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1993

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Articles 31 - 60 of 328

Full-Text Articles in Mechanical Engineering

A Low-Dimensional Model For Chaos In Open Fluid-Flows, David J. Olinger Aug 1993

A Low-Dimensional Model For Chaos In Open Fluid-Flows, David J. Olinger

Mechanical Engineering Faculty Publications

A forced Landau-Stuart equation is studied in order to derive a low-dimensional model describing the temporal behavior of a paradigm open flow, the two-dimensional forced cylinder wake. Numerical results from the model exhibit several characteristics of circle maps, and compare qualitatively to previous experimental results for an oscillating cylinder wake. The low-dimensional model is also shown to reduce to a circle map in the limit of small forcing amplitudes. Observation of circle map dynamics in the forced Landau-Stuart equation strengthens the conjecture that globally unstable fluid flows are amenable to a dynamical systems approach focusing on the study of low-dimensional ...


Advanced Aeronatics Design: Project Based Engineering Education At Wpi, D. J. Olinger, William W. Durgin, Andreas N. Alexandrou Aug 1993

Advanced Aeronatics Design: Project Based Engineering Education At Wpi, D. J. Olinger, William W. Durgin, Andreas N. Alexandrou

Office of the Provost and Vice President of Academic Affairs Scholarship

One element of WPI's project-based curriculum is its interdisciplinary Advanced Aeronautics Design Program. Students participating in the program are involved in the design, construction, and flight testing of non-traditional aircraft such as an ultralight solar-powered vehicle, microwave-powered long endurance aircraft, or a flying oblique wing. The WPI project philosophy and character are described and illustrated using examples from the AAD program.


Analysis Of Sandwich Plates Subjected To Blast Loading, Vijay Prasad Bulla Aug 1993

Analysis Of Sandwich Plates Subjected To Blast Loading, Vijay Prasad Bulla

Master's Theses

A dynamic analysis is presented for the bending response of square sandwich plates with isotropic core and facings under blast type pressure. The maximum central deflections of simply supported plates under static and dynamic loadings are compared for various thicknesses and elastic moduli. The deviation of the thick sandwich plate results from the pure-bending theory results is presented for various core properties. Small deflection dynamic iso-response plots are shown for different core rigidities. To study the limits of small deformation linearity for various sandwich plates, non-linear results for deformations under high pressure loads are compared with the linear results. The ...


Rolling Friction Research Instrument, John P. Ward Aug 1993

Rolling Friction Research Instrument, John P. Ward

Master's Theses

An instrument has been analyzed, designed and constructed that will accurately measure the rolling resistance of metallic spheres an plane surfaces subjected to normal loading which will produce contact stresses approaching material yield.


Numerical Analysis Of The Pullout Problem Of A Fiber Embedded In A Matrix : Comparison With An Approximate Analytical Solution, Ivan Enrique Esparragoza Jul 1993

Numerical Analysis Of The Pullout Problem Of A Fiber Embedded In A Matrix : Comparison With An Approximate Analytical Solution, Ivan Enrique Esparragoza

FIU Electronic Theses and Dissertations

The classical problem of pullout of a long elastic rectilinear round bar (fiber) embedded in an elastic half-space (matrix) is considered before and while local debonding occurs. An approximate analytical solution derived from the elasticity theory, the intuitive Saint Venant's principle, the idea of boundary layer in hydrodynamics, and invariant Γ-integrals is presented. The problem is analyzed numerically by means of the finite element method using the ANSYS program. The cases of loading before and after the initiation of the debonding are studied. Both approaches, analytical and numerical, are compared in order to establish the concidence between them. The ...


Wet Process For Fly Ash Beneficiation, Jiann-Yang Hwang Jul 1993

Wet Process For Fly Ash Beneficiation, Jiann-Yang Hwang

Michigan Tech Patents

A wet process for the beneficiation of a fly ash by-product has the following steps: a) forming a slurry mixture of a fly ash material and a liquid; b) gravitationally separating and collecting a first material fraction of the fly ash having a density less than the liquid by skimming off floating slurry material; c) separating a first magnetic fraction from the slurry by subjecting the slurry to a magnetic field of from about 300 gauss to about 10 kilogauss; d) separating the unbumed carbon from the remaining slurry components by adding an effective amount of an oil having a ...


Variable Structure End Point Control Of A Flexible Manipulator, Shailaja Chenumalla, Sahjendra N. Singh Jul 1993

Variable Structure End Point Control Of A Flexible Manipulator, Shailaja Chenumalla, Sahjendra N. Singh

Electrical and Computer Engineering Faculty Publications

We treat the question of control and stabilization of the elastic multibody system developed in the Phillips Laboratory, Edwards Air Force Base, California. The controlled output is judiciously chosen such that the zero dynamics are stable or almost stable. A variable structure control (VSC) law is derived for the end point trajectory control. Although, the VSC law accomplishes precise end point tracking, elastic modes are excited during the maneuver of the arm. A Linear stabilizer is designed for the final capture of the terminal state.


A Vacuum Four-Ball Tribometer To Evaluate Liquid Lubricants For Space Applications, Masabumi Masuko, William R. Jones Jr, Ralph Jansen, Ben Ebihara, Stephen V. Pepper, Larry S. Helmick Jul 1993

A Vacuum Four-Ball Tribometer To Evaluate Liquid Lubricants For Space Applications, Masabumi Masuko, William R. Jones Jr, Ralph Jansen, Ben Ebihara, Stephen V. Pepper, Larry S. Helmick

Science and Mathematics Faculty Publications

The design and operation of a vacuum tribometer, based on the four-ball configuration, is described. This tribometer evaluates the tribological characteristics of liquid lubricants for space applications. Operating conditions include: room temperature, loads to approximately 1000N, speeds to approximately 500 rpm, and pressures of approximately 10(exp -6)Pa. Tests can also be run at atmospheric pressure with air or nitrogen. Some typical test results are included.


Finite Element Analysis For An Involute Spur Gear Noise Excitation By Impact Effects, Wenbeen Li Jul 1993

Finite Element Analysis For An Involute Spur Gear Noise Excitation By Impact Effects, Wenbeen Li

Electronic Thesis Collection

The purpose of this study includes (1) to identify the relationship between the impact loads or backlash and the sound field pressure of impact direct noise of meshing gears, (2) to show that impact whether or not the impact direct noise contributes to the noise of overall gear system, and (3) to demonstrate how impact direct noise can be predicted. The method used to predict was finite element analysis and numerical solution. This research presents the analytical model of impact direct noise prediction for meshing gear teeth based on the data that the tooth vibration and surface are known by ...


Exergetic Cost Analysis Of A Mechanical Exergy Recycle, Jim Mcgovern Jul 1993

Exergetic Cost Analysis Of A Mechanical Exergy Recycle, Jim Mcgovern

Conference Papers

A mechanical plant that involves an exergy recycle is presented for analysis. It consists of gearboxes and a fluid coupling. There is one input of shaft power to the plant and there are three separate outputs of shaft power. An exergetic cost analysis approach is outlined and applied to the plant.


Studies On Nonequilibrium Phenomena In Supersonic Chemically Reacting Flows, Rajnish Chandrasekhar Jul 1993

Studies On Nonequilibrium Phenomena In Supersonic Chemically Reacting Flows, Rajnish Chandrasekhar

Mechanical & Aerospace Engineering Theses & Dissertations

This study deals with a systematic investigation of nonequilibrium processes in supersonic combustion. The two-dimensional, elliptic Navier-Stokes equations are used to investigate supersonic flows with nonequilibrium chemistry and thermodynamics, coupled with radiation, for hydrogen-air systems. The explicit, unsplit MacCormack finite-difference scheme is used to advance the governing equations in time, until convergence is achieved.

For a basic understanding of the flow physics, premixed flows undergoing finite rate chemical reactions are investigated. Results obtained for specific conditions indicate that the radiative interactions vary substantially, depending on reactions involving HO$\sb2$ and NO species, and that this can have a noticeable influence ...


Boundary Layer Influences On The Subsonic Near-Wake Of A Family Of Three-Dimensional Bluff Bodies, Charles Willliam Alcorn Jul 1993

Boundary Layer Influences On The Subsonic Near-Wake Of A Family Of Three-Dimensional Bluff Bodies, Charles Willliam Alcorn

Mechanical & Aerospace Engineering Theses & Dissertations

A study is reported on subsonic bluff body near-wake flows. It has been determined that one family of bluff bodies, namely slanted-base ogive cylinders, can experience either a closed recirculating near-wake, or a longitudinal vortex near-wake depending on the base slant-angle and the Reynolds number. This suggests a dependence of near-wake parameters on the state of the boundary layer ahead of separation. This report addresses the influence of the boundary layer on the near-wake of slanted-base bluff bodies. Experiments were conducted in two facilities, the 6-inch Magnetic Suspension and Balance System (MSBS) at NASA Langley Research Center and the Old ...


Feedback Control Stabilization Of The No-Motion State Of A Fluid Confined In A Horizontal Porous Layer Heated From Below, Jie Tang, Haim H. Bau Jun 1993

Feedback Control Stabilization Of The No-Motion State Of A Fluid Confined In A Horizontal Porous Layer Heated From Below, Jie Tang, Haim H. Bau

Departmental Papers (MEAM)

We consider a horizontal three-dimensional saturated porous layer, confined in an upright cubic box, heated from below and cooled from above. In the absence of a controller, the fluid maintains a no-motion state for subcritical Rayleigh numbers R < Rc, where Rc, depends on the box’s aspect ratio. Once this critical number is exceeded, fluid motion ensues. We demonstrate that, with the use of feedback control strategies which suppress flow instabilities, one can maintain a stable no-motion state for Rayleigh numbers far exceeding the classical critical one for the onset of convection. To preserve the equilibrium no-motion state of ...


Optimization Of The Seating Position In A Human-Powered Vehicle, Y. Lei, Mohamed Trabia, D. Too Jun 1993

Optimization Of The Seating Position In A Human-Powered Vehicle, Y. Lei, Mohamed Trabia, D. Too

Mechanical Engineering Faculty Publications

Until recently, most of the human-powered vehicles (HPV) were designed focusing solely on its aerodynamics characteristic. In many of these HPV designs, the rider seating position was arbitrarily chosen without consideration of its effect on the rider's comfort and cycling effectiveness. Also, there is no guarantee that the seating position is related to maximum power output. Too (1991) used an experimental approach to determine that the rider will produce the maximum anaerobic power when the seat tube angle of a bicycle is at 75° whereas Hull and Gonzalez (1990) used an engineering approach to optimize the cycling biomechanics. However ...


Nonlinear Dynamic Finite Element Simulation Of Hydroelastic Mounts For Light Weight Vehicles, Talla Jayapal Reddy Jun 1993

Nonlinear Dynamic Finite Element Simulation Of Hydroelastic Mounts For Light Weight Vehicles, Talla Jayapal Reddy

Master's Theses

Modern light weight vehicles generate large noise levels, that may need bulky classical rubber mounts to suppress. Hydroelastic mounts can significantly reduce the vibration level of current production automobiles without weight penalty. However, the highly nonlinear behavior of hydroelastic mounts has not been established yet and its use is, therefore, limited to trial and error design methods.

This study discusses the implementation of nonlinear finite element simulation of hydroelastic mounts using the ANSYS finite element code. Fluid elements are limited to linear analysis and therefore are incompatible with the nonlinear hyperelastic elements. A method is proposed to simulate the fluid ...


Numerical Algorithms For Squaring-Up Non-Square Systems Part Ii: General Case, Pradeep Misra May 1993

Numerical Algorithms For Squaring-Up Non-Square Systems Part Ii: General Case, Pradeep Misra

Pradeep Misra

In this paper, we present numerical algorithms for
squaring a non-square system by finding -additional
columns in input matrix (for tall systems) and by
finding additional rows in output matrix (for wide systems).
Several case are considered depending up the
requirements on the ra of the input-output interaction
matrix.


On Orthogonal Collocation Solutions Of Partial Differential Equations, Herli Surjanhata May 1993

On Orthogonal Collocation Solutions Of Partial Differential Equations, Herli Surjanhata

Dissertations

In contrast to the h-version most frequently used, a p-version of the Orthogonal Collocation Method as applied to differential equations in two-dimensional domains is examined. For superior accuracy and convergence, the collocation points are chosen to be the zeros of a Legendre polynomial plus the two endpoints. Hence the method is called the Legendre Collocation Method. The approximate solution in an element is written as a Lagrange interpolation polynomial. This form of the approximate solution makes it possible to fully automate the method on a personal computer using conventional memory.

The Legendre Collocation Method provides a formula for ...


Coordinate Measuring Machines : A Modern Inspection Tool In Manufacturing, Matthias Richard Mantel May 1993

Coordinate Measuring Machines : A Modern Inspection Tool In Manufacturing, Matthias Richard Mantel

Theses

Coordinate Measuring Machines (CMM) are flexible and universal dimensional measuring devices with the capability for full integration into a CIM information network. Developed as highly precise measuring machines for specially designed measuring rooms, today's CMMs are more and more used in shop floor applications which is a hostile environment for a precise measuring tool. CMMs are offered in a variety of configurations and levels of automation. For the CMM buyer it is therefore essential to have an overview of the different types of CMMs and their subsystems before making a purchasing decision.

To obtain reliable measuring results that are ...


A Mathematical Model For The Prediction Of Depth Of Cut In The Course Of Awj Machining, Naijian Ma May 1993

A Mathematical Model For The Prediction Of Depth Of Cut In The Course Of Awj Machining, Naijian Ma

Theses

The objective of this study is to develop a practical mathematical model for prediction of the depth of cut in the course of Abrasive Water Jet (AWJ) machining. Semi-empirical method which is an integration of theoretical derivation and statistical analysis is used for process description. A theoretical model was constructed based on kinetic energy conservation equation, physical relationship among operating parameters, abrasive size, material properties and cutting results. Then, correlation between the depth of cut and operational parameters was analyzed in order to improve the theoretical model. Finally, a regression equation representing 1000 samples was constructed.

Three statistical criteria were ...


Design And Development Of Flexible Manufacturing Cells - A Case Study, Behrouz Barzani May 1993

Design And Development Of Flexible Manufacturing Cells - A Case Study, Behrouz Barzani

Theses

This paper covers the typical ills of American manufacturing companies and provides steps to selecting a flexible manufacturing cell(s) or system as a remedy. For that reason various definition of different types of flexibilities in manufacturing and the interrelationships between the several types have been examined. In addition, their purposes, means of obtaining them and some measurement and evaluations has been discussed. This was done to cover the basic but necessary requirements for understanding and selecting a flexible manufacturing system. Finally, the design process of a flexible system and its intuitive justification were discussed.


Quasi-Static Deflection Compensation Control Of Flexible Manipulator, Jingbin Feng May 1993

Quasi-Static Deflection Compensation Control Of Flexible Manipulator, Jingbin Feng

Dissertations and Theses

The growing need in industrial applications of high-performance robots has led to designs of lightweight robot arms. However the light-weight robot arm introduces accuracy and vibration problems. The classical robot design and control method based on the rigid body assumption is no longer satisfactory for the light-weight manipulators. The effects of flexibility of light-weight manipulators have been an active research area in recent years. A new approach to correct the quasi-static position and orientation error of the end-effector of a manipulator with flexible links is studied in this project. In this approach, strain gages are used to monitor the elastic ...


Measurement Of The Nonsteady Flow Field In The Opening Of A Resonating Cavity Excited By Grazing Flow, Hans R. Graf, William W. Durgin May 1993

Measurement Of The Nonsteady Flow Field In The Opening Of A Resonating Cavity Excited By Grazing Flow, Hans R. Graf, William W. Durgin

Office of the Provost and Vice President of Academic Affairs Scholarship

Flow past the opening of a cavity can excite acoustic resonance. The periodic velocity field in the region of the cavity opening has been measured for various flow conditions and the vorticity distribution has been computed from the measured data using numerical differentiation. The results indicate that the shear layer rolls up into discreet vortices, which travel across the cavity opening. Two resonances were found. The first is characterized by a single vortex being present and results in the greatest amplitude. The second is characterized by the presence of two vortices which excite a distinct but lesser amplitude resonance. As ...


Minutes Tractor Test And Power Museum April 14th, 1993, Tractor Museum Apr 1993

Minutes Tractor Test And Power Museum April 14th, 1993, Tractor Museum

Museum Planning and Development Documents

Use of tractor test building for museum.


Wobbling Gear Drivetrain For Cordless Screwdriver, David K. Kedrowski, Scott P. Slimak Apr 1993

Wobbling Gear Drivetrain For Cordless Screwdriver, David K. Kedrowski, Scott P. Slimak

Honors Theses

Manufacturers of cordless screwdrivers use two planetary gear trains in series to reduce speed and multiply torque from a small electric motor. Alternately, a nutating gear drivetrain has the potential to create comparable speed reductions and torque multiplications. To apply nutating gear theory to a cordless screwdriver drivetrain, a study of spur gears, planetary gear reducers, bevel gears, and the theory of nutation was undertaken. Finally, a nutating design was proposed. The advantages of a nutating gear drivetrain over a conventional planetary gear train include: a decreased number of drivetrain parts, an ability to use lower-strength gear materials, a higher ...


Fred Chase Preliminary Outline For Tractor Test Museum, Tractor Museum Apr 1993

Fred Chase Preliminary Outline For Tractor Test Museum, Tractor Museum

Museum Planning and Development Documents

No abstract provided.


Ole Miss Engineer 1993 Apr 1993

Ole Miss Engineer 1993

The Ole Miss Engineer

No abstract provided.


Navier-Stokes Simulation Of Quasi-Axisymmetric And Three-Dimensional Supersonic Vortex Breakdown, Hamdy A. Kandil Apr 1993

Navier-Stokes Simulation Of Quasi-Axisymmetric And Three-Dimensional Supersonic Vortex Breakdown, Hamdy A. Kandil

Mechanical & Aerospace Engineering Theses & Dissertations

Computational simulation of supersonic vortex breakdown is considered for internal and external flow applications. The interaction of a supersonic swirling flow with a shock wave in bounded and unbounded domains is studied. The problem is formulated using the unsteady, compressible, full Navier-Stokes equations which are solved using an implicit, flux-difference splitting, finite-volume scheme. Solutions are obtained for quasi-axisymmetric and three-dimensional flows. The quasi-axisymmetric solutions are obtained by forcing the components of the flowfield vector to be equal on two axial planes, which are in close proximity to each other. For the flow in a bounded domain, a supersonic swirling flow ...


Silicon Carbide/Electroless Nickel Composite Plating For Aluminum Substrates, Ben Charbit Apr 1993

Silicon Carbide/Electroless Nickel Composite Plating For Aluminum Substrates, Ben Charbit

Master's Theses

The effectiveness of producing a composite coating by suspending micron-sized particles in an electroless nickel bath while plating a 2024T4 aluminum alloy part was studied. The variation in the count of particles trapped in the nickel coating due to changes in the particle size, concentration of the particles in the bath, and the substrate surface texture was also studied. Particle sizes of 1 micron and 10 microns, concentrations of 15 gr/lt and 30 gr/lt, and polished and blasted textures were used. It was found that this technique is an effective way to produce composite coatings rendering a high ...


Robust Control Of Nonlinear Multibody Flexible Space Structures, Atul G. Kelkar Apr 1993

Robust Control Of Nonlinear Multibody Flexible Space Structures, Atul G. Kelkar

Mechanical & Aerospace Engineering Theses & Dissertations

A generic nonlinear math model of a multibody flexible system is developed. Asymptotic stability of such systems using dissipative compensators is established. It is proved that, under certain conditions, this class of systems exhibit global asymptotic stability under dissipative compensation. The dissipative compensators considered are static as well as dynamic dissipative compensators. The stability proofs are based on passivity approaches, Lyapunov methods, as well as a key property of such systems, i.e., skew-symmetricity of certain matrix. The importance of the stability results obtained is that the stability is robust to parametric uncertainties and modeling errors.

For static dissipative compensators ...


Formal Recognition Of Museum Committee 1993, Tractor Museum Feb 1993

Formal Recognition Of Museum Committee 1993, Tractor Museum

Museum Planning and Development Documents

Recognition of Museum