Aerospace Engineering Commons^™

Citizen Satellite: A Way To Have Low Cost Space Missions For The Unordinary Innovator, Robert J. Twiggs, Amin Djamshidpour, Ted Tagami, Tony So

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Robert Twiggs, Amin Djamshidpour , Ted Tagami, and Tony So titled "Citizen Satellite: A Way to have Low Cost Space Missions for the Unordinary Innovator" from August 7, 2016.

Development Of Functional Requirements For A High-Capacity Airspace System, Noel J. Colon, Jeongjoon Boo, Steven J. Landry

The Summer Undergraduate Research Fellowship (SURF) Symposium

NASA along with other researchers visualizes a future where more aircraft will transport passengers or goods around the world. Thus, they envision increasing air capacity from 10 to 100 times more than the current system without any reduction in efficiency or safety. Many models are being proposed that comply with the necessary requirements to form part of the method needed. However, knowing which of the proposed methods have the most desirable characteristics, such as efficiency and safety, are yet to be determined. For this reason, a standardized method to compare and assess them has to be developed, since is not …

Evaluation Of Strain Distortion Correction Protocol Using Scanning Electron Microscopy And Digital Image Correlation, Alexandra Mallory, Alberto Mello, Michael Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

Scanning electron microscopy in combination with digital image correlation (SEM-DIC) is a useful technique for measuring strain in materials at the micro-scale. In particular, it can be used to identify micro-scale strain localizations that are the precursor to material failure. While SEM produces high resolution images of the microstructure, the images also contain a large amount of distortion that, during DIC, will result in distorted strain values that require correction. In this project, a nickel-based alloy underwent cyclic mechanical fatigue at three different high temperatures to a targeted maximum strain. Scanning electron microscopy imaging was done on a 200x150μm area …

Metamodels Of Residual Stress Buildup For Machining Process Modeling, Stuart B. Mccrorie, Michael Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the process of machining materials, stresses, called residual stresses, accumulate in the workpiece being machined that remain after the process is completed. These residual stresses can affect the properties of the material or cause part distortion, and it is important that they be calculated to prevent complications from arising due to the residual stresses. However, these calculations can be incredibly computationally intensive, and thus other methods are needed to predict the residual stresses in materials for quick decision-making during machining. By using metamodels - a method of representing data where few data points exist - we can achieve an …

High Strain Rate Experiments Of Energetic Material Binder, Roberto Rangel Mendoza, Michael Harr, Weinong Chen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Energetic materials, in particular HMX, is widely used in many applications as polymer bonded explosives (PBX) and rocket propellant. However, when damaged, HMX is known to be an unstable substance which renders it a hazardous material and in some cases unreliable. Finding critical mechanical conditions at high rates that render various forms of energetic materials as unreliable would be vital to understand the effects that vibrations and compression forces have on energetic materials. A better understanding would enable the ability to develop improvements in the manufacturing of PBX and rocker propellant. The method utilized to evaluate the mechanical properties of …

An Experimental Investigation Of Self-Excited Combustion Dynamics In A Single Element Lean Direct Injection (Ldi) Combustor, Rohan M. Gejji

Open Access Dissertations

The management of combustion dynamics in gas turbine combustors has become more challenging as strict NOx/CO emission standards have led to engine operation in a narrow, lean regime. While premixed or partially premixed combustor configurations such as the Lean Premixed Pre-vaporized (LPP), Rich Quench Lean burn (RQL), and Lean Direct Injection (LDI) have shown a potential for reduced NOx emissions, they promote a coupling between acoustics, hydrodynamics and combustion that can lead to combustion instabilities. These couplings can be quite complex, and their detailed understanding is a pre-requisite to any engine development program and for the development of predictive capability …

Particle Modeling Of Non-Equilibrium Field Emission Driven Rf Microplasmas, Siva Sashank Tholeti

Open Access Dissertations

Non-equilibrium microplasmas at atmospheric pressures have been investigated for active flow control, micropropulsion and electronic display applications to name a few. The operational voltages for these microplasmas are on the order of kilovolts. When the electric field at the electrodes reaches GV/m or tens of GV/m either due to reduced interelectrode spacing and surface irregularities or due to carefully designed nanostructures on the electrodes, quantum processes such as field emission and field ionization come into effect. These can potentially reduce the operational voltages of microplasma devices by an order of magnitude. Due to the rarefied and non-equilibrium nature of these …

On The Enhancement Of Thermo-Mechanical And Impact Reliability Of Passive And Active Microelectronic Devices, A R Nazmus Sakib

Mechanical and Aerospace Engineering Dissertations - Archive

Microelectronic devices are an essential part of human life. The idea of Internet of Things (IoT) where all the everyday devices will be connected with each other transmitting information and operating on their own is becoming very popular. A silicon chip which has millions of transistors in it, has been the heart and brain of the everyday components ranging from personal entertainment, communication to Automotive ECU (electronic control Unit), and health care management systems to home security systems. Every aspect of modern human experience is dependent on this tiny silicon chip. Microelectronic devices can be divided into two broad categories …

Investigation Of Exothermic Reaction Dynamics Via Computational Fluid Dynamics Coupled With A Feedback Controller, Siusan Choi

Mechanical and Aerospace Engineering Dissertations - Archive

The control of reaction temperature under continuous flow conditions is important in a variety of chemical manufacturing industries. For many reactions, operating at off-design temperatures can result in the production of undesired products, reduced feedstock conversion and, in some cases, reduced catalyst lifetime. In many exothermic reactions, maintaining a desired set point temperature at high reactant flow rates becomes challenging if the chemical kinetics exhibit highly non-linear behavior. In these situations, the interaction between commonly used linear controllers and the physical system can lead to unexpected dynamic response and undesired swings in reaction temperature. In this research, a computational model …

General Solutions To Temperature Distribution In Orthotropic Systems Subject To Variable Heat Transfer And Biological Systems During Bioheat Transfer, Daipayan Sakar

Mechanical and Aerospace Engineering Dissertations - Archive

Bioheat transfer is the phenomenon of heat transfer in biological systems where the dominant modes of heat transfer are conduction and advection. Other factors such as rate of metabolism that are unique to biological systems contribute significantly towards bioheat transfer. In the present work, the Pennes bioheat equation has been solved for a multilayer system to derive steady state and transient temperature solutions in the multilayer skin tissue with a tumor. In nanoparticle based hyperthermia therapy, the body temperature elevates from the physiological core body temperature, 37 deg. C. Analytical solutions for three different therapeutic techniques have been developed to …

Integration Of A Portfolio-Based Approach To Evaluate Aerospace R&D Problem Formulation Into A Parametric Synthesis Tool, Amit R. Oza

Mechanical and Aerospace Engineering Dissertations - Archive

The focus of this study is to improve R&D effectiveness towards aerospace and defense planning in the early stages of the product development lifecycle. Emphasis is on: correct formulation of a decision problem, with special attention to account for data relationships between the individual design problem and the system capability required to size the aircraft, understanding of the meaning of the acquisition strategy objective and subjective data requirements that are required to arrive at a balanced analysis and/or “correct” mix of technology projects, understanding the meaning of the outputs that can be created from the technology analysis, and methods the …

Performance Analysis, Dynamic Simulation And Control Of Mass-Actuated Airplane, Sukru Akif Erturk

Mechanical and Aerospace Engineering Dissertations - Archive

The control of space, aerial and underwater vehicles requires moment generation mechanisms to change their orientation. In addition to or in place of conventional moment generation actuators, internally moving-mass actuation has been proposed and/or used for such vehicles. The primary principle for mass-actuation is to reposition gravitational force to change the associated moment while the secondary effect may come from the inertial force due to the motion of the masses. Recent development/miniaturization in flight control sensor, computing and actuation, and electric motors and expansion of applications for small UAV (Unmanned Aerial Vehicle) offer a potential for implementation of internal mass-actuation …

Complex Multidisciplinary System Composition For Aerospace Vehicle Conceptual Design, Alexis R. Gonzalez

Mechanical and Aerospace Engineering Dissertations - Archive

Although, there exists a vast amount of work concerning the analysis, design, integration of aerospace vehicle systems, there is no standard for how this data and knowledge should be combined in order to create a synthesis system. Each institution creating a synthesis system has in house vehicle and hardware components they are attempting to model and proprietary methods with which to model them. This leads to the fact that synthesis systems begin as one-off creations meant to answer a specific problem. As the scope of the synthesis system grows to encompass more and more problems, so does its size and …

Experimental Investigation Of Methane Reformer With A Continuous Flow Reactor, Xiao Zhang

Mechanical and Aerospace Engineering Dissertations - Archive

Over the decades, seeking for an alternative energy source has been more and more significant because of increasing demand with rapid industry expansion. Liquid hydrocarbon from Fischer-Tropsch process is considered as an alternative fuel source because the product is considered as subtle for petroleum-derived. Syngas as feedstock for F-T process plays a crucial role in liquid hydrocarbon production. Among several commercial and experiment technologies, the most common technology for syngas production is natural gas reforming. The product from reforming process has proper carbon monoxide/hydrogen ratio for direct application in F-T synthesis. Meanwhile, combined carbon dioxide into reforming reaction has attracted …

Complex Multidisciplinary Systems Decomposition For Aerospace Vehicle Conceptual Design And Technology Acquisition, Amen Omoragbon

Mechanical and Aerospace Engineering Dissertations - Archive

Although, the Aerospace and Defense (A&D) industry is a significant contributor to the United States’ economy, national prestige and national security, it experiences significant cost and schedule overruns. This problem is related to the differences between technology acquisition assessments and aerospace vehicle conceptual design. Acquisition assessments evaluate broad sets of alternatives with mostly qualitative techniques, while conceptual design tools evaluate narrow set of alternatives with multidisciplinary tools. In order for these two fields to communicate effectively, a common platform for both concerns is desired. This research is an original contribution to a three-part solution to this problem. It discusses the …

The Effects Of Temperature And Relative Humidity On Exposure Of Legacy And Future Technology Hardware, Under Real Data Center Conditions In An Ansi/Isa Classified G2 Environment, Oluwaseun Michael Awe

Mechanical and Aerospace Engineering Dissertations - Archive

It is well established that it is safe to operate information technology (IT) equipment in a G1 classified contaminant severity level when operating within specified ASHRAE recommended and allowable limits in an air-side economizer data center. This is basis for which electronic equipment manufacturers provide warranty for their products. IT equipment manufacturers in the US now requires data centers operators to demonstrate that they meet all the specified conditions consistently before fulfilling warranty equipment failure. This places limitation to where data center utilizing air-side economizer can be located. In order to determine the reliability of electronic hardware in higher severity …

Analysis Of Composite Beams With Airfoil Cross-Sections With I-Section Stiffener Under Tension And Bi-Directional Moments, Peter Louis Leboulluec

Mechanical and Aerospace Engineering Dissertations - Archive

Annual wind power generation capacity in the US has increased from 3 gigawatts in 2000 to 61 gigawatts in 2013 and is on track to fulfill 20% of projected U.S. electricity needs (305 gigawatts) by 2030. To enable the increase in electricity generation of wind turbines, longer blades are being designed which require improved engineered blades to handle higher loads. Thus, the wind turbine industry is turning to the use of carbon-epoxy composite materials to take advantage of their low weight yet high strength ratio and improved fatigue resistance. Current analyses to design turbine blades utilize either Finite Element Analysis …

Thermal Energy Storage For Expanded Use Of Data Center Indirect/Direct Evaporative Cooling, Jefferey Luttrell

Mechanical and Aerospace Engineering Dissertations - Archive

Computer cooling system design evolved over time with goals of increasing efficiency and decreasing cost. Early computers were essentially hand-built and very expensive. Reliable operation required aggressive cooling to maintain acceptable component temperatures and this was achieved with relatively low ventilation air temperatures. With time, the scale of operations increased to the point that operating cost began to strongly influence design decisions. Computer room air conditioners consumed substantial amounts of electrical power, in some situations almost as much power as the computer equipment. One cost saving idea used outside air when the ambient temperature fell below the normal cooling supply …

Understanding The Alchemilla Leaf And Its Hydrophobicity, Atul Mohandas Kootathil

Mechanical and Aerospace Engineering Theses - Archive

The Alchemilla leaf has been well known and studied frequently for its hydrophobic ability. However, much difficulty has been met in replicating its microstructure for hydrophobic applications. Also, not much experimental data was found on the behavior of leaf’s microstructure. Gathering information from experimental results may provide new understanding of its wetting properties before attempting to mimetic its wetting behavior. In this research, the focus is to detail the observed solid-water-air interaction on Alchemilla leaf by simulating condensation, evaporation and rainfall conditions, which are the common ways that a plant may interact with water drops in nature. Documenting these observations …

Attitude Stabilization Of Spacecraft Using Moving Masses, Juran Hwang

Mechanical and Aerospace Engineering Theses - Archive

This research investigates the ability of stabilizing spacecraft rotational motion by internal mass actuation. The mass actuation mechanism consists of three internal masses placed along the three axes at some offset distance that can move to induce inertial forces and moments and change the inertia matrix and center of mass. A set of nonlinear equations of motion are developed to model the motion, both orbital and rotational dynamics and kinematics, of a spacecraft with mass and inertial variation due to internal mass actuation, under the gravitational field of Earth. The equations inherently include the inertia effect of the mass motion …

Developing And Validating Energy Models For Indirect And Direct Evaporative Cooling Used In Datacenters, Rajesh Kasukurthy

Mechanical and Aerospace Engineering Theses - Archive

In the present day to day life, Internet of things is everything, i.e., we need internet and telecommunication for almost every task of our life and these require data from data centers. These data centers provide various facilities like data processing, storage, and transmission, and maintenance, operations etc., for performing these tasks, a huge amount of power is consumed by the data center, which in turn generates large amount of heat. As these data centers are to be made operational throughout the year, cooling of data centers is of utmost importance. These cooling systems like air conditioners, economizers and evaporative …

Mechanical Property Evaluation Of Magnesium Rich Primer Coating System Over Aa 2024 T-3 Aluminum Alloy By Nano-Inedntation, Hongyi Qu

Mechanical and Aerospace Engineering Theses - Archive

Aluminum alloy is widely used as a major structural material, such as for wing and fuselage, in aerospace industry. Corrosion is the most insidious form of damage to aluminum alloy, which can cause aircraft structure damage and related safety issue. Coating is generally used in industry to protect metal structure. An alternative to present toxic chromium primer coating system, magnesium rich primer (MgRP) has been developed to protect AA 2024 T-3. Studies have demonstrated the anti-corrosion performance of MgRP. However, the interlayer material heterogeneity can affect the mechanical properties of coating such as modulus, hardness and interfacial behavior. In the …

Active Torque Vectoring For All Wheel Drive Fsae Electric Car, Vikas Tukaram T Pawar

Mechanical and Aerospace Engineering Theses - Archive

UTA Racing is known for building well-engineered FSAE racecars. This year team is building, its first electric car by using AWD in-wheel motor concept car E-16. All wheel drive electric vehicles has an ability to apply instantaneous torque to all four wheels permit increased car performance. An ‘Active Model Based Torque Vectoring System controller’ is designed to realize this objective. The controller was designed to replicate three electronically controlled LSD's on an all-wheel drive platform with different control strategies. This was achieved based on the principal of distributing total driver requested torque between wheels, equivalent to the percentage of the …

Guidance Navigation And Control Implementation For Unmanned Ground Vehicle Using Ni-Myrio, Ishwarya Srinivasan

Mechanical and Aerospace Engineering Theses - Archive

This research effort aims at investigating alternative real-time implementation software and hardware for Guidance, Navigation and Control (GNC) algorithms for an Unmanned Ground Vehicle (UGV). A GNC algorithm was previously developed for a skid-steered tracked UGV to go through assigned waypoints based on encoder counts. The UGV has two electric motors driving the tracks on each side and two encoders providing the speeds of the drive wheels. This algorithm was implemented using Matlab/Simulink-based model running on a mini computer, interfacing with the electric motors and encoders through a specialty control board. This current effort is to implement the same GNC …

Fitting B-Splines Curves To Coarse Data Cloud Using Modified Squared Distance Minimization Method, Vinay Vivek Mhala

Mechanical and Aerospace Engineering Theses - Archive

Additive manufacturing has made us realize that we can fabricate complex shapes that were difficult to manufacture with subtractive processes. Topology optimizations results have complex shapes and have rough surfaces which are difficult to manufacture even by additive manufacturing. To automate the process of converting rough surfaces into smooth surfaces for the benefit of manufacturability would be very desirable. Computing curve segments to approximate point cloud data that represents rough surfaces and then lofting it to have a smooth surface seems to be a promising methodology to achieve automation. We implement B-spline formulation along with Pottmann’s iterative method based on …

Study Of Crack Propagation Under Thermal Loading On A 3d Tsv Package, Subramanian R. Gowtham

Mechanical and Aerospace Engineering Theses - Archive

Today, there is a revolution in going for miniaturization in size of electronic packages. More thinner, lighter and complex packages are in use for almost every electronic device. This initiation was taken to the next level and gives us a whole new ideology called 3D packaging. Currently, 3D packaging is the on-going research in almost all the electronic packaging related industries. 3D package uses Through Silicon Via (TSV) technology that gained momentum in the development and helped packaging system for significant miniaturization and power reduction, which result in increased performance. However, the reliability assessment is needed to evaluate the critical …

Embedding Antenna Shear/Pressure Sensors In Prosthetic Liner Material, Shahanavaz Eilbeigi

Mechanical and Aerospace Engineering Theses - Archive

Published surveys indicated that 40-60% of prosthesis users experience discomfort and skin problems. These studies highlighted the needs for enhanced prosthetic performance and fit. It is extremely difficult to address these problems due to two reasons: first, ambulation create varying areas of shear and pressure on the residual limb, but it is not clear which shear/pressure combinations are acceptable and what is the safe stress level for users. In addition, the volume of the residual limb changes throughout the day and activity level. Therefore, there is a strong need to develop a light, thin, flexible, and wirelessly interrogated sensor for …

Risk-Based Approach To Assessment Of Advanced Technologies For Conceptual Design, Adipratnia Asmady

Master's Theses

The conceptual design phase of an aerospace system development program is typically characterized by short duration and relatively limited resources, yet design decisions are made that have critical implications on program risk. To address the more aggressive requirements, one of these decisions is the selection of advanced technologies. System developers need to assess advanced technologies early on, but are faced with uncertainties surrounding the potential net benefits. The concept introduced in this study is uncertainty characterization as a way to better understand the associated risk. A framework was developed to guide the interaction between the technology developer and the system …

Applications Of The Homotopy Analysis Method To Optimal Control Problems, Shubham Singh

Open Access Theses

Traditionally, trajectory optimization for aerospace applications has been performed using either direct or indirect methods. Indirect methods produce highly accurate solutions but suer from a small convergence region, requiring initial guesses close to the optimal solution. In past two decades, a new series of analytical approximation methods have been used for solving systems of dierential equations and boundary value problems.

The Homotopy Analysis Method (HAM) is one such method which has been used to solve typical boundary value problems in nance, science, and engineering. In this investigation, a methodology is created to solve indirect trajectory optimization problems using the Homotopy …

Numerical Methods For Low-Thrust Trajectory Optimization, Robert E. Pritchett

Open Access Theses

The spacecraft trajectory design process frequently includes the optimization of a quantity of importance such as propellant consumption or time of flight. A variety of methods for trajectory optimization are available, however the efficiency of an approach is dependent on the problem scenario it is applied to. Indirect and direct trajectory optimization methods are examined in this investigation with the goal of assessing the characteristics of each approach, and thereby determining the problem scenarios each is best suited for. Insight is gained from application of each optimization method to three sample problems; a circular-to-circular orbit transfer as well as two …