Aerospace Engineering Commons^™

Thermal Contact Resistance Measurement And Related Uncertainties, Amanda Elizabeth Stark

Mechanical & Aerospace Engineering Theses & Dissertations

Thermal contact resistance is an important parameter in detailed thermal analysis and design of aerospace systems. The ability to determine thermal contact resistance reliably can have a significant impact on the fidelity of thermal models—particularly for space applications. The 2004 NASA Langley Research Center thermal contact resistance test apparatus has been employed to evaluate two methods for inferring estimated interface surface temperatures so that thermal contact resistance can be calculated more accurately. The traditional method of extrapolation is a steady-state approach, while the new method utilizes inverse heat transfer techniques to account for inherent unsteadiness in these quasi-steady-state measurements. The …

Fast Reversible Phase Change Silicon For Visible Active Photonics, Letian Wang, Matthew Eliceiri, Yang Deng, Yoonsoo Rho, Wan Shou, Heng Pan, Jie Yao, Costas P. Grigoropoulos

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Both amorphous and crystalline silicon are ubiquitous materials for electronics, photonics, and microelectromechanical systems. On-demand control of Si crystallinity is crucial for device manufacturing and to overcome the limitations of current phase-change materials (PCM) in active photonics. Fast reversible phase transformation in silicon, however, has never been accomplished due to the notorious challenge of amorphization. It is demonstrated that nanostructured Si can function as a PCM, since it can be reversibly crystallized and amorphized under nanosecond laser irradiation with different pulse energies. Reflection probing on a single nano disk's phase transformations confirms the distinct mechanisms for crystallization and amorphization. The …

Dynamic And Control Of Air-Bearing Spacecraft Simulator, Jacob Joseph Korczyk

Doctoral Dissertations and Master's Theses

An air bearing is being designed as a spacecraft rotational motion simulator, featuring the Sawyer Robot and its control box. The objective is to maneuver the robot as desired, performing operations specific to on-orbit servicing operations while maintaining stability of the system. Before the control can be designed, the dynamics of the platform and the robot must be modeled. The dynamics of the robot can be derived utilizing a Newton-Euler recursive approach. By beginning with a simple pendulum, then adding links (degrees of freedom) to more closely resemble the Sawyer arm, the equations of motion for the robot can be …

Cfd Simulations Of A Propeller-Wing Interaction, Asim Oktay Akdeniz

Mechanical & Aerospace Engineering Theses & Dissertations

In this study, 3-D turbulent flows around a propeller driven aircraft model placed in a subsonic wind tunnel were computationally simulated for qualitative investigation of near field wakes. The geometry of the model was created using commercial mesh generation software, GRIDGEN, and then simulations were performed using a commercial finite volume Reynolds-Averaged Navier-Stokes (RANS) solver FLUENT.

Initial runs were performed to validate the boundary conditions and setup of the problem where a hybrid mesh consisting of multi-blocks was in use. Sliding mesh concept used in the computations. Laminar flow simulation have been utilized and tested besides Spalart-Allmaras and k-ω SST …

Trajectory Simulation With Battery Modeling For Electric Powered Unmanned Aerial Vehicles, Ege Konuk

Mechanical & Aerospace Engineering Theses & Dissertations

Fixed wing electric powered unmanned aerial vehicles (UAVs) has been widely adopted for the last decade in a great number of applications. One of the primary advantages to fixed wing versus multi-rotor designs is the efficiency in forward flight with best possible range and endurance capabilities. In electrically powered air vehicles range and endurance are monitored by the State-of-Charge (SOC) of the battery. To understand the capabilities of the battery, discharge experiments can be conducted in lab environments; however, sometimes the results are difficult to integrate in flight simulations.

In this thesis, a trajectory simulation is developed that can estimate …

Design And Control Of An Arrayed Infrared (Mat-Ir) Heater For Accurate Heating Control During Automated Fiber Placement, Benjamin L. C. Greenberg

Theses and Dissertations

Automated Fiber Placement (AFP) is the primary method for manufacturing of large and complex primary composite structures in the aerospace industry. Predominantly, AFP use infrared heaters to ensure appropriate tackiness between the different composite layers. The task of accurately detecting and obtaining a set uniform temperature, across the nip point/line, has proven to be difficult. Traditional AFP heat processes are mostly open-loop controlled, which can lead to issues with ensuring accurate and uniform heat distributions. The latter need to be obtained to allow for proper material consolidation to occur. Uneven heating could cause degradation at the center or at the …

7-Dof Robotic Arm Xy-Plane Translational Stability, Christopher Dean Alkire

Doctoral Dissertations and Master's Theses

Robotic arms are traditionally mounted to rigid structures as they perform tasks. As a result, the arm’s movement would not affect the position of its mount and its operational space that it is performing a task within would remain constant. If a robotic arm were to function in orbit, the motion of the arm would cause it to rotate and translate about its center of mass, which changes as the joints of the arm rotate.

The purpose of this thesis is to focus on the two-dimensional translational effects of an arm operating on a simulated zero-friction surface and provide a …

Constrained Motion Analysis And Control Of Spacecraft Asteroid Hovering With Formulation Extension In Geometric Mechanics Framework, Wesley Thomas Stackhouse

Doctoral Dissertations and Master's Theses

This thesis studies the constrained motion for a spacecraft hovering over an asteroid, where the Udwadia-Kalaba (UK) formulation is applied for nominal control, and an adaptive controller is developed to account for unknowns in the dynamics. Then, the formulation is extended in the geometric mechanics framework to account for rigid body spacecraft asteroid hovering. Constraints are developed and applied for fully constrained and under-constrained asteroid hovering. The fully constrained solutions provided by the UK fundamental equation are compared to an optimal linear quadratic regulator. An adaptive controller is designed using the UK fundamental equation as a basis in the form …

Interaction Of High Aspect-Ratio Micro-Pillars With Wall Turbulence, Pratik Suhas Deshpande

Doctoral Dissertations and Master's Theses

An experimental study of the interaction between hairy structures modeled as high-aspect ratio micro-pillars (HAMuP) and wall turbulence is presented. Micro-pillars are elastic, hair-like microstructures which have been inspired by naturally occurring examples like lateral line sensors in fish and air flow sensors in bats. The objective of this thesis was two fold: to develop a manufacturing process for consistent production of HAMuP arrays, and to conduct a study focusing on the interaction of HAMuP arrays with wall turbulence. Hotwire anemometry measurements were carried out in two different experimental facilities at three different streamwise locations to describe the interaction between …

A Post-Impact Behavior Of Platelet-Based Composites Produced By Compression Molding, Christopher Eugene Ervin Volle

Mechanical & Aerospace Engineering Theses & Dissertations

Prepreg-based Platelet Molded Compounds (PPMCs) are quickly becoming a widely used method for creating structural components in the aerospace and automotive industries. The discontinuous nature of the platelets used allow good formability of both complex and basic structural components; from seats on commercial airplanes to outer panels of vehicles.

This thesis will look at an important research question of these composites: how PPMCs behave under dynamic loading, e.g. impact and post-impact behavior. Impact is analyzed using recorded force and velocity data to find the absorbed energy. Digital image correlation is used with compression after impact testing to study the propagation …

A Study Of The Aeroacoustics Of Swept Propellers For Small Unmanned Aerial Vehicles, Arthur David Wiedemann

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years, small unmanned aerial vehicles (UAVs) have increased in availability and use in both public and commercial sectors. This increased use of small UAVs or “drones” has the unfortunate consequence of introducing excessive noise into communities where they operate. Implementation of noise reduction methods is necessary if we wish to see expanded use of drones in public areas. With electric propulsion, the primary source of noise is the rotor/propeller used in contemporary multi-rotor configurations. In this thesis, the aerodynamics and acoustic behavior of various swept propellers is examined with computational and experimental methods.

A family of propeller geometries …

Mission Architecture Analysis: Exploring Long-Period Comets From Multiple Staging Orbits, Gabriel Prescinotti Vivan

Masters Theses

Objects that have retained pieces of information about the early Solar System are key to our understanding of its formation and evolutionary history. However, the high delta-V required to reach these objects, such as long-period comets or interstellar objects, makes designing an intercept mission at the time of detection impractical. In this thesis, multiple heliocentric staging orbits are explored to serve as departure positions for future missions, prior to objects’ detections. By utilizing more than one staging orbit concurrently, the set of objects that are reachable is expanded, therefore increasing mission feasibility. Delta-V maps are generated and superimposed; two-impulse burn …

An Argument Against Satellite Resiliency: Simplicity In The Face Of Modern Satellite Design, Dax Linville, Robert A. Bettinger

Faculty Publications

The US Air Force and the wider US government rely heavily on space-based capabilities in various orbital regimes to project national security and sovereignty. However, these capabilities are enabled by the design, launch, and operation of satellites produced with a design methodology that favors large, monolithic, and technologically exquisite space systems. Despite the ability for these satellites to provide enduring and resilient capabilities, they suffer from a woefully long acquisition process that debilitates any prospect of rapid satellite reconstitution in the event of a space war.

Hybrid Non-Destructive Assessment For Flow Induced Vibration Piping Systems Using Coupled Fluid-Structure Interaction, Keen Kuan Kong

Student Works (2020-2029)

Pipelines and piping systems are of great importance in many industries such as water supply, petroleum and petrochemicals and nuclear power generation. They provide transport for high-velocity pressurized fluids operating under time-varying conditions. They are required to operate non-stop for a schedule of 24 hours a day, 7 days a week. Piping vibration failures have been one of the major causes of downtime, fires and explosions in industrial plant over the past 30 years. Failure of piping systems can have disastrous effects, leading to injuries and fatalities as well as to substantial cost to industry and the environment. Flow-induced vibration …

Automation Of Process Planning For Automated Fiber Placement, Joshua A. Halbritter

Theses and Dissertations

Process planning represents an essential stage of the Automated Fiber Placement (AFP) workflow. It develops useful and efficient machine processes based upon the working material, composite design, and manufacturing resources. The current state of process planning requires a high degree of interaction from the process planner and could greatly benefit from increased automation. Therefore, a list of key steps and functions are created to identify the more difficult and time-consuming phases of process planning. Additionally, a set of metrics must exist by which to evaluate the effectiveness of the manufactured laminate from the machine code created during the Process Planning …

Analysis Of Training Programs For The Training Of Air Traffic Controllers For Determining The Field Of Digitization, Sabohat Shukurova, Z.Z. Shamsiev, A. Sterenharz

Technical science and innovation

The article emphasizes the high demands that are put forward to the professional knowledge and skills of air traffic controllers. Attention is drawn to ICAO's civil aviation training policy, which supports the human resource development strategies developed by Member States and the aviation community and provides access to a sufficient number of qualified and competent professionals. Based on this, the feasibility of research and improvement of the educational process of training air traffic controllers is substantiated. As a research method, the collection, processing and analysis of statistical data is used. As the subject of the study, educational programs for the …

Launch Vehicle Design For The Far-Mars Competition, Matthew Boban, Bryce Smoldon, Jonathan Noble, Stefan Johnson, Maxwell Kauker, Nicholas Wright, Andrew Lucka

Discovery Day - Prescott

Zenith Propulsion is constructing a launch vehicle, named Altair, to compete in a competition hosted by the Friends of Amateur Rocketry (FAR) and the Mars Society. The objective for Zenith Propulsion is to design, build and launch Altair to a qualifying altitude of 30,000 feet in the FAR-Mars competition. Altair will utilize a rocket engine that has been in development at Embry-Riddle Aeronautical University’s Prescott campus since late 2018. This engine, named Janus, uses liquid oxygen and Jet-A and is designed to deliver 1000 lbf of thrust. Altair will be launched from the FAR launch site, in Mojave, CA, on …

Space And Defense – Volume Eleven – Number One – Spring 2019, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Nine – Number One – Spring 2016, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Eight – Number One – Spring 2015, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Seven – Number One – Winter 2014, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Six – Number One – Fall 2012, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Five – Number One – Summer 2011, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Four – Number Two – Summer 2010, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Four – Number One – Winter 2010, Space And Defense Journal

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Space And Defense – Volume Three – Number Two – Fall 2009, Space And Defense Journal

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Space And Defense – Volume Three – Number One – Summer 2009, Space And Defense Journal

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Space And Defense – Volume Two – Number Three – Winter 2009, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Two – Number Two – Winter 2008, Space And Defense Journal

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Space And Defense – Volume Two – Number One – Winter 2008, Space And Defense Journal

Space and Defense

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