Engineering Commons^™

Set-Up Of Digital Image Correlation Apparatus, German A. Parada, Michael Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

Digital Image Correlation (DIC) is a valuable and customizable experimental technique employed to analyze localized strain regions on materials by tracking the displacement of points on the surface of the studied material under applied stress. To investigate materials behavior, it is vital to correctly set-up the DIC apparatus so work has been done to ready the equipment to start measurements on two distinct projects. On the first project, the fatigue crack behavior of a high-strength aluminum alloy will be studied by cyclic loading, testing necessary for the safe design of aircraft parts utilizing this novel alloy. DIC will be carried …

Advanced Visualization Techniques Of Hot-Jet Combustion Of Lean And Ultra-Lean Substances, Timothy I. Machin, Li Qiao

The Summer Undergraduate Research Fellowship (SURF) Symposium

Research has been conducted on ignition of natural gas as a potential replacement for fossil fuels. A reason natural gas is not widely used and adapted is because of the harmful emissions created when combusted in rich mixtures, but if the gas can be burned at a lean or ultra-lean equivalence ratio, these emissions can be reduced or even eliminated. One method of burning lean and ultra-lean substances is by use of hot-jet ignition. This method ignites the substance near its combustion temperature, reducing the harmful emissions. This method is not yet fully understood, and so research must be done …

High-Order Shock Capturing For Computational Aeroacoustics, Samuel Otto, Gregory Blaisdell

The Summer Undergraduate Research Fellowship (SURF) Symposium

Jet noise is not only an annoyance to passengers and communities near airports, it is a major contributor to hearing loss in veterans who served on aircraft carriers, as well as a significant limiting factor for the growth of commercial airlines. High-fidelity large eddy simulation (LES) is an important tool for analyzing and predicting jet noise; however the utilized non-dissipative high order finite difference schemes produce instabilities at shock waves. Schemes for capturing shock waves, however, are more dissipative and do a poor job preserving turbulent structures and acoustic waves. To maximize the strengths of both approaches, hybrid methods utilize …

Interaction Model Of Functions In The National Airspace System, Nathan F. Koerschner, Steven J. Landry

The Summer Undergraduate Research Fellowship (SURF) Symposium

The National Airspace System (NAS) is comprehensively described by five functions derived from big-picture goals: (1) conflict detection and resolution, (2) controlling aircraft states, (3) traffic flow management, (4) controlling passenger states, and (5) controlling company resources. It can be reasonably assumed that these functions interact in some way; this interaction is currently unknown. A model of the entire NAS would be helpful in discovering these interactions, yet no such comprehensive model exists. To address this problem an agent-based state-based model was created in MATLAB. To date, only functions (1) and (2) were implemented. Running the model shows that there …

Validation Of Long-Fiber Thermoplastic Composite Models, Christian A. Vuong, Megan Kinney, Michael Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

With increased pressure to reduce energy consumption, long-fiber reinforced thermoplastic composites (LFTs) are of interest to aerospace and automotive industries due to their light weight in combination with other desirable mechanical properties and ease of manufacturing to replace common materials such as aluminum and magnesium. However, the performance of LFTs is highly dependent on microstructural variables such as fiber length and orientation, which are heavily influenced by the manufacturing process. Accurately predicting these factors would allow for more rapid advances in LFTs by reducing the experiments needed for certification and decreasing expenses. While models that serve this purpose exist, the …

The Stability And Control Of The Single Track Vehicles, Shyngys Karimov, Martin Corless

The Summer Undergraduate Research Fellowship (SURF) Symposium

Bicycles, motorcycles and scooters are all examples of the single track vehicles. The dynamics of the single track vehicle involve many degrees of freedom and various modes which govern its performance, making a complicated and interesting research topic. Motorcycle in motion can roll, yaw, and steer about the steering axis. It has three main modes which determine the motion and stability of it, they are weave, capsize, and wobble. The motorcycle performance is limited by the behavior of its modes, and if even one of the modes becomes unstable, the vehicle will roll over, and crash. The goal of this …

Remote Sensing Using Signals Of Opportunity, Alibek Yertay, James L. Garrison

The Summer Undergraduate Research Fellowship (SURF) Symposium

Today, there are more than eight thousand satellites in space. Therefore, Radio Frequency (RF) signals broadcast from satellites can be accessed from almost every point on the earth. There will be number of satellites available at most points on earth with different frequency bands. These satellite signals can be used for remote sensing, therefore software that visualizes footprints of satellites and shows characteristics of every satellite available at any point would be useful in determining which signals are available for reflectometry, method where direct satellite signals and reflected satellite signals are received and compared for analysis of certain area. There …

Testing Of Gelled And Neat Hypergolic Propellants, Bhuvi Swarna Nirudhoddi, Timothee Pourpoint

The Summer Undergraduate Research Fellowship (SURF) Symposium

Hypergolic propellants (hypergols) are propellants that ignite shortly after contact. They omit the requirement of an ignition system, making hypergolic engines simple, reliable and capable of being throttled several times. These advantages make them desirable for deep space missions. However, the applications are severely limited by their toxicity and reactivity. In an effort to increase the safety of manufacturing, shipping, and storing, these propellants can be combined with different gelling agents. The focus of this project is to build an optically accessible combustion chamber pressurized at 200 psi to compare the performance of gelled and neat Monomethyl Hydrazine (MMH) and …

Direct Simulation Monte Carlo Simulation Toolkit For Equilibrium (0d) And Planar Couette Flow (1d), Austin I. Saragih, Alina A. Alexeenko

The Summer Undergraduate Research Fellowship (SURF) Symposium

Visualized simulation tool of Direct Simulation Monte Carlo (DSMC) is essential in aeronautical engineering and gas dynamics, by presenting information that can educate engineers and scientists to preliminarily understand the molecular gas dynamics and direct simulation of gas flows. Two educational tools and models are described for rarified gas flows and simulated particle collisions. A 0-Dimensional DSMC in approach to translational equilibrium was developed to simulate the speed distribution over time and the comparison between the final distribution and the Maxwell-Boltzmann distribution. A 1-Dimensional DSMC for Planar Couette flow was also developed to calculate the number of strikes of the …

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 …

The Comparison Of Composite Aircraft Field Repair Method (Cafrm) With Traditional Aircraft Repair Technologies, Peng Hao Wang

Open Access Dissertations

In the aviation industry, manufacturers made the transition from aluminum to composite materials for the majority of their primary structures over the last few decades. While the design and manufacturing techniques have consistently evolved, field repair methods were consistently overlooked. In this study, specimens fabricated using some of the common repair methods such as the autoclave repair method, and Double Vacuum Debulk (DVD) repair method were tested against the Composite Aircraft Field Repair Method (CAFRM) proposed by the researcher. Specimens were tested with microscopy, acid digestion, short beam shear, and mode I fracture tests. The researcher was able to determine …

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 …

Scalable Autonomous Operations Of Unmanned Assets, Sunghun Jung

Open Access Dissertations

Although there have been great theoretical advances in the region of Unmanned Aerial Vehicle (UAV) autonomy, applications of those theories into real world are still hesitated due to unexpected disturbances. Most of UAVs which are currently used are mainly, strictly speaking, Remotely Piloted Vehicles (RPA) since most works related with the flight control, sensor data analysis, and decision makings are done by human operators. To increase the degree of autonomy, many researches are focused on developing Unmanned Autonomous Aerial Vehicle (UAAV) which can takeoff, fly to the interested area by avoiding unexpected obstacles, perform various missions with decision makings, come …

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 …

More Effective Human Spaceflight Programs And Their International Security Implications, Bert Chapman, Sarag J. Saikia

Libraries Faculty and Staff Scholarship and Research

NASA can more effectively perform its missions by transferring its aeronautic responsibilities to the Federal Aviation Administration and be renamed the National Space Agency. The U.S. must also recognize that space is an emerging arena of international competition and conflict and militarily protect its space assets from China which seeks to use space to restrict the U.S.' ability to defend its strategic interests in regions such as the Western Pacific.

Information Measures For Statistical Orbit Determination, Alinda Kenyana Mashiku

Open Access Dissertations

The current Situational Space Awareness (SSA) is faced with a huge task of tracking the increasing number of space objects. The tracking of space objects requires frequent and accurate monitoring for orbit maintenance and collision avoidance using methods for statistical orbit determination. Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty given by the probability density function (PDF). As even collision events with very low probability are important, accurate prediction of collisions require the representation of the full PDF of the random orbit state. Through representing the full PDF …

International Standardization Compliance In Aviation, Tyler Brogden Spence

Open Access Theses

The commercial aviation industry is global in the sense that passengers travel around the world from destination to destination. It is also global in that the states of the world (countries) regulate the industry domestically and internationally. There is a unique stage where the world comes together to promote aviation, discuss ideas and establish international standards. This stage is the International Civil Aviation Organization (ICAO). The 191 current member states signed treaties acknowledging their commitment to abiding by the standards and practices established by ICAO. No state is 100 percent compliant with international standards, however, and the purpose of this …

Analysis Of Cyberattacks On Unmanned Aerial Systems, Andrew Morris Shull

Open Access Theses

With the increasing power and convenience offered by the use of embedded systems in control applications, such systems will undoubtedly continue to be developed and deployed. Recently, however, a focus on data-centric systems and developing network-enabled control systems has emerged, allowing for greater performance, safety, and resource allocation in systems such as smart power grids and unmanned military aircraft. However, this increase in connectivity also introduces vulnerabilities into these systems, potentially providing access to malicious parties seeking to disrupt the operation of those systems or to cause damage. Given the high potential cost of a failure in these systems in …

Development And Benefit Analysis Of A Sector Design Algorithm For Terminal Dynamic Airspace Configuration, Vincent Joseph Sciandra

Open Access Theses

The National Airspace System (NAS) is the vast network of systems enabling safe and efficient air travel in the United States. It consists of a set of static sectors, each controlled by one or more air traffic controllers. Air traffic control is tasked with ensuring that all flights can depart and arrive on time and in a safe and efficient matter. However, skyrocketing demand will only increase the stress on an already inefficient system, causing massive delays. The current, static configuration of the NAS cannot possibly handle the future demand on the system safely and efficiently, especially since it is …

Effect Of Aviation Fuel Type And Fuel Injection Conditions On The Spray Characteristics Of Pressure Swirl And Hybrid Air Blast Fuel Injectors, Rick Thomas Feddema

Open Access Theses

Feddema, Rick T. M.S.M.E., Purdue University, December 2013. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors. Major Professor: Dr. Paul E. Sojka, School of Mechanical Engineering

Spray performance of pressure swirl and hybrid air blast fuel injectors are central to combustion stability, combustor heat management, and pollutant formation in aviation gas turbine engines. Next generation aviation gas turbine engines will optimize spray atomization characteristics of the fuel injector in order to achieve engine efficiency and emissions requirements.

Fuel injector spray atomization performance is affected by the …

Assessing Variability In Microstructural Influence On Fatigue Crack Growth Behavior, Matthew James Durbin

Open Access Theses

The effect of microstructural variability has long been recognized as a major contributing factor in the scatter of published fatigue data. It is also acknowledged that these effects are generally more prevalent for short cracks and in the threshold region. A number of models exist to explain individual microstructural effects such as grain boundary influence, grain cluster, average grain size, porosity etc. It is the aim of the Aeronautics and Astronautics Fatigue Lab to develop an encompassing model that accurately predicts these effects.

In order to develop this model a range of material data will be required to inform and …

Size And Rate Effects On Mechanical Behavior Of Ultra High Performance Concrete, Boon Him Lim

Open Access Theses

Cor-Tuf, broadly characterize as a reactive powder concrete is a type of cementitious material. Cementitious materials have been observed to exhibit a strain-rate dependent mechanical behavior. The mechanical behavior of cementitious materials can also depend significantly on specimen sizes. Therefore it is crucial to determine the behavior of Cor-Tuf with different specimen sizes for high-rate applications. For this purpose, split Hopkinson pressure bar (SHPB), also known as Kolsky bar was utilized to determine the dynamic behavior of Cor-Tuf for different specimen sizes under uniaxial dynamic compression loading at different strain rates. It was observed that as strain rate increases the …

Evaluation Of Vertical Profiles To Design Continuous Descent Approach Procedure, Pradeep Priyank

Open Access Theses

The current research focuses on predictability, variability and operational feasibility aspect of Continuous Descent Approach (CDA), which is among the key concepts of the Next Generation Air Transportation System (NextGen). The idle-thrust CDA is a fuel economical, noise and emission abatement procedure, but requires increased separation to accommodate for variability and uncertainties in vertical and speed profiles of arriving aircraft. Although a considerable amount of researches have been devoted to the estimation of potential benefits of the CDA, only few have attempted to explain the predictability, variability and operational feasibility aspect of CDA. The analytical equations derived using flight dynamics …

Adaptive Nonlinear Control For Autonomous Ground Vehicles, William Spencer Black

Open Access Theses

We present the background and motivation for ground vehicle autonomy, and focus on uses for space-exploration. Using a simple design example of an autonomous ground vehicle we derive the equations of motion. After providing the mathematical background for nonlinear systems and control we present two common methods for exactly linearizing nonlinear systems, feedback linearization and backstepping. We use these in combination with three adaptive control methods: model reference adaptive control, adaptive sliding mode control, and extremum-seeking model reference adaptive control. We show the performances of each combination through several simulation results. We then consider disturbances in the system, and design …

Flow And Heat Transfer In An L-Shaped Cooling Passage With Ribs And Pin Fins For The Trailing Edge Of A Gas-Turbine Vane And Blade, Irsha Ashok Pardeshi

Open Access Theses

Efficient and effective cooling of the trailing edges of gas-turbine vanes and blades is challenging because there is very little space to work with. In this study, CFD simulations based on steady RANS closed by the shear-stress transport turbulence model were performed to study the flow and heat transfer in an L-shaped duct for the trailing edge under two operating conditions. One operating condition, referred to as the laboratory condition, where experimental measurements were made, has a Reynolds number at the duct inlet of Re_D = 15,000, coolant inlet temperature of T_inlet = 300 K, wall temperature of …

A Pulsed Jet For Generation Of Turbulent Spots In A Mach 6 Boundary Layer, Andrew Daniel Abney

Open Access Theses

Hypersonic vehicles operate in an environment with a high level of boundary-layer pressure fluctuations. The largest of these fluctuations are due to the intermittent passage of turbulent spots within the transition region, and can be sufficiently large to affect internal components of the vehicle. In order to better predict these flow variations, a turbulent spot model could be used. The boundary layer on the Boeing/ AFOSR Mach 6 Quiet Tunnel nozzle-wall provided a convenient location for studying the statistical properties of turbulent spots in a hypersonic boundary layer, including growth rates, convection velocities, and pressure-fluctuation intensities. A valve system was …

Platform Design For Fleet-Level Efficiency Under Uncertain Demand: Application For Military Cargo Aircraft And Fleet, Jung Hoon Choi

Open Access Theses

The aircraft system's role in the United Stated Air Force is crucial. For the U.S. Air Force to maintain its air superiority in the world, the constant maintenance, upgrade, and acquisition of the systems must follow. As the cost of fuel rises and with the recent budget situation, the emphasis is on both running the Air Force fleet more efficiently and acquiring the platform that can reduce the fleet level operating cost and the fuel usage and yet brings same capabilities. The approach presented in the thesis combines approaches from multidisciplinary design optimization and operations research to improve energy efficiency-related …

Turbulence Modeling For Subsonic Separated Flows Over 2-D Airfoils And 3-D Wings, Aaron Michael Rosen

Open Access Theses

Accurate predictions of turbulent boundary layers and flow separation through computational fluid dynamics (CFD) are becoming more and more essential for the prediction of loads in the design of aerodynamic flight components. Standard eddy viscosity models used in many commercial codes today do not capture the nonequilibrium effects seen in a separated flow and thus do not generally make accurate separation predictions. Part of the reason for this is that under nonequilibrium conditions such as a strong adverse pressure gradient, the history effects of the flow play an important role in the growth and decay of turbulence. More recent turbulence …

Chemical Consequences Of Chicxulub Impact Ejecta Reentry, Devon Donald Parkos

Open Access Theses

The Chicxulub impact 66.0 million years ago initiated the second biggest extinction in the Phanerozoic Eon. The global reentry of material ejected by the impact generated a strong pulse of thermal radiation that wiped out much of the terrestrial biota. The cause of the marine extinction, however, has remained elusive. This report shows that reentering ejecta produces enough NOx to acidify the upper ocean and cause a massive marine extinction. Using non-equilibrium chemically reacting flow simulations coupled with atmospheric transport modeling, it is determined that enough NOx reached the stratosphere and precipitated to overpower the carbonate buffer and acidify the …