Aerospace Engineering Commons^™

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 …

The Three-Dimensional Turbulent Boundary Layer On A Rotating Disk, Daniel Digre

Doctoral Dissertations and Master's Theses

Three-dimensional turbulent boundary layers (3DTBL) are seen quite commonly in nature as well as in the engineering applications. Despite this, very few high Reynolds number studies have been carried out on these boundary layers, particularly focusing on eddy structure, eddy scales and their interactions. The current study focused on developing, characterizing and evaluating an experimental framework to study high Reynolds number #3DTBL on a rotating disk with the long-term goal of carrying out high-fidelity measurements. The rotating disk flow is characterized by weak centrifugal pumping which sets up the cross flow that leads to turbulence. The tangential and radial velocities …

Computation Of Hypersonic Flows With Lateral Jets Using K-Ω Turbulence Model, Spatika Dasharati Iyengar

Doctoral Dissertations and Master's Theses

Thermal Protection systems (TPS) are used as shields in space vehicles which encounter high heat and temperatures at the reentry altitudes. Among them, the cooling techniques and the ablative coatings are most popular. However, they have their own weight limitations. In the recent decade, another classification of TPS called the Non-Ablative Thermal Protection systems (NaTPS) have gained significance. The spike-lateral jet method is an NaTPS concept proposed for drag and heat flux reduction in hypersonic nose cones. Numerical simulations are conducted to analyze the effectiveness of spike-lateral jet concept at re-entry altitudes. The spike attached to the hemispherical nose has …

Sub-Orbital Spaceflight – An Addition To Our Multi-Modal Transportation System, Scott Haeffelin

Space Traffic Management Conference

The number of commercial spaceflights will be increasing by orders of magnitude over the next several decades. The current volume of space traffic can be managed on a case-by-case basis and there is little impact to the National Airspace System (NAS). This will change as more spaceports become operational, commercial sub-orbital flight companies begin serving their customers and as the cost of these flights begin to decrease. Current regulatory paths seek to allow the flexibility in the regulations for this industry to flourish while also maintaining a high standard of safety. There are, however, many nearsighted and old fashioned assumptions …

Space Data Integrator (Sdi) And Space Program Integrated Data And Estimated Risk (Spider): Proof-Of-Concept Software Solution For Integrating Launch And Reentry Vehicles Into The National Airspace System (Nas), Devin D. Dickens

Space Traffic Management Conference

The Space Data Integrator (SDI) Project is the initial step to satisfy the Federal Aviation Administration (FAA) strategic initiative to integrate commercial space launch and reentry vehicles into the National Airspace System. The project addresses the needs for greater situational awareness and monitoring, and increased response capability during non-nominal and catastrophic incidents during space operations.

The initial phase of this project leverages current FAA systems, and provide an initial demonstration of capability that will provide for state data from a commercial reentry vehicle to be ingested into a the FAA Traffic Flow Management System, and displayed on Traffic Situation Displays. …

Enhancing Quality Assurance Using Virtual Design Engineering: Case Study Of Space Shuttle Challenger, Kouroush Jenab, Scot Paterson

International Journal of Aviation, Aeronautics, and Aerospace

Virtual Design Engineering is an emerging method of increasing quality of systems. Including Virtual Design as a part of the traditional established Failure Mode, Effects, and Criticality Analysis process greatly enhances hazard and risk analysis while reducing overall costs. In this study these enhancements are explored and expanded upon to discover how overall system quality could be increased and all stakeholders could more accurately understand the hazards involved. Stakeholder misunderstanding or misapplication of hazards is of great importance to complex systems. An illustrative example of how these factors could have changed the outcome of a real-world engineering failure is provided.

Examining Unmanned Aerial System Threats & Defenses: A Conceptual Analysis, Ryan J. Wallace, Jon M. Loffi

International Journal of Aviation, Aeronautics, and Aerospace

The integration of unmanned aerial systems (UAS) into the already complex global aviation system presents new and unique hazards. While many studies have addressed the potential safety concerns of UAS integration, little research has been dedicated to the potential security implications. This study sought to identify potential uses and adaptations of civil UAS systems as weapons of terrorism or crime and potential UAS defenses. Researchers examined 68 academic studies, unclassified government reports, and news articles using Conceptual Analysis to systematically capture and categorize various threats. Using the collected data, researchers developed a UAS threat model for categorically evaluating potential threats. …

A Sliding Mode Lco Regulation Strategy For Dual-Parallel Underactuated Uav Systems Using Synthetic Jet Actuators, N. Ramos-Pedroza, W. Mackunis, M. Reyhanoglu

Publications

"A sliding mode control- (SMC-) based limit cycle oscillation (LCO) regulation method is presented, which achieves asymptotic LCO suppression for UAVs using synthetic jet actuators (SJAs). With a focus on applications involving small UAVs with limited onboard computational resources, the controller is designed with a simplistic structure, requiring no adaptive laws, function approximators, or complex calculations in the control loop. The control law is rigorously proven to achieve asymptotic regulation of both pitching and plunging displacements for a class of systems in a dual-parallel underactuated form, where a single scalar control signal simultaneously affects two states. Since dual-parallel underactuated systems …

Book Review: High G Flight - Physiological Effects And Countermeasures, Stefan Kleinke

International Journal of Aviation, Aeronautics, and Aerospace

This review provides insight on the content and a review of the quality of the recent release of High G Flight - Physiological Effects and Countermeasures from Ashgate Publications.

This review does not reflect the views of IJAAA or ERAU. This work was not peer reviewed.

High G Flight - Physiological Effects and Countermeasures

Global Optimized Isothermal And Nonlinear Models Of Earth’S Standard Atmosphere, Nihad E. Daidzic, Ph.D.,

International Journal of Aviation, Aeronautics, and Aerospace

Both, a global isothermal temperature model and a nonlinear quadratic temperature model of the ISA was developed and presented here. Constrained optimization techniques in conjunction with the least-square-root approximations were used to design best-fit isothermal models for ISA pressure and density changes up to 47 geopotential km for NLPAM, and 86 orthometric km for ISOAM respectively. The mass of the dry atmosphere and the relevant fractional-mass scale heights have been computed utilizing the very accurate eight-point Gauss-Legendre numerical quadrature for both ISOAM and NLPAM. Both, the ISOAM and the NLPAM represent viable alternatives to ISA in many practical applications and …

Examining How Breakdowns In Pilot Monitoring Of The Aircraft Flight Path, Robert Sumwalt, David Cross, Dennis Lessard

International Journal of Aviation, Aeronautics, and Aerospace

Aircraft accident and incident data reveal that serious safety consequences can arise when flight crewmembers fail to properly monitor the aircraft flight path. This research study reviewed human factors literature to better understand why pilots fail to properly monitor, and analyzed accident and incident data. Recommendations for improving monitoring performance were formulated, which may be useful to air carriers in implementing a new Federal Aviation Administration requirement that calls for specific training in monitoring.

Similarity Analysis Of A Swirling Counter-Flow, Jitesh Rane

Doctoral Dissertations and Master's Theses

Swirling counter-flows are used in numerous engineering applications, like combustion, heat exchangers, cyclonic separation and mixing, etc. These swirling counter-flows produce complex flow fields. It is important to study these types of flows in order to use them properly in many applications.

The present work provides insight into the flowfield inside a swirling counter-flow when the fluid is injected tangentially in a cylindrical container. A semi-analytical solution is developed by starting with the full Navier-Stokes equation and using a similarity analysis. A decaying swirl along the axis of the cylinder is assumed, which reduces the Navier-Stokes equations to first order …

Exploring New Lagrangian Cyclers To Enhance Science: Communications With Cubesat Technology, Pedro P. Llanos, Abdiel Santos Galindo, John Ford

Publications

This paper discusses the opportunities that abound by using the CubeSat technology to travel to and communicate with the International Space Station, explore space, monitor space weather, monitor space debris and perhaps travel to Mars.

Bio-Fuel Alternatives In South African Airways (Saa) Operations - Is It An Effective Response To Vulnerability Over Carbon Taxes And Penalty?, Daniel Kwasi Adjekum

International Journal of Aviation, Aeronautics, and Aerospace

The paper did a comparative analysis of the carbon emission and European Union Emission Trading Surcharges (EU ETS) of South African Airways (SAA) current fleet that used aviation jet A1 fuel and the same fleet if it had used a 25% bio-fuel ‘drop in’ for the European routes within the first quarter of the 2014 flying year (FY 14). Operational data in terms of the flight scheduled, aircraft type, total time enroute, route stage length, passenger estimates were obtained through SAA’s flight operations website. An independent t–test was conducted to compare means of the emissions. The mean carbon dioxide …

Slipstream Measurements Of Small-Scale Propellers At Low Reynolds Numbers, Robert W. Deters, Gavin K. Ananda, Michael S. Selig

Publications

The continuing growth in the use of small UAVs has required the need to more fully understand the propellers that power them. Part of this understanding is the behavior of the propeller slipstream. Using a 7-hole probe, the slipstreams of several small-scale propellers (diameters of 4.2, 5, and 9 in) were measured in both static (V∞ = 0) and advancing-flow (V∞ > 0) conditions at several locations downstream. For static conditions, as the slipstream expanded downstream, the maximum values of the axial and swirl velocities decreased. The general shape of the static slipstream was also found to be nearly the same …

Design Of Synthetic Jet Actuator For Flight Control Of Small Uav, Priyanka Pagadala

Doctoral Dissertations and Master's Theses

The main idea of this project is to develop a prototype SJA - Synthetic Jet Actuator to embed into a small UAV with modified Glauert wing cross-section for Active Flow Control. Apart from lift enhancement, drag reduction, or separation control, etc; LCO suppression might be possible by modifying the boundary layer through the use of these actuators. For initial investigation, a wing section with span of 12.4 cm and chord of 14 cm was fabricated and tests were conducted in the subsonic wind tunnel at the free stream velocities of 5 and 10 m / s. From these experiments, lift …

Sensor Fusion And Obstacle Avoidance For An Unmanned Ground Vehicle, Gurasis Singh

Doctoral Dissertations and Master's Theses

In recent years, the capabilities and potential value of unmanned autonomous systems (UAS) to perform an extensive variety of missions have significantly increased. It is well comprehended that there are various challenges associated with the realization of autonomous operations in complex urban environments. These difficulties include the requirement for precision guidance and control in conceivably GPS-denied conditions as well as the need to sense and avoid stationary and moving obstructions within the scene. The small size of some of these vehicles restricts the size, weight and power consumption of the sensor payload and onboard computational processing that can accommodated by …

Uas Capabilities And Performance Modeling For Application Analysis, Brent Terwilliger, Dennis Vincenzi, David Ison, Rene Herron, Todd Smith

Publications

Our team of researchers from Embry-Riddle Aeronautical University-Worldwide has been actively compiling published performance data associated with commercially-off-the-shelf (COTS) group 1 to 3 fixed-wing and vertical takeoff and landing (VTOL) unmanned aircraft systems (UAS) in an effort to develop statistical models of each category. The captured data, which includes maximum speed, cruise speed, endurance, weights, wind limitations, and costs, is used to calculate capabilities including range (one-way and return), time to objective, station keeping duration, maneuver requirements, and derive limited missing information (e.g., component speeds and weights). The benefit from assembling such a unified collection of information and the calculation …

Supersonic Retro-Propulsion Computational Fluid Dynamics Analysis Applied To Future Mars Mission, Margarita Nataly Brandt

Doctoral Dissertations and Master's Theses

Supersonic Retro-Propulsion is one of the most promising emerging technologies being considered by NASA for use in future Mars missions. This new form of Entry Descent Landing has the potential to help increase the allowable payload mass currently constraining many science instruments and operations. Computational Fluid Dynamics was used to show the feasibility of supersonic retro - propulsion in Mars atmospheric conditions. The results presented show the SRP will be able to perform satisfactory using the same conditions that the Curiosity Rover was exposed to during its landing sequence. The plume expansion was analyzed for various cases, moving from free …

Aerodynamic And Structural Design Of A Winglet For Enhanced Performance Of A Business Jet, Nicolas El Haddad

Doctoral Dissertations and Master's Theses

The preliminary design of a winglet to improve the range and fuel burn of the Falcon 10 business jet is presented. Twelve candidate geometries were studied varying the cant angle and the span. The configuration offering the best compromise between induced drag reduction, profile drag increase and weight increase due to the winglet structure and necessary wing structural reinforcement was selected. More refined analysis was performed for that winglet with Reynolds averaged Navier-Stokes computational fluid dynamics and finite element analysis. Range and fuel burn were finally calculated for a typical mission using these refined results. The selected winglet, with a …

Modeling And Simulation Of Radiation From Electronic Transitions In Hypersonic Atmospheric Reentry Flow, Curtis Scholz

Doctoral Dissertations and Master's Theses

A capability for higher accuracy heat transfer modeling in CFD for hypersonic re-entry flows, via inclusion of thermal radiation, is sought. With temperatures reaching tens of thousands of degrees, radiation is known to be significant to chemical reaction rates and thermal boundary layer development, hence surface heat transfer and thermal ablation both to the heat shield and the backshell region of re-entry vehicles. Two current NASA solicitations seek such an improved capability relative to the Mars and Earth entry problems, as uncertainty typically leads to overdesign and excess weight. The present research develops a first physics-based “building block,” which computes …

Attitude Determination & Control System Design And Implementation For A 6u Cubesat Proximity Operations Mission, Francisco J. Franquiz

Doctoral Dissertations and Master's Theses

The purpose of this work is to discuss the attitude determination and control system (ADCS) design process and implementation for a 12 kg, 6U (36.6 cm x 23.9 cm x 27.97 cm) CubeSat class nano-satellite. The design is based on the requirements and capabilities of the Application for Resident Space Object Proximity Analysis and IMAging (ARAPAIMA) proximity operations mission. The satellite is equipped with a cold gas propulsion system capable of exerting 2.5 mN m torques in both directions about each body axis. The attitude sensors include an angular rate gyro and star tracker (STR), supplemented by the payload optical …

Surface Structure And Its Effect On Reducing Drag, Ragini Ramachandran

Doctoral Dissertations and Master's Theses

A miniature subsonic open return wind tunnel was designed and fabricated to measure drag on small test models at low Reynolds numbers. The wind tunnel featured a sensitive strain gauge type load cell. The average drag coefficient of sphere and cube test models were used to validate the miniature wind tunnel, and the values obtained were consistent with published results over the range of Reynolds numbers tested. These initial results gave confidence that the tunnel could be used to study the effects of surface finish on the drag of various models. Several fabrics with differing ribbed surface structures, including a …

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 …

Flying The X-15 And Space Shuttle, Joe H. Engle

ERAU Prescott Aviation History Program

Hear what it was like for Joe H. Engle, USAF/ANG, Ret. to fly both the X-15 and the Space Shuttle. In 1965 Capt. Engle flew the X-15 to 280,600 feet, to become the youngest pilot to qualify as an astronaut and would go on to fly it 15 more times. Selected for NASA space missions, he flew the Space Shuttle “Enterprise” off the top of a modified 747 on glide flight tests. He commanded the orbital test flight of “Columbia” and became the first and only pilot to manually fly an aerospace vehicle from Mach 25 to landing. A remarkable …

The Panther: 2015 Aiaa Design Build Fly, Bryce Milnes, Chris Crawford

Publications

The ERAU Prescott chapter of AIAA participated in the 2015 AIAA Design Build Fly competition at Raytheon Missile Systems in Tucson from April 10-12. A remote controlled aircraft meeting and exceeding all competition performance requirements was designed and fabricated by the 30+ students of the team. Additionally, a 60 page report was submitted detailing the project starting from initial considerations and advancing through flight test verification of aircraft capabilities. The success of this project was enabled by the E-Prize and SGA funding received to support our efforts throughout the year. The lessons learned regarding management and planning, engineering design approaches, …

Unmanned Aerial Vehicle (Uav) Propulsion Research: Conceptual Studies Of “Ultra-Compact Shaft-Less Jet Engines” For Next Generation Uavs, Tyler Eiguren, Trevor Douglas, Tre Buchanan

Publications

Unmanned Aerial Vehicles are becoming more commonly used in today’s society, ranging anywhere from military applications to entertainment for enthusiasts and hobbyists. The complexity of current generation UAV’s propulsive devices, based upon a scaled turbine engine and separate gas & electrically powered rotating fan blades, require regular maintenance for every 24 hours of flight. This added cost coupled with necessary intricate machinery deters UAV designers from such engines, leaving a void in current production. Our research team believes that by combining a simplified alternative compression & combustion process with an electrically driven fan, we can develop an energy efficient, reliable, …

The Design For Manufacturing And Assembly Analysis And Redesign Of An Aircraft Refueling Door Hinge Utilizing Additive Manufacturing, Kurt A. Schwarz

Doctoral Dissertations and Master's Theses

In this thesis, an aircraft door hinge assembly provided by Gulfstream Aerospace was analyzed following an established process called DFMA. The hinge was then redesigned to be additively manufactured, which is uncommon currently in industry for load bearing components. It was shown that the Design for Manufacturing (DFM) guidelines were inadequate when applied to the new technology of additive manufacturing (AM). This was primarily due to AM's unique and unprecedented manufacturing capabilities.

A conservative redesign approach was followed due to a limitation in current AM material properties and time available for analysis. Despite this, a significant improvement in weight reduction …

Numerical Investigation Of Tonal Noise On A Transitional Airfoil Under Varying Conditions, Warren W. Hiner

Doctoral Dissertations and Master's Theses

The generation of discrete acoustic tones is a problem of interest in transitional airfoils. Such tones exist for moderate Re below 2,000,000 and for low to moderate angles of attack. The purpose of this study is to use linear stability theory to study the growth of instabilities on the pressure and suction surfaces of airfoils for varying Re between 144,000 and 468,000 and angles of attack between 0˚ and 12˚. High accuracy 2D simulations based on an Implicit Large Eddy Simulation (ILES) code are conducted for a NACA0012 airfoil for varied conditions, and linear stability analysis is performed to predict …

Determination Of A Simplified High-Order Vortex Equation For Radial Equilibrium With Cfd Verification, Travis K. Matsumoto

Doctoral Dissertations and Master's Theses

The goal of this thesis is to determine a flow model that provides a better blade design over current design techniques utilizing a hybrid vortex model. This hybrid vortex model combines the well-established simple radial equilibrium vortex models into a higher order equation that will establish the basis for a more flow-accurate model. In this paper, we will discuss the basis and derivation of these vortex models, the shortcomings of current techniques, and verification of the new vortex model with empirical data via Computational Fluid Dynamic (CFD). The simple radial equilibrium equation set has been known to the scientific community …