Matching Items (100)
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- All Subjects: Aerospace Engineering
- Genre: Masters Thesis
- Creators: Arizona State University
- Member of: ASU Electronic Theses and Dissertations
- Resource Type: Text
Description
Additively Manufactured Thin-wall Inconel 718 specimens commonly find application in heat exchangers and Thermal Protection Systems (TPS) for space vehicles. The wall thicknesses in applications for these components typically range between 0.03-2.5mm. Laser Powder Bed Fusion (PBF) Fatigue standards assume thickness over 5mm and consider Hot Isostatic Pressing (HIP) as conventional heat treatment. This study aims at investigating the dependence of High Cycle Fatigue (HCF) behavior on wall thickness and Hot Isostatic Pressing (HIP) for as-built Additively Manufactured Thin Wall Inconel 718 alloys. To address this aim, high cycle fatigue tests were performed on specimens of seven different thicknesses (0.3mm,0.35mm, 0.5mm, 0.75mm, 1mm, 1.5mm, and 2mm) using a Servohydraulic FatigueTesting Machine. Only half of the specimen underwent HIP, creating data for bothHIP and No-HIP specimens. Upon analyzing the collected data, it was noticed that the specimens that underwent HIP had similar fatigue behavior to that of sheet metal specimens. In addition, it was also noticed that the presence of Porosity in No-HIP specimens makes them more sensitive to changes in stress. A clear decrease in fatigue strength with the decrease in thickness was observed for all specimens.
ContributorsSaxena, Anushree (Author) / Bhate, Dhruv (Thesis advisor) / Liu, Yongming (Committee member) / Kwon, Beomjin (Committee member) / Arizona State University (Publisher)
Created2021
Description
Building and optimizing a design for deformable media can be extremely costly. However, granular scaling laws enable the ability to predict system velocity and mobility
power consumption by testing at a smaller scale in the same environment. The validity of
the granular scaling laws for arbitrarily shaped wheels and screws were evaluated in
materials like silica sand and BP-1, a lunar simulant. Different wheel geometries, such as
non-grousered and straight and bihelically grousered wheels were created and tested
using 3D printed technologies. Using the granular scaling laws and the empirical data
from initial experiments, power and velocity were predicted for a larger scaled version
then experimentally validated on a dynamic mobility platform. Working with granular
media has high variability in material properties depending on initial environmental
conditions, so particular emphasis was placed on consistency in the testing methodology.
Through experiments, these scaling laws have been validated with defined use cases and
limitations.
ContributorsMcbryan, Teresa (Author) / Marvi, Hamidreza (Thesis advisor) / Berman, Spring (Committee member) / Lee, Hyunglae (Committee member) / Arizona State University (Publisher)
Created2022
Description
Sydney University has developed a variant of the well-known Sydney/Sydnie piloted jet burner. The introduction of this new burner is for a purpose referred to as airblast atomization. This variant comprises a retractable needle that can be translated within the co-flowing airstream. The performance of the computational simulation is based on a high-pressure turbulent jet having three different recess lengths considering acetone as the fuel. The computational analysis is performed using the primary atomization process in which the bulk amount of liquid transitions into tiny droplets. In the Volume-of-Fluid (VOF) model, the velocity field and pressure field are used to get the atomization locations. The quadratic formula is applied to atomization locations to calculate the mean drop size (Sauter Mean Diameter). The droplets are injected from the atomization locations and tracked considering as the point particles. The steady-state Sauter mean diameter particles are computed using the User Define Memory (UDM) code. The velocity field, droplet size (Sauter mean diameter), and droplet trajectory are compared with the experimental data for the validation protocol.
ContributorsPatel, Ankitaben Vasantbhai (Author) / Lee, Taewoo TL (Thesis advisor) / Kim, Jeonglae JK (Committee member) / Rykaczewski, Konrad KR (Committee member) / Arizona State University (Publisher)
Created2021
Description
Rooftop photovoltaic (PV) systems are becoming increasingly common as the efficiency of solar panels increase, the cost decreases, and worries about climate change increase and become increasingly prevalent. An under explored aspect of rooftop solar systems is the thermal effects that the systems have on the local area. These effects are investigated in this paper to determine the overall impact that solar systems have on the heating and cooling demands of a building as well as on the efficiency losses of the solar panels due to the increased temperature on the panels themselves. The specific building studied in this paper is the Goldwater Center for Science and Engineering located in the Tempe campus of Arizona State University. The ambient conditions were modeled from a typical July day in Tempe. A numerical model of a simple flat roof was also created to find the average rooftop temperature throughout the day. Through this study it was determined that solar panels cause a decrease in the maximum temperature of the rooftop during the day, while reducing the ability of the roof to be cooled during the night. The solar panels also saw a high temperature during the day during the most productive time of day for solar panels, which saw a decrease in total energy production for the panels.
ContributorsNaber, Nicholas (Author) / Huang, Huei-Ping (Thesis advisor) / Phelan, Patrick (Committee member) / Bocanegra, Luis (Committee member) / Arizona State University (Publisher)
Created2022
Description
Localization tasks using two-way ranging (TWR) are making headway in modern daynavigation applications as an alternative to legacy global navigation satellite systems
(GNSS) such as GPS. There is not currently literature that provides a closed-form
expression for estimation performance bounds on position and attitude when a TWR
system is employed. A Cramer-Rao Lower Bounds (CRLB) is derived for position
and orientation estimation using both 2-D and 3-D geometries. A literature review is
performed to give background and detail on the tools needed for a thorough analysis of
this problem. Popular Least Squares techniques and solutions to Wahba’s problem are
compared to the derived bounds as proof of correctness using Monte Carlo simulations.
A brief exploration on estimation performance using an Extended Kalman Filter for
non-stationary users is also looked at as an introduction to future extensions to this
work. The literature Applications like the CHP2 system are discussed as well to show
how secure, inexpensive and robust implementation of TWR is highly feasible.
i
ContributorsWelker, Samuel (Author) / Bliss, Daniel (Thesis advisor) / Herschfelt, Andrew (Committee member) / Tsakalis, Konstantinos (Committee member) / Arizona State University (Publisher)
Created2022
Description
This thesis describes the extension of an aircraft-style time-step integrating mission performance simulation to address aero-spaceplane design challenges. The result is a computationally lean program compatible with current Multi-Disciplinary Optimization schemes to assist in the conceptual design of hypersonic vehicles. To do this the starting aircraft style “Mission Code” required enhancements to the typical point-mass simulation for high altitude and high Mach flight. Stability parameters and the rigid-body modes of Short-Period and Dutch-Roll are tracked to understand time-domain limits to aerodynamic control, along with monitoring the Lateral Control Departure Parameter to ensure that the aircraft is not prone to spin. Additionally, experience has shown that for high Mach Number flight designers must consider aerothermodynamic effects early in the vehicle design process, and thus, an engineering level aerothermodynamic model is included. Comparisons to North American X-15 flight test datasets demonstrate the validity of this method in that application, and trade studies conducted show the utility of this application.
ContributorsGriffin, Jack Aidan (Author) / Takahashi, Timothy (Thesis advisor) / Dahm, Werner (Committee member) / Rodi, Patrick (Committee member) / Arizona State University (Publisher)
Created2022
Description
As the push to develop ever more efficient aircraft increases, the use of lightweight composite materials to meet this push has increased. Traditional aircraft structural component sizing has revolved around the tensile yield strength of materials. Since composite materials excel in tensile strength, these traditional sizing tools provide overly optimistic weight reduction predictions. Furthermore, composite materials, in general, are weak under compression and shear. Thus, proper structural sizing yields heavier-than-expected designs. Nevertheless, a wing using thin, lightweight composites in the primary load-bearing components significantly impacts its static aeroelastic properties. These thin structures have a decreased flexural rigidity, making them more susceptible to bending. The bending of swept wings decreases the design wing twist and dihedral angle, potentially impacting the aerodynamic performance and the lateral stability and control, respectively. This work aims to determine what, if any, are the effects of excessive static aeroelastic properties on the aerodynamic performance of an aircraft. Does the perceived gain in the theoretical reduction in structural weight outweigh the potential reduction in aerodynamic performance?
ContributorsWebb, Benjamin David (Author) / Takahashi, Timothy (Thesis advisor) / Herrmann, Marcus (Committee member) / Perez, Ruben (Committee member) / Arizona State University (Publisher)
Created2022
Description
This thesis addresses the issue of assessing longitudinal and lateral-directional trim capability during the conceptual design process. Modern high-performance aircraft are likely to feature complex flight control systems where the control system may independently command every control surface to develop necessary moments. However, to prove stability and controllability on such an aircraft requires a near-final set of control laws. This requirement is onerous at the conceptual design level, where engineering methods need to facilitate rapid, multidisciplinary design optimization trades. This work considers the differences in Attainable Moment Sets across a wide variety of airframes using a simplified “pre-mix” approach to controls as well as a model where the control systems have independent command authority over each control surface. This work indicates that the “independent-single-panel” model offers modest improvements in attainable moments over a “pre-mix” strategy. This suggests that a “pre-mix” approach used to assess basic combined trim problems will not lead to an overly conservative final design.
ContributorsHeinz, Joshua Holden (Author) / Takahashi, Timothy (Thesis advisor) / Dahm, Werner (Committee member) / Cotting, M. Christopher (Committee member) / Arizona State University (Publisher)
Created2023
Description
This work uses Arizona State University’s (ASU) newly developed high-speed vehicle stability and control screening methodologies to reverse-engineer famous United States Air Force (USAF) flight tests from the 1950s and 1960s. This thesis analyzes the root cause of Chuck Yeager's fateful 1953 supersonic spin in the Bell X-1A to become the "Fastest Man Alive". This thesis then takes a look back at Neil Armstrong's inadvertent atmospheric skip in the North American X-15 and his subsequent hypersonic flight months later. The fundamental flying qualities assessment shown in this work begins with calculating rigid-body frequencies and damping ratios of an aircraft to Military Standard (MIL) requirements, and uses these to create a full, classical stability and control analysis of a high-speed vehicle. Through reverse engineering the flight envelopes and missions for the above aircraft, it appears that the near-disasters of each flight were due to a confluence of then overlooked, yet fundamental, aerodynamic instabilities.
ContributorsLorenzo, Will (Author) / Takahashi, Timothy T (Thesis advisor) / Dahm, Werner J.A. (Committee member) / Grandhi, Ramana V (Committee member) / Arizona State University (Publisher)
Created2023
Description
Formula 1 car front wings have evolved significantly over the last fifty years. Looking back at the past decade shows significant changes made due to rules and regulations by the Federation Internationale de l'Automobile and an increased understanding of aerodynamic concepts. There seems to be a trend where aerodynamic design concepts, previously seen in aviation, are being applied to Formula 1 front wings; this helps race teams increase downforce and reduce drag. This thesis analyzes these changes made over the past years and relates the material back to material that was learned by the aviation industry and attempts to synthesize conceptual Formula 1 front Wing designs using VORLAX, a vortex lattice panel method, used in the aviation industry. This insight would be beneficial for Formula 1 teams as there are budget and time restrictions applied to Computational Fluid Dynamic and wind tunnel testing, but panel methods are run in a matter of seconds as opposed to hours or days. So, if verified, preliminary designs can be rapidly tested to optimize the workflow and reduce the time required for Computational Fluid Dynamic and wind tunnel testing.
ContributorsRatnayake, Sajana Sathsara (Author) / Takahashi, Timothy T (Thesis advisor) / Perez, Ruben E (Committee member) / Kim, Jeonglae (Committee member) / Arizona State University (Publisher)
Created2023