparative damage assessment, which studies the initiation, progression and final failure in stitched and unstitched composites under axial compression, reveals that …

Elements Of Space Chapter 2: Entering Space & The Age Of Rockets, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Elements of Space Chapter 2: Entering Space & The Age of Rockets" from September 3, 2013.

Adopting A Kinetic Energy Recovery System For Helicopters, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Scattering, Adsorption, And Langmuir-Hinshelwood Desorption Models For Physisorptive And Chemisorptive Gas-Surface Systems, Brook I. Bentley

Theses and Dissertations

Surface effects limit the performance of hypersonic vehicles, micro-electro-mechanical devices, and directed energy systems. This research develops methods to predict adsorption, scattering, and thermal desorption of molecules on a surface. These methods apply to physisorptive (adsorption and scattering) and chemisorptive (thermal desorption) gas-surface systems, and are developed under the Direct Simulation Monte Carlo construct. The novel adsorption and scattering contribution, the Modified Kisliuk with Scattering method, predicts angular and energy distributions, and adsorption probabilities. These results agree more closely with experiment than the state-of-the-art Cercignani-Lampis-Lord scattering kernel. Super-elastic scattering is predicted. Gas-adlayer interactions are included for the first time. The …

Architecting Integrated System Health Management For Airworthiness, Kerwin C. Teong

Theses and Dissertations

Integrated System Health Management (ISHM) for Unmanned Aerial Systems (UAS) has been a new area of research - seeking to provide situational awareness to mission and maintenance operations, and for improved decision-making with increased self-autonomy. This research effort developed an analytic architecture and an associated discrete-event simulation using Arena® to investigate the potential benefits of ISHM implementation onboard an UAS. The objective of this research is two-fold: firstly, to achieve continued airworthiness by investigating the potential extension of UAS expected lifetime through ISHM implementation, and secondly, to reduce life cycle costs by implementing a Condition-Based Maintenance (CBM) policy with better …

Qualitative Methods Used To Develop And Characterize The Circulation Control System On Cal Poly's Amelia, Eric N. Paciano

Master's Theses

The circulation control system onboard Cal Poly's Advanced Model for Extreme Lift and Improved Aeroacoustics was a critical component of a highly complex wind tunnel model produced in order to fulfill the requirements of a NASA Research Announcement awarded to David Marshall of the Aerospace Engineering Department. The model was based on a next generation, 150 passenger, regional, cruise efficient, short take-off and landing concept aircraft that achieved high lift through circulation control wings and over-the-wing mounted engines. The wind tunnel model was 10-ft in span, used turbine propulsion simulators, and had a functioning circulation control system driven from tunnel …

Characterizing G-Loading, Swirl Direction And Rayleigh Losses In An Ultra Compact Combustor, Jacob D. Wilson

Theses and Dissertations

Previous research has been conducted showing significant benefits on combustion efficiency and stability by creating high centripetally accelerated, also known as g-loaded, combustion environments. Ultra Compact Combustor systems decrease size and weight of the overall engine by burning in a circumferential direction around a hybrid vane row where the high equivalence ratio cavity flow is quick quenched to lean by the core flow. The hybrid vane row integrates the compressor, combustor, and turbine for further length reduction and weight savings. Fuel and air are brought into the cavity and combusted in a high g-loaded environment driven by air injection at …

Trajectory Optimization For Spacecraft Collision Avoidance, James W. Sales Jr.

Theses and Dissertations

The last several decades have resulted in an unfortunate byproduct of space exploration and development: orbital debris. Satellites in Low Earth Orbit have been required to make an ever increasing number of course corrections in order to avoid collisions. Despite efforts to the contrary, collisions continue to occur, each time creating additional debris and increasing the requirement for the remaining satellites to maneuver. Every required maneuver decreases a satellite's service life. The purpose of this study is to develop a minimum thrust profile to maneuver an orbiting satellite out of its projected error ellipse before a collision occurs. For comparison, …

Correlational Study Of Open Circuit Resonant (Sansec) Sensor’S Electric Field Distribution On Lightning Attachment, Kayla M. Farrow, Linda L. Vahala

Electrical & Computer Engineering Faculty Publications

NASA Langley Research Center (LaRC) is conducting research to develop an open circuit SansEC (Sans Electric Connection) sensor to provide lightning strike protection (LSP) in conjunction with damage detection and diagnosis for composite aircraft. SansEC sensors are simplistic devices consisting of an open circuit conductive trace shaped in a planar geometric spiral. The length and width of the conductive trace as well as the gap separation between adjacent turns determines the inductance, resistance and capacitance of the LRC circuit and its associated resonant response. When the sensor is placed on a composite substrate, the electric impedance of the substrate is …

Assessment - Introduction To Sse-120: Sataellites & Space Systems I, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

PowerPoint presentation for Introduction to SSE-120: Sataellites & Space Systems I - Assessment given by Bob Twiggs on August 19, 2013 at Morehead State University.

Work Ethics For Sse-122: Satellites & Space Systems (Fall 2013), Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

PowerPoint presentation by Professor Bob Twiggs on work ethics for SSE-122: Satellites & Space Systems for the fall 2013 semester, created on August 8, 2013.

Introduction To Sse-120: Sataellites & Space Systems I, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

PowerPoint presentation for Introduction to SSE-120: Sataellites & Space Systems I given by Bob Twiggs on August 6, 2013 at Morehead State University.

Mechanical Design Of Pird (Principal Investigator Rack Drawer) For Sofia, Hari Prasad Shetty Mr., Murali Krishna Kandlagunta Mrs., John Miles Mr., Zaheer Ali Mr.

STAR Program Research Presentations

SOFIA, the world’s largest airborne observatory with 2.5-meter diameter infrared telescope is equipped with 7 instruments: EXES, FIFI-LS, FLITECAM, FORCAST, GREAT, HAWC, and HIPO. Flying at altitudes between 39,000 and 45,000 feet, SOFIA avoids 99% of the atmospheric water vapor, records and analyzes the infrared radiation from the cosmos. SOFIA is able to observe the occultation of stars by solar system objects. By determining the size, compositions, and atmospheric structures of these objects, SOFIA can help answer the questions on creation and evolution of the universe, formation of the stars and planets, and nature of black hole at the center …

If It Isn’T Tested, It Doesn’T Work: Automated Verification Of Sofia Data Handling Software, Garrett Holthaus, Brett Stroozas, Zaheer Ali

STAR Program Research Presentations

This project involves writing code to automate the verification testing of the Data Handling Working Group (DHWG) software tools for the Stratospheric Observatory for Infrared Astronomy (SOFIA). The DHWG tools extract engineering data from SOFIA missions. Engineering data includes a variety of information on the operations and status of SOFIA systems during a flight, including computer network traffic, user commands, and images acquired from cameras mounted on the telescope assembly. It is important to review engineering data because this data can lead to the discovery of any problems or inefficiencies in SOFIA hardware and software. Analysis of engineering data can …

Experimental Investigation Of Blowing Effects On Turbulent Flow Over A Rough Surface, Mark A. Miller, Alexandre Martin, Sean C. C. Bailey

Mechanical Engineering Faculty Publications

A high Reynolds number turbulent channel flow facility was used to study the combined effects of roughness and flow injection on the mean flow and turbulence characteristics. It was found that the additional momentum injection through the surface enhanced the roughness effects and for the mean flow the effect of blowing was indistinguishable from that of increased roughness. However, for the turbulence statistics, this analogy broke down in that the addition of blowing resulted in behavior which did not follow that predicted by Townsend’s hypothesis. This was observed as a reduction of outer-scaled Reynolds stress well into the outer layer. …