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Articles 1 - 27 of 27

Full-Text Articles in Engineering Science and Materials

In Situ Mechanical Characterization Of The Mixed- Mode Fracture Strength Of The Cu/Si Interface For Tsv Structures, Chenglin Wu, Congjie Wei, Yanxiao Li Jan 2019

In Situ Mechanical Characterization Of The Mixed- Mode Fracture Strength Of The Cu/Si Interface For Tsv Structures, Chenglin Wu, Congjie Wei, Yanxiao Li

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In situ nanoindentation experiments have been widely adopted to characterize material behaviors of microelectronic devices. This work introduces the latest developments of nanoindentation experiments in the characterization of nonlinear material properties of 3D integrated microelectronic devices using the through-silicon via (TSV) technique. The elastic, plastic, and interfacial fracture behavior of the copper via and matrix via interface were characterized using small-scale specimens prepared with a focused ion beam (FIB) and nanoindentation experiments. A brittle interfacial fracture was found at the Cu/Si interface under mixed-mode loading with a phase angle ranging from 16.7° to 83.7°. The mixed-mode fracture ...


Computational Dynamics And Virtual Dragline Simulation For Extended Rope Service Life, Muhammad Wardeh Jan 2018

Computational Dynamics And Virtual Dragline Simulation For Extended Rope Service Life, Muhammad Wardeh

Doctoral Dissertations

"The dragline machinery is one of the largest equipment for stripping overburden materials in surface mining operations. Its effectiveness requires rigorous kinematic and dynamic analyses. Current dragline research studies are limited in computational dynamic modeling because they eliminate important structural components from the front-end assembly. Thus, the derived kinematic, dynamic and stress intensity models fail to capture the true response of the dragline under full operating cycle conditions. This research study advances a new and robust computational dynamic model of the dragline front-end assembly using Kane's method. The model is a 3-DOF dynamic model that describes the spatial kinematics ...


Mechanics Of Impulse Force Reduction For Mitigating Dump Truck Vibrations Under Hislo Conditions, Danish Ali Jan 2016

Mechanics Of Impulse Force Reduction For Mitigating Dump Truck Vibrations Under Hislo Conditions, Danish Ali

Masters Theses

"The deployment of large capacity shovels and dump trucks, for achieving economic bulk production capacities, has resulted in high impact shovel loading operations (HISLO). These large shovels generate high impact forces when loading dump trucks with over 100-ton passes under gravity. The impact forces also generate high frequency shock waves, which cause severe truck vibrations, and thus, expose dump truck operators to high levels of whole body vibrations (WBV). The dynamic impact force generates these vibrations, and thus, there is a need to develop efficient technologies to eliminate or reduce its impact. Existing literature and industry practice show that this ...


Helical Force Flow: A New Engineering Mechanics Model For Biological Materials, Jeffery S. Thomas Jan 2009

Helical Force Flow: A New Engineering Mechanics Model For Biological Materials, Jeffery S. Thomas

Doctoral Dissertations

"The author has long speculated that the prevalence of helical structures in botany and zoology hints to an optimized pathway for force and/or energy transfer. His goal has been to realize an alternative approach to the standard stress analysis used in engineering in order to more efficiently and accurately deal with biological materials. Improved tools for these natural materials should in turn aid the design and analysis of engineered materials. Following the role of a navigator in leaf C. Levesque's book "Breakthrough Creativity", the author typically searches for ideas in a variety of places, including physics, materials science ...


The Analysis Of An Axially Symmetric Submerged Membrane Shell, Walter Earl Wehmeyer Jan 1972

The Analysis Of An Axially Symmetric Submerged Membrane Shell, Walter Earl Wehmeyer

Masters Theses

"The general theory of large elastic deformations is applied to the problem of a liquid-filled, axisymmetric membrane which is supported on a rigid horizontal plane and subjected to a variable external pressure. The variable external pressure is caused by submerging the membrane to various depths. The variation of the hydrostatic pressure in the inflating medium as well as in the surrounding environment is considered. By assuming large meridional deformations the stress field and the deformed shapes of a submerged membrane made of a neo-Hookean material are obtained. The effect of the initial shape on the deformed configuration of the membrane ...


A Study Of The Effect Of Drilled Holes On The Concentration Of Elastic Stresses Around A Notch, Glenn Michael Kmecz Jan 1972

A Study Of The Effect Of Drilled Holes On The Concentration Of Elastic Stresses Around A Notch, Glenn Michael Kmecz

Masters Theses

"Hole drilling as a method for improving the toughness of notch weakened tensile specimens is investigated by means of a photoelastic technique. Tests were performed on 20%, 40%, 60%, and 80% notch depth specimens machined from PSM-1 photoelastic material. The basic criteria for success was no increase in the elastic stress concentration factor. The photoelastic results were verified by a finite element stress analysis of the 60% notch depth specimens. Comparison of the experimental and numerical results provide conclusive proof that no increase in the elastic stress concentration factor occurs when proper positioning of the drilled holes is accomplished"--Abstract ...


A Comparison Of Analytical And Experimental Approaches In Determining The Thermoelastic Stresses Around A Cylindrical Inclusion Of Elliptical Cross-Section, Kenneth Byron Oster Jan 1972

A Comparison Of Analytical And Experimental Approaches In Determining The Thermoelastic Stresses Around A Cylindrical Inclusion Of Elliptical Cross-Section, Kenneth Byron Oster

Masters Theses

"Three approaches are used to determine the principal stress differences in an infinite elastic medium containing a cylindrical inclusion of elliptic cross-section due to a uniform temperature change. First, the two-dimensional equations of thermoelasticity are solved resulting in equations for the stress components anywhere in the medium material. Second, boundary displacements based on stress-strain relations are used as input displacements in a finite element program of the medium. Third, these same boundary displacements are used as input displacements on a photoelastic model simulating the medium. The problem is treated as one of plane strain in the first approach and one ...


Normal Mode Method Applied To The Transient Longitudinal Vibrations Of A Finite Rod With Material Damping And Viscoelastic Dispersion, David Arthur Levene Jan 1971

Normal Mode Method Applied To The Transient Longitudinal Vibrations Of A Finite Rod With Material Damping And Viscoelastic Dispersion, David Arthur Levene

Masters Theses

"Longitudinal vibrations of a finite rod with material damping and frequency dependent material properties are examined. The normal mode method is used to investigate the transient response of a rod which is free to move in the longitudinal direction and is subjected to a transient longitudinal loading condition at one end. The equations of motion are derived and solved using both the differential equations approach and the energy methods approach of the normal mode method. The effects of material damping and frequency dependent material properties are considered by formulating the stress-strain relation for the material such that the modulus of ...


An Energy Solution For Vibration Characteristics Of Free Thin Cylinders, Dale Elmer Leanhardt Jan 1971

An Energy Solution For Vibration Characteristics Of Free Thin Cylinders, Dale Elmer Leanhardt

Masters Theses

"In this report the flexural vibrations of the walls of free, thin, circular cylinders are considered. Theoretical expressions are developed for the natural frequencies by extending the approximate energy method of Arnold and Warburton to the free-free case. Furthermore, the developed expressions are shown to apply, as special cases, to the fixed-fixed and simply-supported cylinders analyzed by Arnold and Warburton. The energy solution for free-free cylinders is checked both experimentally using a 3500 pound-force, 5 to 2000 hertz, vibration exciter and numerically using the well documented SABOR IV-DYNAL finite element program. While the derived energy method accounts for any prescribed ...


An Investigation Of Stress In The Monowall Construction System Subjected To Racking Loads, Louis Alex Kuhlmann Jan 1971

An Investigation Of Stress In The Monowall Construction System Subjected To Racking Loads, Louis Alex Kuhlmann

Masters Theses

"Several methods of analysis were employed to investigate the stress conditions of concrete block built in the MONOWALL Construction System, when subjected to racking loads. MONOWALL is a technique of assembling blocks with adhesive rather than conventional portland cement mortar. The analyses used in this study included strain gages on full-scale walls, photoelastic models, and a mathematical solution. Each method of analysis is reported separately in detail and the results compared to each other"--Abstract, page ii.


Hydrostatic Extrusion Of Tubular Products, John Lester Roth Jan 1971

Hydrostatic Extrusion Of Tubular Products, John Lester Roth

Masters Theses

"The production of quality tubular products by hydrostatic extrusion has been demonstrated to be a highly satisfactory method. The forming of tubes by the floating mandrel method has been accomplished on mild steel, aluminum alloy, and brass. This thesis describes the method, equipment design and operation, and the results obtained in the hydrostatic tube extrusion. A discussion on the advantages of the use of hydrostatic over conventional extrusion is included. The hydrostatic extrusion system designed for this study is described in detail"--Abstract, page ii.


Free Vibrations Of Circular Cylindrical Shells, Sushil Kumar Sharma Jan 1971

Free Vibrations Of Circular Cylindrical Shells, Sushil Kumar Sharma

Masters Theses

"In this report bending theory of shells is used to determine the natural frequencies and mode shapes of circular cylindrical shells. The governing eighth-order system of differential equations has been put in a form which is especially suitable for numerical integration and application of different sets of homogeneous boundary conditions. The Holzer method is used to solve the eigenvalue problem. During numerical integration of the differential equations, the exponentially growing solutions are suppressed whenever they become larger than previously selected values. Numerical results are obtained for various shell geometry parameters and for three different sets of homogeneous boundary conditions. These ...


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 ...