Structures and Materials Commons^™

Dual Graphene Patch Antenna For Ka Band Satellite Applications, Mohammed Amin Rabah, Mohammed Bekhti

International Journal of Aviation, Aeronautics, and Aerospace

Currently; grapheme offers a new opportunity to use in space technology and this is due to its amazing properties like conductivity, strength, flexibility and transparency which allows us to exploit new generation of ultra-fast nanoscale components; Since future wireless communication techniques are geared towards the use of the high frequency spectrum and many recent research prove this trend. This letter presents a proposal for design of a dual graphene-based antenna to use in new communication techniques in Ka band, where the proposed antenna can work for uplink and dowlink frequencies at same time since it has return loss less then …

Shape-Stabilization Of Pcm/Hdpe Composites With 3d-Printing Applications For Battery Thermal Management, Thomas Benjamin Freeman

Doctoral Dissertations and Master's Theses

Phase-change materials (PCMs) are a useful alternative to more traditional methods of thermal management of Li-ion batteries in electric or hybrid-electric vehicles. PCMs are materials which absorb large amounts of latent heat and undergo solid-to-liquid phase change at near-constant temperature. The goal of this thesis is to experimentally investigate the thermal properties of a novel shape-stabilized PCM/HDPE composite extruded filament. The extruded filament can then be used in a 3D printer for custom PCM/HDPE shapes. These custom PCM/HDPE shapes can be used to help reduce weight, energy consumption, and complexity of the thermal management of the ESS. The PCM used …

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, 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. …

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 …

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 …

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 …

Mechanical And Electrical Characterization Of Carbon Fiber/Bucky Paper/Zinc Oxide Hybrid Composites, Suma Ayyagari

Doctoral Dissertations and Master's Theses

The quest for multifunctional carbon fiber reinforced composites (CFRPs) expedited the use of several nano reinforcements such as zinc oxide nanorods (ZnO) and carbon nanotubes (CNTs). Zinc oxide is semi-conductor with good piezoelectric and pyroelectric properties. These properties could be transmitted to CFRPs when a nanophase of ZnO is embedded within CFRPs. In lieu of ZnO nanorods, Bucky paper comprising mat of multiwall-carbon nanotubes (MWCNTs) could be sandwiched in-between laminae to construct a functionally graded composite with elevated electrical and thermal conductivities. In this study, a low temperature ( 90_C) hydrothermal synthesis method was utilized to grow ZnO nanorods on …

Development And Characterization Of Piezoresistive Nanocomposites For Sensing Applications, Muhammad Anees

Doctoral Dissertations and Master's Theses

Carbonnanotube basedhybrid nanocomposites are known to exhibit remarkable electrical and mechanical properties with many potentials in strain and damage sensing applications. In this work, we fabricate hybrid nanocomposites with carbon nanotube (CNT) sheet and graphene nanoplatelets (GNP) as fillers with epoxy matrix. An improvement in both electrical conductivity and piezoresistivity is observed with the combination of CNTs and GNPs, indicating the formation of efficient hybrid conductive networks for strain and electrical transfer in the material. Different matrix materials have been compared to investigate the effect of matrix and to choose the one that yields increased strains, flexibility, and electromechanical response. …

The Shaping Of Things That Are: How Airplane Windows Took Their Shape, Morgan Lopez

Student Works

Have you ever wondered why your airplane's windows are rounded? It is not for aesthetic appeal.

The first commercial jetliner windows' sole purpose was appearance; a squared window afforded an impressive view of the earth, but the view was not without consequence.

Design Of Variable Stiffness Composite Panels For Maximum Strength, Joel P. Hurley

Doctoral Dissertations and Master's Theses

The purpose of this research is to explore the design of variable stiffness composites and develop an automated framework to model, analyze and optimize these structures. Variable stiffness composites have been shown to exhibit increased strength and stiffness over traditional constant stiffness composites by tailoring fiber orientations for specific load conditions. This is achieved by allowing the fiber orientation to vary spatially across the design domain. Motivation for new design methods is driven by the recent advancements in composite additive manufacturing, such as automated fiber placement machines, which allow fiber reinforcements to be placed along prescribed trajectories during manufacturing. Through …

Integration Of Macro-Fiber Composite Material On A Low Cost Unmanned Aerial System, May Chong Chan

Doctoral Dissertations and Master's Theses

The development, deployment, and operation of Unmanned Aerial Systems (UAS) have grown exponentially in recent years and have provided researchers with the opportunity to gain hands-on experience with aircraft in a manner that was previously limited to institutions and companies with large budgets. This allows the generation and testing of UAS advanced technologies using low cost systems. The scope of this thesis does not aim to make vast improvements to the control strategy itself, but to expand upon previous UAV work carried out at Embry-Riddle by designing, implementing, and demonstrating a simulation environment for mechanical and Macro-Fiber Composite (MFC) actuated …

Performance Characterization Of Ceramic Matrix Composites Through Uniaxial Monotonic Tensile Testing, Jóhannes Pétursson

Doctoral Dissertations and Master's Theses

Ceramic matrix composite (CMC) samples were tested in order to characterize their mechanical performance and provide metrics for material process refinement and component design. Monotonic, uniaxial tensile testing of an uncoated carbon fiber reinforced silicon carbide ceramic at room temperature was performed following ASTM standard C1275 to measure ultimate tensile strength and elastic modulus. Equipment verification was carried out through alignment measurement with a gaged tensile specimen using ASTM E1012 to ensure the monotonic nature of the testing equipment. Tensile strength data was treated with Weibull statistical models to produce A and B-basis strength properties for design values.

An alternative …

Windshield Defrost And Deice Using Carbon Nanotube Composite, Santhosh Kumar Loganathan

Doctoral Dissertations and Master's Theses

Carbon nanotubes (CNT) are well known for their high thermal and electrical conductivities and can offer a great advantage by converting the applied electrical energy into instant heat with minimum energy loss. The goal of this research is to develop a very thin CNT layer sandwiched between two layers of glass substrate in order to generate instant heat through electrodes. The thin CNT layer is fabricated using the CNTRENETM solution, which is a mixture of single-walled nanotubes (SWNTs) (~75%), double-walled nanotubes (DWNTs), and multi-walled nanotubes (MWNTs) with an average CNT length of ~0.4 - 0.6 μm. The thin layer is …

From Xst To F-117a, Alan Brown

ERAU Prescott Aviation History Program

Learn the remarkable story of stealth technology from the man often referred to as “Mr. Stealth.” From 1975-1989 Alan Brown was a member of Lockheed “Skunk Works”, becoming program manager & chief engineer for the F-117A Stealth Fighter from initial concept until the first production aircraft was built, 1978 to 1982. Hear the inside story of the many challenges faced by the stealth program and how they were solved.

Improving Damage Tolerance Of Composite Sandwich Structures Subjected To Low Velocity Impact Loading: Experimental And Numerical Analysis, Ravi B. Gondaliya

Doctoral Dissertations and Master's Theses

Sandwich structures with composite facing skins have seen applications in variety of sectors including aerospace and automobile, owing to their high specific mechanical properties. However, there is a need to develop better damage tolerant sandwich structures since conventional composite facing skins exhibit low impact resistance in the transverse direction. Here, composite skin sandwich structures with three different impact resistant core materials were fabricated and tested both experimentally and numerically. Neat CFRP and 2024-T3 aluminum alloy sheets were also investigated. Cores utilizing impact resistant D3O® were found to have very favorable weight specific energy absorbing properties at higher impact velocities as …

Low-Velocity Impact Analysis Of Composite Repair Patches Of Different Shapes, Sarvesh Baliga

Doctoral Dissertations and Master's Theses

The area under crack for various structures can be effectively repaired by the use of composite materials. Low velocity impact can cause barely visible damage to the interior structure of laminated composite. These impacts can cause delamination in composite materials. In this study, a Finite Element Analysis was conducted using Abaqus/Explicit and the results of the analysis were compared to the experimental data from literature. E-glass/epoxy composite laminate was subjected to a low velocity impact test. To study the effect of patch repair, a composite patch was applied on a cracked laminate and a low velocity impact was then conducted …

Phased Array Beamsteering In Composite Laminates For Guided Wave Structural Health Monitoring, Peter Osterc

Doctoral Dissertations and Master's Theses

In this study a guided wave phased array beamsteering approach is applied to composite laminates. Current beamsteering algorithms derived for isotropic materials assume omnidirectional wave propagation. Due to inherent anisotropy in composites, guided wave propagation varies with direction and wavefronts no longer have perfect circular shapes.

By examining slowness, velocity and wave curves, as well as amplitude variation with direction for a given composite laminate, the wavefront from a single source can be described as a function of the angle of propagation and distance from origin. Using this approach, a more general delay and sum beamforming algorithm for composite laminates …

Suborbital Spaceflight: A Student Team’S Plan To Send A Rocket To Space, Bryce Chanes, William Carpenter, Julio Benavides, Matthew Haslam, Brenda Haven

Aviation / Aeronautics / Aerospace International Research Conference

The Eagle Space Flight Team was created with the goal of becoming the first undergraduate team to design, build, and launch a rocket capable of suborbital spaceflight. In order to achieve this goal, the team will have to design a rocket capable of atmospheric flight at speeds over Mach 5 and launch it on one of the largest amateur rocket motors ever made. Over the next three years, the team will progress towards accomplishing this feat through a series of incremental test flights. Before the space flight, the team will build three sub-scale rockets designed to reach altitudes of 30,000’, …

Development, Analysis, And Comparison Of Electromechanical Properties And Electrode Morphology Of Ionic Polymer Metal Composites, Balaji Sivasubramanian

Doctoral Dissertations and Master's Theses

With smart materials and adaptive structures being nudged into mainstream technology progressively, the smart composites are donning a predominant role as indispensable structures. Among these, the Ionic Polymer Metal Composites (IPMC), with their large bending deformation and relaxation characteristics at very low voltages are attractive as transducers in many areas of application. The actuation and sensing properties of IPMC have been sought after for various engineering functions. The paper focuses on manufacturing various types of IPMC. Combining the ionic polymer with platinum electrodes, gold sputter coated electrodes and multi-walled carbon nanotube Bucky paper electrodes to create enhanced IPMCs, comparative analysis …

Achieving Global Range In Future Subsonic And Supersonic Airplanes, Nihad E. Daidzic Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

No commercial airplane in service today is able to fly half great-circle distances over the globe and achieve the non-stop or the global range to any antipodal location on Earth. A subsonic jetliner has the optimum cruising speed at Mach numbers approaching the drag divergence Mach number while still preserving relatively high aerodynamic efficiency. Various fuel-flow laws were used to investigate the cruise performance of subsonic and supersonic aircraft. The effect of wind and aircraft weight and how it affects the optimal cruising airspeed was investigated. Of all different operational cruising techniques, the cruise-climb at high Mach numbers is the …

To Study The Effect Of Catalyst On The Physical Parameters Of Carbon Spheres, Tejas Shailesh Mehta

Doctoral Dissertations and Master's Theses

The discovery of fullerenes has opened up modern studies in carbon materials. Carbon nanoparticles have a large surface area and demonstrate good conductivity. Their unique properties has gained attention in many areas such as water filtration, hydrogen storage and battery electrodes. In this research, carbon spheres with high specific area and uniformity were grown using the Chemical Vapor Deposition (CVD) process with silicon substrates, ethylene (C2H4) as a carbon precursor and argon as the inert gas. We observe that the morphology of carbon spheres largely depend on the experimental conditions, including CVD time duration, temperature, catalyst and flow of gases. …

Molecular Dynamics Model Of Carbon Nanotubes In Epon 862/Detda Polymer, Guttormur Arnar Ingvason

Doctoral Dissertations and Master's Theses

The aerospace industry is interested in increasing the strength while reducing the weight of carbon fiber composite materials. Adding single walled carbon nanotubes (SWCNT) to a polymer matrix can achieve that goal by improving delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential to represent the interactions between the atoms of the polymer and the SWCNT. This …

The Application Of Advanced Composites For The Construction Of Commercial Transport Aircraft, Mark D. Severson

Graduate Student Works

This individual Capstone project examined and evaluated current industry methods of testing, certification, and maintenance of advanced composite materials for the construction of commercial transport aircraft and the FAA regulations governing their use. The project critically compared and contrasted existing FAA standards and regulations governing the testing, certification, and maintenance of advanced composites for commercial transport aircraft structural applications with current industry practices to determine whether there were any areas of conflict between the two in order to accept or reject that current testing, certification, and maintenance procedures for advanced composites used in primary and secondary commercial transport aircraft structures …

Validation Of Proposed Metrics For Two-Body Abrasion Scratch Test Analysis Standards: In Principle, Any Scratch Can Be Analyzed By This Method, Kenneth W. Street, Ryan L. Kobrick, David M. Klaus

Publications

Abrasion of mechanical components and fabrics by soil on Earth is typically minimized by the effects of atmosphere and water. Potentially abrasive particles lose sharp and pointed geometrical features through erosion. In environments where such erosion does not exist, such as the vacuum of the Moon, particles retain sharp geometries associated with fracturing of their parent particles by micrometeorite impacts. The relationship between hardness of the abrasive and that of the material being abraded is well understood, such that the abrasive ability of a material can be estimated as a function of the ratio of the hardness of the two …

Structural Damage Classification Using Support Vector Machines, Xiang Li

Doctoral Dissertations and Master's Theses

In this research, a methodology to classify crack and corrosion metallic damages using a time-frequency representation method and support vector machines is investigated. Piezoelectric ceramic actuators are utilized to generate guided wave signals on a set of aluminum beam coupons with different damage features, such as types, locations, and thicknesses. The short-time Fourier transform is applied to analyze the measured signals. For damage classification, the spectrograms obtained from finite element models are employed to train a two-class support vector machine learning classifier. The classifier is able to correctly classify different types of damages based upon the measured signals collected from …

An Experimental Investigation Of Glare And Restructured Fiber Metal Laminates, Adelina Vanessa Benedict

Doctoral Dissertations and Master's Theses

Fiber Metal Laminates (FMLs) are a group of materials fabricated by bonding glass/epoxy layers within metal layers. This class of materials can provide good mechanical properties, as well as weight savings. An FML known as Glass Laminate Aluminum Reinforced Epoxy (GLARE) was studied. An experimental investigation comprising of microscopy and tensile testing was carried out using different grades of GLARE. Microscopy revealed the construction details of GLARE, while tensile testing provided means of measuring and analyzing its stress-strain responses. Next, different metal surface pretreatment methods were explored. These included sandblasting, Phosphoric Acid Anodizing (PAA), and AC-130 Sol-Gel treatment. Woven S-2 …

Ultimate Compression After Impact Load Prediction In Graphite/Epoxy Coupons Using Neural Network And Multivariate Statistical Analyses, Alexandre David Grégoire

Doctoral Dissertations and Master's Theses

The goal of this research was to accurately predict the ultimate compressive load of impact damaged graphite/epoxy coupons using a Kohonen self-organizing map (SOM) neural network and multivariate statistical regression analysis (MSRA). An optimized use of these data treatment tools allowed the generation of a simple, physically understandable equation that predicts the ultimate failure load of an impacted damaged coupon based uniquely on the acoustic emissions it emits at low proof loads. Acoustic emission (AE) data were collected using two 150 kHz resonant transducers which detected and recorded the AE activity given off during compression to failure of thirty-four impacted …

Validation Of Proposed Metrics For Two-Body Abrasion Scratch Test Analysis Standards, Ryan L. Kobrick, David M. Klaus, Kenneth W. Street

Publications

The objective of this work was to evaluate a set of standardized metrics proposed for characterizing a surface that has been scratched from a two-body abrasion test. This is achieved by defining a new abrasion region termed “Zone of Interaction” (ZOI). The ZOI describes the full surface profile of all peaks and valleys, rather than just measuring a scratch width as currently defined by the ASTM G 171 Standard. The ZOI has been found to be at least twice the size of a standard width measurement, in some cases considerably greater, indicating that at least half of the disturbed surface …

Three-Body Abrasion Testing Using Lunar Dust Simulants To Evaluate Surface System Materials, Ryan L. Kobrick, Kenneth G. Budinski, Kenneth W. Street Jr., David M. Klaus

Publications

Numerous unexpected operational issues relating to the abrasive nature of lunar dust, such as scratched visors and spacesuit pressure seal leaks, were encountered during the Apollo missions. To avoid reoccurrence of these unexpected detrimental equipment problems on future missions to the Moon, a series of two- and three-body abrasion tests were developed and conducted in order to begin rigorously characterizing the effect of lunar dust abrasiveness on candidate surface system materials. Two-body scratch tests were initially performed to examine fundamental interactions of a single particle on a flat surface. These simple and robust tests were used to establish standardized measurement …