Engineering Commons^™

Methods For Synthesizing A Four-Bar Mechanism So It Will Have A Low Value Of Jerk., Ronald D. Brenner

Masters Theses

"The purpose of this thesis is to find a method of synthesis, for a four-bar mechanism, so that the mechanism that is synthesized will have a low value of jerk. In the field of synthesis there has been little or no effort made to consider jerk when designing mechanisms.

Jerk is defined as the time rate of change of acceleration. Jerk can also be expressed as being proportional to the time rate of change of the inertia forces. When the jerk is large the effect on the link of a mechanism is the same as that of an impact load. …

A Study Of The Angular Velocity In A Liquid Induced By A Vortex In An Emptying Container, James Paul Hartman

Masters Theses

"Previously a limited amount of investigation has been done to describe the rotational motion of fluid in a draining tank. To date tank design has been based on trial and error, since the physical mechanisms of actual draining have not been recognized. This investigation has been made to develop a technique for the measurement of the motion of the fluid during the draining process and to present the results of the observed surface velocity of the liquid as a function of depth of fluid and its distance from the center of the vortex core. Many previous investigators of vortex behavior …

An Investigation Of Optimum Journal Bearings., Kulin Purshotam Maskai

Masters Theses

"Not much has been done towards calculating the "Optimum Bearing" from the point of view of maximum load capacity or minimum friction. It has been found that there 1 is not much difference in the "Optimum Bearing" proportions, as calculated, considering either minimum friction or maximum load capacity

Journal bearings are commonly used and they play a very important role in reducing friction and wear. Engineers use past experience in choosing a bearing for the given conditions. A bearing design can be obtained if 'Optium Bearing' proportions are calculated as suggested by Kingsbury (1) in his article on 'Optium Conditions …

A Study Of Rotational Critical Speeds For A Multi-Mass, Multi-Span System, Pravinchandra M. Upadhyay

Masters Theses

"It is well known that the unbalanced inertia forces present in rotating shafts set up violent vibrations in a transverse direction at certain speeds known as critical speeds, whirling speeds or whipping speeds. Therefore one who deals with the design of rotating machine parts, such as turbine rotors, multi-cylinder engine crankshafts etc., must consider transverse vibrations of rotating parts.

Practical solutions for finding the critical speeds of simple rotating systems, such as a single disk on a shaft with a single span, were derived by many authors. But as the number of loads and spans increases the problem becomes complex …

Investigation Of Ablation Materials, John Martyn Schattyn

Masters Theses

"The desired result of this paper is to determine what effect the physical and thermal properties of a material have on the ability of that material to act as an ablation heat shield. On the basis of their physical properties, five materials, nickel, beryllium, fused quartz, teflon, and phenolic-nylon, were chosen as examples.

The tools used for this study are heat transfer equations involving a change in material phase. The resulting criteria may be assumed applicable to any material exhibiting one of the four types of ablation processes"--Abstract, page 2.

The Effect Of Reradiation On Heat Transmission, Arvindkumar M. Shah

Masters Theses

"In heat transmission by radiation, it is very easy to find the heat transmitted from one surface to another. Much work has been done in this area. The problem becomes complicated when the two surfaces are enclosed or joined by an enclosure. Such problems frequently arise in the design of furnaces. One problem is linked with the economy of fuel, by proper consideration of heat losses through the openings in furnace walls such as doors and burner openings. A second problem is associated with the heating capacity and useful heat transfer through the openings such as heat ports in walls …

Heat Transfer Through A Honeycomb Sandwich Panel, Jayantilal J. Darji

Masters Theses

"Progress brought about by human ingenuity and technological developments has been always accompanied by fresh problems, the successful solution of which enables still further progress.

The recent developments in space exploration and exploitations are astounding. The coming years are likely to bring forth many remarkable achievements. Except for several engineering problems encountered with these developments the pace of progress is to study the heat transfer from honeycomb sandwich panels as an outer skin of high performance flight vehicles. The quantity of heat transferred through the panel is important in study of such vehicles, and methods or equations for determining this …

Analysis Of A Char-Forming Ablator, William J. Reilly

Masters Theses

"The purpose of this thesis is to conduct an analytical analysis of a char-forming ablation material. This is one phase of ablation heat transfer.

Fourier's general equation for one dimensional heat conduction is transformed to moving coordinates and is then solved using the applicable boundary conditions. Solutions of this equation are valid for initial studies in ablation heat transfer"--Abstract, page ii.

Methods For The Determination Of The Thermal Conductivity Of Solids., A. M. Sivadasan

Masters Theses

"The thermal conductivity of materials is of considerable practical and theoretical interest. Numerous publications on this subject have been presented with widely varying approaches and applications being made. Perhaps for no other thermal property are the published results so widely divergent and subject to such great uncertainty, particularly at high temperatures. This is partly due to unsolved difficulties in measurement, but perhaps to an even greater extent to the fact that the thermal conductivity of a material depends on its physical characteristics as well as some environmental factors such as humidity and temperature. In the case of metals or alloys, …

The Design, Construction, And Calibration Of A Hydrodynamic Journal Bearing Testing Machine., John H. Roberts

Masters Theses

"The purpose of this investigation was to design, construct, and calibrate a journal bearing testing apparatus. The design, construction, and operation of the apparatus are described.

Two bronze bearings with length to diameter ratios of 1.0 and 0.5 were tested using a gravity oil reed system. The speed and the location of inlet oil supply were varied, and the resulting coefficients or friction, oil flow rates, outlet oil temperatures, bearing shell temperatures, and eccentricities of the bearings were determined. These results were evaluated and compared with theoretical solutions.

The results compared favorably with the theoretical solutions and substantiated the use …

An Investigation Of A Constant Velocity Paper Unwinding Device, Jerry L. Gilmore

Masters Theses

"This thesis outlines one approach in designing a system which involves a second order nonlinear differential equation. A large number of variables are involved in this analysis. Therefore, there are many solutions to the problem but only a few of these will satisfy all required conditions. The analysis will be aided by the use of an analog computer. This computer can be manipulated to obtain optimum values for the different variables.

The computer results are presented in graphical form. Reasonable values for the different variables are obtained from these graphs.

The characteristics of the unwinding device were simulated on the …

Convective Heat Transfer In Small Enclosed Air Spaces., Joseph Charles Kroutil

Masters Theses

No abstract provided.

Parameters In Ablation Heat Sheilds, Franklin Chang Liang Lin

Masters Theses

"The desired result of this paper is a method of determining temperature distribution and burn off rate in a semi-infinite rod or shield subjected to a large heat flux. The possible methods of determination were investigated, and it was felt that an analytical approach turned out to be the most feasible.

The analytical analysis employed involves the use of the Fourier's general equation for one dimensional heat flow. Transformations from stationary to moving coordinates reduces the problem from unsteady state to steady state boundary conditions. The resulting equations can be applicable to the extent for the heat flow problems involving …

Thermocouple Shape Influence On Response In A Dynamic Compressible Fluid Atmosphere, Philip J. Steger

Masters Theses

"This investigation was performed to determine whether the geometrical shape of a thermocouple used to measure the temperature of a dynamic fluid atmosphere had any affect on its recovery factor and time response.

A converging nozzle was used to establish a dynamic fluid stream in which shaped silver solder junctions of copper-constantan thermocouples were tested. The velocity of the working fluid, air, was about 1000 ft/sec at the test point.

The investigation was successful, within experimental limits, in determining that the recovery factor of a bare thermocouple junction is not influenced by geometrical shape The results agreed substantially with available …

The Design, Construction, And Calibration Of An Apparatus To Determine The Thermal Conductivity Of Solids, Alan Edward Stephenson

Masters Theses

"Many pieces of equipment have been designed to determine the thermal conductivity of solids. They all, however, depend on the application of Fourier's equation of heat conduction in solids to determine the thermal conductivity. The apparatus used in this investigation is a modification of the guarded hot plate method used by the American Society for Testing Materials. Operation of the device is given in a step by step procedure both as a guide for others and also to show how it was operated during calibration of the apparatus. Data obtained in the calibration is given in tabular and graphical form …

A Study Of Rotational Critical Speed For A Multi-Mass System, Richard K. Brockmann

Masters Theses

"The object of this thesis is to demonstrate, by use of an IBM-1620 digital computer, a fast efficient method for locating natural frequencies of multi-mass rotational systems. Stress and deflection characteristics are examined at these frequencies also.

The shafts considered in this thesis are simply supported and symmetrically loaded with five concentrated masses. These five masses are placed at increments of 10 inches on a 60 inch shaft. The variable to be examined is shaft diameter, which is varied from 0.2 inch to 1 inch by increments of 0.2 inch. The effect of shaft weight, which is a function of …

Experimental Stress Analysis Of Bolts In A Flange Coupling, Bansidhar Shah

Masters Theses

"This thesis deals with the strength of a bolted joint which is subjected to tensile and bending loads. The purpose of this investigation was to derive expressions for the stresses developed in the bolts and the load producing separation of the joint.

A laboratory study of a flange coupling was made and the behaviour of flange bolts under different clamping forces was studied in tension and bending tests. The strain in the bolt was measured by mounting the strain gages on the shank of the bolt. From this, a graph of applied load versus strain in the bolt was plotted. …

A Parametric Study Of The Heat Transfer Characteristics Of A Moving Band Heat Exchanger, Larry Hyde Brim

Theses and Dissertations

In recent years much attention has been devoted to the development of efficient heat exchangers. The regenerative or moving matrix heat exchanger is one type which has been considered. Most regenerative heat exchangers use one of the conventional types of high area matrices mounted in a drum or disk in such a manner that it can be moved in a continuous cycle from a cold fluid stream to a hot fluid stream and back again. A rather different approach to the design of a regenerative heat exchanger which has been patented in this country is a set of flexible moving …

Stress Analysis Of An Infinite Cylinder With An Irregular Shaped Cavity Using Complex Variable Techniques, Gerald H. Lindsey

Theses and Dissertations

The advancement of modern technology has brought with It a demand upon the engineer for more thorough analysis techniques. This has been precipitated by the advent of missiles and space-craft that do not permit regular inspections to determine causes of failure, crack propagation, design weaknesses, etc. Thus, a more complete analytical work must be performed to facilitate a foreknowledge of reaction and performance of a particular design to its environment.

A Literature Review Covering The Effect Of Residual Stresses On Fatigue Strength Of Steel, Clarence A. Calder

Theses and Dissertations

Fatigue fracture usually is defined as the failure of a part at a stress below its breaking stress due to repetitive loading conditions. It is now a well known fact that a part, designed for a maximum stress well below the yield point of the material, may be very apt to fail under cyclic loading conditions over a period of time. The metal appears to "wear out" after a time just like humans do and fatigue failure occurs. Metal fatigue may be contrasted to animal fatigue in that l) its detection before the latter stages is normally difficult if not …

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.

The Aerodynamic Drag Of Spheres, Leon Rouzelle Scott

Theses and Dissertations

A literature survey was conducted to determine the factors which affect aerodynamic drag of spheres. Graphs are presented which show the effect of each variable where such information was available. Equipment was designed and built for the purpose of studying the effects of acceleration on the aerodynamic drag of spheres. Special emphasis was placed on the measurement and control of each of the other variables which can affect the drag. Tests were conducted using large spheres in air and water to show that the method presented can produce a valid determination of the drag coefficients. The numerical values of the …

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.

Test 822: Massey-Ferguson Super 90 (Diesel), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …

Irrigating Dry Season Crops In The Ord Valley : How To Prepare Land For Sowing, D F. Beech

Journal of the Department of Agriculture, Western Australia, Series 4

THE best way to grow dry season crops of safflower, linseed and rapeseed under irrigation in the Ord Valley is by sowing on to broad flat ridges, separated by small furrows 3 ft. 6 in. apart.

This system of sowing is called the "corrugation" method.

The Effects Of Tillage Implements On Cereal Yields, H M. Fisher

Journal of the Department of Agriculture, Western Australia, Series 4

Careful soil preparation is essential for cereal crops grown without fallow on clover ley land.

Crops give better yields where the land is broken up with a mouldboard or disc plough rather than a scarifier or similar machine.

The implements differ appreciably in their capacity to control weed growth and this is largely responsible for variations in cereal yields. "Takeall" disease is reduced by efficient weed control.