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Masters Theses

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Articles 61 - 75 of 75

Full-Text Articles in Engineering Science and Materials

A Study Of The Effects Of Pressure-Induced Viscosity Changes On The Fluid Flow Characteristics In A Circular Tube, Robert Charles Weber Jan 1970

A Study Of The Effects Of Pressure-Induced Viscosity Changes On The Fluid Flow Characteristics In A Circular Tube, Robert Charles Weber

Masters Theses

"A method of determining the response of fluids under high pressure to quick-release into the atmosphere is presented in this report. The analytical efforts have been formulated into two parts, a closed-form solution and a numerical analysis. By assuming constant viscosity of the fluid a closed-form solution was obtained. The assumption of constant viscosity was found to be acceptable for the test fluids up to an initial pressure of approximately 10,000 psi. A numerical analysis became necessary for initial pressures over 10,000 psi, where the variable viscosity of the fluid had to be considered. The experimental work was ...


Failure Of Lined And Unlined Small-Scale Cavities In Rock-Like Materials, Seung-Ki Yang Jan 1970

Failure Of Lined And Unlined Small-Scale Cavities In Rock-Like Materials, Seung-Ki Yang

Masters Theses

"The strain conditions around statically loaded circular openings in rock-like materials and corresponding cavity-wall displacements were determined experimentally with resistance strain gages. The models were fabricated with lined and unlined openings simulating underground tunnels. Tests were performed with models of two different materials in plane stress and plane strain. Rock-like materials were designed and the strain gages were embedded at selected points within each model. The models often failed by tensile splitting through the opening early in the loading cycle causing the strains at certain points to deviate considerably from the theoretical values. Tangential strains on the vertical axis were ...


The Design, Construction And Experimental Verification Of A Split Hopkinson Bar, Woosoon Bai Jan 1970

The Design, Construction And Experimental Verification Of A Split Hopkinson Bar, Woosoon Bai

Masters Theses

"This thesis presents the design considerations for a dynamic loading device utilizing a projectile fired from a tube. Also included is a preliminary investigation of the stress-strain relation, under dynamic loading with the device, for a plaster known as Hydrostone. Design of the unit is based on the split Hopkinson pressure bar originally developed by Kolsky and on a similar unit in use at the Lawrence Radiation Laboratory, Livermore, California. The strain pulses along the pressure bars are sensed by resistance wire strain gages and displayed on an oscilloscope. The oscilloscope traces are photographed and manually digitized for insertion into ...


Vibration Of An Internally Damped Tapered Truncated Cantilever Beam, Chimanbhai Magandas Patel Jan 1969

Vibration Of An Internally Damped Tapered Truncated Cantilever Beam, Chimanbhai Magandas Patel

Masters Theses

"This thesis provides a vibration analysis of an internally damped, tapered, truncated, cantilever beam. Using two formulations of the problem based on: (1) Discrete mass and (2) continuous mass distribution, solutions are given for a beam having square cross section with linear depth and linear width variation. A Kelvin viscoelastic material for the beam is assumed. The vibration of the beam is considered to produce plane stress in the material, and the stress-strain relationship is applied only to the strain in the plane of bending. An exact solution for frequency of oscillation, mode shape, and steady state response is obtained ...


Effects Of Pressure On The Mechanical Properties Of Magnesium, Joseph George Hoeg Jan 1968

Effects Of Pressure On The Mechanical Properties Of Magnesium, Joseph George Hoeg

Masters Theses

"The data collected in an attempt to evaluate the pressure dependency of the mechanical properties of extruded AZ31B-F magnesium alloy are presented herein. This information was compiled from the results of compression tests run in hydraulic fluid environments pressurized to 50,000 psi, and tension tests run in the atmosphere. Specimen axial load and longitudinal strain were recorded and converted to effective stress and effective strain parameters for presentation. The term pressure is defined, in this report, as the negative average of the principal stresses or, essentially, the negative of the hydrostatic component of stress. The effective stress and strain ...


An Analysis Of Dirac Delta Generated Spherical Waves In An Infinite Maxwell Medium, William F. Breig Jan 1968

An Analysis Of Dirac Delta Generated Spherical Waves In An Infinite Maxwell Medium, William F. Breig

Masters Theses

"It is an accepted fact that the simple Maxwell and Voigt models do not usually represent the behavior of real materials. In order to make the results of a model more realistic, other combinations of springs and dashpots must be considered. To understand the more complicated models, it is desirable to have a knowledge of the Maxwell model since this element usually occurs either in series or in parallel in the advanced models. This investigation reports solutions of the spherical wave equation in both the elastic and viscoelastic media. Laplace transform techniques are used to obtain the parameters; stress, velocity ...


A Numerical (Matrix) Solution For The Vibration Frequencies And Modes Of A Nonuniform Rectangular Plate With Arbitrary Edge Conditions, F. David Utterback Jan 1968

A Numerical (Matrix) Solution For The Vibration Frequencies And Modes Of A Nonuniform Rectangular Plate With Arbitrary Edge Conditions, F. David Utterback

Masters Theses

"The material presented in this thesis is designed to provide the practicing engineer with a practical, approximate method of solution for the increasingly important problem of plate vibrations. The technique presented herein is basically an application of the use of generalized coordinates to describe the elastic and inertial properties of a finite element representation of a nonuniform rectangular plate. The plate will be idealized by utilizing a modification of the grid work technique developed by Hrennifkoff as a lattice work of interconnecting beams. By employing the elastic displacements as generalized coordinates, the only required compatibility conditions are that the displacements ...


Dynamic Response Of A Simply Supported Beam To An Accelerating Point Load, Joseph Victor Cusumano Jan 1967

Dynamic Response Of A Simply Supported Beam To An Accelerating Point Load, Joseph Victor Cusumano

Masters Theses

"An analysis based on linear theory is presented for determining the dynamic response of a simply supported beam on an elastic foundation acted upon by a moving time dependent point force with axial forces included. This thesis extends the present theory to include an analysis of a point force accelerating uniformly across the beam. In particular, it is shown that the customary resonance conditions which are prevalent for a point force moving with uniform velocity no longer exist for the case of a point force accelerating uniformly across the beam.

The basic problem and its solution are presented for a ...


Stresses In A Thick Spherical Shell, David Wayne Moore Jan 1967

Stresses In A Thick Spherical Shell, David Wayne Moore

Masters Theses

"This thesis reports a method to evaluate the stresses in a segment of a thick spherical shell. In the numerical examples loads due to thermal expansion as the shell is constrained at the free edge and a dead load acting vertically downward were considered for a shell assumed pinned but free to rotate and for a shell assumed completely fixed at the edge. A concrete shell was specifically studied but the method would also apply to a shell of any homogeneous, isotropic material"--Abstract, page i.


Collision And Pursuit Course Terminal Closures For Spacecraft To Satellite Rendezvous, John Anthony Campbell Jan 1967

Collision And Pursuit Course Terminal Closures For Spacecraft To Satellite Rendezvous, John Anthony Campbell

Masters Theses

"Collision and pursuit course closure maneuvers were studied for correcting position and velocity errors in the terminal phase of spacecraft to satellite rendezvous.

Minimum values of the ratio of initial range to velocity necessary to achieve rendezvous were determined for collision closures as a function of the initial line of sight. The time and velocity increment required for rendezvous were computed as a function of initial conditions.

Pursuit closure maneuvers were analyzed and time and velocity increments defined as a function of initial range, closing velocity, line of sight angle and angular velocity.

The velocity increments required were significantly higher ...


Plastic Deformation Of Thin Plates With A Spherical Indenter, Benjamin Jen-An Chang Jan 1967

Plastic Deformation Of Thin Plates With A Spherical Indenter, Benjamin Jen-An Chang

Masters Theses

"A method of determining the stress distribution in a thin plate deformed with a spherical indenter is presented in this report. The analysis is formulated in cylindrical coordinates and utilizes the basic principles of plasticity (von Mises yield criteria, Luwig stress-strain equation, Hencky Deformation theory, etc.). The problem is solved through the utility of a displacement function that, by virtue of its definition, automatically assures that the condition of volume constancy is satisfied. The boundary conditions are selected on the basis of having average, or integrated, effects corresponding to the physical constraints of the problem. Numerical integration is introduced to ...


The Effect Of Combined Torsional And Bending Loads On A Channel Beam With One End Restrained From Warping, David M. Schaeffer Jan 1966

The Effect Of Combined Torsional And Bending Loads On A Channel Beam With One End Restrained From Warping, David M. Schaeffer

Masters Theses

"Channel beams have been designed with the main purpose of giving large resistance to bending while the torsional strengths are known to be relatively small. In this experiment, a cantilevered channel beam was loaded with a concentrated load at the free end, first through the experimentally determined shear center and then through the centroid of the cross section. For each loading condition, the strains were measured with the aid of SR-4 strain gages placed at intervals along the length of the beam. With the aid of a computer, the strains were converted into longitudinal stresses and these stresses were compared ...


Modal Characteristics Of A Vibrating Truss, Edd Leighman Ghent Jr. Jan 1966

Modal Characteristics Of A Vibrating Truss, Edd Leighman Ghent Jr.

Masters Theses

"In this thesis, a complete technique is presented for the vibration analysis of any planar structure which can be classified in the broad category of trusses or frames. Although a theoretical backdrop is included for the' sake of completeness, the intent is to provide a technique that is readily adapted to computer usage and can be handled with a minimum of confusion or misunderstanding.

The problem is solved by the use of a displacement technique wherein the inertia and stiffness properties of a structure are calculated by superimposing the contributions of each component of the structure. The calculation of these ...


Comparison Of Plastic Stress-Strain Material Properties As Determined From Conventional Experiments, Wen Mo Chen Jan 1966

Comparison Of Plastic Stress-Strain Material Properties As Determined From Conventional Experiments, Wen Mo Chen

Masters Theses

"In problems of engineering design, it is usually assumed that the stress-strain diagrams of a given material, as obtained from different loading conditions, are the same. In fact, by using the classical theory of plasticity, it can be shown that, with an appropriate selection of stress and strain related parameters, the diagrams should coincide.

Three different materials - magnesium, aluminum and steel, have been tested under tension, compression, torsion and bending loads. Stress-strain diagrams were constructed from these observations. This thesis presents an analysis of the relative agreement between the theoretical and experimental results of these materials"--Abstract, page i.


A Photoelastic Study Of The Stresses In A Deep Beam Using Partial Mirrors For Isochromatic Fringe Sharpening And Fringe Multiplication, Edward M. Raney Jan 1966

A Photoelastic Study Of The Stresses In A Deep Beam Using Partial Mirrors For Isochromatic Fringe Sharpening And Fringe Multiplication, Edward M. Raney

Masters Theses

"This paper is a photoelastic investigation of the stresses in a deep beam using partial mirrors to obtain isocromatic fringe sharpening and fringe multiplication. This method may be of particular value in photoelastic work for obtaining full field fringe multiplication and fringe sharpening for models which exhibit low fringe orders.

The photoelastic model used in this investigation is a deep beam with a length to depth ratio of one. A uniform load is applied over the center one-half of the beam. The beam is supported by two uniform loads distributed over a length of one-quarter the span.

A first approximation ...