Thermally Stable Super-Hydrophobic Surface Creation,
2018
Portland State University
Thermally Stable Super-Hydrophobic Surface Creation, Caleb Turner
Maseeh Summer Undergraduate Research Experience
Thermally stable super-hydrophobic surface coatings are critical to applications in low gravity fluid dynamics, and in particular Leidenfrost effects. The challenges of manufacturing different super-hydrophobic coatings that are thermally stable, semi-transparent, and environmentally safe at desired operating temperatures is pursued in order to explore the applications of such coatings aboard spacecraft. A catalog of surface coating manufacturing procedures is tabulated with measures for static contact angle, thermal stability, and transparency. These quantities and methods serve as a foundation for both technology applications and follow on experimentation concerning low gravity fluid mechanics at the Portland State Dryden Drop Tower lab.
Fracture Initiation In A Transversely Isotropic Solid: Transient Three Dimensional Analysis,
2018
University of Kentucky
Fracture Initiation In A Transversely Isotropic Solid: Transient Three Dimensional Analysis, Louis Milton Brock
Mechanical Engineering Faculty Publications
A transversely isotropic solid is at rest, and contains a semi-infinite, plane crack. The axis of rotational material symmetry lies in the crack plane. Application of normal point forces to each face of the crack causes transient 3D growth. The related problem of discontinuities in displacement and traction that exist on regions that exhibit dynamic similarity is first considered. Analytic results are obtained in integral transform space. These lead to equations of the Wiener–Hopf type for the fracture problem. Analytic solutions are again obtained and, upon inversion, subjected to a dynamic energy release rate criterion that includes kinetic energy. A …
Active Vibration Control Of Helicopter Rotor Blade By Using A Linear Quadratic Regulator,
2018
LSU New Orleans
Active Vibration Control Of Helicopter Rotor Blade By Using A Linear Quadratic Regulator, Md Mosleh Uddin
LSU New Orleans Theses and Dissertations
Active vibration control is a widely implemented method for the helicopter vibration control. Due to the significant progress in microelectronics, this technique outperforms the traditional passive control technique due to weight penalty and lack of adaptability for the changing flight conditions. In this thesis, an optimal controller is designed to attenuate the rotor blade vibration. The mathematical model of the triply coupled vibration of the rotating cantilever beam is used to develop the state-space model of an isolated rotor blade. The required natural frequencies are determined by the modified Galerkin method and only the principal aerodynamic forces acting on the …
A Novel Magnetorheological Fluid Damper For A Small Spacecraft With Flexible Appendages,
2018
Embry-Riddle Aeronautical University
A Novel Magnetorheological Fluid Damper For A Small Spacecraft With Flexible Appendages, Robert Waelchli
Doctoral Dissertations and Master's Theses
Small satellites have become increasingly popular over the past thirty years, particularly since the adoption of the common CubeSat architecture early this century. Because of their restricted volume and electrical budgets however, there are practical limits to the missions that small satellites may adopt. One potential near-term solution to the problem of limited electrical power may be the adoption of larger, flexible solar arrays. However, spacecraft with flexible appendages have historically presented attitude control challenges relating to platform stability given the dynamic response of the flexible components to applied torques. These challenges may be particularly disruptive to a small spacecraft …
Experimental Investigation Of Enhanced Damage Resistant Fiber Metal Laminates,
2018
Embry-Riddle Aeronautical University
Experimental Investigation Of Enhanced Damage Resistant Fiber Metal Laminates, Cannelle Metang Tefoung
Doctoral Dissertations and Master's Theses
Fiber metal laminates (FMLs) are hybrid composite structures made from fiber reinforced polymeric materials sandwiched between layers of thin metal alloy sheets. FMLs combine the advantages of metallic materials and fiber reinforced matrix systems. Some of these advantages include: lighter weight, enhanced impact tolerance, improved corrosion resistance, better fire resistance, longer fatigue life, greater tensile strength, easier repair ability and maintainability, etc. The most well-known commercially available FML is GLARE (Glass Laminate Aluminum Reinforced Epoxy), however there are ongoing issues, which include a very high fabrication cost compared to many competing material systems and substantial delamination upon impact and failure. …
Ultrasonic Nondestructive Evaluation Of Metal Additive Manufacturing.,
2018
University of Louisville
Ultrasonic Nondestructive Evaluation Of Metal Additive Manufacturing., Venkata Karthik Nadimpalli
Electronic Theses and Dissertations
Metal Additive Manufacturing (AM) is increasingly being used to make functional components. One of the barriers for AM components to become mainstream is the difficulty to certify them. AM components can have widely different properties based on process parameters. Improving an AM processes requires an understanding of process-structure-property correlations, which can be gathered in-situ and post-process through nondestructive and destructive methods. In this study, two metal AM processes were studied, the first is Ultrasonic Additive Manufacturing (UAM) and the second is Laser Powder Bed Fusion (L-PBF). The typical problems with UAM components are inter-layer and inter-track defects. To improve the …
Model-Assisted Probability Of Detection Of Flaws In Aluminum Blocks Using Polynomial Chaos Expansions,
2018
Missouri University of Science and Technology
Model-Assisted Probability Of Detection Of Flaws In Aluminum Blocks Using Polynomial Chaos Expansions, Xiaosong Du, Leifur Leifsson, Robert Grandin, William Meeker, Ronald Roberts, Jiming Song
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Probability of detection (POD) is widely used for measuring reliability of nondestructive testing (NDT) systems. Typically, POD is determined experimentally, while it can be enhanced by utilizing physics-based computational models in combination with model-assisted POD (MAPOD) methods. With the development of advanced physics-based methods, such as ultrasonic NDT testing, the empirical information, needed for POD methods, can be reduced. However, performing accurate numerical simulations can be prohibitively time-consuming, especially as part of stochastic analysis. In this work, stochastic surrogate models for computational physics-based measurement simulations are developed for cost savings of MAPOD methods while simultaneously ensuring sufficient accuracy. The stochastic …
Numerical Simulation Of A High Strain Rate Biaxial Compression Apparatus,
2018
Washington University in St. Louis
Numerical Simulation Of A High Strain Rate Biaxial Compression Apparatus, Michael Lagieski
McKelvey School of Engineering Graduate Student Theses & Dissertations
Few experimental methods today are capable of exploring the strength of materials at high strain rates (105 s-1). Those that are capable, such as the Split Hopkinson Bar, Taylor Anvil and Plate Impact suffer from instability and are generally limited to one dimensional wave propagation. Of particular interest is material response under biaxial compression, similar to that seen in inertial confinement fusion. Laser fusion fuel pellets typically undergo large strain rates as well as plastic deformation and non-linear behavior. This work briefly outlines an experimental procedure designed to replicate these large strain rates under biaxial compression using …
Determination Of Chemical Notch, KChem On Aluminum And Steel When Subjected Under Slow Strain Rate Test In Corrosive Environment,
2018
Western Michigan University
Determination Of Chemical Notch, KChem On Aluminum And Steel When Subjected Under Slow Strain Rate Test In Corrosive Environment, Joshua Teo Lee Kuok
Masters Theses
When designing for any mechanical components or system, the question would arise as to how the material would react to the loads subjected on it? Would the component survive its service load? How would it react to environmental corrosion? To answer these questions, the technique used in this thesis paper is the Slow Strain Rate Test (SSRT) method. Aluminum and steel were chosen as the material to be tested in this paper. Al 7075-T651, and Al 6061-T651 was chosen due to its wide range of application, high strength to weight ratio and ease of machinability. It is highly used in …
Manufacturing Process Simulation – On Its Way To Industrial Application,
2018
University of Applied Sciences Augsburg
Manufacturing Process Simulation – On Its Way To Industrial Application, Dennis Otten, Tobias A. Weber, Jan-Christoph Arent
International Journal of Aviation, Aeronautics, and Aerospace
Manufacturing process simulation (MPS) has become more and more important for aviation and the automobile industry. A highly competitive market requires the use of high performance metals and composite materials in combination with reduced manufacturing cost and time as well as a minimization of the time to market for a new product. However, the use of such materials is expensive and requires sophisticated manufacturing processes. An experience based process and tooling design followed by a lengthy trial-and-error optimization is just not contemporary anymore. Instead, a tooling design process aided by simulation is used more often. This paper provides an overview …
Effects Of Manufacturing Process Variables On Ultrasonic Testing In Electron Beam Melted Ti-6al-4v,
2018
Air Force Institute of Technology
Effects Of Manufacturing Process Variables On Ultrasonic Testing In Electron Beam Melted Ti-6al-4v, Andrew D. Durkee
Theses and Dissertations
Further research on validating additive manufacturing production quality is required before the realization of direct print-to-fly application of critical components. This research examines the response of ultrasonic testing as a function of various manufacturing variables in electron beam melted samples of Ti-6Al-4V. Four dimensionally identical blocks with 6 spherical voids at varying depths were manufactured using different combinations of stock powder, edge treatments, and void melting. Scans were completed on two sides of each specimen with the transducer focused on the mid-plane. Additionally, one specimen was scanned 6 times, with the focal plane adjusted for each scan to match the …
Creep Of Hafnium Diboride -20 Vol% Silicon Carbide At 1500°C In Air,
2018
Air Force Institute of Technology
Creep Of Hafnium Diboride -20 Vol% Silicon Carbide At 1500°C In Air, Glen E. Pry
Theses and Dissertations
Refractory metal borides, commonly referred to as Ultra High Temperature Ceramics (UHTCs), exhibit a number of unique properties, such as extremely high melting temperature and hardness, chemical stability, high electrical and thermal conductivity and corrosion resistance. It has been demonstrated that the addition of SiC improves the oxidation resistance of ZrB2- and HfB2-based UHTCs above 1200°C by modifying the composition of the oxide scale. Addition of SiC retards the oxidation rate of ZrB2 and HfB2 by forming a protective layer of borosilicate glass. Creep deformation is one of the critical criterion for structural application of ceramics at elevated temperatures. Compression …
A Study Of The Hexakis Icosahedron Vacuum Lighter Than Air Vehicle And The Effects Of Air Evacuation On The Structural Integrity,
2018
Air Force Institute of Technology
A Study Of The Hexakis Icosahedron Vacuum Lighter Than Air Vehicle And The Effects Of Air Evacuation On The Structural Integrity, Anthony A. Castello
Theses and Dissertations
The research this paper focuses on is comparing the structural differences between the icosahedron and hexakis icosahedron frame and skin for use as a vacuum lighter than air vehicle (VLTAV), analyzing the stress concentrations in the hexakis icosahedron both with and without the skin, and finding the optimal location and size of the air evacuation method for creating the internal vacuum. Previous research to date has identified dynamic loading on the structure and optimization of the structure, but this will be the first research to analyze the manufacturing of the structure through the development of the air evacuation design. Findings …
Study Of Abnormal Grain Growth In Beta Annealed Ti-6al-4v Forgings,
2018
Air Force Institute of Technology
Study Of Abnormal Grain Growth In Beta Annealed Ti-6al-4v Forgings, Lee R. Morris
Theses and Dissertations
Beta annealed Ti-6Al-4V has been used extensively in current aerospace platforms due to properties such as high strength to weight ratio. Recent inspections during aircraft production have revealed regions of excessive grain sizes, resulting in quarantined parts and excessive time spent on root cause analysis and risk mitigation efforts. Uncertainty surrounding these parts has led to increased costs and may cause future aircraft production delays. Part manufacturers have intermittently reported problems with abnormal grain growth in these alloys for years, but to date no supplier has been able to determine the source of this microstructural phenomenon. Leveraging common Finite Element …
Aerial Port Of The Future: Developing Paperless Operations,
2018
Air Force Institute of Technology
Aerial Port Of The Future: Developing Paperless Operations, Peter J. Williams
Theses and Dissertations
Air Mobility Command (AMC) is combatting manning mismatches with antiquated processes and equipment in Aerial Port operations, and has chosen to address these issues through an initiative called “Aerial Port of the Future.” This initiative is designed to understand challenges in Aerial Ports and implement technological tools, where appropriate, to aid AMC Airmen in their duties of transporting goods and personnel through military channels. Oftentimes, personnel are forced to utilize technology that may not meet their needs, and in turn may resist implementation of the imposed technology. Therefore, first, this research identifies potential technologies designed to improve Aerial Port efficiency …
Aerodynamic Analysis Of Low Speed Wing Design Using Taguchi L9 Orthogonal Array,
2018
Embry-Riddle Aeronautical University
Aerodynamic Analysis Of Low Speed Wing Design Using Taguchi L9 Orthogonal Array, Kenneth Witcher, Ian Mcandrew, Elena Vishnevskaya
Publications
The study of aerodynamics has been preoccupied with understanding flight at increasing speeds and ultimately supersonic. Today, this pursuit has advanced the science for both Hypersonic and Transonic flight to near Mach 1 supporting economical commercial flight operations. This research presents the data from a Taguchi array on low speed with twin wing designs to establish the design parameters for their use in low speed and high altitude. Also presented is how aerodynamic advantages can be achieved through understanding the interactions of parameters and their use. This is compared to operational effectiveness when applied to remotely piloted aircraft that are …
Characterizing The Influence Of Matrix Ductility On Damage Phenomenology In Continuous Fiber-Reinforced Thermoplastic Laminates Undergoing Quasi-Static Indentation,
2018
Missouri University of Science and Technlogy
Characterizing The Influence Of Matrix Ductility On Damage Phenomenology In Continuous Fiber-Reinforced Thermoplastic Laminates Undergoing Quasi-Static Indentation, A. Yudhanto, H. Wafai, G. Lubineau, R. Yaldiz, N. Verghese
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The use of thermoplastic matrix was known to improve the impact properties of laminated composites. However, different ductility levels can exist in a single family of thermoplastic matrix, and this may consequently modify the damage phenomenology of thermoplastic composites. This paper focuses on the effect of matrix ductility on the out-of-plane properties of thermoplastic composites, which was studied through quasi-static indentation (QSI) test that may represent impact problem albeit the speed difference. We evaluated continuous glass-fiber reinforced polypropylene thermoplastic composites (GFPP), and selected homopolymer PP and copolymer PP that represent ductile and less ductile matrices, respectively. Several cross-ply laminates were …
Assessment And Comparison Of Aviation Manufacturing Industries Throughout Mexico And Brazil,
2018
Embry-Riddle Aeronautical University
Assessment And Comparison Of Aviation Manufacturing Industries Throughout Mexico And Brazil, Omar E. Morsi, Kelly A. Whealan-George, Aaron D. Clevenger
International Journal of Aviation, Aeronautics, and Aerospace
This literature review serves to provide insight and understanding in regards to the evolving aviation manufacturing industry throughout the globe and more specifically, Mexico and Brazil. Increased demand for aircraft units both in the commercial and private sectors have led to unprecedented expansions in aircraft manufacturing across the industry. In order to illuminate certain potentials and current growth levels of such industries, this review will delve into an array of information and specifications in regards to economic, political, and cultural influences throughout both Mexican and Brazilian markets respectively. In conclusion, the review will identify the transformation of an aviation manufacturing …
Thermal-Fatigue And Thermo-Mechanical Equivalence For Transverse Cracking Evolution In Laminated Composites,
2018
West Virginia University
Thermal-Fatigue And Thermo-Mechanical Equivalence For Transverse Cracking Evolution In Laminated Composites, Javier Cabrera Barbero
Graduate Theses, Dissertations, and Problem Reports (ETD)
Carbon fiber reinforced plastics (CFRP) are potential materials for many aerospace and aeronautical applications due to their high specif strength/weight and a low coeffcient of thermal expansion (CTE) resulting in a high long-term stability. Among candidate structures, the re-entry reusable launch vehicles (RLV), the fuel oxidant storage and transportation at cryogenic temperature, space satellites, and aircraft structure (frame, wings, etc...) can be highlighted. However, CFRP are prone to internal damage as a result of high residual stresses and thermal fatigue loading. In this study, micro-cracking damage evolution in laminated composites subjected to monotonic cooling and thermal cyclic loads is developed …
Optimal Sintering Temperature Of Ceria-Doped Scandia Stabilized Zirconia For Use In Solid Oxide Fuel Cells,
2018
University of Central Florida
Optimal Sintering Temperature Of Ceria-Doped Scandia Stabilized Zirconia For Use In Solid Oxide Fuel Cells, Amanda K. Assuncao
Honors Undergraduate Theses
Carbon emissions are known to cause decay of the Ozone layer in addition to creating pollutant, poisonous air. This has become a growing concern among scientists and engineers across the globe; if this issue is not addressed, it is likely that the Earth will suffer catastrophic consequences. One of the main culprits of these harmful carbon emissions is fuel combustion. Between vehicles, power plants, airplanes, and ships, the world consumes an extraordinary amount of oil and fuel which all contributes to the emissions problem. Therefore, it is crucial to develop alternative energy sources that minimize the impact on the environment. …
