Modeling Of Fracture And Durability Of Paste-Bonded Composite Joints Subjected To Hygro-Thermal-Mechanical Loading,
2013
Missouri University of Science and Technology
Modeling Of Fracture And Durability Of Paste-Bonded Composite Joints Subjected To Hygro-Thermal-Mechanical Loading, David Lee Harris
Masters Theses
"The objective of the research is to characterize the behavior of composite/composite joints with paste adhesive using both experimental testing and analytical modeling. In comparison with the conventional tape adhesive, joining composites using paste adhesive provides several advantages. The carbon fiber laminate material systems employed in this study included IM7 carbon fibers and 977-3 epoxy matrix assembled in prepreg tape, and AS4 carbon fibers and 977-3 epoxy matrix as a five-harness satin weave. The adhesive employed was EA 9394 epoxy. All laminates and test specimens were fabricated and inspected by Boeing using their standard propriety procedures. Three types of test …
Prediction Of Foreign Object Debris/Damage (Fod) Type For Elimination In The Aeronautics Manufacturing Environment Through Logistic Regression Model,
2013
University of Texas at El Paso
Prediction Of Foreign Object Debris/Damage (Fod) Type For Elimination In The Aeronautics Manufacturing Environment Through Logistic Regression Model, Natalia V. Espino
Open Access Theses & Dissertations
Foreign Object Debris/Damage (FOD) is a costly and high-risk problem that aeronautics industries such as Boeing, Lockheed Martin, among others are facing at their production lines every day. They spend an average of $350 thousand dollars per year fixing FOD problems. FOD can put pilots, passengers and other crews' lives into high-risk. FOD refers to any type of foreign object, particle, debris or agent in the manufacturing environment, which could contaminate/damage the product or otherwise undermine quality control standards. FOD can be in the form of any of the following categories: panstock, manufacturing debris, tools/shop aids, consumables and trash. Although …
Pressure And Heat Flux Effects On The Heat Transfer Characteristics Of Liquid Methane,
2013
University of Texas at El Paso
Pressure And Heat Flux Effects On The Heat Transfer Characteristics Of Liquid Methane, Chance Paul Garcia
Open Access Theses & Dissertations
The heat transfer effects on liquid methane are investigated with the use of a carbo-thermal rig at the Center for Space Exploration Technology Research (cSETR) located at the University of Texas at El Paso (UTEP). The cSETR carbo-thermal rig design approach is presented along with the design of a methane condensing mobile unit (MCMU) to supply the laboratory and rig with liquid methane. The proposed research will generate useful insight in to heat transfer coefficient behavior, non-dimensional correlations, different flow conditions, varied inlet conditions, and varied heat flux for a subscale test article applicable to a regenerative cooled rocket engine …
Solid-Fuel Regression Rate Modeling For Hybrid Rockets,
2013
University of California, Irvine
Solid-Fuel Regression Rate Modeling For Hybrid Rockets, Francesca Favaro, W. Sirignano, M. Manzoni, L. Deluca
Faculty Publications
The regression rate of the solid fuel is a primary parameter in the performance analysis for a hybrid rocket. Many studies in the past few years have theoretically claimed, or experimentally shown, a dependence of the regression rate on the chamber total pressure. Such behavior is generally traced back to the presence of oxygen below the flame zone and of heterogeneous reactions occurring at the surface and affecting the pyrolysis law. An experimental program was performed at the Space Propulsion Laboratory of the Politecnico di Milano showing, within the explored operating conditions and the associated uncertainty bands, a neutral trend …
Robust Control Methods For Nonlinear Systems With Uncertain Dynamics And Unknown Control Direction,
2013
Embry-Riddle Aeronautical University
Robust Control Methods For Nonlinear Systems With Uncertain Dynamics And Unknown Control Direction, Chau T. Ton
Doctoral Dissertations and Master's Theses
Robust nonlinear control design strategies using sliding mode control (SMC) and integral SMC (ISMC) are developed, which are capable of achieving reliable and accurate tracking control for systems containing dynamic uncertainty, unmodeled disturbances, and actuator anomalies that result in an unknown and time-varying control direction. In order to ease readability of this dissertation, detailed explanations of the relevant mathematical tools is provided, including stability denitions, Lyapunov-based stability analysis methods, SMC and ISMC fundamentals, and other basic nonlinear control tools. The contributions of the dissertation are three novel control algorithms for three different classes of nonlinear systems: single-input multiple output (SIMO) …
Payload Charging Events In The Mesosphere And Their Impact On Langmuir Type Electric Probes,
2013
University of Oslo
Payload Charging Events In The Mesosphere And Their Impact On Langmuir Type Electric Probes, T. A. Bekkeng, Aroh Barjatya, U. P. Hoppe, A. Pedersen, J. I. Moen, M. Friedrich, M. Rapp
Publications
Three sounding rockets were launched from Andøya Rocket Range in the ECOMA campaign in December 2010. The aim was to study the evolution of meteoric smoke particles during a major meteor shower. Of the various instruments onboard the rocket payload, this paper presents the data from a multi-Needle Langmuir Probe (m-NLP) and a charged dust detector. The payload floating potential, as observed using the m-NLP instrument, shows charging events on two of the three flights. These charging events cannot be explained using a simple charging model, and have implications towards the use of fixed bias Langmuir probes on sounding rockets …
A Computational Study Of Driven Micro-Cavities In Supersonic Flat Plate Flow,
2013
Missouri University of Science and Technology
A Computational Study Of Driven Micro-Cavities In Supersonic Flat Plate Flow, Thomas Ryan Rehmeier
Masters Theses
"Driven micro-cavities embedded in the wall beneath turbulent supersonic boundary layers are analyzed using two-dimensional computational fluid dynamics. This concept is a passive flow control technique in which very small cavities formed by arrays of thin vertical walls are oriented transverse to the flow direction and underlie the boundary layer. The purpose is to reduce or eliminate skin friction drag. Various micro-cavity configurations were analyzed at locations (0.1 m and 1 m) downstream of the leading edges of flat plates, for free-stream Mach numbers of 1.2, 2.0, and 3.0. Results focus on net drag reduction achieved, cavity flow-field effects, perforation …
Effect Of Stitch Density On Tensile Properties And Damage Mechanisms Of Stitched Carbon/Epoxy Composites,
2013
Missouri University of Science and Technlogy
Effect Of Stitch Density On Tensile Properties And Damage Mechanisms Of Stitched Carbon/Epoxy Composites, Arief Yudhanto, Naoyuki Watanabe, Yutaka Iwahori, Hikaru Hoshi
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Experimental investigation is performed to study tensile properties, damage initiation and development in stitched carbon/epoxy composites subjected to tensile loading. T800SC-24kf dry preforms with tow orientation of [+45/90/-45/02/+45/902/-45/0]s are stitched using 200 denier Vectran® thread. Modified-lock stitch pattern is adopted, and stitch density is varied, viz. moderate density (stitched 6 x 6: stitch density = 2.8 cm-2) and high density (stitched 3 x 3: stitch density = 11.1 cm-2). The stitched preforms are then infiltrated by epoxy XNR/H6813 using resin transfer molding process. Tensile test is conducted to obtain in-plane mechanical properties (tensile strength, failure strain, tensile modulus and Poisson's …
Unmanned Autonomous Object Retrieval: Old Dominion University 2013 International Aerial Robotics Competition Entry,
2013
Old Dominion University
Unmanned Autonomous Object Retrieval: Old Dominion University 2013 International Aerial Robotics Competition Entry, Johnathan Bailey, Austin Boyd, Chung-Hao Chen, Stephen Dailey, Lisa Henderson, Jeremy Stuart, Christina Williams
Electrical & Computer Engineering Faculty Publications
This paper describes the design implementation of a Quadrotor Unmanned Aerial Vehicle (UAV) with the capability of exploring indoor locations without the assistance of external aids. For relative position, the use of a laser range sensor, an optical flow sensor, and sonar sensor combined allows for the vehicle to generate mapping information. With relative position in mind, the vehicle uses vision algorithms to recognize immediate obstacles, sign, and entry ways to allow for quick movement responses and object recognition. A proportional-integral-differentiator controller allows for flight stability and mitigation in the tight confines of the indoor spaces. A mapping algorithm allows …
Elastic–Plastic Analysis And Strength Evaluation Of Adhesive
Joints In Wind Turbine Blades,
2013
University of Nebraska–Lincoln
Elastic–Plastic Analysis And Strength Evaluation Of Adhesive Joints In Wind Turbine Blades, Yi Hua, Ananth Ram Mahanth Kasavajhala, Linxia Gu
Department of Mechanical and Materials Engineering: Faculty Publications
The objective of this paper is to investigate the performance of adhesive joints of carbon/epoxy wind turbine blade subjected to combined bending and tension loadings through finite element method. The influence of adhesive material properties and geometrical details including fillet and imperfections was examined in terms of interlaminar stresses in the adhesive layer. The variation of stress intensity with change in adhesive shear modulus has also been investigated, while contour integral method was used for evaluating the stress intensity factors (SIF) at the imperfection tip. Furthermore, the strength of the joint was assessed through the crack initiation and propagation analysis. …
Nonlinear Control For Dual Quaternion Systems,
2013
Embry-Riddle Aeronautical University
Nonlinear Control For Dual Quaternion Systems, William D. Price
Doctoral Dissertations and Master's Theses
The motion of rigid bodies includes three degrees of freedom (DOF) for rotation, generally referred to as roll, pitch and yaw, and 3 DOF for translation, generally described as motion along the x, y and z axis, for a total of 6 DOF. Many complex mechanical systems exhibit this type of motion, with constraints, such as complex humanoid robotic systems, multiple ground vehicles, unmanned aerial vehicles (UAVs), multiple spacecraft vehicles, and even quantum mechanical systems. These motions historically have been analyzed independently, with separate control algorithms being developed for rotation and translation. The goal of this research is to study …
Dynamics And Control Of Higher-Order Nonholonomic Systems,
2013
Embry-Riddle Aeronautical University
Dynamics And Control Of Higher-Order Nonholonomic Systems, Jaime Rubio HerváS
Doctoral Dissertations and Master's Theses
A theoretical framework is established for the control of higher-order nonholonomic systems, defined as systems that satisfy higher-order nonintegrable constraints. A model for such systems is developed in terms of differential-algebraic equations defined on a higher-order tangent bundle. A number of control-theoretic properties such as nonintegrability, controllability, and stabilizability are presented. Higher-order nonholonomic systems are shown to be strongly accessible and, under certain conditions, small time locally controllable at any equilibrium. There are important examples of higher-order nonholonomic systems that are asymptotically stabilizable via smooth feedback, including space vehicles with multiple slosh modes and Prismatic-Prismatic-Revolute (PPR) robots moving open liquid …
Constraint Enforcement Methods For Command Governor Based Adaptive Control Of Uncertain Dynamical Systems,
2013
Missouri University of Science and Technology
Constraint Enforcement Methods For Command Governor Based Adaptive Control Of Uncertain Dynamical Systems, Simon P. Schatz, Tansel Yucelen, Eric N. Johnsony, Florian Holzapfelz
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Recently, research has been conducted in order to improve the transient behavior of adaptively controlled uncertain nonlinear dynamical systems. In this paper, an adaptive control architecture is extended in order to achieve predictable transient performance in the presence of state constraints. The methodology at hand is based on a robust command governor framework, which is a dynamical system adjusting the trajectory of a given command in order to track a certain desired closed-loop reference model both in transient time and steady-state. Specifically, the command, which is applied on the reference model and the actual system, is changed by the command …
Neuropredictive Control And Trajectory Generation For Slung Load Systems,
2013
Missouri University of Science and Technology
Neuropredictive Control And Trajectory Generation For Slung Load Systems, Gerardo De La Torre, Eric N. Johnson, Tansel Yucelen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper presents a neuropredictive trajectory generation architecture for slung load systems. The presented architecture integrates the real-time trajectory generation method with a system uncertainty identifying neural network. It is shown that the effect of system uncertainty on a model predictive control approach can be mitigated by the use of neural networks. A numerical example of an uncertain slung load system is shown to demonstrate the effectiveness of the presented framework.
Consensus Protocols In Networked Multiagent Systems For Cluttered And Hostile Environments,
2013
Missouri University of Science and Technology
Consensus Protocols In Networked Multiagent Systems For Cluttered And Hostile Environments, Gerardo De La Torre, Eric N. Johnson, Tansel Yucelen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Consensus refers to the agreement of networked agents upon certain quantities of interest and has widespread applications in diverse areas in science and engineering. This paper focuses on a new consensus protocol for networked multiagent systems operating in cluttered and hostile environments. Specifically, a consensus optimization algorithm is introduced that renders the Laplacian potential to be a nonincreasing function while minimizing a cost function and satisfying state and cost constraints. In addition, we show how to choose this cost function and the aforementioned constraints in order to decay the Laplacian potential to zero strictly. The proposed framework depends on a …
Interacting Stress Concentration Factors And Their Effect On Fatigue Of Metallic Aerostructures,
2013
Missouri University of Science and Technology
Interacting Stress Concentration Factors And Their Effect On Fatigue Of Metallic Aerostructures, David Warren Whitley
Doctoral Dissertations
"During fabrication of certain aerostructure components, a situation can arise where a hole is mislocated so that it interferes with a radius, chem-mill step, machined step, or some other similar detail. The interaction of stress concentration effects between a hole and step are not well understood and the resulting impact on fatigue performance is difficult to predict. There exists a need for fatigue data that can be used to determine the analysis methods for evaluation of the interaction of machined steps and fastener holes. In this dissertation, the effect of stress concentrations placed in close proximity to each other and …
Libration Point Orbits Near Small Bodies In The Elliptic Restricted Three-Body Problem,
2013
Missouri University of Science and Technology
Libration Point Orbits Near Small Bodies In The Elliptic Restricted Three-Body Problem, Bharat Mahajan
Masters Theses
"In this study, the feasibility of using libration point orbits to explore small solar system bodies, including asteroids and comets, is considered. A novel design for a small body mission is proposed that makes use of libration point orbits as "parking" orbits. In considering a human exploration mission to asteroids or comets, these "parking" orbits may provide benefits including a safe vantage point for staging/observation, reduced perturbation effects from the nonuniform gravitational field of the body, fewer communication blackouts, ease of guidance and control of a lander on the surface, etc. Because small solar system bodies have extremely low mass …
Observability-Enhanced Dual-Filter Design For Attitude Estimation With Minimum Observations,
2013
Missouri University of Science and Technology
Observability-Enhanced Dual-Filter Design For Attitude Estimation With Minimum Observations, Jason D. Searcy
Doctoral Dissertations
"Determining spacecraft attitude in real time using only magnetometer data presents a challenging filtering problem. A flexible and computationally efficient method for solving the spacecraft attitude using only an inexpensive and reliable magnetometer would be a useful option for satellite missions, particularly those with modest budgets. The primary challenge is that magnetometers only instantaneously resolve two axes of the spacecraft attitude. Typically, magnetometers are used in conjunction with other sensors to resolve all three axes. However, by using a filter over an adequately long orbit arc, the magnetometer data can yield full attitude, and in near real time. The method …
Efficient Uncertainty Quantification In Aerospace Analysis And Design,
2013
Missouri University of Science and Technology
Efficient Uncertainty Quantification In Aerospace Analysis And Design, Yi Zhang
Doctoral Dissertations
"The main purpose of this study is to apply a computationally efficient uncertainty quantification approach, Non-Intrusive Polynomial Chaos (NIPC) based stochastic expansions, to robust aerospace analysis and design under mixed (aleatory and epistemic) uncertainties and demonstrate this technique on model problems and robust aerodynamic optimization. The proposed optimization approach utilizes stochastic response surfaces obtained with NIPC methods to approximate the objective function and the constraints in the optimization formulation. The objective function includes the stochastic measures which are minimized simultaneously to ensure the robustness of the final design to both aleatory and epistemic uncertainties. For model problems with mixed uncertainties, …
Radar Based Navigation In Unknown Terrain,
2012
Air Force Institute of Technology
Radar Based Navigation In Unknown Terrain, Kyle J. Kauffman
Theses and Dissertations
There is a great need to develop non-GPS based methods for positioning and navigation in situations where GPS is not available. This research focuses on the development of an Ultra-Wideband Orthogonal Frequency Division Multiplexed (UWB-OFDM) radar as a navigation sensor in GPS-denied environments. A side-looking vehicle-fixed UWB-OFDM radar is mounted to a ground or aerial vehicle continuously collecting data. A set of signal processing algorithms and methods are developed which use the raw radar data to aide in calculating the vehicle position and velocity via a simultaneous localization and mapping (SLAM) approach. The radar processing algorithms detect strong, persistent, and …
