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 …

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.

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 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.

Transonic Small-Disturbance Theory/Integral Boundary Layer Airfoil Data For The Low-Fidelity Common Research Model, Jeffrey D. Taylor, Douglas Hunsaker

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Lift, Drag, and Moment Coefficient data for the Low-Fidelity Common Research Model wing airfoil sections.

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 …

Coalescence Speed Of Two Equal-Sized Nanobubbles, Eric Bird, Jun Zhou, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In This Work, We Use Molecular Dynamics (MD) Simulations Coupled with Continuum-Based Theoretical Analysis to Study the Coalescence Dynamics of Two Equal-Sized Nanobubbles (NBs). We First Derive a Governing Equation for the Evolution of the Capillary Bridge Radius between Two Coalescing NBs from the Axisymmetric Navier-Stokes Equation. to Verify the Prediction from the Governing Equation, We Carry Out MD Simulations of the Coalescence of Two NBs in a Lennard-Jones Fluid System and Directly Measure the Bridge Radius, Rb, as a Function of Time, T. by Varying the Bubble Diameter, We Change the NB Ohnesorge Number from 0.46 to 0.33. in …

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, …

Hypersonic Heat Transfer Load Analysis In Star-Ccm+, Robert Comstock

Master's Theses

This thesis investigates the capabilities of STAR-CCM+, a Computational Fluid Dynamics (CFD) software owned by Siemens, in predicting hypersonic heat transfer loads on forward-facing surfaces. Results show that STAR-CCM+ predicted peak heat transfer loads within +/- 20% of experimental data on the leading edge of a delta wing design from the X-20 Dyna-Soar program with 73^o of sweep. Steady-state laminar simulations were run as replications of wind tunnel tests documented in NASA CR-535, a NASA technical report that measured and studied the hypersonic pressure and heat transfer loads on preliminary X- 20 wing designs across a wide range of …

Conical Orbital Mechanics: A Rework Of Classic Orbit Transfer Mechanics, Cian Anthony Branco

Mechanical & Aerospace Engineering Theses & Dissertations

Simple orbital maneuvers obeying Kepler’s Laws, when taken with respect to Newton’s framework, require considerable time and effort to interpret and understand. Instead of a purely mathematical approach relying on the governing relations, a graphical geometric conceptual representation provides a useful alternative to the physical realities of orbits. Conic sections utilized within the full scope of a modified cone (frustum) were employed to demonstrate and develop a geometric approach to elliptical orbit transformations. The geometric model in-question utilizes the rotation of a plane intersecting the orbital frustum at some angle β (and the change in this angle) in a novel …

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 …

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 …