Aerospace Engineering Commons^™

Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks

Theses and Dissertations

Experimental research was conducted on the effects of surface roughness on ultrasonic non-destructive testing of Electron Beam Melted (EBM) additively manufactured Ti-6Al-4V. Additive Manufacturing (AM) is a developing technology with many potential benefits, but certain challenges posed by its use require further research before AM parts are viable for widespread use in the aviation industry. Possible applications of this new technology include, Aircraft Battle Damage Repair (ABDR), small batch manufacturing to fill supply gaps, and replacement for obsolete parts. The research presented here assesses the effectiveness of ultrasonic inspection in detecting manufactured flaws in EBM manufactured Ti-6Al-4V. EBM products are …

Evaluation Of Unmanned Aircraft Flying Qualities Using Jsbsim, Joshua P. Kim

Theses and Dissertations

Flying qualities data can be used to predict the future performance of aircraft; however, no flying qualities requirements exist for Unmanned Aerial Vehicles (UAVs). The intent of flying qualities requirements is to guarantee the safety and operational effectiveness of the aircraft. Flying qualities requirements have been extensively researched and specified for fixed-wing and rotary-wing manned aircraft based on a substantial database of assessments. The critical issue today in flying qualities is how to extend them to pilotless aircraft. A simulation study using an open-source flight dynamics model (JSBSim) was conducted to perform various performance maneuvers and evaluate how well the …

Geolocation Of Rf Emitters Using A Low-Cost Uav-Based Approach, Michael A. Magers

Theses and Dissertations

The proliferation of unmanned aerial vehicles (UAVs) in both military and civilian settings has prompted great interest in finding new and innovative ways to utilize these tools. One such application is to locate ground-based radio emitters from a UAV platform. The goal of this research is to study the feasibility of a low-cost (on the order of $1000) UAV geolocation platform. To accomplish this goal, a series of both real-world flight testing and computer simulated scenarios were conducted. Simulations for different sensor uncertainties and approach path scenarios such as loiter and button hook patterns were investigated. Results showed that a …

Real-Time Implementation Of Vision-Aided Monocular Navigation For Small Fixed-Wing Unmanned Aerial Systems, Timothy I. Machin

Theses and Dissertations

The goal of this project was to develop and implement algorithms to demonstrate real-time positioning of a UAV using a monocular camera combined with previously collected orthorectified imagery. Unlike previous tests, this project did not utilize a full inertial navigation system (INS) for attitude, but instead had to rely on the attitude obtained by inexpensive commercial off-the-shelf (COTS) autopilots. The system consisted of primarily COTS components and open-source software, and was own over Camp Atterbury, IN for a sequence of flight tests in Fall 2015. The system obtained valid solutions over much of the flight path, identifying features in the …

Visual-Ins Using A Human Operator And Converted Measurements, Turner J. Montgomery

Theses and Dissertations

A method human operated INS aiding is explored in which the pilot identifies and tracks a ground feature of unknown position over a short measurement epoch using an E/O sensor. One then refers to Visual-INS. In contrast to current research trends, a human operator is entrusted with visually tracking the ground feature. In addition, a less conventional measurement linearization technique is applied to generate “converted” measurements. A linear regression algorithm is then applied to the converted measurements providing an estimate of the INS horizontal velocity error and accelerometer biases. At the completion of the measurement epoch, the INS is corrected …

Force And Moment Measurements Applicable To A Flexible Weapons System, James B. Sellers

Theses and Dissertations

Continuing the development of the 6-DOF Motion Test Apparatus (MTA) for performing dynamic wind tunnel tests revealed the importance of a capable data acquisition (DAQ) system for collecting and analyzing data. Assembling and testing the DAQ system in conjunction with the MTA, AFIT Low-Speed Wind Tunnel, and a selection of high-performance sensors was the primary focus of this research. Specifically, acquiring time-accurate aerodynamic force and moment measurements on a variety of test models was of high importance. With the established real-time DAQ system hardware, a National Instruments (NI) LabVIEW program was created to acquire data from an ATI Nano25-E force …

Electro-Mechanical Characterization Of Carbon Nanotube Sheets In Simulated Space Environments: The Dawn Of “Carbon Spacecraft”, Jacob W. Singleton

Theses and Dissertations

Carbon nanotube (CNT) materials are exciting candidates for spacecraft by virtue of their unprecedented specific mechanical and electrical properties. Analysis in this thesis identifies 14 types of CNT-sheets with distinct variables, and discovers the mechanisms controlling macroscopic properties. Specimen variables include acid treatment, polymer coatings, production method, and combinations. Mechanical testing includes tensile-tests and investigation with scanning electron microscopy and energy-dispersive x-ray spectroscopy. Physical properties testing include electromagnetic interference (EMI) shielding effectiveness (SE) and electrical conductivity. This research also highlights the resilience of CNT-sheets to atomic oxygen and thermal fatigue qualifying them for performance in space. EP CNT-sheets have decreased …

Analysis Of A Near Real-Time Optimal Attitude Control For Satellite Simulators, Ryan M. Patrick

Theses and Dissertations

Dynamic optimization of spacecraft attitude reorientation maneuvers can result in significant savings in attitude determination and control system size, mass, and power. Optimal control theory is generally applied using an open loop trajectory which is vulnerable to disturbances. A closed loop implementation of optimal control has been difficult to achieve due to the computational requirements needed to quickly compute solutions to the optimal control problem. This research focuses on evaluating a near real-time optimal control (RTOC) system for large angle slew maneuvers on the Air Force Institute of Technology's spacecraft simulator called SimSat. A near RTOC algorithm computes optimal control …

Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 700°C In Air And In Silicic Acid-Saturated Steam, Matthew W. Piper

Theses and Dissertations

Aircraft structural and engine components are subjected to elevated temperature and steam environments during operation. Turbine blades experience particularly harsh conditions that are approaching the operating temperature limits of current Nickel-based superalloys even with active cooling. Ceramic matrix composites (CMCs), which demonstrate high specific strength and specific stiffness and maintain these properties at elevated temperatures such that active cooling is not required, are prime candidates to replace superalloys as the materials for turbine blades. Ceramic matrix composites are composite materials that consist of a ceramic matrix with fiber reinforcement. This research investigated a silicon carbide (SiC) fiber, Hi-Nicalon™ S, which …

Military Applications Of High-Altitude Satellite Orbits In A Multi-Body Dynamical Environment Using Numerical Methods And Dynamical Systems Theory, Meredith M. Wilmer

Theses and Dissertations

The circular restricted three-body problem (CR3BP) is a simplified dynamical model for a satellite under the gravitational influence of both the Earth and the Moon, maintaining closer fidelity to the gravitational environment experienced by a high-altitude Earth-orbiting spacecraft than modeling in the Earth-satellite two-body problem. Resonant orbit arcs are used to determine an initial guess to input into an algorithm that computes a trajectory solution with specific design requirements and constraints. A test case uses this method to compute a lunar fly-by transfer solution requiring less than two-body transfer methods and offers an unusual pathway that adds an unpredictability element …

Investigation Into Active Spanwise Camber Deformation On The Lateral Stability And Roll Control Of The X-56a Compared To Conventional Ailerons, Eric T. Yerly

Theses and Dissertations

"This research compares the stability and roll characteristics of an X-56A using AFRL’s Variable Camber Complaint wing technology to actively change wing camber compared to conventional ailerons deflected at set angles. An analysis of the stability and roll characteristics was modeled using a 3-D vortex lattice theory simulation, and that data was compared to wind tunnel testing to verify and validate the model results. Wind tunnel data was collected using 19 inch 3-D printed scale models with wings fabricated with a pre-determined percentage of camber deformation, as well as models with fixed aileron deflections. The full span model changed camber …

Development Of Design A Drop-In Hydrogen Fueling Station To Support The Early Market Buildout Of Hydrogen Infrastructure, Abdulhakim Amer A. Agll, Tarek A. Hamad, Yousif M. Hamad, Sushrut G. Bapat, John W. Sheffield

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper provides a design of a drop-in hydrogen fueling station. Drop-in stations are expected to be an important factor in the introduction of hydrogen fueling infrastructure. The stations not only allow a streamlined introduction of hydrogen in the vehicle fueling infrastructure, but also, acts as mini pilot plants that can allow for detailed control studies. The effect of the location and availability of utilities, the closeness to residential area, unintended safety concerns, people outlook towards hydrogen, etc. are some of the factors that can be readily studied with such drop-in stations. The proposed design of a drop-in station mainly …

Session B-4: Stem Integration: Statistics Is The Connection, Karen Togliatti, Lindsey Herlehy

Professional Learning Day

In this activity, participants will complete a STEM-integrated lesson incorporating problems in aerodynamics. Using the mathematical, science and engineering practice standards, they will design and model parachutes to determine a life-size chute to support their body weight. Participants will also consider design criteria for rate of descent, and graphically represent data and mathematical information as a scatter plot.

A Study On Flow Development In An Apu-Style Inlet And Its Effect On Centrifugal Compressor Performance, Fangyuan Lou

Open Access Dissertations

The objectives of this research were to investigate the flow development inside an APU-style inlet and its effect on centrifugal compressor performance. The motivation arises from the increased applications of gas turbine engines installed with APU-style inlets such as unmanned aerial vehicles, auxiliary power units, and helicopters. The inlet swirl distortion created from these complicated inlet systems has become a major performance and operability concern. To improve the integration between the APU-style inlet and gas turbine engines, better understanding of the flow field in the APU-style inlet and its effect on gas turbine is necessary.

A research facility for the …

Effect Of Low Velocity Impact On The Vibrational Behavior Of A Composite Wing, Richard M. De Luna

Master's Theses

Impact strength is one of the most important structural properties for a designer to consider, but it is often the most difficult to quantify or measure. A major concern for composite structures in the field is the effect of foreign objects striking composites because the damage is often undetectable by visual inspection. The objective for this study was to determine the effectiveness of using dynamic testing to identify the existence of damage in a small scale composite wing design. Four different impact locations were tested with three specimens per location for a total of 12 wings manufactured. The different impact …

Lunar Icecube Space Mission, Robert J. Twiggs, Eric Jerde

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professors Bob Twiggs and Eric Jerde titled "Lunar IceCube Space Mission" from March 1, 2016.

Cognitive Loading, Affect Regulation And Aerodynamic Considerations In Uninhabited Aerial Vehicle Systems Refueling Operations, Sam Holley, Ian R. Mcandrew

Publications

Factors influencing aerodynamics involved in aerial refueling illustrate the potential for specialist operators to manage these operations for remotely piloted vehicles. The authors review aerodynamic characteristics of uninhabited aerial systems during refueling, drogue and boom design and associated flight dynamics, cognitive factors associated with control transfer and refueling, and affective components and their influence on decision making and operator performance. Attention is directed to cognitive loading and encoding challenges, with considerations for hippocampal mapping and hemispheric asymmetry. Implications for system state awareness are examined. Advantages for specially trained refueling pilot operators are discussed and recommendations given for areas of concentration.

Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall

Faculty Publications

The thermal properties of carbon nanotube- (CNT-) sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an …

Overview Of Eps-1 For Spacecraft, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on an "Overview of EPS-1 for Spacecraft" from Febuary 15, 2016.

Overview Of Eps-2 For Spacecraft, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on an "Overview of EPS-2 for Spacecraft" from February 15, 2016.