Open Access. Powered by Scholars. Published by Universities.^{®}
 Institution
 Keyword

 Aerospace engineering and engineering mechanics (6)
 Aerospace engineering (4)
 Mechanical engineering (3)
 Aviation (3)
 Aerospace Engineering (3)

 Vibration (2)
 Engineering mechanics (2)
 Signal processing (2)
 Department of Statistics (2)
 Airfoil (2)
 Dynamic Programming (2)
 Neurocontrollers (2)
 Caroline Islands (1)
 Adaptive Critic Based Neural Networks (1)
 Aircraft Stabilization (1)
 Aerospace vehicle navigation (1)
 2D Linear Problem (1)
 Aircraft Control (1)
 Advanced fluidflow codes (1)
 Chassis (1)
 Chemical engineering (1)
 Advanced (1)
 Algorithm (1)
 Bearings (1)
 Blunt projectiles (1)
 1D Infinite Horizon Problem (1)
 Article (1)
 Acoustic (1)
 Buckling (1)
 Adaptive Neural Networks (1)
 Publication

 Retrospective Theses and Dissertations (11)
 Theses  Daytona Beach (9)
 Mechanical & Aerospace Engineering Theses & Dissertations (6)
 Mechanical and Aerospace Engineering Faculty Research & Creative Works (4)
 Aerospace Engineering Publications (2)

 Scholarship Collection (2)
 Flightlines Newsletter (2)
 Faculty Books and Monographs (1)
 Engineering Management & Systems Engineering Theses & Dissertations (1)
 Iowa State University Patents (1)
 D. K. Chaturvedi Dr. (1)
 Master's Theses (1)
 wanxmkkfsfrs wanxmkkfsfrs (1)
 Electrical and Computer Engineering Faculty Research & Creative Works (1)
 Aerospace Engineering (1)
 Electrical Engineering & Computer Science Faculty Publications (1)
 Geological and Atmospheric Sciences Publications (1)
 Undergraduate Honors Capstone Projects (1)
 George H Baker (1)
 Mathematics, Engineering and Computer Science Undergraduate Theses (1)
 Dissertations and Theses (1)
 Aerospace Engineering Conference Papers, Presentations and Posters (1)
 Center for Nondestructive Evaluation Publications (1)
 Publication Type
Articles 31  52 of 52
FullText Articles in Engineering
Finite Element Nonlinear Random Response Of Composite Panels Of Arbitrary Shape To Acoustic And Thermal Loads Applied Simultaneously, Roger R. Chen
Finite Element Nonlinear Random Response Of Composite Panels Of Arbitrary Shape To Acoustic And Thermal Loads Applied Simultaneously, Roger R. Chen
Mechanical & Aerospace Engineering Theses & Dissertations
The nonlinear random response of composite plates to the simultaneously applied, combined acoustic/thermal loads are investigated in this dissertation. A finite element formulation for the nonlinear random response is developed. The threenode Mindlin plate element with improved transverse shear is extended and employed. The extension includes the development of the thermal geometric matrix, the mass matrix, the first order and secondorder nonlinear stiffness matrices, and the thermal and mechanical load vectors. An innovative solution procedure has been created which is believed to be the first attempt to analyze nonlinear random response of complex composite panels subjected to simultaneous acoustic ...
Nonlinear Analysis Of Composite Beams Under Random Excitations, Snorri Gudmundsson
Nonlinear Analysis Of Composite Beams Under Random Excitations, Snorri Gudmundsson
Theses  Daytona Beach
The vibration responses of three unsymmetrically laminated beams, that are excited with a Gaussian random forcing function, are studied in this thesis. The beams are analyzed nonlinearly and compared to linear results, indicating some important corrections. The solution procedure begins with the derivation of the general equation of motion using Galerkin's method. Then, two approaches are taken in the solution. First, the equation of motion is attacked directly employing a real time RungeKutta numerical analysis. Second, the method of equivalent linearization is used. The thesis finds the results from the two approaches to be in a close agreement, although ...
Proceedings Of The First Annual Nebraska Aviation Education Association Conference, James E. Crehan, Uno Aviation Institute
Proceedings Of The First Annual Nebraska Aviation Education Association Conference, James E. Crehan, Uno Aviation Institute
Faculty Books and Monographs
UNOAI Report 945
Scattering Of Longitudinal Elastic Waves From An Anisotropic Spherical Shell, John Mittleman, Ronald A. Roberts, R. Bruce Thompson
Scattering Of Longitudinal Elastic Waves From An Anisotropic Spherical Shell, John Mittleman, Ronald A. Roberts, R. Bruce Thompson
Center for Nondestructive Evaluation Publications
An exact solution for scattering of ultrasound from a spherically orthotropic shell is presented. The shell is assumed to be embedded in an isotropic elastic medium, and the core surrounded by< the shell is also assumed to be isotropic. The shell itself is assumed to be “spherically orthotropic,” with five independent elastic constants (the spherical analog of a transversely isotropic material in Cartesian coordinates). Field equations for this material are presented,and these equations are shown to be separable. Working with the displacement vector, we find that the radius dependent part of the solution satisfies coupled secondorder ordinary differential equations. This system of equations is solved using the method of Frobenius,and results in four independent series determined by material properties to within a multiplicative constant. Use of boundary conditions expressed^{ }in terms of stresses and displacements at the inner and outer shell radii completes the solution. Numerical results for arange of shell elastic constants show that this solution matches known analytic results in the special case of isotropy and matches previously developed finite difference results for anisotropic elastic constants.The effect of shell anisotropy on farfield scattering amplitude isexplored for an incident plane longitudinal wave.
Parallel Surface Reconstruction Through Virtual Milling , Kumaran Kalyanasundaram
Parallel Surface Reconstruction Through Virtual Milling , Kumaran Kalyanasundaram
Retrospective Theses and Dissertations
Surface definition deals with representing a surface analytically using a finite number of parameters and with acceptable levels of error. In the past few years it has become a key discipline in Computational Fluid Dynamics (CFD). Recent advances in computers and numerical algorithms have made it possible for CFD practitioners to attempt flow solutions about complex threedimensional geometries. The first step in this process is having a numerical representation of the shape. In many cases of interest such a representation already exists; i.e., aircraft designed on a computer. Such ComputerAided Design (CAD) descriptions do not exist, though, for objects ...
Adaptive Nonlinear Attitude Control Of Spacecraft , Cheng Tang
Adaptive Nonlinear Attitude Control Of Spacecraft , Cheng Tang
Retrospective Theses and Dissertations
Three adaptive nonlinear control approaches are proposed for attitude control of a Space Station. These control algorithms avoid the need for linearization, either by truncating a Taylor series or by a feedback linearization approach, which poses some difficulties in the presence of both uncertain mass properties and external disturbances. Global stability of the Space Station is guaranteed;A conventional linearquadratic regulator synthesis technique is investigated. This linear control scheme provides a natural way to select control gains for the known spacecraft system parameters. Simulation results reveal that the uncertain mass property causes the nonlinear Space Station to be uncontrollable;On ...
Optimal Turning Maneuvers For SixDegreeOfFreedom High AngleOfAttack Aircraft Models , JenNai Chou
Optimal Turning Maneuvers For SixDegreeOfFreedom High AngleOfAttack Aircraft Models , JenNai Chou
Retrospective Theses and Dissertations
Various MinimumTime Turning Maneuvers for two high angleofattack, sixdegreeoffreedom, aircraft models have been investigated. The primary aircraft model is for a nonlinear 6DOF F16 fighter aircraft with high angleofattack maneuverability. The other model is for a linearized 6DOF F18 fighter which also can be flown in the high angleofattack range. Standard 6DOF equations are employed except that the Quaternion attitude representation system is used instead of Euler Angles to avoid the pitch angle singularity of Euler Angles;These Optimal Control problems have been transformed into Nonlinear Programming problems via Parameter Optimization techniques. Different parameterization techniques were tested on the Van ...
Unstructured Grid Algorithms For Two And ThreeDimensional Flows On Parallel Computers , Thomas Hans Ramin
Unstructured Grid Algorithms For Two And ThreeDimensional Flows On Parallel Computers , Thomas Hans Ramin
Retrospective Theses and Dissertations
The NavierStokes equations are solved numerically for twoand threedimensional viscous laminar flows. The domain is discretized using triangular control volumes in two dimensions and tetrahedra in three dimensions, using existing grid generators. The flow solvers are implemented on a variety of computers, including distributed memory parallel computers;A finitevolume approach is used to discretize the governing flow equations in conservation law form using conserved variables. A cell centered approach is used where the unknowns are computed at the center of each control volume. Both explicit and implicit solution strategies are pursued. In the twodimensional version of the algorithm an explicit ...
Coupled Compressible And Incompressible Finite Volume Formulations For The Large Eddy Simulation Of Turbulent Flow With And Without Heat Transfer , WenPing Wang
Retrospective Theses and Dissertations
A coupled finite volume approach for solving the timedependent NavierStokes equations is developed for application to the large eddy simulation (LES) of turbulent flow. The preconditioning strategy of coupling the incompressible NS equations and providing acceleration of iterative convergence in both compressible and incompressible formulations is employed. Three different spatial discretization schemes along with the regular/staggered grid arrangements are evaluated on both twodimensional laminar flows and threedimensional turbulent flows;No distinctive differences are found in laminar flow cases, but the staggered grid appears to provide a better resolution of the turbulence statistics over a regular one in the simulation ...
Flow Diagnostics, Chemically Reacting Turbulent Flow Modeling And Turbulent Mixing : A Summary Of Project Studies In Combustion, Bahman Ghorashi
Flow Diagnostics, Chemically Reacting Turbulent Flow Modeling And Turbulent Mixing : A Summary Of Project Studies In Combustion, Bahman Ghorashi
Scholarship Collection
No abstract provided.
Unstructured Surface And Volume Decimation Of Tessellated Domains , Kevin Joseph Renze
Unstructured Surface And Volume Decimation Of Tessellated Domains , Kevin Joseph Renze
Retrospective Theses and Dissertations
A general algorithm for decimating unstructured discretized data sets is presented. The discretized space may be a planar triangulation, a general 3D surface triangulation, or a 3D tetrahedrization. The decimation algorithm enforces Dirichlet boundary conditions, uses only existing vertices, and assumes manifold geometry. Local dynamic vertex removal is performed without history information while preserving the initial topology and boundary geometry. The tessellation at each step of the algorithm is preserved and, in the pathological case, every interior vertex is a candidate for removal. The research focuses on how to remove a vertex from an existing unstructured ndimensional tessellation, not on ...
A Compliant Model For Estimation And Optimization Of Damping In Vibrating Structures , Thomas Jeffrey Thompson
A Compliant Model For Estimation And Optimization Of Damping In Vibrating Structures , Thomas Jeffrey Thompson
Retrospective Theses and Dissertations
Proposed future space missions involve large structures which must maintain precise dimensional tolerances even during dynamic maneuvers. In order to attenuate disturbances in the many modes of vibration of such a structure, active and passive vibration control are proposed. The passive control is to be achieved by placing viscous or viscoelastic members or materials within a structure in order to absorb energy. Ascertaining the best combination of locations for such treatments is difficult due to the large number of cases, each of which requires computationally expensive complex eigenvalue analyses of a finite element model to compute modal damping values;In ...
Ultrasonic Nondestructive Evaluation Techniques And The Effects Of Fiber Architecture On Mechanical Performance In MultiDirectionally Reinforced Textile Composites , Richard Douglas Hale
Ultrasonic Nondestructive Evaluation Techniques And The Effects Of Fiber Architecture On Mechanical Performance In MultiDirectionally Reinforced Textile Composites , Richard Douglas Hale
Retrospective Theses and Dissertations
Constant load stress rupture tests were performed on alloy 908. The test matrix used varied oxygen concentration, applied load, temperature, and percent cold work. The effect of modifying surface residual stresses on intergranular oxidation and cracking was examined using constant strain Cring tests;The mechanism for high temperature intergranular fracture in alloy 908 is stress assisted intergranular oxidation cracking. A direct correlation between percent intergranular fracture and oxygen concentration was observed. This result was comparable to the oxidation assisted, intergranular fracture behavior of alloy 718. Internal oxidation, for temperatures at or near 650∘ C and under an applied tensile stress ...
Synthesis Of Launch Vehicle Design And Trajectory Optimization, Veena Savithri Dorairajan
Synthesis Of Launch Vehicle Design And Trajectory Optimization, Veena Savithri Dorairajan
Retrospective Theses and Dissertations
http://www.worldcat.org/oclc/32804161
Turbulent Scalar Transport Using TwoPoint Statistical Closure Theory , Robert Charles Sanderson
Turbulent Scalar Transport Using TwoPoint Statistical Closure Theory , Robert Charles Sanderson
Retrospective Theses and Dissertations
The turbulent transport of a passive scalar (Corrsin's problem with diffusion) and of an active scalar in stably stratified fluids is studied using linear analysis (rapid distortion theory or RDT), Kraichnan's direct interaction approximation (DIA) and direct numerical simulation (DNS). The results are compared with each other and with laboratory experiments. The numerical results compare favorably with the experiments of Sirivat and Warhaft, Budwig, Tavoularis and Corrsin and Stillinger and Itsweire of van Atta's group. The RDT study reveals that much of the qualitative behavior observed in experiments, such as the tendency for the system to evolve ...
Numerical Investigation Of Type Ii NonNewtonian De/AntiIcing Fluid Effects On TakeOff Performance For General Aviation Aircraft , Dennis James Cronin
Numerical Investigation Of Type Ii NonNewtonian De/AntiIcing Fluid Effects On TakeOff Performance For General Aviation Aircraft , Dennis James Cronin
Retrospective Theses and Dissertations
Ground icing, while preventable with glycol based freezing point depressant fluids, accounts for nearly 4050 civil accidents a year according to one account. More viscous than Type I fluids, Type II fluids are inherently nonlinear in their shear stressrate of strain relationship having smaller relative viscosity at higher shear rates. The nonlinearity makes properly scaled windtunnel testing difficult and computational methods are employed in this study to look at the aerodynamic effects of the deicing fluid on global performance during typical takeoff maneuvers for general aviation. The method is tested on a twodimensional NACA 0012 airfoil under typical takeoff simulation ...
Adaptive Critic Based Neural Networks For Control (Low Order System Applications), S. N. Balakrishnan, Victor Biega
Adaptive Critic Based Neural Networks For Control (Low Order System Applications), S. N. Balakrishnan, Victor Biega
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Dynamic programming is an exact method of determining optimal control for a discretized system. Unfortunately, for nonlinear systems the computations necessary with this method become prohibitive. This study investigates the use of adaptive neural networks that utilize dynamic programming methodology to develop near optimal control laws. First, a one dimensional infinite horizon problem is examined. Problems involving cost functions with final state constraints are considered for one dimensional linear and nonlinear systems. A two dimensional linear problem is also investigated. In addition to these examples, an example of the corrective capabilities of critics is shown. Synthesis of the networks in ...
A New Neural Architecture For Homing Missile Guidance, S. N. Balakrishnan, Victor Biega
A New Neural Architecture For Homing Missile Guidance, S. N. Balakrishnan, Victor Biega
Mechanical and Aerospace Engineering Faculty Research & Creative Works
We present a new neural architecture which imbeds dynamic programming solutions to solve optimal targetintercept problems. They provide feedback guidance solutions, which are optimal with any initial conditions and timetogo, for a 2D scenario. The method discussed in this study determines an optimal control law for a system by successively adapting two networks  an action and a critic network. This method determines the control law for an entire range of initial conditions; it simultaneously determines and adapts the neural networks to the optimal control policy for both linear and nonlinear systems. In addition, it is important to know that the ...
Fuzzy Logic In Restructurable Flight Control Systems, S. N. Balakrishnan, H. S. Ho
Fuzzy Logic In Restructurable Flight Control Systems, S. N. Balakrishnan, H. S. Ho
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper, a fuzzy logic controller (FLC) is proposed for restructurable flight control systems. The role of the FLC is to stabilize the aircraft upon a fault occurrence. The FLC derives pitch/roll/yaw controls from a generic knowledge base characterized by 49 ifthen rules. A linearized model representative of a modern jet fighter provides the basis for the numerical simulation. Simulated faults include various degrees of surface loss at the right stabilator, combined with reduced ailerons and rudder control power. The FLC accomplishes the stabilization task under test conditions without any knowledge of the system parameters. The numerical ...
System Modeling And Control Of Smart Structures, Frank J. Kern, Leslie Robert Koval, K. Chandrashekhara, Vittal S. Rao
System Modeling And Control Of Smart Structures, Frank J. Kern, Leslie Robert Koval, K. Chandrashekhara, Vittal S. Rao
Electrical and Computer Engineering Faculty Research & Creative Works
This paper presents multidisciplinary research and curriculum efforts at the University of MissouriRolla in the smart structures area. The primary objective of our project is to integrate research results with curriculum development for the benefit of students in electrical, and mechanical and aerospace engineering and engineering mechanics. The approach to the accomplishment of curriculum objectives is the development of a twocourse sequence in the smart structures area with an integrated laboratory. The research portion of the project addresses structural identification and robust control methods for smart structures. A brief summary of the research results and a description of curriculum development ...
A Nonlinear Dynamic Method For Supporting LargeScale DecisionMaking In Uncertain Environments, Wayne Woodhams
A Nonlinear Dynamic Method For Supporting LargeScale DecisionMaking In Uncertain Environments, Wayne Woodhams
Engineering Management & Systems Engineering Theses & Dissertations
This research developed a methodology for supporting decision making by reducing uncertainty in decision environments which are too large, dynamic and complex to be treated by traditional quantitative and simulation techniques. These environments are complex because of the free choice associated with human involvement, and the existence of a large number of interrelated factors which influence the outcomes of the decision process. They are dynamic because the ground rules affecting those interrelationships are constantly changing. Uncertainty cannot be treated probabilistically, since identification of a full set of outcomes and factors of influence is not possible.
The venue for the investigation ...
Hamiltonian Based Adaptive Critics For Aircraft Control, S. N. Balakrishnan, Jie Shen
Hamiltonian Based Adaptive Critics For Aircraft Control, S. N. Balakrishnan, Jie Shen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Aircraft designs are becoming more complex in order to either operate more efficiently as in the commercial sector or to push the performance envelopes as in the military sector. An interesting outcome of this scenario is that `control'' has come to play an important role in helping realize these objectives. Increasingly, control is becoming an integral part of an aircraft design rather than an afterthought. More effective and efficient control of an aircraft is certain to lead to improved performance at a lower cost