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The Development Of A Phase Locked Wind Turbine Blade Finite Element Model To Predict Loads And Deflections During Fatigue Testing, Kyle Freeman

Master's Theses - Daytona Beach

Full scale blade testing provides blade manufacturers with quantitative data in order to assess blade design, manufacturing and durability. Structural testing is a requirement in order to design reliable blades, and to develop a further understanding of the dynamics involved in a modern turbine blade. Blade tests can be conducted in either a single axis or dual axis configurations. Historically, fatigue testing has been performed by utilizing forced displacement systems. These systems do not allow for the load phase angle to be controlled, and the maximum load application in the edge and flap directions are allowed to vary. The PhLEX …

The Development Of An Adaptive Control System For A Phase-Locked Excitation (Phlex) Method For Advanced Wind Turbine Blade Fatigue Testing, William Michael Haupfear

Master's Theses - Daytona Beach

The National Renewable Energy Laboratory's (NREL) National Wind Technology Center (NWTC) provides the means necessary for advanced wind turbine blade testing. To improve on the current testing methods, a new testing method is being developed using the existing dual-axis fatigue testing capabilities in conjunction with another actuator to provide a phase-locked excitation method with adaptive algorithms and advanced control system strategies. This testing method will provide a more representative loading of the blade for fatigue testing as compared to loading seen in the field. The control system will integrate the MTS software and controller with a supervisory controller, programmed in …

Investigation Of Scaling Effects For A Synthetic Jet Actuator Using High And Low Fidelity Analyses, Amandine Bourlier

Master's Theses - Daytona Beach

This research presents an investigation on the scaling effects for synthetic jet actuators using Ansys-CFX and a Lumped Element Model (LEM). Synthetic jets or zero net mass-flux devices use a vibrating diaphragm to generate an oscillatory flow through a small orifice. A synthetic jet actuator can be used on MAVs as thrust generator or fixed on an airfoil for flow separation control. A Computational Fluid Dynamics (CFD) model was created, using Ansys-CFX, to be validated against referred publications. The use of mesh adaption is discussed. This baseline model was then used to complete a scaling analysis using a set of …

Neural Network Burst Pressure Prediction In Composite Overwrapped Pressure Vessels Using Mathematically Modeled Acoustic Emission Data, Junya Iizuka

Master's Theses - Daytona Beach

The purpose of this research was to predict burst pressures in composite overwrapped pressure vessels (COPV) using mathematically modeled acoustic emission (AE) data. The AE data were collected during hydrostatic burst (hydroburst) testing often 15-inch (380 mm) diameter COP Vs. The data gathered during these tests were filtered in order to remove long duration hits, multiple hit data, and obvious outliers. Based on the duration, energy, and amplitude of the AE hits, the filtered data were classified into the various failure mechanisms of composites using a MATLAB based self-organizing map (SOM) neural network. Previous research has demonstrated that the parameters …

Estimation Of Air Flow Angles Derived From An Inertial Navigation System, Brett Douglas Mather

Master's Theses - Daytona Beach

The purpose of this study is to explore the use of an Inertial Navigation System as a primary method for measuring aircraft air flow angles in flight testing. The traditional methods used to measure air flow angles consist of sensors external to the aircraft, such as an air data boom or an angle of attack probe. The advantage of using INS to measure air flow angles would be in the simplicity of the instrumentation. All components could be fixed internally, leaving minimal external modifications to the aircraft necessary for instrumentation. This would reduce costs and instrumentation time and enable air …

Pilot Perception Of Light Emitting Diodes Versus Incandescent Elevated Runway Guard Lights, Hilary Stevens

Doctoral Dissertations and Master's Theses

Pilots must understand and be aware of the purpose of each airport sign, light and marking, for there are numerous. The Federal Aviation Administration (FAA) is planning on replacing the current incandescent lighting with far more economical LED airport lighting. In preparation for this change, two experiments were conducted for this thesis. Experiment 1 attempted to determine what pilots know about the meaning of the signs, markings and lights on the taxiways and runways through a questionnaire that was developed with the FAA. Experiment 2 evaluated pilot perception of LED lighting compared to current incandescent elevated runway guard lights.

The …

System Identification And State Estimation For Intake Manifold Charge Flow Temperature Of A Compression Ignition Diesel Engine, Ryle D. Maxson

Master's Theses - Daytona Beach

Intake manifold charge temperature is a factor used in mean value engine models (MVEMs) for the calculation of intake mass air charge and oxygen flow. More stringent emission requirements have led to increased deployment of more advanced engine combustion models onto production engine controllers. Measurement of the temperature via physical thermocouple sensors mounted to the engine intake manifold is both slow, in comparison to the changing conditions of an engine, and undesirable due to the cost and increased complexity of extra sensors. A state estimation model has been evaluated that imitates the function of the intake manifold temperature sensor reading, …

The Taiwan Civil Aviation Safety Reporting (Tacare) System In Aircraft Maintenance: An Evaluation Of The Acceptance Of Voluntary Incident Reporting Programs For Maintenance Personnel In Taiwan, Yi-Fan (Tom) Chen

Master's Theses - Daytona Beach

The purpose of this research was to examine the effectiveness of the Taiwan Civil Aviation safety reporting (TACARE) system for maintenance personnel to improve aircraft safety. The research evaluated what are the issues that affect the participation of the TACARE system. The understandings of the safety culture for maintenance personnel in Taiwan were also analyzed. The research was conducted with a mixed method. The survey and interview were developed to sample the acceptance and opinions regarding the TACARE system for the maintenance personnel in Taiwan. Statistical analysis of the data from 605 survey respondents and 9 interviewees concluded the maintenance …

Extension To Multiple Species Of A Two-Equation Turbulence Model For High Speed Flows, Martin Horvath

Master's Theses - Daytona Beach

The Wilcox (2006) k-co turbulence model has been extended to multiple species and implemented in a CFD code for high speed flows using the Steger-Warming flux-vector splitting scheme. The model was chosen because compressibility corrections are not required, nor are viscous damping factors or wall functions to produce the law of the wall, and it has previously been validated for approximately one hundred test cases ranging from incompressible to hypersonic flow regimes. Initial validation cases using first-order accuracy have been performed, including a Mach 2.5 flow past a backward-facing step and a Mach 2.85 flow into a 24° compression corner. …

Nonlinear Observers For Human-In-The-Loop Control Systems, Samuel Kitchen Mckinley

Master's Theses - Daytona Beach

The development of models for a human-in-the-loop with hardware is an area of ongoing research. The ability to simulate a human-in-the-loop with hardware provides a platform for better understanding the dynamics of human and machine cognition. A human-in-the-loop model provides information that can be used to design more efficient human interfaces and smarter autonomous assistant controllers. This can make a complex task such as flying an aircraft safer and more accessible. This thesis explores different possibilities for human operator models to be modeled in the loop with a vehicle. A human is modeled as a linear state feedback controller in …

Redesigning Airport Diagrams With Principles Of Cognitive Psychology, Jacob Miller

Master's Theses - Daytona Beach

The aviation community strives for air travel to be the safest form of transportation. The National Transportation Safety Board published a “Most Wanted” list to acknowledge the most threatening safety issues, and runway safety and runway incursions were at the top of their list. Furthermore, runway incursion statistics by the Federal Aviation Administration show that pilot deviations were the most common cause for runways incursions. Misunderstandings of airport diagrams may be one reason for pilot deviations. While navigating through airport taxiways, pilots refer to their airport diagrams as a map of the airport. Unfortunately, airport diagrams are not designed with …

Numerical Simulation Of A Liquid Jet Atomization And Break-Up Using Ansys-Cfx 12.0, Yash Akhil Bhatt

Master's Theses - Daytona Beach

Break-up and atomization characteristics of JetA liquid fuel were investigated numerically. The results have been compared to various experimental results to evaluate the accuracy of the numerical model. The CFD code ANSYS-CFX 12.0 was used to carry out the steady state analysis at different time scales. A comparison between the atomization characteristics of a pressure jet atomizer and an air-blast atomizer is shown. By employing a Lagrangian particle tracking method to track the path of the liquid particles, the liquid jet/spray phenomena was studied in light of low and high back pressure environments. The 'BLOB' primary atomization model and the …

Neural Network Fatigue Life Prediction In Notched Aluminum Specimens From Acoustic Emission Data, Muhammed Arif Okur

Master's Theses - Daytona Beach

This purpose of this research was to identify fatigue crack growth and predict failure for 7075-T6 aluminum notched bars under uniaxial tensile loading using acoustic emission (AE) data. The experiments performed in this study extend the results obtained by previous researchers who used maximum cyclic loads of 4,000, 3,000, and 2,000 pounds at a stress ratio of R = 0.0 and a frequency of 1 Hz to perform the fatigue tests. For this research the cyclic load remained at 2,000 pounds, but an additional ten specimens were tested in order to increase the amount of AE data available to the …

Effect Of Time Pressure And Task Uncertainty On Human Operator Performance And Workload For Autonomous Aerial Vehicle Missions, Trevor Peterson

Master's Theses - Daytona Beach

Unmanned aircraft systems (UAS) are being utilized at an increasing rate for a number of military applications. The potential for their use in the national airspace is also of interest to the Federal Aviation Administration, but there are some concerns about the safety of flying unmanned aircraft. The role of a UAS operator differs from that of a pilot in a manned aircraft, and this new role creates a need for a shift in interface and task design in order to take advantage of the full potential of these systems. This study examined the effect of time pressure and task …

Acoustic Emission Fatigue Crack Monitoring Of A Simulated Aircraft Fuselage Structure, Jeremy James Lucas

Doctoral Dissertations and Master's Theses

The purpose of this research was to replicate the fatigue cracking that occurs in aircraft placed under loads from cyclical compression and decompression. As a fatigue crack grows, it releases energy in the form of acoustic emissions. These emissions are transmitted through the structure in waves, which can be recorded using acoustic emission (AE) transducers. This research employed a pressure vessel constructed out of aluminum and placed under cyclical loads at 1 Hz in order to simulate the loads placed on an aircraft fuselage in flight. The AE signals were recorded by four resonant AE transducers. These were placed on …

Parametric Viscous Analysis Of Gust Interaction With Stationary And Elastically Mounted Airfoil, Timothy M. Hollenshade Jr.

Master's Theses - Daytona Beach

This thesis details the development and implementation of a module within a high-accuracy numerical viscous analysis code to simulate the nonlinear interaction of SD7003 airfoil with non-uniform, unsteady incoming flow. The study is focused on the low-Re number unsteady flows typical of MAV applications in which a gust encounter can induce a particularly significant aerodynamic and aeroelastic response. Efficient source models are developed to introduce sharp-edge and time-harmonic gust perturbations with specified amplitude, frequency and duration inside the computational domain through the source terms in the governing momentum equations. Parametric analysis of gust-airfoil interactions for different steady airfoil loads is …