Aerospace Engineering Commons^™

Manufacturing And Instrumentation Of An Open End Compressed Air Shock Tube, Josue O. Ruiz

Master's Theses

Shock tubes have been used extensively to study shock wave structures and high speed flow features. The purpose of constructing this open end shock tube was to have the ability to produce shock waves in a laboratory setting but also understand the exit flow coming out which can be applied to future studies that are beyond the scope of this work. This undertaking would require that an open end shock tube be built and instrumented with PCB Integrated Circuit Piezoelectric (ICP) Pressure Sensor Model 113B24 that would then be connected to a PCB Model 482C05 Signal Conditioner with the purpose …

A Design Methodology For Continuous Fiber Additive Manufacturing Using Advanced Computer Aided Engineering Techniques, Nicholas Venter

Mechanical and Aerospace Engineering Theses - Archive

A design methodology for Continuous Carbon Fiber Additive Manufacturing (CCFAM) developed using Computer Aided Engineering (CAE) techniques takes advantage of both the mechanical strength of composite materials and the Fused Filament Fabrication (FFF) method. By performing topology optimization and Finite Element Analysis (FEA) on a load-bearing part, engineers can design much lighter optimized parts that are just as strong as those produced using FFF. This weight reduction is achieved by relying on the mechanical strength of continuous carbon fibers printed alongside a traditional thermoplastic matrix. The FFF additive manufacturing method enables the production of complex shapes, which can match the …

Effect Of Underfill Material & Gap Height On Reliability Of Low-K Large-Die Flip Chip Package Under Thermal Loading, Paul Crisanth

Mechanical and Aerospace Engineering Theses - Archive

The reliability assessment of package assembly is important to predict the performance of any microelectronic devices. Formation of fatigue cracks at the interface between the solder joint and component is the common failure occurring in widely used microelectronic devices. Lead-free solders and advanced silicon process nodes with the low-k dielectrics flip chip package are used and are facing significant reliability challenges. The mismatch of coefficient of thermal expansion (CTE) between the chip and substrate affect solder joint reliability. The underfill encapsulant packaging is widely used to improve chip device reliability. In this paper, we are studying the effect of different …

An Innovative Fuzzy Backstepping Sliding Mode Controller For A Tri-Rotor Unmanned Aerial Vehicle, Shiqian Wang, Jingjuan Zhang, Qian Zhang, Chaoying Pei

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The dynamical model of a Tri-Rotor Unmanned Aerial Vehicle (UAV) is presented in this paper. The Tri-Rotor has three rotors with two fixed-pitch propellers and a tiltable propeller to control the yaw displacement. The model is obtained via the Newton–Euler approach and a nonlinear control strategy called fuzzy backstepping sliding mode control is proposed for the attitude stabilization and altitude tracking of the vehicle. The designed controller consists of a backstepping sliding mode controller and a fuzzy logic controller. For the problem of determining the backstepping sliding mode control coefficients, an optimization method of gradient descent algorithm has been used. …

Optical Flow Method For Blood Flow Velocimetry Based On Digital X-Ray Subtraction Angiography: A Brief Review, Zifeng Yang

Mechanical and Materials Engineering Faculty Publications

Detailed blood flow information has been recognized as the key information for diagnosis of vascular diseases, such as vascular stenosis and aneurysms. Optical flow method (OFM) is an emergent technique as a tool to analyze the digital x-ray subtraction angiographic images of blood vessels to obtain the detailed blood flow distribution in vascular systems. A brief review isconstructed to discuss the status, applicability, accuracy and future direction of the optical flow technique in the physical study of vascular flow.

A Comparative Study Of Wooden And Hyrbid Composite Crossarms Of An Electric Utility Pole, Rohit Avadhani

Mechanical and Aerospace Engineering Theses - Archive

Most of the cross arms in the country are made from wood. Wood, although easily accessible, has its own defects. Environmental effects which includes the expansion and contraction of wood over the years which will disrupt its structural integrity, the presence of termites and other insects which dig into wood and destroy it from the inside, Materials wastage when it comes to improving the structural strength by increasing the cross-sectional thickness and height The replacement of wood with composites seems like a logical idea and also a solution to most of the problems. The applications of composites in our day …

Effect Of Solder Voids And Distance To Neutral Point (Dnp) On Sjr Of Wcsp Under Reflow Condition And Thermal Cycling, Aniruddha Doiphode

Mechanical and Aerospace Engineering Theses - Archive

Since the introduction of Chip Scale Packages (CSP’s) in the early 2000s, they have become one of the biggest packaging trends in recent history. There are currently over 50 different types of CSP’s available throughout the industry and the numbers are increasing almost daily. Wafer Level Chip Scale Package’s (WCSP) is kind of CSP’s used widely due to its small form factor which offers efficient use of limited space and miniaturization of the electronic device. On the other hand, small form factor typically incurs greater initial cost in product design and development. In an electronic device, it is equally important …

Strength And Damage Prognosis Of Adhesive Bond And Inter-Ply Hybrid Composites Based On Dielectric Properties, Priyanshu K. Banerjee

Mechanical and Aerospace Engineering Theses - Archive

Composite materials have found their applications in a wide range of industries particularly in the aerospace and automotive sectors. This is because they are comparatively light-weight and provide a much better corrosion and wear resistance as compared to other ceramics and metals. Adhesive bonding can be used to improve the stress distribution between these composite materials. Moreover, adhesive bond decreases the weight and concentration of stresses in the structure. Broadband Dielectric Spectroscopy, BbDS is a robust tool used for analyzing the dielectric properties of a polymer composite. This method can be used to monitor the curing process of the specimen. …

Multiphase Flow Modeling And Analysis Of Phased Filling Process For Pulsed Detonation Engine, Nirmal Kumar Umapathy

Mechanical and Aerospace Engineering Theses - Archive

Filling of reactants into a pulsed detonation engine (PDE) should be carried out quickly because any lengthening of the fill time will lead to an increased cycle time. The fill process and, the purge process constitutes a large proportion of time in a cycle. The purpose of this research was to improve the time of fill by implementing various injection geometries in two injection schemes with five different premixed stoichiometric fuel-air mixture injected at wide range of velocity. The different configurations examined were end wall injection, side wall injection with ports angled and normal to the flow direction and staggered …

An Investigation Of Topology Optimization For Coupled Thermo-Structural Loading For Additive Manufacturing, Vaibhav Shankar Gaikwad

Mechanical and Aerospace Engineering Theses - Archive

This work investigates the ability of topology optimization methods to design multifunctional components with coupled thermo-structural loading for fabrication with additive manufacturing technologies. Topology Optimization is a mathematical approach developed to perform design optimization with the purpose of reducing material usage, while maximizing the structural and thermal performance, in accordance to specific design constraints. Additive manufacturing provides the capability to create internal structures and complex surfaces developed by topology optimization that would not be possible to produce by conventional manufacturing. The more structurally efficient configuration generated by topology optimization and fabricated with additive manufacturing can result in components with improved …

Numerical Study Of Droplet Evaporation, Ritul Gandhi

Mechanical and Aerospace Engineering Theses - Archive

Droplet evaporation plays a vital role in various engineering fields such as air/fuel premixing, inkjet printing and many more. The high rate of power dissipation from the integrated circuits and chips of electronic devices creates a need for cooling it to achieve their optimal functionality. The high rate of cooling can be achieved by thin film evaporation of water by phase change as compared to the air cooling methods. Therefore, the study of droplet evaporation is necessary to understand the underlying physics and effects of different parameters on cooling performance. Numerical study of droplet evaporation has been done by using …

Numerical Characterization Of The Flow Field And Heat Transfer Inside The Receiver Of A Parabolic Trough Solar Collector Carrying Supercritical Co2, Samad Gharehdaghimollahajloo

UNLV Theses, Dissertations, Professional Papers, and Capstones

The aim of this research is to provide a detailed numerical analysis of flow field and heat transfer inside the heat collecting element of a parabolic trough collector. The parabolic trough collector is used as the boiler in a direct Super Critical Carbon Dioxide (S-CO2) Brayton cycle.

A single collector is modeled and analyzed with different inlet conditions. The working fluid is supercritical since its pressure is increased to above critical pressure in the compressor while its temperature reaches 300 °C after passing through the recuperators and before entering the solar field. For the first time, this research considers both …

Aerodynamic Analysis Of Low Speed Wing Design Using Taguchi L9 Orthogonal Array, Kenneth Witcher, Ian Mcandrew, Elena Vishnevskaya

Publications

The study of aerodynamics has been preoccupied with understanding flight at increasing speeds and ultimately supersonic. Today, this pursuit has advanced the science for both Hypersonic and Transonic flight to near Mach 1 supporting economical commercial flight operations. This research presents the data from a Taguchi array on low speed with twin wing designs to establish the design parameters for their use in low speed and high altitude. Also presented is how aerodynamic advantages can be achieved through understanding the interactions of parameters and their use. This is compared to operational effectiveness when applied to remotely piloted aircraft that are …

Optimized Thruster Allocation Utilizing Dual Quaternions For The Asteroid Sample Return Mission (Osiris-Rex), Asher Smith

Doctoral Dissertations and Master's Theses

As spacecraft require higher positional accuracy from the attitude control systems, new algorithm developments, along with sensor and actuator resolution and range improvements are necessary to achieve the desired science accuracies. For agile 6-Degrees of freedom (6-DOF) spacecraft with redundancy, the actuators are usually oversized or overpopulated to meet the desired slew requirements. Currently, most spacecraft utilize an over-actuated thruster system to produce 6-DOF control. This thesis presents a simulation of the OSIRIS-REx mission during the descent phase to the asteroid Bennu, with a focus on utilizing dual quaternion dynamics and a newly developed thruster allocation method. The dual quaternion …

Mechanical And Electrical Characterization Of Carbon Fiber/Bucky Paper/Zinc Oxide Hybrid Composites, Suma Ayyagari

Doctoral Dissertations and Master's Theses

The quest for multifunctional carbon fiber reinforced composites (CFRPs) expedited the use of several nano reinforcements such as zinc oxide nanorods (ZnO) and carbon nanotubes (CNTs). Zinc oxide is semi-conductor with good piezoelectric and pyroelectric properties. These properties could be transmitted to CFRPs when a nanophase of ZnO is embedded within CFRPs. In lieu of ZnO nanorods, Bucky paper comprising mat of multiwall-carbon nanotubes (MWCNTs) could be sandwiched in-between laminae to construct a functionally graded composite with elevated electrical and thermal conductivities. In this study, a low temperature ( 90_C) hydrothermal synthesis method was utilized to grow ZnO nanorods on …

Aviation Propulsive Lithium-Ion Battery Packs State-Of-Charge And State-Of-Health Estimations And Propulsive Battery System Weight Analysis, Jingsi Lilly

Doctoral Dissertations and Master's Theses

Aviation propulsive battery pack research is in high demand with the development of electric and hybrid aircraft. Accurate inflight state-of-charge and state-of-health estimations of aviation battery packs still remain challenging. This thesis puts efforts on estimating the state-of-charge, state-of-health, and remaining energy of a lithium- ion propulsive battery pack with a recursive least squares based adaptive estimator. By reading the system measurements (discharging currents and terminal voltages) with persistent excitation, the proposed estimator can determine the present internal parameters of the battery cells and further interpolate them into state-of-charge, state-of-health, and the remaining energy information. The validation results indicate that …

Aerodynamic And Performance Analysis Of A Morphing Helicopter Rotor System, Vinay Gopal Krishnan

Doctoral Dissertations and Master's Theses

The purpose of this study was to investigate the effect of rotor morphing, specifically variable rotor speed and variable blade twist, on various parameters such as the distribution of angle of attack, lift, power, thrust and/or other metrics describing the performance of a helicopter rotor. A MATLAB based blade element theory model was developed and executed for different flight conditions. The model was validated against the flight test data of a UH-60. Effects on power, lift to drag ratio and rotor drag from variations in blade twist, rotor speed, rotor radius and blade chord was analyzed. Morphing cases were applied …

Design Of Flight Control Laws For A Novel Stratospheric Dual-Aircraft Platform, Cindy Nshuti

Doctoral Dissertations and Master's Theses

Dual-aircraft platform (DAP) is a novel concept that features two glider-like unmanned aerial systems (UAS) tethered via a thin adjustable cable allowing them to sail back-and-forth, without propulsion, using vertical wind shear. DAP offers the potential of a low-cost atmospheric satellite. This thesis presents the results of an initiative to demonstrate this novel flight concept through modeling, simulation, and flight testing at Embry-Riddle Aeronautical University (ERAU). A realistic simulation environment, described herein, was developed to support the development and testing of flight control systems. This environment includes nonlinear aerodynamic models for the aircraft, a multi-element cable dynamics model, propeller-motor thrust …

A Study On The Control, Dynamics, And Hardware Of Micro Aerial Biomimetic Flapping Wing Vehicles, Siara Hunt

Doctoral Dissertations and Master's Theses

Biological flight encapsulates 400 million years of evolutionary ingenuity and thus is the most efficient way to fly. If an engineering pursuit is not adhering to biomimetic inspiration, then it is probably not the most efficient design. An aircraft that is inspired by bird or other biological modes of flight is called an ornithopter and is the original design of the first airplanes. Flapping wings hold much engineering promise with the potential to produce lift and thrust simultaneously. In this research, modeling and simulation of a flapping wing vehicle is generated. The purpose of this research is to develop a …

Experimental Study Of Global Luminescent Oil-Film (Glof) Skin-Friction Meter On Delta Wings, Patrick Nicholas Wewengkang

Masters Theses

This thesis describes how the Global Luminescent Oil-Film (GLOF) Skin-Friction Meter can be applied experimentally to extract skin-friction from a set of images. In this study, the effect of oil viscosity, experimental sample size, and step size were considered to see how they would affect the extracted skin-friction using the GLOF method. These results were then compared to published literature on skin-friction diagnostics of delta wings, based on observations of critical characteristics such as reattachment and separation lines. Delta wings of 50°, 55°, 60°, 65°, and 70° sweep angles were built and placed in the Small Wind Tunnel (SWT) at …

2017 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for summer and fall 2017. Includes photographs, upcoming events, recent publications, and student profiles.

Sensitivity Of Facial Organs Of Pythons As Deduced By Radiation Heat Transfer Analysis Under Varying Environmental Conditions, Rama Wairagkar

Theses and Dissertations

Predicting the behavior of snakes has been an interest to several scientists for the last few decades. Even though considerable amount of research has been carried out pertaining to snakes, there remains a degree of curiosity regarding their striking ability, live prey detection at locations where visual clues are unobtainable, thermosensation and the phenomena that drives these conducts. Researches carried out so far have moderately disregarded the perception of sensitivity of facial pits of snakes and its characteristics under contrasting temperature domains. This thesis attempts to undertake a computational analysis of the sensitivity of facial pits of Burmese pythons under …

System Study Of An On-Orbit Additive Manufacturing Cubesat, Juliette Isabelle Bido

Theses and Dissertations

The AddCube mission aims to demonstrate additive manufacturing technology in microgravity on a CubeSat platform by 3D-printing a 1-meter long rectangular beam on orbit. To accomplish this task, Made In Space Inc. (MIS) will provide the Extended Structure Additive Manufacturing Machine – CubeSat (ESAMM-C) payload. The high power required by the ESAMM-C payload creates a complex thermal problem within the spacecraft due to tight volume constraints associated with CubeSats. To cope with this problem, an in depth worst-case thermal analysis of the integrated spacecraft is conducted and an appropriate thermal management system for the mission is designed. Temperature regulation is …

Flight Testing Angle-Of-Attack Warning Combinations On Part 23 Aircraft, Jennifer Grey Geehan

Theses and Dissertations

The high number of accidents involving General Aviation (GA) aircraft leads to a need for improved methods to warn pilots of high angles of attack (AOA) and impending stall. Such methods must be certified by the Federal Aviation Administration (FAA) under Federal Aviation Regulations Part 23 regarding their effectiveness in preventing departures from controlled flight. Therefore, methods of compliance must be developed to certify Part 23 aircraft equipped with AOA warning or limiting systems. The research objectives were to (a) determine methods for the evaluation of AOA warning and limiting systems and to (b) evaluate the effectiveness of baseline combinations …

Implementation And Verification Of A Synthetic Eddy Method (Sem) In The Eagle3d Compressible Flow Solver, Patrick Kopper

Doctoral Dissertations and Master's Theses

The objective of this thesis is to implement and evaluate a Synthetic Eddy Method (SEM) into the Eagle3D compressible flow solver. Both the ability of Eagle3D to resolve unsteady turbulent ow field and capability of the SEM to reproduce given Reynolds stress profiles to start realistic turbulent behavior are verified using common academic cases. Eagle3D is a Computational Fluid Dynamics (CFD) solver using a novel combination of a Bounded Central Differencing (BCD) scheme with Weighted Essentially Non-Oscillatory (WENO) approximation to reduce numerical dissipation. SEM is a modern synthetic turbulence method able to reproduce an arbitrary Reynolds stresses specification on discretionary …

Development Of A Remotely-Piloted Vehicle Platform To Support Implementation, Verification, And Validation Of Pilot Control Systems, Sean O’Toole

Doctoral Dissertations and Master's Theses

This thesis presents the development of a research test bed and the use of a set of metrics for evaluating handling qualities with pilot in the loop configuration. The main objective of this study is to provide software and hardware tools to support performance evaluation of control systems designed to compensate for Pilot Induced Oscillations (PIOs). A remotely-piloted vehicle presented in this thesis consists of an RC aircraft modified to be flown from a ground station cockpit. The unmanned aerial system has a high-speed on-board processing system capable of simulating different conditions during flight such as injecting actuator failures and …

Coorstek- Spine Discectomy, Rhett Prestwich, Logan Bolingbroke, Ryan Thomsen, Aaron Blanchard, Kayla Park

Undergraduate Honors Capstone Projects

The objective is to design improved instrumentation for performing a spine discectomy. In particular, the instrument should remove the nucleus pulposus without damaging the annulus in order to prepare the spine disc for the insertion of an artificial spacer. As more nucleus pulposus is removed from the disc, the spine will fuse more quickly and completely after the artificial spacer is inserted. The current process involves removing the nucleus pulposus piece by piece with pituitary rongeurs. This process is slow and often incomplete.

A Comparison Study Of Composite Laminated Plates With Holes Under Tension, Joun S. Kim

Master's Theses

A Comparison Study of Composite Laminated Plates with Holes under Tension

A study was conducted to quantify the accuracy of numerical approximations to deem sufficiency in validating structural composite design, thus minimizing, or even eliminating the need for experimental test. Error values for stress and strain were compared between Finite Element Analysis (FEA) and analytical (Classical Laminated Plate Theory), and FEA and experimental tensile test for two composite plate designs under tension: a cross-ply composite plate design of [(0/90)4]s, and a quasi-isotropic layup design of [02/+45/-45/902]s, each with a single, centered hole of 1/8” diameter, and 1/4" diameter (four sets …

Electron Yield Measurements Of High-Yield, Low-Conductivity Dielectric Materials, Justin Christensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Materials exposed to the space plasma environment acquire electric charge, which can have harmful effects if it leads to arcing or electrostatic breakdown of important spacecraft components. In fact, spacecraft charging is the leading environmentally induced cause of spacecraft anomalies. This study focuses on measuring electron yield, a property of materials that describes how many electrons are ejected from a material under energetic electron bombardment, which can vary depending on the energy of incident electrons. Intrinsic electron yield is defined as the average number of electrons emitted per incident electron from an electrically neutral material. The specific aim of this …

The Influence Of Varying Fiber Stacking Sequence On The Tensile, Impact, And Water Absorption Properties Of Unidirectional Flax/E-Glass Fiber Reinforced Epoxy Composite, Mohammed F. Al-Edhari

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis includes the study of the mechanical performance of two different types of fibers reinforced hybrid composites. Two kinds of fibers, natural fiber (flax) and synthetic fiber (E-glass), are used to reinforce epoxy resin. To evaluate the effective properties of the hybrid composites, a micromechanical analysis of the structure genome (SG) of a unidirectional fiber hybrid composites is performed using nite element analysis (FEA). Both fibers are assumed to be circular and packed in a hexagonal pattern. The effects of varying volume fractions and fiber locations, of the two fibers, on the elastic properties of the hybrid composites are …