Aerospace Engineering Commons^™

On-Board Artificial Intelligence For Failure Detection And Safe Trajectory Generation, Eduardo Morillo

Doctoral Dissertations and Master's Theses

The use of autonomous flight vehicles has recently increased due to their versatility and capability of carrying out different type of missions in a wide range of flight conditions. Adequate commanded trajectory generation and modification, as well as high-performance trajectory tracking control laws have been an essential focus of researchers given that integration into the National Air Space (NAS) is becoming a primary need. However, the operational safety of these systems can be easily affected if abnormal flight conditions are present, thereby compromising the nominal bounds of design of the system's flight envelop and trajectory following. This thesis focuses on …

Noise And Propulsive Efficiency Interactions For Rotors And Propellers At Constant Thrust, Riccardo Roiati

Doctoral Dissertations and Master's Theses

In the emerging market of Advanced Air Mobility (AAM), aerospace companies have been designing and prototyping electric and hybrid vehicles to revolutionize travel. These vehicles must have low noise and particulate emissions while also having enough propulsive efficiency to complete the mission. This thesis aims to study the relationship between noise and propulsive efficiency as related to any aircraft equipped with an electric motor and a variable pitch rotor/propeller. The combination of the electric motor with the variable pitch propeller/rotor allows for a decoupled rotational speed and torque generation, meaning that the electric motor can generate the same amount of …

Certification Basis For A Fully Autonomous Uncrewed Passenger Carrying Urban Air Mobility Aircraft, Steve Price

Student Works

The Urban Air Mobility campaign has set a goal to efficiently transport passengers and cargo in urban areas of operation with autonomous aircraft. This concept of operations will require aircraft to utilize technology that currently does not have clear regulatory requirements. This report contains a comprehensive analysis and creation of a certification basis for a fully autonomous uncrewed passenger carrying rotorcraft for use in Urban Air Mobility certified under Title 14 Code of Federal Regulations Part 27. Part 27 was first analyzed to determine the applicability of current regulations. The fully electric propulsion system and fully autonomous flight control system …

Additively Manufactured Lenses For Modulating Guided Waves In Laminated Composites, Hajar Righi

Theses and Dissertations

Composite materials have increasingly been used as an alternative to metals and other isotropic materials for primary structural components in aerospace industries. Unlike traditional isotropic materials, composite materials are known to have complex internal microstructures. Therefore, it is essential to develop methods for the inspection, evaluation, and monitoring of composite materials. Ultrasonic-guided waves and, more precisely, Lamb waves have proven to be an efficient and accurate technique for the non-destructive testing. Since guided waves are dispersive and multimodal, it is important to develop a practical method to manipulate Lamb waves to achieve better structural health monitoring and non-destructive inspection results. …

Quasi 1d Modelling Of A Scramjet Engine Cycle Using Heiser-Pratt Approach, Asmaa Chakir

Theses and Dissertations

Scramjet engines are key for sustained hypersonic flights. Analytic models play a critical role in the preliminary design of a scramjet engine configuration. The objective of this research is to develop and validate a quasi-1D model for the scramjet engine encompassing inlet, isolator and combustor, to evaluate the impact of flight conditions and design parameters on the engine functionality. The model is developed assuming isentropic flow in the inlet with a single turn; modified Fanno-flow equations in the isolator that account for the area change of the core flow; and the combustor is modeled using Heiser-Pratt equations accounting for the …

Development And Deployment Of A Dynamic Soaring Capable Uav Using Reinforcement Learning, Jacob Adamski

Doctoral Dissertations and Master's Theses

Dynamic soaring (DS) is a bio-inspired flight maneuver in which energy can be gained by flying through regions of vertical wind gradient such as the wind shear layer. With reinforcement learning (RL), a fixed wing unmanned aerial vehicle (UAV) can be trained to perform DS maneuvers optimally for a variety of wind shear conditions. To accomplish this task, a 6-degreesof- freedom (6DoF) flight simulation environment in MATLAB and Simulink has been developed which is based upon an off-the-shelf unmanned aerobatic glider. A combination of high-fidelity Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) in ANSYS Fluent and low-fidelity vortex lattice (VLM) …

Resilience Monitoring For Multi-Filter All-Source Navigation Framework With Assurance, Jonathon S. Gipson, Robert C. Leishman

Faculty Publications

The Autonomous and Resilient Management of All-source Sensors (ARMAS) framework monitors residual-space test statistics across unique sensor-exclusion banks of filters (known as subfilters) to provide a resilient, fault-resistant all-source navigation architecture with assurance. A critical assumption of this architecture, demonstrated in this paper, is fully overlapping state observability across all subfilters. All-source sensors, particularly those that only provide partial state information (altimeters, TDoA, AOB, etc.), do not intrinsically meet this requirement. This paper presents a novel method to monitor real-time overlapping position state observability and introduces an observability bank within the ARMAS framework, known as stable observability monitoring (SOM). SOM …

Commercial Airliner Winglet Design Optimization – A Case Study, Anthony Gutierrez

Symposium of Student Scholars

The objective of this research is to determine the effect on aerodynamic performance due to changes of winglets design variables found of the Boeing 737-700 aircraft. The various winglet types studied in this research include the blended, canted, wingtip fence and split scimitar. The variables include height, sweep angle, taper ratio, and the inclination angle. These variables are altered in 5% increments from -15% to +15% of their original baseline values. Each altered winglet design only changes one variable at a time while keeping all other variables constant. The altered models are compared to the original by finding the aerodynamic …

Actively Guided Cansats For Assisting Localization And Mapping In Unstructured And Unknown Environments, Cary Chun, M. Hassan Tanveer

Symposium of Student Scholars

When navigating in unknown and unstructured environments, Unmanned Arial Vehicles (UAVs) can struggle when attempting to preform Simultaneous Localization and Mapping (SLAM) operations. Particularly challenging circumstance arise when an UAV may need to land or otherwise navigate through treacherous environments. As the primary UAV may be too large and unwieldly to safely investigate in these types of situations, this research effort proposes the use of actively guided CanSats for assisting in localization and mapping of unstructured environments. A complex UAV could carry multiple of these SLAM capable CanSats, and when additional mapping and localization capabilities where required, the CanSat would …

Unmanned Aerial System Design For Civil Engineering Operations – A Vip Study, Ezra Robles, Harrison Vicknair, Derek Price, Logan Westra, George Pitcock, Joshua Diamond, Bhuvan Saraswat, Jeremiah Prayor, Fon Saliki

Symposium of Student Scholars

Unmanned Aerial System Design for Civil Engineering Operations – A Case Study

The objective of the project is to design and build a modular Unmanned Aerial System (UAS) that meets the specifications set forth by United Consulting – a local civil engineering company. These specifications are achieved through three unique missions. In each mission, data is collected using different methods. These missions include land surveying, bridge structure inspection and manhole probing. The key requirements of the drone are to maintain a minimum flight time of 30 minutes and the ability to receive and transmit telemetry, photographic and video data from …

Conceptual Design Level Airframe/Propulsion Integration Using The Generic Synthesis Framework Avds., Harinkumar Patel

Mechanical and Aerospace Engineering Dissertations - Archive

In the past few decades there has been a significant growth in commercial aerospace transportation encompassing both atmospheric and space flight. In fact, the aircraft industry has seen several generations of engines and vehicles developed. While the space launch sector has switched from exclusively expandable rockets systems to including reusable rocket systems. Now, the current push in the industry is to develop a reusable in-atmosphere hypersonic transportation system. The development of any aircraft entails communicating the interactions among the principal design disciplines (aerodynamics, propulsion, structures, materials, etc.). For hypersonic vehicles, the interdependence of these interactions is enhanced to a level …

Robust Synthesis Methods For Cooperative Systems, Baris Taner

Mechanical and Aerospace Engineering Dissertations - Archive

Cooperative systems, like any other dynamic systems, suffer in performance because of uncertainty yet there is an added layer of uncertainty due to the communication among agents. Therefore, analytic solution to these problems are hard if not impossible. With the advancements in the linear and non-linear methods, i.e. linear matrix inequalities (LMI) and non-linear transformations, robust performance analysis and controller synthesis for cooperative systems can be reformulated as optimization problems with LMI constraints as has been done in the last two decades. Another aspect of the problem becomes visible as the cooperative system grows larger and that necessitates faster solution …

Effect Of Centrifugal Force On The Load Capacity Of Thrust Gas Bearing, Rakan Mohammed Haidar

Mechanical and Aerospace Engineering Theses - Archive

It has been known for many decades that both rigid and foil thrust bearings are two options in the market for high-speed turbomachinery systems. Their advantages encompass the lower manufacturing cost, the lighter weight, and the flexibility in allowing “component misalignment and runout.” When the operating fluid is air, the classical lubrication theory works perfectly. Any additional terms of the inertia effect might be somehow less significant and sometimes negligible since the viscous forces will be dominant, but this may not be the case if the bearing operates in a harsh environment, such as a high-pressure environment. Nonetheless, this is …

Energy Analysis Of Rear Door Heat Exchangers In Data Centers With Dynamic Workload Distribution, Sai Abhideep Pundla

Mechanical and Aerospace Engineering Theses - Archive

In recent years, applications including IoT (Internet of Things), content delivery, and 5G have created a large demand for low-latency access to data processing and data storage. Traditional centralized data centers weren’t designed with those use cases in mind. Small data centers such as edge computing data centers and colocation data centers house more than half of all servers across the United States. Rear Door Heat exchangers (RDHx) provide an energy-efficient cooling solution to traditional CRAC/CRAH - based cooling methods by localizing the heat removal from the rack. With more control over air distribution through a shorter path between the …

Numerical Analysis Of Hybrid Server Immersed In Synthetic Dielectric Fluid, Bhavana Reddy Mandadi

Mechanical and Aerospace Engineering Theses - Archive

In recent years there has been a phenomenal development in cloud computing, networking, virtualization, and storage, which has increased the demand for data centers. With this increase, there is a demand for higher CPU (Central Processing Unit) performance and an increase in the Thermal Design Power (TDP). Maintaining the CPU temperature within the specified parameters for air-cooled servers is a challenge in thermal engineering (due to performance). One of the components of the Data Centers with the largest energy consumption is the cooling system, which uses over 40% of the energy. Advancements in DRAMs and the increased support of CPUs …

Conceptual Gas Turbine Hybrid Engine Design For High Speed Rail Locomotive Propulsion, Frank Roger Tennyson

Mechanical and Aerospace Engineering Theses - Archive

The modern experimental jet train developed by Bombardier Transportation was designed to partner with the present day electrified Acela high speed trains. The Jet train would provide transportation to areas (Rural etc.), as well as transcontinental capabilities to existing towns and cities where electrified propulsion units are not feasible. The Bombardier Jet Train utilizes petroleum-based fuel, diesel engine power, and multiple turboshaft engines, for higher speeds. The Pratt and Whitney PW150 engine design parameters will be used to develop the Conceptual Hybrid Turbo Shaft Engine (CHTS). The newer Conceptual Hybrid Turbo Shaft Engine (CHTS) should increase engine performance, lower specific …

Thermally Charging Capacitor: A New Protocol To Accurately Measure The Thermoelectric Potential, Amit Phalak

Mechanical and Aerospace Engineering Theses - Archive

Harvesting energy from waste heat would benefit in creating sustainable systems. Specifically, thermoelectric energy conversion can be used for low-grade waste heat recovery. However, the efficiency of conventional solid-state (i.e., semiconductor) has reached to the upper limit and could not make any advancement for more than 30 years. As a paradigm shift from solid-state thermoelectric conversion, in this study, ionic thermoelectric phenomena in liquid are explored. An electrolyte, with disproportionate size of anions and cations, when subjected to a temperature gradient can experience induced ion separation. In the phenomenon known as “Soret effect”, the smaller ions with higher mobility move …

An Integrated Design Tool For Tow-Steered Composite Laminate In Abaqus, Twinkle Kothari

Mechanical and Aerospace Engineering Theses - Archive

The material of choice for contemporary aircraft and its component design over the past few decades has shifted more and more toward fiber-reinforced composites. This is mainly due to the improved strength, lightweight, corrosion resistance, design flexibility, and durability of composites over traditional metals. Advanced tailorable composites such as tow-steered composites can be designed and fabricated with fibers following prescribed curvilinear paths, which provides improved mechanical performance compared with unidirectional fiber-reinforced composites (UDFRCs). However, the potential of tow-steered composites oftentimes fails to be exploited due to the lack of design tools. Currently, there are no commercially available design tools for …

Lifting-Line Predictions For Life And Twist Distributions To Minimize Induced Drag In Ground Effect, Kyler Church

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The elliptic lift distribution produces the minimum induced drag for a given wingspan and desired lift outside of ground effect. This distribution can be generated on any wing by using geometric and/or aerodynamic twist. However, in ground effect, the elliptic lift distribution is not necessarily that which minimizes induced drag. The present work uses a modern numerical lifting-line algorithm to evaluate how the optimum lift distribution varies as a function of height above ground. The algorithm is also used to obtain the twist distributions that should be applied to wings of varying aspect ratios and taper ratios to produce the …

Dual-Band Circularly Polarized Shared Aperture Antenna For Cubesat Communication System, Syed Salman Kabir

Graduate Theses and Dissertations (2019 - present)

For space exploration, a special class of small satellite known as CubeSat, has become popular in academia and industry in recent years. Due to its low cost and short development time, researchers prefer CubeSat over large-scale satellites wherever possible. In academia, CubeSat has major applications in the field of space atmosphere, space-to-ground communication, weather forecasting, etc. Like other spacecrafts, CubeSat uses multiple antennas in different frequency bands to establish a communication link with ground stations. Recent CubeSat missions are generating a large amount of data which cannot be downlinked using conventional antennas. The demand for a compact antenna system that …

Cryogenic Flow Boiling Heat Transfer On Additively Manufactured Liquid Rocket Engine Cooling Channels, Debra Jazmin Ortega

Open Access Theses & Dissertations

The enhancement of flow boiling heat transfer is critical because it can solve thermal management issues seen across all engineering and manufacturing applications. Even though advancements are being made, more studies are needed to understand the behavior of forced convective boiling further.Currently, there are four major issues in the field of regenerative cooling of liquid rocket engines. 1. The cooling channels are typically manufactured using conventional machining, while aerospace industries are currently exploring the additive manufacturing approach. 2. The experimental critical heat flux values for cryogenic fluids are either lower or very close to the model predictions; however, the effect …

Carbon Fibers From Bio-Based Precursors Derived From Renewable Sources, Sagar Kanhere

All Dissertations

Carbon fibers have the highest strength and modulus among all known fibers and are used as reinforcements in high-performance composites [1]. Carbon fibers also have a very low density relative to metals. Therefore, carbon fibers possess ultrahigh specific strength and modulus, which make them desirable for high-performance light-weight composites. A vast majority of commercial carbon fibers are produced from PAN precursors that are expensive, which limits the use of PAN-derived carbon fibers to aerospace applications (e.g., airplanes). However, for costsensitive applications, there is a need for low-cost, moderate performance carbon fibers. Lignin is a low-cost by-product of pulping and biorefining …

Project Management And Systems Engineering Framework For Educational Cubesat Missions, Bailey Garrett

Master's Theses

The rising complexity of CubeSat missions and the unique challenges faced by educational CubeSat programs lead to high rates of mission failure. Implementing project management and systems engineering practices can alleviate these challenges and improve mission success rates for educational CubeSat developers. However, existing project management and systems engineering resources are too cumbersome and often assume the student has a base-level understanding of project management and systems engineering fundamentals. A new universal project management and systems engineering framework was created and tailored specifically to the needs of an educational CubeSat mission. The framework was designed to accommodate first-time CubeSat developers, …

Effects Of Atomic Oxygen On Outgassing Of Silicone Materials, Samuel Westrick

Master's Theses

An important consideration for spacecraft material selection is the space environment that the spacecraft will be operating in. Two features of the space environment that drive material selection are material outgassing and the presence of atomic oxygen in low Earth orbit (LEO). Materials that are considered for use in space are tested to be able to understand how they’ll outgas on orbit and how they’ll respond to interactions with atomic oxygen. However, testing to understand how atomic oxygen interaction with a material will affect how the material will outgas is rare and not standardized. This thesis used a vacuum chamber …

Artificial Neural Network For Predicting Heat Transfer Rates In Supercritical Carbon Dioxide, Vinusha Dasarla Giri Babu

Doctoral Dissertations and Master's Theses

Supercritical carbon dioxide as a working fluid in a closed Brayton cycle is proving to be more efficient than a conventional steam-based Rankine engine. Understanding the heat transfer properties of supercritical fluids is important for the design of a working engine cycle. The thermophysical properties of supercritical fluids tend to vary non-linearly near the pseudo-critical region. Traditionally, empirical correlations are used to calculate the heat transfer coefficient. It has been shown in the literature and within our own studies that these correlations provide inaccurate predictions near the pseudo-critical line, where heat transfer may be deteriorated or enhanced, resulting from strong …

Natural 2d Layered Mineral Cannizzarite With Anisotropic Optical Responses, Arindam Dasgupta, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Cannizzarite is a naturally occurring mineral formed by van der Waals (vdW) stacking of alternating layers of PbS-like and Bi2S3-like two-dimensional (2D) materials. Although the PbS-type and Bi2S3-type 2D material layers are structurally isotropic individually, the forced commensuration between these two types of layers while forming the heterostructure of cannizzarite induces strong structural anisotropy. Here we demonstrate the mechanical exfoliation of natural cannizzarite mineral to obtain thin vdW heterostructures of PbS-type and Bi2S3-type atomic layers. The structural anisotropy induced anisotropic optical properties of thin cannizzarite flakes are explored through angle-resolved polarized Raman scattering, linear dichroism, and polarization-dependent anisotropic third-harmonic generation. …

2022 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for summer and fall 2022. Includes photographs, upcoming events, recent publications, and student profiles.

Accelerated Aging Of Adhesively Bonded Composite Joints For Use In Material Screening And Selection During Development: A Review And Case Study, Marie Danielle Flanigan

Theses and Dissertations

Adhesively bonded structures are used in many high-tech industries such as aerospace, automotive, and defense. The application of these joints using composite adherends has increased in recent years because of improved strength-to-weight ratio, design flexibility, and lower concern for corrosion. Quality acceptance of these structures largely depends on reliability and durability which includes influence of environmental service conditions on long-term behavior. Characterization of long-term behavior presents a difficult challenge to those involved in material selection and design due to the long service life of the joint compared to the development time available and complexity of the degradation mechanisms. Therefore, different …

Characterizing Climb And Propeller Performance For A Fixed Pitch, Single-Engine, Electric Aircraft, Austin Lawrence Andwan

Theses and Dissertations

Electric aircraft are on the horizon. Both industry and regulators have an abundance of flight tests ahead to ensure safe operation of these new aircraft. Conventional performance standards regaurding edurance, climb performance and cruise conditions are largely not applicable to assessing an electrically propulsed aircraft. While battery technologies are the current barrier for electric aircraft, there also hasn’t been much flight testing to reveal their unique performance trends. This experiment focus’s on characterizing some of these performance trends obtained through a level flight and climb test in the Pipistrel Velis Electro. The rate-of-climb did not exhibit a decrease when the …

Comparison Of Stability And Control Characteristics Of The Pipistrel Virus Sw And Pipistrel Velis Electro, Sean Gregory Gunther

Theses and Dissertations

This document finds the stability and control affects of electric powerplant conversion on a pre-existing internal combustion powered Pipistrel Virus SW through comparison with the Pipistrel Velis Electro. Testing included analysis of both static and dynamic stability on the longitudinal and lateral-directional axes of the airplane. Due to the light sport airplane being used in testing, some of the intedended tests were unable to be performed, however, conclusions were still capable of being made. The primary conclusion is that electric conversion of an airframe has no significant negative consequences, with the airplane still exhibiting positive stability on all three axes. …