Engineering Commons^™

Performance Enhancement And Characterization Of An Electromagnetic Railgun, Paul M. Gilles

Master's Theses

Collision with orbital debris poses a serious threat to spacecraft and astronauts. Hypervelocity impacts resulting from collisions mean that objects with a mass less than 1g can cause mission-ending damage to spacecraft. A means of shielding spacecraft against collisions is necessary. A means of testing candidate shielding methods for their efficacy in mitigating hypervelocity impacts is therefore also necessary. Cal Poly’s Electromagnetic Railgun was designed with the goal of creating a laboratory system capable of simulating hypervelocity (≥ 3 km/s) impacts. Due to several factors, the system was not previously capable of high-velocity (≥ 1 km/s) tests. A deficient projectile …

Analysis Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Dustin P. Graves, Kyle D. Moore, Anthony N. Palazotto

Faculty Publications

Excerpt: The celestial icosahedron geometry is considered as a potential design for a vacuum lighter than air vehicle. The goal of this research is ultimately to determine the feasibility of the design and to understand the initial fluid-structure interaction of the vacuum lighter than air vehicle and the surrounding airflow.

Axial Compressor Based On Plastic Additive Manufacturing, Chris Phu

Mechanical Engineering Undergraduate Honors Theses

Turbomolecular pumps designed to function in very low pressures tend to be too prohibitively expensive for student researchers. On the other hand, while conventional pumps are affordable, they can’t function in extreme low pressures. An additively manufactured axial compressor however is inexpensive to manufacturer and only needs to be build up enough pressure for a conventional pump to function. After many design iterations, a final iteration that is near vacuum chamber ready has been 3D printed and tested for spin functionally. The designed axial compressor is easy to assemble and very modular. Conclusions from each of the design iterations is …

2019 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for summer and fall 2019. Includes photographs, upcoming events, recent publications, and student profiles.

Magnetic Field Induced Ferrofluid Droplet Breakup In A Simple Shear Flow At A Low Reynolds Number, Md Rifat Hassan, Cheng Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The breakup phenomenon of a ferrofluid droplet in a simple shear flow under a uniform magnetic field is numerically investigated in this paper. The numerical simulation, based on the finite element method, uses a level set method to capture the dynamic evolution of the droplet interface between the two phases. Focusing on small Reynolds numbers (i.e., Re ≤ 0.03), systematic numerical simulations are carried out to analyze the effects of magnetic field strength, direction, and viscosity ratio on the breakup phenomenon of the ferrofluid droplet. The results suggest that applying a magnetic field along α = 45° and 90° relative …

Remote Sensing, Modeling, And Spectroscopic Studies Of Gigantic Jets And Lightning Leaders, Levi Boggs

Theses and Dissertations

This dissertation focuses on four interrelated investigations with the ultimate goal of better understanding electrical phenomena in the lower and upper atmosphere. The four investigations utilized observations and data analysis for electrical discharges occurring in the troposphere, such as cloud-to-ground and intracloud discharges, and discharges occurring in the stratosphere/lower ionosphere, known as gigantic jets. The observations are from ground-based high-speed cameras and lightning locating systems, space-borne lightning imagers, and remote and in-situ meteorological instrumentation. Numerical modeling was also performed to study the lightning associated with gigantic jets by using a stochastic lighting propagation model. Finally, this dissertation focuses on the …

Dynamics Considerations Dedicated To Study Bodies In High-Altitude Free Fall, Michelle Carolina Rodriguez

Theses and Dissertations

The objective of this thesis is to develop a simulation model to study the dynamics of a rigid body in free fall. A set of 6 degrees of freedom (DOF) equations is developed to reflect the dynamic and trajectory characteristics over time. The simulation models a body dropped at different altitudes ranging from 30,480 – 39,624 m (100,000 – 130,000 ft). The trajectory of the body is analyzed using a mathematical nonlinear dynamics model. The mathematical model was developed in MATLAB and Simulink which can be modified for different geometries and conditions. The model was validated by testing that the …

Earth – Mars Cycler Vehicle Conceptual Design, Bhumika Patel

Theses and Dissertations

This thesis summarizes a conceptual design for an Earth – Mars Cycler vehicle designed to transfer astronauts between Earth and Mars. The primary objective of the design study is to accommodate the crews’ needs and to estimate the overall mass and power required during Earth – Mars transfer. The study defines a concept of operations and system functional requirements and discusses the systems breakdown and subsystems design analysis. Systems developed for the cycler vehicle is designed primarily for the S1L1 cycler trajectory. The initial sizing of cycler subsystems is based on reference data from historical human spaceflight. The study performed …

Wall-Jet Turbulence And Mixing Control By Way Of A Pulsed Inlet Velocity, Cristale D. Garnica Vallejo

Doctoral Dissertations and Master's Theses

Understanding wall-jet-induced turbulence and mixing is an important challenge in modern engineering, as drag reduction and mixing enhancement are attainable by modifying the flow development. Simulations are performed to investigate the effect on skin friction and flow mixing due to introducing controlled perturbations, at the initial shear layer of a planar wall-jet using jet inlet cyclic pulsing. The billow production by the Kelvin-Helmholtz instability, the instability that drives turbulence in a wall-jet, is modified by the excitation of the inlet velocity profile by a sine wave perturbation. Two types of wall-jet simulations are carried out, a two-dimensional compressible case at …

Navigational Feasibility Of Flyby / Impact Missions To Interstellar Objects, Declan Moore Mages

Master's Theses

In October 2017, the first interstellar object, designated 1I/2017 U1 and more commonly referred to as Oumuamua, was detected passing through our solar system by the Pan-STARRS telescope, followed recently by the detection of 2I/Borisov in August 2019. These detections came much sooner than thought possible, and have redefined our understanding of the population of interstellar objects. With the construction of the next generation of powerful observatories, future detections are estimated to occur as frequently as two per year, and while there is significant scientific understanding to be gained from observing these objects remotely, a spacecraft sent to intercept one …

Dynamic Pressure Sensing For The Flight Test Data System, Marc Y. Goupil

Master's Theses

This thesis describes the design, assembly, and test of the FTDS-K, a new device in the Boundary Layer Data System (BLDS) family of flight data acquisition systems. The FTDS-K provides high-frequency, high-gain data acquisition capability for up to two pressure sensors and an additional three low-frequency pressure sensors. Development of the FTDS-K was separated into a core module, specialized analog subsystem, and practical testing of the FTDS-K in a flow measurement mission. The core module combines an nRF52840-based microcontroller module, switching regulator, microSD card, real-time clock, temperature sensor, and trio of pressure sensors to provide the same capabilities as previous-generation …

Numerical Treatment Of Schrödinger’S Equation For One-Particle And Two-Particle Systems Using Matrix Method, Spatika Dasharati Iyengar

Doctoral Dissertations and Master's Theses

With an increased interest in accurately predicting aerothermal environments for planetary entry, recent researches have concentrated on developing high fidelity computational models using quantum-mechanical first principles. These calculations are dependent on solving the Schrödinger equation using molecular orbital theory techniques. They are either approximate solutions to actual equations or exact solutions to approximate equations. Exact solutions have not found favor due to the computational expense of the problem. Hence, a novel numerical approach is developed and tested here using linear algebraic matrix methods to enable precise solutions.

The finite-difference technique is used to cast the Time-Independent Schrödinger equation (TISE) in …

Revolution In Autonomous Orbital Navigation (Raon), Rachit Bhatia

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spacecraft navigation is a critical component of any space mission. Space navigation uses on-board sensors and other techniques to determine the spacecraft’s current position and velocity, with permissible accuracy. It also provides requisite information to navigate to a desired position, while following the desired trajectory. Developments in technology have resulted in new techniques of space navigation. However, inertial navigation systems have consistently been the bedrock for space navigation.

Recently, the successful space mission GOCE used on-board gravity gradiometer for mapping Earth’s gravitational field. This has motivated the development of new techniques like cold atom accelerometers, to create ultra-sensitive gravity gradiometers, …

Investigating The Effects Of Altitude And Flap Setting On The Specific Excess Power Of A Pa-28-161 Piper Warrior, Tjimon Meric Louisy

Theses and Dissertations

The high number of General Aviation (GA) accidents attributed to Loss of Control suggests that GA pilots are lacking low speed awareness and are unable to appropriately recognize when the aircraft is in a low energy state. There is, therefore, an urgent need for the development of an energy management system which is applicable to GA aircraft that can alert the pilot in situations of low energy conditions and recommends to the pilot the appropriate corrective action to restore conditions to a safe energy state. This will require the development of an algorithm that governs this energy management system that …

A Reinforcement Learning Approach To Spacecraft Trajectory Optimization, Daniel S. Kolosa

Dissertations

This dissertation explores a novel method of solving low-thrust spacecraft targeting problems using reinforcement learning. A reinforcement learning algorithm based on Deep Deterministic Policy Gradients was developed to solve low-thrust trajectory optimization problems. The algorithm consists of two neural networks, an actor network and a critic network. The actor approximates a thrust magnitude given the current spacecraft state expressed as a set of orbital elements. The critic network evaluates the action taken by the actor based on the state and action taken. Three different types of trajectory problems were solved, a generalized orbit change maneuver, a semimajor axis change maneuver, …

Experimental Characterization Of Thermal-Hydraulic Performance Of A Microchannel Heat Exchanger For Waste Heat Recovery, James Yih, Hailei Wang

Mechanical and Aerospace Engineering Faculty Publications

Given size and performance advantages, microchannel heat exchangers are becoming increasingly important for various energy recovery and conversion processes. In this study, detailed experimental measurements were conducted to characterize flow and heat transfer performance of a microchannel heat recovery unit (HRU) manufactured using standard photochemical etching and diffusion bonding processes. According to the global flow and temperature measurement, the HRU has delivered the predicted thermal performance under various oil and air flow rates. As expected, the heat transfer effectiveness varies between 88% and 98% for a given air and oil flow rates while it increases with air inlet temperature due …

An Investigation Of High-Speed Consolidation And Repair Of Carbon Fiber - Epoxy Composites Through Ultrasonic Welding, David A. Hoskins

LSU Master's Theses

Adhesive repair of carbon fiber composite structures is commonly done on damaged structures to extend the service life. This method requires careful preparation of the damaged surface with intricate steps to ensure good bonding between the repair patch and the parent structure by means of an adhesive film. As with many forms of composite manufacturing, it is required to perform vacuum bagging, debulking, and a heated cure depending on the resin. All these steps make the repair process costly and time consuming.

In this present work, an alternative method of repair is investigated which explores the experimental feasibility of using …

A Co-Optimal Coverage Path Planning Method For Aerial Scanning Of Complex Structures, Zhexiong Shang, Justin Bradley, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

The utilization of unmanned aerial vehicles (UAVs) in survey and inspection of civil infrastructure has been growing rapidly. However, computationally efficient solvers that find optimal flight paths while ensuring high-quality data acquisition of the complete 3D structure remains a difficult problem. Existing solvers typically prioritize efficient flight paths, or coverage, or reducing computational complexity of the algorithm – but these objectives are not co-optimized holistically. In this work we introduce a co-optimal coverage path planning (CCPP) method that simultaneously co-optimizes the UAV path, the quality of the captured images, and reducing computational complexity of the solver all while adhering to …

Development Of Cislunar Space Logistics Networks For Satellite Constellation Support Using Event-Driven Generalized Multi-Commodity Network Flows, Alexander R. Collins

Theses and Dissertations

As space becomes an increasingly congested domain, the risk of damage to satellite constellations is increasing. In response, there is an increasing need for capabilities for unmanned repair, refueling, and reconstitution (R3) of those constellations. Cislunar orbits offer a promising storage and low-cost transfer solution for on-orbit service vehicles and replacement satellites to leverage those capabilities. This research makes use of mixed-integer linear programming-based logistics models to determine the situations in which a cislunar mission architecture would offer a cost-effective alternative to Earth-based R3. The network models presented in this research make use of the latest developments in Event-Driven Generalized …

Sustainable Aviation Fuels Approval Streamlining: Auxiliary Power Unit Lean Blowout Testing, Erin E. Peiffer, Joshua S. Heyne, Meredith Colket

Mechanical and Aerospace Engineering Faculty Publications

An underpinning hindrance in the market penetration of sustainable aviation fuel is the approval process for alternative jet fuels. One solution to this is to develop low-cost screening tools that can be implemented earlier in the approval process. Auxiliary power unit combustors historically show the most sensitivity to physical and volatile fuel properties, making it a useful tool in assessing potential alternative jet fuel effects at test conditions representative of operability stability limits. It is hypothesized that these observations can be explained via timescale analysis considering fuel droplet breakup and evaporation, combustor mixing, and chemical reactivity timescales on the progression …

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …

Transport Phenomena In The Knudsen Layer Near An Evaporating Surface, Eric Bird, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using the Combination of the Kinetic Theory of Gases (KTG), Boltzmann Transport Equation (BTE), and Molecular Dynamics (MD) Simulations, We Study the Transport Phenomena in the Knudsen Layer Near a Planar Evaporating Surface. the MD Simulation is First Used to Validate the Assumption Regarding the Anisotropic Velocity Distribution of Vapor Molecules in the Knudsen Layer. based on This Assumption, We Use the KTG to Formulate the Temperature and Density of Vapor at the Evaporating Surface as a Function of the Evaporation Rate and the Mass Accommodation Coefficient (MAC), and We Use These Vapor Properties as the Boundary Conditions to Find …

Gelatine Cavity Dynamics Of High-Speed Sphere Impact, Akihito Kiyama, Mohammad M. Mansoor, Nathan B. Spiers, Yoshiyuki Tagawa, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

We investigate the impact and penetration of a solid sphere passing through gelatine at various impact speeds up to 143.2 m s^-1 Tests were performed with several concentrations of gelatine. Impacts for low elastic Froude number Fr_e a ratio between inertia and gelatine elasticity, resulted in rebound. Higher Fr_e values resulted in penetration, forming cavities with prominent surface textures. The overall shape of the cavities resembles those observed in water-entry experiments, yet they appear in a different order with respect to increasing inertia: rebound, quasi-seal, deep-seal, shallow-seal and surface-seal. Remarkably, similar to the We – Bo phase …

Unmanned Aircraft System (Uas) Technology And Applications In Agriculture, Samuel C. Hassler, Fulya Baysal-Gurel

Agricultural and Environmental Sciences Faculty Research

Numerous sensors have been developed over time for precision agriculture; though, only recently have these sensors been incorporated into the new realm of unmanned aircraft systems (UAS). This UAS technology has allowed for a more integrated and optimized approach to various farming tasks such as field mapping, plant stress detection, biomass estimation, weed management, inventory counting, and chemical spraying, among others. These systems can be highly specialized depending on the particular goals of the researcher or farmer, yet many aspects of UAS are similar. All systems require an underlying platform—or unmanned aerial vehicle (UAV)—and one or more peripherals and sensing …

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …

Risk Mitigation For Low Latitude Ground-Based Augmentation System (Gbas) Precision Approach Operations, Richard Walter Cole

Doctoral Dissertations and Master's Theses

The ground-based augmentation system (GBAS) is a safety-critical system consisting of the hardware and software that augments the Global Positioning System (GPS) to provide precision approach and landing capability and is one of the navigational cornerstones of the International Civil Aviation Organization's (ICAO) global transition to space-based technologies. In low latitude regions, where the space-based augmentation system (SBAS) cannot provide adequate precision approach service due to large system errors induced by ionospheric delays, GBAS is the best option to provide the primary navigation function for the modernized global air traffic system. The purpose of the study was to identify patterns …