Digital Commons Network^™

Finite Element Analysis Of Torsional Concentric Composite Shaft Using Isoparametric Circular Element, Yee-Haur Wong

Theses

Finite Element Method is used to analyze the concentric composite material shaft subjected to torsion. Isoparametric circular ring element has been formulated to solve the one-dimensional problem. An intermaterial element at the interface has been developed to accomodate the changing modulus of rigidity.

Solutions of Prandtl's stress functions are used to compute shear stresses and torque in the composite shaft. Results of torque of the composite shaft are established using convergence tests of homogeneous solid and hollow shafts. Good agreement with classical solutions are obtained for homogeneous solid and hollow shafts.

A Torsional Concentric Composite Chart has been developed showing …

Characterization Of Material Removal In The Course Of Abrasive Waterjet (Awj) Machining, Yu Yang

Theses

The objective of this study is to develop a practical procedure for prediction of the results of abrasive waterjet (AWJ) machining. The first stage of the study involves the development of the technique for prediction of the rate of material removal in the course of abrasive waterjet (AWJ) machining. A new parameter, Exergy Distribution Density (EDD), is introduced and used in order to characterize the cutting conditions. EDD, determined as the kinetic energy of particles delivered to a unit length of the generated surface, is the function of diameters of the sapphire nozzle (Dn) and the focusing tube (Dc), the …

Composite Structure Ultimate Strength Prediction From Acoustic Emission Amplitude Data, James Lewis Walker Ii

Master's Theses - Daytona Beach

The acoustic emission (AE) given off by a structure as it is stressed provides a passive means to characterize flaw growth activity in complex structures. This thesis demonstrates how the qualitative analysis of AE data can be refined to provide a quantitative tool for predicting the ultimate strength of composite tensile test specimens. From an original sample set of only six specimens, a multivariate statistical analysis was used to generate an ultimate strength prediction equation. The variables of the multivariate statistical analysis were obtained through the mathematical modeling of the specimen’s AE amplitude distributions produced during proof testing. Ultimate strengths …

Radon Pressure Differential Project; Phase Ii Infiltration, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Testing has been done on 50 central Florida homes to assess and characterize house infiltration rates in new (age five years or less) Florida homes. These 50 were drawn randomly from a sample of 70 homes which had been previously tested to determine house airtightness, air distribution system leakage, and pressure differentials. The 50 homes had an average airtightness of 7.31 air changes per hour at 50 Pascals (ACH50). Significant leaks were found in the ductwork in a majority of homes tested, both on the supply and return sides of the air handler. When the air distribution system was sealed …

The Dynamics Of Bicycling : An Analytical And Experimental Investigation To Determine The Principles Of Design, Sylvester Yen

Theses

Bicycles have existed in working order for a century. They are mechanical products whose dynamic characteristics are highly nonlinear. This has to some extent prevented detailed analysis and for the most part design has been made from practical experience. The advent of computers has markedly changed the techniques and procedures used to calculate the performance of a bicycle. Bicycling began long ago, and since the first bicycle was demonstrated, bicyclists, scientists and engineers have designed thousands of different bicycles considering safety, comfort to ride and ease of control. Nonetheless, nobody claims to fully understand bicycling. If the fundamental principles exist, …

Space Structures: Issues In Dynamics And Control, H. Benaroya, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

A selective technical overview is presented on the vibration and control of large space structures, the analysis, design, and construction of which will require major technical contributions from the civil/structural, mechanical, and extended engineering communities. The immediacy of the U.S. space station makes the particular emphasis placed on large space structures and their control appropriate. The space station is but one part of the space program, and includes the lunar base, which the space station is to service. This paper attempts to summarize some of the key technical issues and hence provide a starting point for further involvement. The first …

Development Of A Perturbation Generator For Vortex Stability Studies, John Edward Riester Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Theory predicts vortex instability when subjected to certain types of disturbances. It was desired to build a device which could introduce controlled velocity perturbations into a trailing line vortex in order to study the effects on stability. A perturbation generator has been designed and manufactured which can be attached to the center-body of an airfoil type vortex generator. Details of design tests and manufacturing of the perturbation generator are presented. The device produced controlled perturbations with frequencies in excess of 250 Hz. Preliminary testing and evaluation of the perturbation generator performance was conducted in a 4 inch cylindrical pipe. Observations …

The Effectiveness Of Viscoelastic Damping Treatments On A Flexible Manipulator Subjected To Torsional Loads, Leah L. Remias

Mechanical & Aerospace Engineering Theses & Dissertations

The advent of new technology has led to an increasing number of missions in space. The space shuttle Remote Manipulator System (RMS) is a lightweight flexible manipulator currently used in NASA space missions. The future role of the RMS and similar flexible manipulators may include in-space construction and assembly tasks. Because these tasks require precise motion and short settling time of the end-point oscillations, effective vibration control schemes are being investigated.

Passive damping techniques have shown to provide a considerable amount of damping in controlling flexural vibrations. In this research passive damping via constrained viscoelastic damping treatments is explored as …

Edge Matching Of Aerial Scenery Using Fourier Descriptors, Ananth Kittappa

Theses

In this report an integrated method of classifying aerial images as related to photo stereo grammetry is discussed. In this method, an investigation of Fourier descriptors as features for the edge matching approach is carried out. The efficient calculation of the Fourier Descriptors is made possible by applying the polygonal approximation method to the original edges. In order for the features to be invariant to rotation, scaling and starting point shift, a normalization technique is adopted. Initially the Fourier Descriptors are tested for synthesized test datasets and it was proved that the variances of the Normalized Fourier Descriptors was a …

Characteristic Shape Recognition With Fuzzy Dustering, Kalpesh J. Patel

Theses

The problem of shape detection has been treated as one of clustering. A fuzzy-shell clustering(FSC) has been formulated as non linear least squares with fuzzy memberships as weights. An improved FSC algorithm has been proposed based on this formulation to partition the input feature vectors into hyper-spheres. To illustrate the usefulness of improved FSC we have provided numerous examples in 2-D space. The idea has been extended to fuzzy ellipsoidal-shell clustering (rESC). A FESC algorithm has been proposed to partition the input feature vectors into ellipsoidal patterns. To substantiate our claims regarding usefulness of this algorithm we have provided many …

Use Of A Generalized Set Of Variables In Fluid Flow Calculations, Pawel Chwalowski

Mechanical & Aerospace Engineering Theses & Dissertations

In fluid flow calculations, a set of generalized field variables is used to replace the more conventional choice of either the conserved variables, or the primitive variables. This generalized set of variables represents an infinite number of possible choices for the specific set of field variables. For algorithms of both the implicit and explicit type, the resulting effect of a change in field variables on a steady-state flow solution is in general relatively small. However, for implicit algorithms, a consistent linearization with respect to the new variables results in dramatic changes in the overall matrix conditioning of the linear systems …

Navier-Stokes Simulations Of Flows About Complex Configurations Using Domain Decomposition Techniques, Kamran Fouladi-Semnani

Mechanical & Aerospace Engineering Theses & Dissertations

An algorithm is developed to obtain numerical simulations of flows about complex configurations composed of multiple and nonsimilar components with arbitrary geometries. The algorithm uses a hybridization of the domain decomposition techniques for grid generation and to reduce the computer memory requirement. Three dimensional, Reynolds-averaged, unsteady, compressible, and complete Navier-Stokes equations are solved on each of the subdomains by a fully-vectorized, finite-volume, upwind-biased, approximately-factored, and multigrid method. The effect of Reynolds stresses is incorporated through an algebraic turbulence model with several modifications for interference flows. The present algorithm combines the advantages of an efficient, geometrically conservative, minimally and automatically dissipative …

Grid Generation And Flow Computation About A Martian Entry Vehicle, John Edward Stewart

Mechanical & Aerospace Engineering Theses & Dissertations

A number of vehicles are currently being proposed for a manned mission to Mars. One of these vehicles has a modified blunt-nosed cone configuration. Experimental results have been obtained for this vehicle in 1968. These results show lift-over-drag ratios comparable to those needed for Mars entry. Computations are performed here to verify the earlier results and to further describe the flight characteristics of this vehicle.

An analytical method is used to define the surface of this vehicle. A single-block volume grid is generated around the vehicle using an algebraic Two-Boundary Grid Generation algorithm (TBGG) and transfinite interpolation. Euler solutions are …

Numerical Investigation Of A Non-Newtonian Material Through A Sudden Pipe Expansion, V. G. Masanja

Tanzania Journal of Engineering and Technology (TJET)

A numerical method for solving two dimensional elliptic boundary-value problems of fourth order is used for finding stationary solutions of the equations of motion for a laminar flow through a sudden pipe expansion of an incompressible non-Newtonian fluid with a constitutive equation of the Reiner-Rivlin (R-R) type. Results for the Newtonian fluid, which is a special case, are in excellent agreement with those by previous investigators and they demonstrate the reliability, superiority and accuracy of the method. Results for the non-Newtonian cases could be of value for fixing ideas about visco-elastic behaviour although the R-R fluid allows only inelasticity: this …

Coke Oven Emissions: A Case Study Of Technology-Based Regulation, John D. Graham, David R. Holtgrave

RISK: Health, Safety & Environment (1990-2002)

After examining and analyzing the experience with coke ovens, the authors conclude that attempts to force technology beyond its demonstrated competence can be both expensive and ineffective in controlling hazards. They also suggest implications for pending proposals to further control air pollution.

Parallel Implementation Of A Recursive Least Squares Neural Network Training Method On The Intel Ipsc/2, James Edward Steck, Bruce M. Mcmillin, K. Krishnamurthy, M. Reza Ashouri, Gary G. Leininger

Computer Science Faculty Research & Creative Works

An algorithm based on the Marquardt-Levenberg least-square optimization method has been shown by S. Kollias and D. Anastassiou (IEEE Trans. on Circuits Syst. vol.36, no.8, p.1092-101, Aug. 1989) to be a much more efficient training method than gradient descent, when applied to some small feedforward neural networks. Yet, for many applications, the increase in computational complexity of the method outweighs any gain in learning rate obtained over current training methods. However, the least-squares method can be more efficiently implemented on parallel architectures than standard methods. This is demonstrated by comparing computation times and learning rates for the least-squares method implemented …

Statistical Process Control For High Precision Deep Drawn Sheet Metal Parts, Sunil S. Shah

Theses

In today's world, industrial expertise has come to be judged in terms of the quality of the product. Good quality has become the ultimate aim in a manufacturing environment, which leads to many innovations for ease in the inspection of parts. In considering a metal working company like Hudson Tool & Die Company, a study of the various operations and the application of Statistical Process Control to the forming operations is performed using STORM software. Important characteristics have been carefully studied with regards to metal forming like uniform metal thickness, radius of the bend, depth of the drawing operation. In-depth …

Development Of Air-Break Circuit Breaker, Ravi Kanth Korrapati

Theses

This thesis describes the development of an Air-Break circuit breaker, for Heinemann Electric Co., New Jersey, using I-DEAS CAD software. The physical properties obtained from the software, for the components of the armature assembly and the contact arm and the carriage, are used in determining the initial forces on a helical delay spring and in calculating accelerations of links in the trip mechanism. The trip mechanism is a four-bar mechanism with a spring as a coupler. Two second order differential equations define the motion of its links, the contact arm and the carriage. A time history of the links is …

Investigation Of Material Erosion By Abrasive Water Jet Cutting, Fang Hu

Theses

This study is concerned with the investigation of material erosion phenomena occurring in the abrasive waterjet (AWJ) cutting process.

A series of scratches were generated by the abrasive waterjet on the polished surface of aluminum samples. The tests were carried out at different traverse speeds, abrasive flow rates, diameters of sapphire nozzles, diameters of carbide tubes and initial abrasive particle sizes. Material volume loss in the erosion zone was measured directly or calculated by the use of the suggested mathematical models. An analysis of experimental results enabled us to introduce a new process criterion, particle distribution density, which determines the …

Computer-Aided Planning For Automatic Assembly Of Printed Circuit Boards, Qin Xiang

Theses

A study of printed circuit board assembly in the context of process planning and optimization of assembly motion is presented. A knowledge-based system is developed utilizing software packages VP-Expert, dBase 3 for the Universal automatic assembly machines. The planning of time-optimal assembly motion falls into the travelling salesman problem whose solution is obtained using a composite algorithm. Branch-and-bound algorithm is also discussed for solving the travelling salesman problem.

Modeling Packed Bed Catalytic Reactors, Jing Yang

Theses

Catalytic reactors provide a potentially important tool in the control of process emissions to the environment. This work provides a detailed chemical/physical model for analysing the operational characteristics of packed bed catalytic reactors. Mass, momentum, and energy conservation equations are written for the gas and solid phases. Heterogeneous and homogeneous reactions are used to convey the required stoichiometry, reaction rate, and heat release rate. Reaction in each phase is modeled as a one-step, global reaction. Heat and mass transfer, fluid friction, and axial heat conduction in the solid phase are modeled using suitable literature correlations. The resulting non-linear, first-order differential …

An Investigation Of The Dynamics Of Abrasive Waterjet Formation, Md. Ekramul Hasan Khan

Theses

The aim of this research was to investigate the jet formation and the jet behavior, as characterized by the velocity field, the force exerted by the jet on a work-piece and the jet geometry. The velocity and force distributions were measured using a laser transit anemometer (LTA) and a piezoelectric force transducer (PFT) respectively for constant water pressure (334.6 MPa) supply. The jet structure and its instantaneous behavior were visualized by the used of high speed filming. LTA and PFT measuring techniques were established and verified. The measurements were performed under different operating conditions. It was found that at a …

Teaching Mechanical Design Using The Axiomatic Approach, Lisa E. Hailey

Theses

Many authors on the subject of design state that it cannot be taught, it must be learned through experience. This thesis offers a method in which design can be taught to senior mechanical engineering students. The axiomatic approach to design, authored by Dr. Nam P. Suh of the Massachusetts Institute of Technology, states that all good designs follow two axioms, the independence axiom and the information axiom. By teaching students to use these axioms, and the corollaries and theorems derived from the axioms, educators can teach students the basic concepts of good design.

To show how this approach can be …

A Comparative Study Of Edge Detection Techniques, Jaskaran Singh Dhaliwal

Theses

The problem of detecting edges in gray level digital images is considered. A literature survey of the existing methods is presented. Based on the survey, two methods that are well accepted by a majority of investigators are identified. The methods selected are: 1) Laplacian of Gaussian (LoG) operator, and 2) An optimal detector based on maxima in gradient magnitude of a Gaussian-smoothed image. The latter has been proposed by Canny[], and will be referred as Canny's method. The purpose of the thesis is to compare the performance of these popular methods. In order to increase the scope of such comparison, …

Simulation Of Random Packing Of Hard Spheres Using Monte Carlo Method, Sung-Ho Park

Theses

A computer based method of generating a random packing of hard spheres is described. Using a Monte Carlo method as employed in the field of Computational Statistical Physics, packing of hard spheres are generated and analyzed.

The mean packing fractions for the present assemblies of 1000 spheres are 0.555±0.015 after pouring and 0.582±0.018 after 10 cycles of shaking. These values are approximately 5 to 6 per cent lower than the experimental results of G.D. Scott[30], but similar with the result of Visscher & Bolsterli [17].

The mean coordination numbers are 5.97 and 6.33 for the pouring and shaking case, respectively. …

Effective Use Of Management Information Systems In Manufacturing, Bhavik Shah

Theses

Information is the catalyst of management and the ingredient that coalesces the managerial functions of planning, organizing, actuating and controlling. The implementation of management information system (MIS) provides the vehicle by which management process can be administered and integrated. Information is at the core of creative thinking, which leads to new ways of improving products, process and services to the invention of new devices and to discovery of new marketable concepts. Thus information for an organization has a dual application for internal operation and external marketing potential.

The organization studied was a small to medium sized batch manufacturer of healthcare …

The Optimal Design Process : Integrating Creativity And The Axiomatic Approach, John V. P. Tirrell

Theses

This thesis will show that the optimal design process incorporates both creativity and the axiomatic approach. An examination of past and current design methods will substantiate the need for the integration of these components. Creativity is the designer's tool to produce innovative designs which transcend existing design solutions. Creativity is also an integral element of the axiomatic approach to design. In the axiomatic approach, two design axioms are applied to efficiently ascertain the best design solution from the infinite number of choices. Application of the design axioms, theorems, and corollaries streamlines the design process. The integration of creativity and the …

Cad/Cam : An Analysis And Application To An Industrial Environment, Kulendu Vyas

Theses

This work is intended to explore details of CAD/CAM techniques and to check its application in medium size industry. To achieve this goal, a thorough study has been carried out on current CAD/CAM techniques, keeping in mind it's requirements, source and application, considering both the hardware and software side of it. To check application of CAD/CAM in an industrial environment, Schering Plough corporation was chosen as a subject. The main theme behind this application to the Schering Corp. was to develop the CAD/CAM capability within company, in order to gain better control over the quality and productivity, and to reduce …

Adhesion Effects In Micro Mechanisms, Dennis Alan Kalgren

Theses

Dielectric resonators (DR) are suitably shaped objects made of high dielectric constant materials like TiO2, BaO, ZnO, and accessory ingredients, which can function as electrical resonators covering a very wide frequency range upto 40GHz. The physical dimensions of dielectric resonators are in mm range. High dielectric constant material resonators seem to be ideally suited for microwave applications because of their miniature size, low loss, insensitivity to magnetic dc biasing fields, and ability to concentrate large RF magnetic fields in small volumes. However temperature stabilization of dielectric resonators is an important consideration as the center frequency is a function of temperature. …

Design Of Spatial Linkages For Dwell Function Generation, Donald F. Kelly

Theses

Certain single-loop spatial linkages containing spherical pairs may be used as dwell function generators. Analysis and design of these linkages, however, may be too complex for the practicing engineer.

In this study a method is presented, where the set of link lengths representing a linkage are determined from a smaller set of design parameters. Graphical relationships are also found between the design parameters and functional requirements for dwell, such as output function amplitude and dwell range. These graphs may be used as design charts, and design becomes the calculation of link lengths from design parameters chosen to satisfy the functional …