Aerospace Engineering Commons^™

Automating Aerospace Synthesis Code Generation A Tool For Generic Vehicle Design And Technology Forecasting, Thomas Peter Mccall

Mechanical and Aerospace Engineering Dissertations - Archive

The principal development and deliverable of this research is a generic synthesis assembling decision support environment for early conceptual design that automates the assembly of synthesis architectures for enhanced product exploration and technology forecasting. The objective of this research is to develop a baseline environment to assess complex vehicle automated synthesis architecture synthetization procedures for adaptation into a greater cognitive system. This tool has been developed as a precursory and developmental task in an initiative towards an artificial intelligence design and research assistant peer. The artificial intelligence peer is a perceived course for future design system evolution in the continued …

Using Numerical Modeling To Determine Viscous Losses Within Helium Turbomachinery, Benjamin Uhlig

Mechanical and Aerospace Engineering Theses - Archive

As the consumption of energy has increased relentlessly over the last few decades, the need for reliable clean energy generation has increased as well. Currently, nuclear power is the only method capable of providing a stable supply of clean energy, although the nuclear energy generation process still requires improvement. Specifically, there is a need to increase efficiencies while reducing the risks of radioactive contamination. It is possible that both these issues may be mitigated using helium as the working fluid. However, the performance of turbomachinery using helium must be evaluated before its use can be implemented. To do this, Balaji …

Determination Of Landing Zones Of Quadrotors Experiencing In-Flight Failures, Ahmet Tolcu

Mechanical and Aerospace Engineering Theses - Archive

In recent years, unmanned aerial vehicles (UAVs), commonly known as drones, have attained considerable prominence in a wide range of areas ranging from military operations, including surveillance, intelligence, and reconnaissance, to nonmilitary sectors such as delivery, entertainment, and agriculture. The low cost, small size, and ease of use of quadrotors provide significant advantages for such missions. At the same time however, the occurrence of physical failures in such vehicles, particularly if these failures occur while flying over highly populated areas, can pose considerable risk to people and premises on the ground. This thesis investigates scenarios of power loss due to …

Experimental Assessment Of Rack-Level Dynamic Direct To Chip Liquid Cooling For Data Center And It Equipment Reliability, Amith Mathew

Mechanical and Aerospace Engineering Theses - Archive

Data centers are used by organizations for storing, processing and distribution of data. These data centers are run through-out the year due to which their thermal management is a growing concern. A popular way of eliminating such thermal cooling issues is Liquid cooling. Conventionally Liquid cooling involves the supply of constant liquid flow (water or refrigerant) through the IT rack irrespective of the IT load, which in a Multi-chip module causes hotspots and temperature gradients across the module due to non-uniform heating. A dynamic cold-plate and a regulatory flow control device (FCD) is incorporated in this experimental set-up to assist …

Attitude Determination And Control Of Arksat-1, Jared Gilliam

Mechanical Engineering Undergraduate Honors Theses

ARKSAT-1 is a nanosatellite developed at the University of Arkansas as part of NASA’s CubeSat Launch Initiative (CSLI). The goal of ARKSAT-1 is to utilize an LED emitter paired with a ground-based tracking system to perform measurements of the composition of the atmosphere using spectroscopy. As part of its function, it is imperative that the satellite is able to control its orientation so that the emitter is aligned as closely as possible with the ground tracker. To do this, the attitude control system of ARKSAT-1 uses magnetic actuators to create a torque on the satellite by interacting with Earth’s magnetic …

Closed-Loop Propulsive Control For Very Low Perigee Orbit Energy Management And Stabilization, Tyler J. Gardner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Within the past decade, the United States Air Force has begun exploring options for using smaller satellites, known as SmallSats and CubeSats, to decrease the time it takes to design and build new satellites. If used properly, a rapid development environment for satellites could improve the Air Force's ability to respond to new technologies and threats. Other organizations such as NASA and universities have been using SmallSats and CubeSats for research and development missions.

While smaller satellites are usually much cheaper to develop and require less time to create, limited volume strictly constrains the size of instrumentation and avionics that …

Analytic Guidance Strategies For Passively Safe Rendezvous And Proximity Operations, Simon Shuster

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A safety ellipse is a type of relative motion trajectory that is commonly used for unmanned rendezvous and proximity operations. As the name suggests, safety ellipses are passively safe relative motion trajectories, which means that their natural motion inherently maintains a low collision risk. The focus of this dissertation is the derivation, analysis, and application of guidance strategies that reconfigure, establish, and exit a safety ellipse. The guidance strategies consist of a set of ∆v vectors and impulse times, all written in closed form. Through applications of optimal control theory and parameter optimization, it is shown that these maneuver …

High Performance Thermal Straps For A Full Range Of Application Temperatures, M. Ralphs, M. Sinfield, M. Felt

Space Dynamics Laboratory Publications

Thermal straps are an essential component when using vibration sensitive instruments and cryocoolers in close proximity. Thermal straps conduct heat from the instrument to the cryocooler while limiting the amount of mechanical vibration the cryocooler transfers back to the instrument. Thermal straps are made from flexible, thermally conductive materials. Traditionally, they are made of metal – aluminum or copper, mostly – that has been formed into thin foils, wires, or braids to provide greater flexibility while still providing good thermal conductivity. These metallic straps, if made from pure metals, provide superior thermal performance at cryogenic temperatures ( < 60 K ) where their thermal conductivities peak to extraordinary levels. Pyrolytic graphite sheet (PG S) thermal straps have a thermal conductance that peaks at higher temperatures – approximately 160 K – and provide much higher mass-specific thermal conductance at temperatures above 60 K than metallic straps. This paper discusses the pros and cons of aluminum, copper, and PG S thermal straps along with different techniques to test their thermal and mechanical performance.

Interplanetary Trajectory Optimization With Automated Fly-By Sequences, Emily Ann Doughty

Master's Theses

Critical aspects of spacecraft missions, such as component organization, control algorithms, and trajectories, can be optimized using a variety of algorithms or solvers. Each solver has intrinsic strengths and weaknesses when applied to a given optimization problem. One way to mitigate limitations is to combine different solvers in an island model that allows these algorithms to share solutions. The program Spacecraft Trajectory Optimization Suite (STOpS) is an island model suite of heterogeneous and homogeneous Evolutionary Algorithms (EA) that analyze interplanetary trajectories for multiple gravity assist (MGA) missions. One limitation of STOpS and other spacecraft trajectory optimization programs (GMAT and Pygmo/Pagmo) …

Numerical Analysis Of A Circulation Control Wing, Luke W. Bodkin

Master's Theses

The objective of this thesis was to develop an experimental method to research circulation control wings using numerical analysis. Specifically, it is of interest to perform 3D wind tunnel testing on a circulation control wing in the Cal Poly Low Speed Wind Tunnel (CPLSWT). A circulation control wing was designed and analyzed to determine the feasibility of this testing.

This study relied on computational fluid dynamics (CFD) simulations as a method to predict the flow conditions that would be seen in a wind tunnel test. A CFD simulation was created of a wing model in a wind tunnel domain. Due …

Spacecraft Trajectory Optimization Suite (Stops): Design And Optimization Of Multiple Gravity-Assist Low-Thrust (Mgalt) Trajectories Using Modern Optimization Techniques, Michael G. Malloy

Master's Theses

The information presented in the thesis is a continuation of the Spacecraft Trajectory Optimization Suite (STOpS). This suite was originally designed and developed by Timothy Fitzgerald and further developed by Shane Sheehan, both graduate students at California Polytechnic State University, San Luis Obispo. Spacecraft utilizing low-thrust transfers are becoming more and more common due to their efficiency on interplanetary trajectories, and as such, finding the most optimal trajectory between two planets is something of interest. The version of STOpS presented in this thesis uses Multiple Gravity-Assist Low-Thrust (MGALT) trajectories paired with the island model paradigm to accomplish this goal. The …

B-Plane Targeting With The Spacecraft Trajectory Optimization Suite, Jared Graef

Master's Theses

In interplanetary trajectory applications, it is common to design arrival trajectories based on B-plane target values. This targeting scheme, B-plane targeting, allows for specific target orbits to be obtained during mission design. A primary objective of this work was to implement B-plane targeting into the Spacecraft Trajectory Optimization Suite (STOpS). This work was based on the previous versions of STOpS done by Fitzgerald and Sheehan, however STOpS was redeveloped from MATLAB to python. This updated version of STOpS implements 3-dimensional computation, departure and arrival orbital phase modeling with patched conics, B-plane targeting, and a trajectory correction maneuver. The optimization process …

Investigation On The Use Of Small Aperture Telescopes For Leo Satellite Orbit Determination, Luis R. Curiel Iii

Master's Theses

The following thesis regards the use of small aperture telescopes for space domain awareness efforts. The rapidly populating space domain was motivation for the development of a new operation scheme to conduct space domain awareness feasibility studies using small telescopes. Two 14-inch Schmidt-Cassegrain Telescopes at the California Polytechnic State University and the Air Force Research Lab in Kirtland AFB, NM, in conjunction with a dedicated CCD camera and a commercial DSLR camera, were utilized to conduct optical observations on satellites in Earth orbit.

Satellites were imaged during August 2019, and from January 2020 to March 2020, resulting in the collection …

Field Testing The Effects Of Low Reynolds Number On The Power Performance Of The Cal Poly Wind Power Research Center Small Wind Turbine, John B. Cunningham

Master's Theses

This thesis report investigates the effects of low Reynolds number on the power performance of a 3.74 m diameter horizontal axis wind turbine. The small wind turbine was field tested at the Cal Poly Wind Power Research Center to acquire its coefficient of performance, C­_p, vs. tip speed ratio, λ, characteristics. A description of both the wind turbine and test setup are provided. Data filtration and processing techniques were developed to ensure a valid method to analyze and characterize wind power measurements taken in a highly variable environment. The test results demonstrated a significant drop in the …

Design And Validation Of An Led-Based Solar Simulator For Solar Cell And Thermal Testing, Matthew Gunther

Master's Theses

An LED-based solar simulator has been designed, constructed, and qualified under ASTM standards for use in the Cal Poly Space Environments Laboratory. The availability of this simulator will enhance the capability of undergraduate students to evaluate solar cell and thermal coating performance, and offers further research opportunities. The requirements of ASTM E927-19 for solar simulators intended for photovoltaic cell testing were used primarily, supplemented by information from ASTM E491-73 for solar simulators intended for spacecraft thermal vacuum testing. Three main criteria were identified as design goals - spectral match ratio, spatial non-uniformity, and temporal instability. An electrical design for an …

Analysis Of Glass Transition Temperature Of Pcb & Substrate Using Dynamic Mechanical Analysis & Thermomechanical Analysis, Shristi Yadav

Mechanical and Aerospace Engineering Theses - Archive

Electronic Packaging materials and their properties examines the array of packaging architecture, outlining the classification of materials and their use for various tasks requiring performance over time. Glass transition temperature plays a vital role in the field of Electronic Packaging. It is the temperature range where the material changes from a rigid glassy material to a soft (not melted) material and is usually measured in terms of the stiffness or modulus. The commonly used component in today’s electronics world are PCBs and substrate which are an integral part of it. There are few known ways of finding out the Glass …

Analysis Of After Impact Characteristics And Structural Optimization Of Cfrp Composite Plate, Zhennan He

Doctoral Dissertations and Master's Theses

Low-velocity impact (LVI) on composites may cause Barely Visible Impact Damage (BVID), which is one of the most common damage types and may result in a decrease in strength of the composite. The objectives of this research were (a) to identify the characteristics of a carbon/epoxy composite plate after low-velocity impact, (b) to create a validated model to simulate the impact process and progressive failure, and (c) to perform sizing and shape optimization of the laminate for improving the damage resistance of the plate. As a part of this thesis, composite plates were fabricated using carbon fiber reinforced polymer (CFRP) …

Foundations Of The Geometric Mechanics Udwadia-Kalaba Framework For Rigid Body Constrained Motion Analysis, Brennan S. Mccann

Doctoral Dissertations and Master's Theses

Presented herein are multiple tools for constrained motion analysis extended to different dynamical frameworks. The Udwadia-Kalaba (UK) formalism for the constrained motion analysis of a point mass is a well-documented and applied methodology. Here, UK formulation is generalized to the dynamics of rigid bodies on nonlinear manifolds in the geometric mechanics framework. This approach simultaneously treats rotational and translational motion in a unified method without encountering singularites or non-uniqueness, issues that would arise were attitude parameterization sets used. The viability of this geometric mechanics UK formalism is demonstrated for the cases of fully and underconstrained systems. The nominal UK formalism …

Relative Attitude Dynamics And Control Of Spacecraft Using Electrostatic Torque, John Galjanic

Doctoral Dissertations and Master's Theses

Recent years have seen an increased interest in spacecraft formation flying, with many applications requiring that the members of these formations maintain specific relative attitude configurations. One low-cost method that has been considered to accomplish this is the use of electrostatic torques, which are generated by charging the surfaces of involved spacecraft to allow interaction without physical contact. The research presented in this thesis analyzes a pair of cylindrical-bodied spacecraft operating in deep space. Specifically, the suitability of using electrostatic torques as an actuator to synchronize the two spacecraft's attitude responses is under consideration. The study considers a simplified case, …

Flexible Strain Detection Using Surface Acoustic Waves: Fabrication And Tests, Rishikesh Srinivasaraghavan Govindarajan

Doctoral Dissertations and Master's Theses

Over the last couple of decades, smart transducers based on piezoelectric materials have been used as sensors in a wide range of structural health monitoring applications. Among them, a Surface Acoustic Wave sensor (SAW) offers an overwhelming advantage over other commercial sensing technologies due to its passive, small size, fast response time, cost-effectiveness, and wireless capabilities. Development of SAW sensors allows investigation of their potential not only for measuring less-time dependent parameters, such as pressure and temperature, but also dynamic parameters like mechanical strains. The objective of this study is to develop a passive flexible SAW sensor with optimized piezoelectric …

Parametric Analysis Of Particle Spreading With Discrete Element Method, Yuxuan Wu

Doctoral Dissertations and Master's Theses

The spreading of metallic powder on the printing platform is vital in most additive manufacturing methods, including direct laser sintering. Several processing parameters such as particle size, inter-particle friction, blade speed, and blade gap size affect the spreading process and, therefore, the final product quality. The objective of this study is to parametrically analyze the particle flow behavior and the effect of the aforementioned parameters on the spreading process using the discrete element method (DEM). To effectively address the vast parameter space within computational constraints, novel parameter sweep algorithms based on low discrepancy sequence (LDS) are utilized in conjunction with …

Numerical Analysis Of Multi-Functional Surface Acoustic Wave Sensor, Xin Xu

Doctoral Dissertations and Master's Theses

A surface acoustic wave (SAW) sensor can have broad industrial applications due to its compact size, low cost-effectiveness, and versatility of sensible measurands, as well as the wireless capabilities. In this study, a theoretical modeling approach accompanied by a MATLAB-based algorithm of the SAW device is first presented. With the designed dimensional parameters and selected material properties, numerical analyses are performed using COMSOL Multiphysics to validate the theoretical results. Various postprocessing responses of the propagated SAWs in both time and frequency domains, such as time delay, insertion loss, and frequency shift, are examined to evaluate the device performances. Also, the …

A Comparison Of Pid And Sliding Mode Controllers When Applied To The Orbit Raising Of A Satellite Using Solar Sail Propulsion, Kayla Marie Ormiston

Doctoral Dissertations and Master's Theses

Solar Sail spacecraft have become increasingly popular due to their ability to perform long term missions without the need for propellant. Because solar sail propulsion is so unique, most research has been focused on developing new mechanical control techniques. However, it can be argued that more advanced control algorithms can be used to mitigate the shortcomings of commonly used control actuators, specifically reaction wheels, when applied to solar sails. This thesis will research how a sliding mode controller compares to a PID controller with respect to settling time and state response error over a range of maximum reaction wheel torque …

Electro-Optic Satellite Constellation Design Using Multi-Objective Genetic Algorithm, Yasin Tamer

Theses and Dissertations

Satellite constellation design is a complex, highly constrained, and multidisciplinary problem. Unless optimization tools are used, tradeoffs must be conducted at the subsystem level resulting in feasible, but not necessarily optimal, system designs. As satellite technology advances, new methods to optimize the system objectives are developed. This study is based on the development of a representative regional remote sensing constellation design. This thesis analyses the design process of an electrooptic satellite constellation with regional coverage considerations using system-level optimization tools. A multi objective genetic algorithm method is used to optimize the constellation design by utilizing MATLAB and STK integration. Cost, …

Analysis For Hybrid Rocket Fuel Regression Using Stereolithographic Geometry, Michael P. King

Theses and Dissertations

Hybrid Rocket Engines (HRE) have characteristically low fuel regression that limits their performance. Additive manufacturing and rapid prototyping can possibly solve some of the problems with Hybrid propulsion regression by creating geometry not possible with conventional manufacturing. This work is attempting to make geometric regression simulation of HRE easier by using STereoLithography (STL files) as the geometry. This analysis sets flow conditions, boundary conditions, propellant selection, and allows for fuel geometry to be altered to simulate geometry’s effects on regression rate and propellant performance. This model can be used for more advanced geometric analysis to improve and predict performance.

Experimental And Computational Analysis Of Progressive Failure In Bolted Hybrid Composite Joints, John S. Brewer

Theses and Dissertations

Composite materials are strong, lightweight, and stiff making them desirable in aerospace applications. However, a practical issue arises with composites in that they behave unpredictably in bolted joints, where damage and cracks are often initiated. This research investigated a solution to correcting the problem with composite bolted joints. A novel hybrid composite material was developed, where thin stainless steel foils were placed between and in place of preimpregnated composite plies during the cure cycle to reinforce stress concentrations in bolted joints. This novel composite was compared to control samples experimentally in quasi-static monotonic loading in double shear configuration in 9-ply …

An Analysis Of The Benefits And Difficulties Of Aerial Magnetic Vector Navigation, Aaron J. Canciani, Christopher J. Brennan

Faculty Publications

Recent successful flight tests have demonstrated scalar magnetic anomaly navigation to be a viable GPS-alternative navigation system. These flight tests matched magnetic field measurements to maps of the Earth's crustal magnetic field in order to navigate. Scalar magnetic navigation uses only the magnetic field intensity, not direction, in order to navigate. While it appears obvious to extend aerial magnetic navigation to use the full vector field, in practice there are substantial obstacles to doing so. This article explores the key challenges of magnetic vector navigation including current sensor limitations, lack of high frequency magnetic vector maps of the Earth's crust, …

Assessing Observer Stations For Cislunar Space Domain Awareness, Michael S. Rosenof

Theses and Dissertations

With renewed worldwide interest in cislunar space, the need for reliable domain awareness in that extended region of space is clear. This investigation quantifies the suitability of several possible stations for observer satellites in cislunar space by calculating the specific irradiance each would observe as they track satellites in various realistic lunar free-return trajectories across a decade, using reflected sunlight. This investigation includes one class of free return trajectories for target satellites, eleven distinct observer stations, and three different metrics for comparing the effectiveness of each observer station or combination of observer stations for sensing targets using reflected sunlight. The …

Development Of A Single Emitter Ionic Liquid Ion Source Research Platform, Thomas V. Kerber

Masters Theses

A single emitter ionic liquid ion source using porous borosilicate glass was developed. Two emitters with different radii of curvatures were tested using 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI-BF₄). I-V curves of the currents on the extractor electrode and a collector plate were obtained for potential differences between the emitter and the extractor ranging from 0 V to 3500 V. For the first emitter chip, extraction began near 2400 V. The highest emission current measured on the first chip was 80 µA at 3500 V with an interception current on the extractor of 4.86 µA. An new collector plate was used …

Experimental Analysis Of Heat Generation In Carbon, Mounisha Ganesan

Doctoral Dissertations and Master's Theses

The purpose of this research is to study a novel non-covalent functionalization technique of single-walled carbon nanotubes (SWCNTs) and to examine the feasibility of using carbon nanotube films as thin film heaters. We developed a unique methodology to synthesize a well dispersed, environmentally friendly solution of CNTs that could be easily spin coated as well as spray coated on different substrates based on the application. Using the produced solutions, thin films of SWCNTs were fabricated on a glass substrate. Two sets of experiments were conducted to study the influence of polyaromatic moiety and the pH on the electro thermal characteristics …