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Full-Text Articles in Aerospace Engineering

Development And Processing Of Shape Memory Polymer Composites (Smpcs) For Application In Structural Robotics And Robotic Sensors., Kavish Sudan Aug 2024

Development And Processing Of Shape Memory Polymer Composites (Smpcs) For Application In Structural Robotics And Robotic Sensors., Kavish Sudan

Electronic Theses and Dissertations

Shape Memory Polymers (SMPs) have attracted significant attention since their introduction in the 1980s due to their remarkable ability to regain their original shape from a temporarily deformed state when exposed to an external stimulus, typically heat. This shape memory effect, driven by thermal transitions such as the glass transition temperature (Tg) or melting temperature (Tm), has made SMPs highly attractive for applications in soft robotics, aerospace, and biomedical devices. However, SMPs face challenges such as limited mechanical strength, thermal stability, and electrical conductivity, which hinder their broader adoption in advanced applications. To address these challenges, …


Development Of A Passive Drag Reduction Modification For The 25° Ahmed Body Using Large Eddy Simulation, Skylar Polek Aug 2024

Development Of A Passive Drag Reduction Modification For The 25° Ahmed Body Using Large Eddy Simulation, Skylar Polek

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the field of automotive aerodynamics, the Ahmed body is a generic vehicle-shaped bluff body which is meant to generalize the rear end of fastback and hatchback vehicles. Specifically, an Ahmed body with a rear slant angle of 25° has seen common use due to its resemblance of common rear windshield shapes as well as its notoriously complex wake structure. This research focuses on simulating the flow over a 25° in various situations with an ultimate goal of drag reduction. First, a simple benchmark of the k-ω shear stress transport (SST), large eddy simulation (LES) with the Smagorinsky-Lilly subgrid scale …


Trade-Offs In Lighting For Dic Strain Measurements In Vibration-Based Fatigue Testing, Jacob R. Rigby Aug 2024

Trade-Offs In Lighting For Dic Strain Measurements In Vibration-Based Fatigue Testing, Jacob R. Rigby

All Graduate Theses and Dissertations, Fall 2023 to Present

Vibration based fatigue testing offers a fast and efficient method for determining the breaking point of a material. This method often uses a device, called a strain gage, to measure the deformation of a test sample at a single spot on the test sample. However, these strain gages often break before testing is complete. To overcome this premature break, a laser vibrometer is often used to measure the amount of movement or the speed of the test sample throughout the vibration test. The deformation measured by the strain gage is compared against the amount of movement or velocity of the …


Tension–Compression Fatigue Of A Hybrid Polymer-Matrix/Ceramic-Matrix Composite At Elevated Temperature, Marina B. Ruggles-Wrenn, Joshua Schmidt Jul 2024

Tension–Compression Fatigue Of A Hybrid Polymer-Matrix/Ceramic-Matrix Composite At Elevated Temperature, Marina B. Ruggles-Wrenn, Joshua Schmidt

Faculty Publications

Fully reversed tension–compression fatigue of a hybrid material comprising polymer matrix composite (PMC) co-cured with a ceramic matrix composite (CMC) was investigated. The PMC portion had a polyimide matrix reinforced with 15 plies of carbon fibers woven in an eight-harness satin weave (8HSW). The CMC portion had three plies of a quartz-fiber 8HSW fabric in a zirconia-based ceramic matrix. The hybrid PMC/CMC was developed for use in aerospace thermal protection systems (TPS). Hence, the experimental setup aimed to simulate the TPS service environment—the CMC side was kept at 329 °C, whereas the PMC side was open to laboratory air. Compression …


Space Program: Center For Space Research - Austin, Texas #3, Robert J. Twiggs Jul 2024

Space Program: Center For Space Research - Austin, Texas #3, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Space Program: Center for Space Research - Austin, Texas #3" from July 29, 2024.


Space Radiation Assessment And Mitigation: Meeting The Growing Demand For Shielding Solutions By Enhancing Models And Exploring Novel Shielding Opportunities, M. Laura Sorgi Johann Jul 2024

Space Radiation Assessment And Mitigation: Meeting The Growing Demand For Shielding Solutions By Enhancing Models And Exploring Novel Shielding Opportunities, M. Laura Sorgi Johann

Doctoral Dissertations and Master's Theses

The rapid growth of satellite technology and the increasing presence of vulnerable technology and human life in space have highlighted the need for improved shielding materials. Industry standard protocols for shielding are being pushed to their limits as we gain a deeper understanding of the harsh space environment and as chip sizes approach the scale of radiation wavelengths. Furthermore, the commercialization of space is attracting interest from industries such as pharmaceuticals and semiconductor crystal growing, as they explore the potential benefits of zero-gravity production environments. However, the eagerness to develop lighter shielding and the lack of consideration for existing tools …


Space Program: Center For Space Research - Austin, Texas #2, Robert J. Twiggs Jul 2024

Space Program: Center For Space Research - Austin, Texas #2, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Space Program: Center for Space Research - Austin, Texas #2" from July 29, 2024.


Exploring Small-Scale Propellers Performance At Low Advance Ratios, Ali Akber Mollick, Sara Catto, Forrest E. Ames, Clement Tang Jul 2024

Exploring Small-Scale Propellers Performance At Low Advance Ratios, Ali Akber Mollick, Sara Catto, Forrest E. Ames, Clement Tang

Mechanical Engineering Student Publications

The performance of small-scale propellers was experimentally measured at low advance ratios and Reynolds numbers. The propeller diameters range from 14 to 19 inches, with all propellers having the same pitch value of 12. Using a thrust stand situated in a low-speed open-circuit wind tunnel, the propeller thrust, torque, and angular speed were measured at various freestream velocities. The results from this study offer insights on the performance of small propellers at low advance ratios and low Reynolds numbers. Propeller performance results at these conditions tend to be limited in the literatures. At the same pitch value of 12, the …


Modeling Powder Spreadability In Powder-Based Processes Using The Discrete Element Method, Austin T. Sutton, M. Hossein Sehhat, Ming C. Leu, Joseph W. Newkirk Jul 2024

Modeling Powder Spreadability In Powder-Based Processes Using The Discrete Element Method, Austin T. Sutton, M. Hossein Sehhat, Ming C. Leu, Joseph W. Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Powder-bed fusion (PBF) processes refer to a subset of Additive Manufacturing (AM) techniques where powder is spread on the build-plate before melting (by a laser or electron beam). While PBF processes are attractive due to their ability for realizing complex structures that are either difficult or impossible to create through conventional means, the parts fabricated with these techniques can exhibit defects such as pores, inclusions, and excessive surface roughness. To minimize these defects, much research has been dedicated towards process maturation by optimizing laser or electron beam parameters. However, these developmental efforts typically do not address the recoating process where …


Vertiport Ventures: Assessing Operational Feasibility For Evtol Integration In São Paulo’S Helipad And Heliport Infrastructure, Peter E. O'Reilly, Ramy A. Rahimi, Jorge Luiz Rosa Marques, Marco Aurélio Feitosa De A. L. Babadopulos1 Jul 2024

Vertiport Ventures: Assessing Operational Feasibility For Evtol Integration In São Paulo’S Helipad And Heliport Infrastructure, Peter E. O'Reilly, Ramy A. Rahimi, Jorge Luiz Rosa Marques, Marco Aurélio Feitosa De A. L. Babadopulos1

Publications

The objective of this study is to assess the operational viability of introducing Electric Vertical Take-Of and Landing (eVTOL) vehicles in São Paulo and its metropolitan area, utilizing existing helipads and helicopter infrastructure. eVTOL aircraft, capable of vertical take-of and landing like helicopters, difer from traditional helicopters in their propulsion systems, with eVTOLs typically featuring multiple smaller electric motor-driven propulsion units instead of internal combustion engines and mechanical transmissions (Schuchardt et al. 2023). The study specifcally targets eVTOLs with the capacity to transport a minimum of four passengers and one pilot for distances of at least 50 km. Appendix provides …


Notes For Contributors, Space And Defense Jul 2024

Notes For Contributors, Space And Defense

Space and Defense

No abstract provided.


Waging Peace On The Final Frontier 64th Academy Assembly Proceedings, Space And Defense, Madison Walker Jul 2024

Waging Peace On The Final Frontier 64th Academy Assembly Proceedings, Space And Defense, Madison Walker

Space and Defense

In October 2022, the 64th annual Academy Assembly at the U.S. Air Force Academy took up the theme of “Waging Peace on the Final Frontier.” The following are proceedings of roundtables held by select undergraduates from around the country on questions of space policy & strategy.


Revitalizing America's Low-Yield Deterrent, Alex Kleitz Jul 2024

Revitalizing America's Low-Yield Deterrent, Alex Kleitz

Space and Defense

An array of low-yield weapons will play a vital role in integrated deterrence. *The following essay, submitted in June 2022, earned the Junior Division USSTRATCOM General Larry D. Welch Deterrence Writing Award.


Annual Truman Lecture Usafa 64th Academy Assembly, John Shaw Jul 2024

Annual Truman Lecture Usafa 64th Academy Assembly, John Shaw

Space and Defense

In October 2022, on the occasion of the 64th annual Academy Assembly, focused on “Waging Peace on the Final Frontier,” the deputy commander of USSPACEOM Lieutenant General John Shaw spoke at the Air Force Academy’s endowed Truman Lecture, which itself was created to inspire cadets toward careers in National Security leadership.


Usafa 64th Academy Assembly Banquet Keynote On Nasa Transformation, Madison Walker, Lori Garver Jul 2024

Usafa 64th Academy Assembly Banquet Keynote On Nasa Transformation, Madison Walker, Lori Garver

Space and Defense

In October 2022, at the 64th annual Academy Assembly, focused on “Waging Peace on the Final Frontier,” the former deputy administrator of NASA the Honorable Lori Garver spoke at the Air Force Academy’s 64th Academy Assembly banquet keynote on the implications of NASA transformation for international security. She was introduced in a pre-recorded video by Susan Eisenhower, honorary founder of USAFA’s Eisenhower Center, and interviewed by USAFA Institute for Future Conflict Fellow Madison Walker.


The Unified Command Plan For A New Cold War, David Stilwell Jul 2024

The Unified Command Plan For A New Cold War, David Stilwell

Space and Defense

No abstract provided.


Protecting The Cosmos: Defining Celestial Bodies In The Outer Space Treaty, David Epstein Jul 2024

Protecting The Cosmos: Defining Celestial Bodies In The Outer Space Treaty, David Epstein

Space and Defense

Lack of a clear definition of the term “celestial bodies” as used in the 1967 Outer Space Treaty risks exporting legal and political conflict into the cosmos. *This essay is updated from a previously published version and appears here by permission of the Journal of Space Law at Ole Miss.


Editor's Note, Damon Coletta Jul 2024

Editor's Note, Damon Coletta

Space and Defense

No abstract provided.


Table Of Contents, Space And Defense Jul 2024

Table Of Contents, Space And Defense

Space and Defense

No abstract provided.


Front Matter, Space And Defense Jul 2024

Front Matter, Space And Defense

Space and Defense

No abstract provided.


Space And Defense Volume 15 No. 1 Spring 2024 (Whole Issue), Space And Defense Jul 2024

Space And Defense Volume 15 No. 1 Spring 2024 (Whole Issue), Space And Defense

Space and Defense

No abstract provided.


Computational Fluid Dynamics Visualization For Unmanned Aerial Systems In Bridge Inspections, Kristoffer B. Borgen, John Mott Jul 2024

Computational Fluid Dynamics Visualization For Unmanned Aerial Systems In Bridge Inspections, Kristoffer B. Borgen, John Mott

Journal of Aviation Technology and Engineering

Bridge inspections are an expensive and time-consuming process, varying significantly with a bridge’s style, height, width, and length. Inspections create interruptions that interfere with bridge use, as the examination requires partial or total closure, causing traffic delays. Unmanned aerial system (UAS) use has increased significantly over the past decade, including assistance and coordination during bridge inspections. However, the impact on a UAS from high winds and turbulent airflows induced by a bridge’s structure can decrease flight safety during inspections. Visualization of these hazards is difficult for UAS operators; therefore, a process to estimate the velocity and locations of these hazardous …


Space Program: Center For Space Research - Austin, Texas #1, Robert J. Twiggs Jul 2024

Space Program: Center For Space Research - Austin, Texas #1, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Space Program: Center for Space Research - Austin, Texas" from July 12, 2024.


Slimsat, Robert J. Twiggs, Nick Pugh Jul 2024

Slimsat, Robert J. Twiggs, Nick Pugh

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs and Nick Pugh titled "SlimSat" from July 11, 2024.


A Study Of Directionality Effects In Three-Beam Coaxial Titanium Wire-Based Laser Metal Deposition, Remy Mathenia, Braden Mclain, Todd Sparks, Frank Liou Jul 2024

A Study Of Directionality Effects In Three-Beam Coaxial Titanium Wire-Based Laser Metal Deposition, Remy Mathenia, Braden Mclain, Todd Sparks, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Coaxial wire-based laser metal deposition is a versatile and efficient additive process that can achieve a high deposition rate in the manufacturing of complex structures. In this paper, a three-beam coaxial wire system is studied, with particular attention given to the effects of the deposition direction and laser beam orientation on the resulting bead geometry symmetry. With the three-beam laser delivery, the laser spot pattern is not always symmetric with respect to the deposition direction. Single titanium beads are deposited in different directions and at varying deposition rates, and the bead profile is quantitatively scored for multiple symmetry measures. Through …


Analytical And Fem Models For Thermal Analysis And Residual Stresses Using Wire Arc-Based Welding And Additive Manufacturing Of Sus304, Muhammad Arif Mahmood, Usman Tariq, Mihai Oane, Frank Liou Jul 2024

Analytical And Fem Models For Thermal Analysis And Residual Stresses Using Wire Arc-Based Welding And Additive Manufacturing Of Sus304, Muhammad Arif Mahmood, Usman Tariq, Mihai Oane, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Austenitic stainless steel, also known as SUS304, has a wide industrial application. The resultant residual stresses and deformation due to arc welding play a critical role in an in-service SUS04 part failure. Various experimental studies have been presented to predict residual stresses and part deformation. However, these techniques are expensive and time-consuming owing to the trial-and-error approach, limiting their application to industrial applications. Based on the emergent need, this study introduces two simulation models based on analytical and FEM techniques for thermal distribution and residual stress estimation. The experimentally calibrated models results have been implemented for SUS304 multi-pass arc welding. …


In Situ Synthesis, Characterization And Photocatalytic Efficacy Of Silver-Enhanced Mxene And Graphene Nanocomposites, Kishore Chand, M. Mustafa Azeem, Muhammad Nazim Lakhan, Mukhtiar Ahmed, Muhammad Jehanzaib Aslam, Ahmer Hussain Shah Jul 2024

In Situ Synthesis, Characterization And Photocatalytic Efficacy Of Silver-Enhanced Mxene And Graphene Nanocomposites, Kishore Chand, M. Mustafa Azeem, Muhammad Nazim Lakhan, Mukhtiar Ahmed, Muhammad Jehanzaib Aslam, Ahmer Hussain Shah

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The emergence of 2D materials has significantly expanded the wide range of nanomaterials with diverse applications. Notably, their high conductivity, catalytic efficiency, and hydrophobicity have fueled heightened research interests for water treatment applications. This research aimed to investigate the synthesis and characterization of MXene and reduced graphene oxide (rGO) nanocomposites with silver nanoparticles (Ag) for enhanced catalytic activity in the decomposition of Direct Blue-24 dye. In this study, we employed well-established methods, previously documented in the literature, to prepare two distinct nanocomposites. Novel nanocomposites, namely reduced graphene oxide–silver nanoparticles (rGO–Ag) and MXene–silver nanoparticles (MXene–Ag), were synthesized using the hydrothermal and …


In Situ Synthesis, Characterization And Photocatalytic Efficacy Of Silver-Enhanced Mxene And Graphene Nanocomposites, Kishore Chand, M. Mustafa Azeem, Muhammad Nazim Lakhan, Mukhtiar Ahmed, Muhammad Jehanzaib Aslam, Ahmer Hussain Shah Jul 2024

In Situ Synthesis, Characterization And Photocatalytic Efficacy Of Silver-Enhanced Mxene And Graphene Nanocomposites, Kishore Chand, M. Mustafa Azeem, Muhammad Nazim Lakhan, Mukhtiar Ahmed, Muhammad Jehanzaib Aslam, Ahmer Hussain Shah

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The emergence of 2D materials has significantly expanded the wide range of nanomaterials with diverse applications. Notably, their high conductivity, catalytic efficiency, and hydrophobicity have fueled heightened research interests for water treatment applications. This research aimed to investigate the synthesis and characterization of MXene and reduced graphene oxide (rGO) nanocomposites with silver nanoparticles (Ag) for enhanced catalytic activity in the decomposition of Direct Blue-24 dye. In this study, we employed well-established methods, previously documented in the literature, to prepare two distinct nanocomposites. Novel nanocomposites, namely reduced graphene oxide–silver nanoparticles (rGO–Ag) and MXene–silver nanoparticles (MXene–Ag), were synthesized using the hydrothermal and …


Optimization Of A Plate Beam System For Energy Harvesting Using A Piezoelectric Material, Jose Manuel Almendros Espantaleon Jul 2024

Optimization Of A Plate Beam System For Energy Harvesting Using A Piezoelectric Material, Jose Manuel Almendros Espantaleon

Doctoral Dissertations and Master's Theses

With a continuously growing demand for power, driven by the need to reduce our environmental footprint, this research provides an examination of the potential of energy harvesting with smart materials technology and its practical applications. The energy harvesting system considered here works on generating energy through vibrations of a piezoelectric material beam which will undergo sustained vibrations due to flow of air over its surface. It is assumed that sustained limit cycle oscillations of this system will occur at the flutter velocity. This research creates an optimization framework to obtain the best values of parameters that will result in the …


Assessing The Impact Of Spacecraft Fragmentation In The Cislunar Region, Marta Lopez Castro Jul 2024

Assessing The Impact Of Spacecraft Fragmentation In The Cislunar Region, Marta Lopez Castro

Doctoral Dissertations and Master's Theses

In the last decades, space missions have followed great advancements due to technological improvements and the extensive research developed in the field. Some of these missions are increasingly focusing on satellites orbiting the Moon. The Cislunar region is known to have a higher non-linear chaotic component in the dynamics compared to the low-Earth environment. This research is focused on studying the impact that a satellite explosion has in the Cislunar vicinity. The study is conducted for different periodic orbits that are key destinations for Cislunar traffic. By varying the initial conditions, simulations of explosions at different locations of the orbits …