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The Propagation Of Elastic-Plastic Strain Waves Through The Joint Between A Solid Rod And A Cylindrical Shell., Richard Rhorer

Mechanical Engineering ETDs

When a solid body collides with another solid body a disturbance, called a strain or stress wave, propagates through both objects. These strain waves have been investigated both experimentally and theoretically. Some of this work is summarized by Kolsky (1) and Goldsmith (2).

On Stable Fractures In A Uniaxial Stress Field, Barry P. Shafer

Mechanical Engineering ETDs

The general interests of engineers in fracture mechanics are oriented through their interest in the structural strength. The studies branched into two major areas in fracture theory, namely the initiation problem and the stability problem. Although some of the initiation problems could be approached through the existing failure theories, other aspects are still active research subjects, such as the statistical theory of fracture. In the stability problem, we are faced with a situation in which the adverse condition already exists because cracks are present. Whether the presence of the crack under the loading condition is insignificant or critical is the …

Solution Of Poisson's Equation In Two-, And Axisymmetric Three-Dimensional Geometry By Means Of A Capacitively-Coupled Conductive Paper Analog, Donald L. Hanson

Mechanical Engineering ETDs

Poisson’s equation is encountered in many branches of engineering analysis. For example, the velocity distribution of a fluid in steady laminar flow through a duct is described by Poisson’s equation. The stress distribution within cylindrical (including non-circular) torsion bars is described by the same equation. The temperature distribution within a body having distributed internal heat sources is still another physical quantity which requires the solution of Poisson’s equation for its determination. The internal heat sources of this last example may be of electrical, chemical, or nuclear origin.

Measurement Of Pressure And Velocity In A Heat Generated Acoustic Wave, Hernan Hirsch

Mechanical Engineering ETDs

The purpose of this study is (1) to investigate experimentally the magnitude and the phase angle between acoustic pressure ad velocity of the Sondhauss oscillation; (2) to investigate experimentally the pressure times velocity diagram; (3) to investigate experimentally the pressure versus volume diagram and its analogy to the Stirling heat engine, (4) to list observations of the behavior of the gas inside the tube, and the possible influence of these observations on the sound pressure level or velocity of the flow.

Temperature And Stress Distributions Produced In Long Circular Cylinders Cooled By Emission Of Thermal Radiation, Robert S. Pritchard

Mechanical Engineering ETDs

This study involves the determination of the temperature and stress distributions produced in long circumferentially symmetric circular cylinders cooled by emission of thermal radiation from the lateral surface. Temperature and strain responses obtained from an experimental model are presented for a set of parameters which correspond to the highest strain level which could be accurately determined with the strain gages. These responses are in good agreement with the results obtained by solution of an appropriate mathematical model. Temperature responses obtained from the same model, but having a higher initial temperature, are also presented and compared with analytical results. Reasonably good …

Cavity Effect In A Pressure Bar, Kenneth B. Simmons

Mechanical Engineering ETDs

The investigation deals with certain aspects of wave propagation in a rod containing a penny-shaped cavity, particularly fracture related to the presence of the cavity. When a rod containing a cavity is subjected to a compressive stress pulse, part of the pulse is transmitted past the cavity and part is reflected. When the end of the rod is free, the cavity is subjected to a reflected tensile pulse which, if strong enough, can cause fracture. The existence of the cavity tends to weaken the rod since there is a reduction in the cross-sectional area and a stress concentration effect. Epoxy …

Temperature Distribution And Thermal Stresses In Radiation-Cooled Circular Cylinders, William E. Putman Jr.

Mechanical Engineering ETDs

This study involves the determination of the transient temperature distribution and thermal stresses in a solid circular cylinder cooled by thermal radiation. The analytical solutions are presented in dimensionless form. Theoretical results are shown for temperature distribution and thermal stresses in the nondimensional form. Certain of these results are given in the dimensional form for the model cylinder used in this investigation.

The uranium-zirconium prototype element was thought to be undesirable for this investigation. Therefore, similitude was used to select a model which could be used for the experimental work. A solid, cylindrical, epoxy model was constructed, and thermocouples were …

The Development Of A Temperature Probe And Temperature Survey Of The Interaction Of An Oblique Shock Wave And A Turbulant Boundary Layer, Donald M. Yano

Mechanical Engineering ETDs

The purpose of this investigation was to develop a miniature air temperature probe and to measure temperatures in the interaction region of an oblique shock wave and a turbulent boundary layer.

Whole-Field Methods In The Measurement Of Post-Elastic Surface Strains, Siew Poh Chan

Mechanical Engineering ETDs

Several whole-field methods were studied and a new technique was developed for the purpose of measuring post-elastic surface strains in metals. Critical evaluation was given to the following experimental techniques: the moire effect and the birefringent coating.

Transient Response Of Linear Undamped And Lightly Damped Lumped Spring-Mass Systems By Graphica Techniques, Richard O. Brooks

Mechanical Engineering ETDs

Responsive motions of linear undamped and lightly damped lumped spring mass systems subjected to transient inputs can be determined by several methods. All these methods require solving of the differential equation in some manner. Practically all techniques for solving the differential equations involve higher mathematics.

Experimental Investigation Of The Interaction Of An Oblique Shock Wave With A Turbulent Boundary Layer, Amado Arthur Trujillo

Mechanical Engineering ETDs

The purpose of the investigation was to accurately describe the interaction of a shock wave and a turbulent boundary layer based upon the measurement and subsequent analysis of both static and impact pressure throughout the interaction region.

A Study Of Temperature Measurement Precision In Debye-Scherrer Specimens During High Temperature X-Ray Diffraction Measurement Of Thermal Expansion, Roy Glenn Merryman

Mechanical Engineering ETDs

The literature cited covers a comprehensive survey on temperature measurement methods in thermal expansion determination utilizing X-ray diffraction from 1921 through 1961 and a compilation of all published data on the thermal expansion of gold from 1916 through 1960 and magnesium oxide from 1906 through 1961. References for comparison of the MgO results with those of the Bureau of Mines Interlaboratory Program of Thermal Expansion Measurements on MgO are also presented. The literature on temperature measurement was limited to those articles featuring camera design or temperature conditions, since to examine publications on all phases of thermal expansion was found to …

Determination Of Thermal Stresses At Interior Points, Siegfried Thunborg Jr.

Mechanical Engineering ETDs

Existing theory was used to determine the thermal stresses and strains throughout a long thick walled cylinder under equilibrium thermal conditions when the thermal gra­dient through the wall is dependent on radial position only.

A thick walled cylindrical model, made of a plastic material, was constructed and strain gages were imbedded in and mounted on the cylinder to determine strains at interior and surface locations. The cylinder was subjected to equi­librium and transient thermal conditions and thermal strains were measured. In the equilibrium thermal condition the measured strains were compared with those predicted by theory.

The results show that imbedded …

Radial Dislocations In Plane Stress., William J. Sieger

Mechanical Engineering ETDs

The elastic dislocation theory was used to obtain stress potentials for the dual dislocation problem. These solutions give the stress field for an infinite plane region containing a centrally located circular hole with two radial dislocations originating from opposite sides of the hole and extending into the region along a line perpendicular to the axis of applied load. Solutions were obtained for both the case of a linear dislocation relation along the cuts and for a parabolic relation.

Plastic Models For The Study Of Thermal Stresses, Carl W. Theisen

Mechanical Engineering ETDs

The purpose of this thesis was to determine and evaluate an experimental method for accurately measuring thermal stresses in structural shapes subjected to large transient thermal gradients, without introducing the problems of high temperature instrumentation, or expensive and elaborate test facilities. Most experimental methods consist of mounting high temperature strain gages on the prototype or model of the metal structure to be evaluated, thermal shocking the structure and then recording the accompanying strains. This method is used quite extensively in the aircraft field, and in others, where the effects of thermal stresses must be considered. However, problems are encountered when …

The Development Of A Static Pressure Probe For The Interaction Region Of Shock Waves And Boundary Layers, John Rode

Mechanical Engineering ETDs

The purpose of this investigation was to develop a static pressure probe for measuring static pressures in the region of interaction of a shock wave and a boundary layer. Requirements of such a probe are: small size to permit measurement of pressure variations within the thin boundary layer, pressure coefficient close to unity to permit precise static pressure measurements in regions of unknown and varying velocity and proper response to large pressure gradients.

A Shell-Theory Analysis Of Transient Thermal Stresses In Moderately Thick-Walled Cylinders, Thomas K. Mckinley

Mechanical Engineering ETDs

This paper investigates the validity of extending the concepts of shell theory to transient thermoelastic problems involving moderately thick-walled shells. The region of study is a moderately thick-walled cylinder which is constrained radially at both ends and is exposed to a uniform, time-dependent heating (or cooling) at one end. The cylinder walls are assumed to be adiabatic, and inertia effects are neglected in the development.

It is concluded from the results of this investigation that the extension of shell theory to moderately thick-walled cylindrical regions subjected to axial, time-dependent temperature variations is an analytical method of approach.

Adaptation Of Beggs Deformeter Apparatus To The Solution Of Three-Dimensional Problems, Roland L. Finley

Mechanical Engineering ETDs

In the area of structural analysis and structural design, numerous efforts have been made and more are yet to be made toward solving statically indeterminate problems easily and with a high degree of accuracy. Fortunately, the great majority of such problems can be solved by one or more of the many mathematical methods that are normally used. However, the mathematical solutions become exceedingly difficult if and when it is desired to use irregularly shaped structural members.

The Control And Measurement Of Minute Curvatures In A Steel Shaft, Donald F. Wilkes

Mechanical Engineering ETDs

The primary purpose of this thesis was the solution of several special problems relating to the establishment, adjustment, and measurement of small elastic curvatures and the associated strains in a metal shaft. The solution of these problems was an important link in the development of a new type of seismometer for measuring extremely long periods with vibrations (up to 60 seconds). To achieve the sensitivity and long natural period of vibration required for accurate measurements of long-period waves, the seismometer employs a seismic mass which is suspended on an air film and constrained to follow an essentially horizontal guide rod. …

The Control And Measurement Of Minute Curvatures In A Steel Shaft, Donald F. Wilkes

Mechanical Engineering ETDs

The primary purpose of this thesis was the solution of several special problems relating to the establishment, adjustment, and measurement of small elastic curvatures and the associated strains in a metal shaft. The solution of these problems was an important link in the development of a new type of seismometer for measuring extremely long period with vibrations (up to 60 seconds). To achieve the sensitivity and long natural period of vibration required for accurate measurements of long-period waves, the seismometer employs a seismic mass which is suspended on an air film and constrained to follow an essentially horizontal guide rod. …

Shape Factors For Conduction Of Heat, Harry J. Otway

Mechanical Engineering ETDs

The purpose was to measure the heat conduction shape factors for cylinders and square prisms enclosed by spheres and to estimate the accuracy of the following approximation. This approximation is that of matching the area of the cylinder or prism to an equivalent sphere and then applying the analytical solution for concentric spheres.

A Study Of A Plane Dislocation Problem, Daniel D. Kana

Mechanical Engineering ETDs

This paper treats a more complete solution to the logarithmic spiral problem. Some changes in the basic dislocation theory are first accomplished to generalize the form of functions involved. The resulting equations are then applied to the logarithmic spiral dislocation at a hole in a large plate. A complete solution of pertinent stresses is obtained. Data are calculated to obtain the required dislocation relation along the logarithmic spiral cut, circumferential stress at the hole, and maximum shear stress along the dislocation cut.

Critical Masses Of Oralloy Cylinders With Multiple Reflectors Of Medium Z Elements, David P. Wood

Mechanical Engineering ETDs

Critical mass is influenced mainly by the density, concentration, and shape of the fissionable material, the degree of neutron moderation, and the type and thickness of reflector material. Most of these parameters have been explored in detail at the Pajarito Remote-Control Laboratory (1) and the present series of measurements has the purpose of investigating reflector materials in the middle of the periodic table for the more subtle influence of their resonance scattering structure.

An Experimental Method For Three-Dimensional Dynamic Stress Analysis, Larry E. Williams

Mechanical Engineering ETDs

It is the purpose of this thesis to present an evaluation of a method of experimental dynamic stress analysis utilizing electrical resistance strain gauges located internally. If it can be shown that the proposed experimental procedure is valid, then the transient stress phenomena could be continuously recorded from an internal, integral strain gauge placed at any desired location and in any orientation in a suitable model.

Effect Of Strain Rate And Temperature On The Stress-Strain Characteristics Of Plastics, Walter W. Joseph

Mechanical Engineering ETDs

The stress-strain characteristics of a material are a measure of the energy absorption characteristics of that material. Generally, plastics show permanent deformation at low values of strain but will withstand a large amount of strain before reaching their ultimate strength. Therefore, in effect, plastics are good energy absorbing materials. If the packaging designer could predict the effect of variation in strain rate and temperature on the stress-strain characteristics of a given plastic, his designs would be more reliable.

The Design Of A Solar Powered Air Conditioning System For An Albuquerque Office Building, Kuo S. Lee

Mechanical Engineering ETDs

The purpose of this investigation is to predict the performance of a solar powered jet refrigeration system for summer air conditioning, to measure the performance of the solar heat collector at the Bridgers and Paxton building in Albuquerque, and to design a Freon-12 ejector and generator for collection to that collector.

The Design, Construction And Investigation Of A Water Gravity Wave Analog Of Two-Dimensional Compression Waves In Gases, John H. Tenbrink

Mechanical Engineering ETDs

The purpose of this investigation was to design equipment for investigating and demonstrating supersonic air flow using water; to fabricate, assemble and calibrate this equipment; and to obtain and evaluate data on the validity of the supersonic flow analogy and the range of the equipment for classroom use.

Analysis Of Cushioned Impact By Wave Propagation Techniques, Lowell P. Martin

Mechanical Engineering ETDs

A typical problem of wave propagation which has received substantial attention concerns the longitudinal vibrations of a long, slender, uniform elastic rod after it has been dropped on one end.

The purpose of this investigation was to extend the problem to include the effect of cushioning material attached to the impacting end of a rod similar to that described above; and to conduct experiments designed to verify the analysis. This study is essentially the first step toward the analysis, by wave propagation methods, of many practical impact problems encountered in military airborne operations, experimental rocket programs, and the packaging industry.

A New Design Key Locked Insert And Automatic Key Installation Tool, Holt J. Gay

Mechanical Engineering ETDs

There has been an increasing need for a better steel insert or bushing between aluminum and steel bolts in the last few years with the rapid growth of the aircraft and missile industries. The steel insert or bushing threaded internally and externally, by increasing the area of contact with the aluminum raises the strength of the bolt fastening combination approximately 300 per cent or causes a 125,000 PSI bolt to fail rather than 40,000 PSI aluminum to fail. In addition, galling and seizing are practically eliminated. A bolt installed and removed just a few times in aluminum is likely to …

The Design, Construction, And Testing Of A Centrifugal Compressor Installation, James V. Neely

Mechanical Engineering ETDs

The purpose of this investigation was to design and build the equipment necessary to couple a Dodge automobile engine to an Allison aircraft engine supercharger; to assemble and instrument this instillation in such a manner that performance characteristics of the single stage centrifugal compressor could be determined; and to present and evaluate the data obtained in terms of appropriate dimensionless parameters.