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Transient Response Of Linear Elastic Structures Determined By The Matrix Exponential Method, William Christopher Terrill Stoddart

Masters Theses

This investigation was undertaken to develop a numerical solution for the transient response of linear, elastic structures based on the matrix exponential solution for first order, linear, constant coefficient differential equations. The investigation was prompted by the need for an economical technique that can be used to analyze multidegree of freedom systems exemplified by piping and structural components associated with nuclear power plants.

A mathematical model characterizing the behavior of linear, elastic structures was developed by using state variables of displacement and velocity. The structure consists of beam elements of uniformly distributed mass, weightless springs, and rigid masses. The stiffness …

Basic Instrumentation Of A Three-Zone Convection Coater Dryer For Calculation Of Heat And Mass Balances, Byron H. Mckinstry

Masters Theses

No abstract provided.

Three Dimensional Elastic Wave Propagation In Bodies Of Revolution, Robert S. Pritchard

Mechanical Engineering ETDs

This dissertation describes solution of a class of problems of three dimensional (non-symmetrical) elastic wave propagation in bodies of revolution. The method of analysis is expansion into circumferential modes followed by solution of an approximate numerical scheme using a digital computer. The material constituting the body has been assumed homogeneous, isotropic, linearly elastic and only one mate­rial may appear in the body. A load may be applied either by a pressure blast or by a target body acting over some portion of the boundary. The loading functions may vary around the circumference. Three dimensional wave motion is analyzed by expanding …

The Design Of A Laser Doppler Velocimeter, Marlo R. Anderson

Theses and Dissertations

A relatively new method of measuring local velocity in a fluid stream has been devised which eliminates some of the inherent problems of the traditional methods. This method senses the Doppler shift of light scattered from a laser beam incident on particles suspended in the fluid. The Doppler shift is proportional to the particles (or fluid) velocity. This new technique has several distinct advantages over the more traditional methods of velocity measurement.

An Optimization Technique Applied To The Determination Of Modal Damping Coefficients, Craig C. Smith

Theses and Dissertations

Although analytical techniques are generally available for the simulation of dynamic systems, often these techniques require a great deal of computer time and storage. This difficulty was vividly pointed out by a previous thesis undertaken in this Department by R. L. Webster (1). Mr. Webster undertook the determination of orthotropic material properties using dynamic response test data from plates. A major difficulty which was encountered was the enormous amount of computer time required for the simulation. This thesis is an investigation of a method which when fully developed, may provide the ability to simulate such systems much more efficiently.

A Data Reduction Technique For Drag-Coefficient Data For Spheres, Stephen Thomas Merrell

Theses and Dissertations

The object of this investigation was to obtain a reliable technique for finding the drag coefficient for a sphere falling at a non-constant velocity through air. And then to apply this technique to the data collected by R. G. Lunnon in 1925^(4)*.

A Dynamic Model Of A Small Manufacturing Company, Abraham John

Theses and Dissertations

A manufacturing company typically has the objective of maximizing the long-term value of its common stock while satisfying its customers. To achieve this, the company might increase the quantity and improve the quality of production. Since the company is operating in a dynamic environment, its policies should be dynamic also, to achieve its objective.

A Study Of The Effects Of Some Parameters Of The Galloping Of Electric Transmission Lines, Leland J. Coleman

Theses and Dissertations

Freezing rainstorms coupled with moderate winds have often been observed to cause telephone lines and power transmission cables to begin bouncing up and down. This slow frequency high amplitude oscillation, or galloping as it is sometimes called, can build up to large amplitudes before the oscillation either damps out or persists at some constant amplitude. It has been reported by Edwards and Livingston [1] that the amplitude of galloping on transmission lines has been as large as forty feet. Galloping oscillations occur at relatively low frequencies; from .1 to 1 Hz. [1] near the natural frequency of the suspended cable.

Theoretical And Experimental Evaluation Of Cardiac State Utilizing Indicator Dilution Methods For Nonuniform Ventricular Mixing, Stanley Myron Welland

Dissertations

This research is directed toward the development and application of a new approach to the evaluation of cardiac work to diagnose cardiac state. A procedure has been developed for calculating the work performed on the fluid by the left ventricle during the heartbeat. The procedure involves the continuous direct measurement of ventricular fluid mixture temperature during and following the controlled injection, through a catheter, of a known volume of cold saline into the left ventricle. The measured mixture temperatures are used to calculate continuous ventricular volumes during the systolic and diastolic functions of the heartbeat. Plotting measured ventricular pressure versus …

On The Classification Of The Solution Space Of Linear Anisotropic Elasticity, Richard Clement Carman

Dissertations

A method is developed within the framework of Synge's function-space interpretation of problems in linear elasticity which allows the consideration of solutions to problems for anisotropic media in terms of the solutions of a corresponding isotropic problem and corresponding simpler anisotropic problems. The isotropic solution and simpler anisotropic solutions establish points in each of the statically and kinematically admissible spaces for the anisotropic problem. The established points are used to define sets of vectors in the statically and kinematically admissible spaces. The linear independence of these vectors can then be determined by a pair of criteria developed in this work. …

Triaxial Stress Effects In Weldments Associated With The Heat Affected Zone, Rohit A. Mehta

Theses and Dissertations

The welding of steel occupies an important place as a major fabricating process in industry. The welding of steel has been a subject of research for many years, and much information has been obtained about the strength of weldments.

Determination Of Effective Strain For The Strainhardening Of Aluminum Subjected To Completely Reversed Strain Combinations, Navin M. Patani

Theses and Dissertations

It is known that subrecrystallization plastic deformation increases the strength of a metal. The amount of strengthening that may be acquired can be approximated using a strainhardening equation and a simple given strain. The purpose of this thesis was to determine the effective strain for predicting strainhardening for annealed aluminum subjected to completely reversed strain combinations.

Particle Dynamics In The Mixing Of A Particle-Laden Stream With A Secondary Stream In A Duct, William Doyle Cranney

Theses and Dissertations

The purpose of this thesis is to review the history and discuss the present work being done in particle-gas flow, with application to air- augmentation of a particle-carrying, fuel-rich gas jet. A drawing of the model considered is shown in Figure 1, with the area of interest labeled. The thesis is intended as a thorough literature review and analysis.

Temperature Protection For Fruit Trees By Air-Supported Plastic Structures, Ram T. Gadhavi

Theses and Dissertations

The greatest weather enemy in all fruit destruction is the late spring frost which moves across the country under the high pressure areas that are occasionally seen on the weather maps, and kills the fruit buds.

An Investigation Of A Computer Technique For Determining The Characteristic Parameters Of A Viscoelastic Model With Hysteresis Effects From Transient Experimental Data, Stephen Jack Clark

Theses and Dissertations

The object of this work was to develop a computer technique for determining the characteristic parameters of spring-mass system with hysteresis effects from transient experimental data. The technique was intended to be utilized to determine the parameters of models of systems where complex geometry and rate dependent properties would make a determination of the model parameters most difficult, and where the parameters typically obtained from static test would not characterize the rate dependent properties accurately.

A Survey Of Literature On The Pyrolysis Of Wood And Other Cellulosic Solids, Kenneth P. Sasine

Theses and Dissertations

The study of the ignition of wood and other cellulosic materials has resulted in the publication of a large amount of literature. As an aid in the planning and interpretation of future research, it was felt that a survey of a representative body of literature should be made. With this as its motivation, the present work was initiated.

A Feasibility Study Of The Application Of Bondgraph Modeling And Computerized Nonlinear Model Parameter Identification Techniques To The Cardiovascular System, Randall L. Taylor

Theses and Dissertations

Recent years have witnessed an increasing trend for people in the medical and engineering professions to couple their talents in a more united effort to better understand the functioning of the human body. This union of technologies has meant the introduction of new viewpoints and techniques in the field of physiological research. The engineers' basic tool, mathematical modeling, has perhaps been one of the most noticeable additions. There has been a significant amount of work done in recent years along these lines of deriving mathematical models to express the functioning of a subsystem of the body, and then, using analog, …

Non-Linear Analysis Of Electrocardiogram Tracings In Detection Of Occult Coronary Artery Disease, Joseph Robert Levitt

Dissertations

The general problem of identifying significant characteristics of a system by analyzing the properties of a signal emitted by that system is common to many disciplines, biological as well as physical. In general, achievement of a satisfactory solution depends on the capability of assigning membership of candidate signals to one of a number of mutually exclusive categories:

In this study, a new technique of processing the standard electrocardiograms from human subjects has been developed. This technique employs a set of non-linear transformations which enable the assignment of electrocardiograms into one of two Mutually exclusive categories. The first category is that …

Extension And Application Of The Sedov-Berdichevskii Variational Principle, Francis X. Prendergast

Dissertations

The Sedov-Berdichevskii variational principle is extended, and this extended principle is employed in the construction of a shell theory.

The extension of the principle is accomplished by the use of Lagrangian multipliers, and a redefinition of terms in order to maintain the original generality of the principle. The Euler equations of the extended variational principle provide, in addition to those obtained in the original principle, elastic and plastic kinematic relations, and, elastic and plastic constitutive relations. Also, the Euler equations of the original principle are obtained in a physically more meaningful form. Examples are given which show how this principle …

Dynamic Stress Concentrations About An Epilliptical Discontinuity In An Elastic Solid, Kenneth Roy Schroll

Dissertations

The redistribution of dynamic stresses caused by the presence of an elliptical discontinuity in an infinite isotropic homogeneous elastic solid is examined. The solutions are obtained for the special cases of the rigid immovable inclusion and the vacuous cavity inclusion, and numerical results are presented.

The solutions to the wave equations in elliptical coordinates are expressed in series of the elliptical geometry eigenfunctions. Application of the boundary conditions, vanishing displacements for the rigid immovable inclusion and vanishing stresses for the cavity inclusion, yields in each case two infinite sets of linear algebraic equations for the expansion coefficients of the series …

The Computer Evaluation Of The Natural Frequencies Of Vibrating Circular Plates With Free, Fixed And Simply Supported Edges, Thomas Michael Juliano

Theses

The natural frequencies of the transverse vibration of a thin, isotropic, circular plate with free, clamped, and simply supported edge conditions were studied extensively. The frequency equation for each edge condition was derived from the classical partial differential equation of plate vibration. These equations, which are in terms of Bessel functions, were then solved numerically to find the natural frequencies. Since the accuracy of the Bessel function values is very important in evaluating these frequencies, a comprehensive digital computer program was devised to calculate these values to eleven digit accuracy. In this Bessel function program four different methods were required …

Magnetohydrodynamic Stability Of Laminar Flow In The Entrance Region Of A Parallel-Plate Channel, Thomas Eldon Eaton

Masters Theses

"The hydrodynamic stability of laminar flow of an electrically conducting fluid flowing in a parallel-plate channel with an applied transverse magnetic field is investigated. The linear perturbation theory of hydrodynamic stability along with the assumption of low magnetic Reynolds number is applied to the governing equations to derive the governing rnagnetohydrodynarnic stability equation. A finite difference scheme is employed to numerically solve the magnetohydrodynamic stability equation. Neutral stability characteristics of the flow in the entrance region are obtained and presented. The neutral stability characteristics of the fully developed Hartmann flow are also re-examined and compared with those of a previous …

Interface Thermal Conductance With Metal Screens As Interstitial Material, William Edward Stewart Jr.

Masters Theses

"This thesis reports the results of an experimental investigation to determine the thermal conductance at the interface of metal specimens separated by wire mesh. Sets of metal specimens of copper, 2024-T4 aluminum, and 304 stainless steel were used. The specimens were cylindrical, axially aligned, and hydraulically loaded. All tests were conducted in an air environment. Pressure applied to the specimens ranged from 50 to 500 psig. Surface roughness of the interfaces varied from 5 to 20 micro inches. The wire mesh separators were of 304 stainless steel in 20, 30, 40, and 50 mesh. Results of the experiments show that: …

Influence Of Film Thickness On The Performance Of Solid Lubricants, Sunil Vishwanath Mahale

Masters Theses

"The object of this investigation was to determine the effect of lubricant film thickness on the coefficient of friction and on the wear life of solid lubricants. Bonded molybdenum disulphide and bonded graphite were the lubricants tested. Dow Corning's LFW-1 and Falex lubricant tester were the two machines used for testing these lubricants. The lubricants were sprayed on the specimen surface. Pretreatment, spraying and curlng were done according to standard or manufacturer's recommended procedures. During the entire research, the procedure for experimentation was followed according to ASTM No. 2625 on Falex and CRC recommendations on LFW-1 machine. It was found …

An Investigation Of Nucleate And Film Boiling Heat Transfer From Copper Spheres, William David Hardin

Doctoral Dissertations

"This study consisted primarily of a laboratory investigation involving nucleate and film boiling heat transfer from copper spheres with saturated liquid nitrogen at atmospheric pressure. An initial study was directed towards obtaining reproducible boiling heat flux versus ΔT curves in the nucleate boiling region from surface conditions created by single and/or multiple glass bead peenings. The variables of bead size, nozzle line operating pressure, and distance a copper surface should be placed from the nozzle outlet were checked. The results indicated that a final peening of the surface with 0.0017-0.0035 inch diameter glass beads, a nozzle line pressure of approximately …

Development And Application Of Cartesian Tensor Mathematics For Kinematic Analysis Of Spatial Mechanisms, Robert Myrl Crane

Doctoral Dissertations

"The complexity of spatial mechanisms in themselves and the absence of an attractive analytical tool for their study has left this field of engineering analysis largely unexplored. In recent years several analytic methods have emerged. One of the most attractive of these is the tensor method. Literature surveys reveal that the tensor method is largely unexploited in the U.S.A., with regard to spatial mechanisms as well as simpler kinematic problems. The purpose of this work is to develop tensor mathematics for application to the kinematic analysis of spatial mechanisms. Methods are developed for position solutions and the determination of velocities …

Bound-Free Continuum Radiation From Non-Gray Nonisothermal Shock Layers, Chu Yih Wang

Masters Theses

"This study investigates the continuum radiative flux from nonisothermal stagnation shock layers composed of atomic gases. The general equations for the composition are derived and the Rankine-Hugoniot equations are simplified and solved to give the thermodynamic conditions of the shock layers. To accurately model the stagnation shock layer, the plasma must be considered to be nonisothermal. In the current study, linear shock layer temperature profiles are assumed. Consequently, the fluid dynamics and the radiation are uncoupled. The radiation model assumes one-dimensional radiative energy transport and considers only continuum processes. The radiative flux is calculated by considereing ground to free state …

Mutually Dependent Heat And Mass Transfer In Laminar Tube Flow, Gary Alfred Scheffel

Masters Theses

"An investigation is performed of the mutually dependent heat and mass transfer in laminar and hydrodynamically fully developed gas flow in a tube. Sublimation of mass occurs at the tube wall so that heat and mass transfer take place between the wall and the flowing gas stream. The wall of the tube is thermally insulated from the external environment with the result that the heat of sublimation is supplied by convective transport from the gas. The solution of this problem requires the simultaneous consideration of the energy and diffusion equations, with coupling provided by the boundary conditions. Mathematical expressions are …

Vibration Of A Rotating Cantilever Beam With An Independently Rotating Disk On The Free End, Darrell Blaine Crimmins

Masters Theses

"This thesis provides a vibration analysis of a rotating cantilever beam with an independently rotating thin circular disk on the free end. The exact differential equations of the system as defined by classical Bernoulli-Euler beam theory are written using the methods of the calculus of variations. The exact equations are not solved, but two different approximations are found by assuming a cubic polynomial deflection curve and applying the equation of Lagrange. The solutions are restricted to small deflections of the beam and a shaft stiffness which permits a deflection in only a single plane. Nonlinear differential equations result in the …

Analysis Of Elastic Thermal Stresses By Station-Function Collocation Methods, Jaw-Kuang Wang

Masters Theses

"An approximate method for the solution of thermal stress problems is presented. The method makes use of polynomial approximations to reduce the partial differential equation to a system of linear algebraic equations or a set of first-order ordinary differential equations. This results in satisfying the differential equation at a finite number of stations. The boundary conditions are satisfied identically. Two examples of the method, presented in detail, indicate that the solutions of the biharmonic equation for the stress function and the Fourier equation for the temperature distribution have good accuracy with a minimum of labor. A generalized method is derived …