Mechanical Engineering Commons^™

Correlation Between Particle Velocities And Conditions Of Abrasive Waterjet Formation, Wei-Long Chen

Dissertations

The velocities of water and abrasive particles in abrasive waterjet(AWJ) were measured by the use of Laser Transit Anemometer(LTA). A setup for the velocity measurement was constructed and a statistical technique was used to improve the accuracy of the velocity determination. A comparison of the magnitude of velocities determined by LTA, Piezoelectric Force Transducer and Schlieren Photograph clearly indicates the feasibility of the use of LTA.

The velocities of water and particles were measured for different diameters of water and slurry nozzles, abrasive mass flow rates and particle sizes. The performed experiments enabled us to evaluate the effects of conditions …

Kinematic Synthesis Of Mechanisms For Multiply Separated Positions, Hyoung Jun Kim

Dissertations

The rigid body motion is studied in a combination of finitely and infinitesimally separated positions in planar, spherical, and spatial kinematics. A general new method for determining the locations of points and/or lines in a rigid body moving through finitely and infinitesimally separated positions is developed. These points and/or lines would satisfy the constraints of various types of binary links for planar, spherical, and spatial mechanisms.

A unified form of circle-point curve equation is derived for finitely and multiply separated position problems in planar and spherical motions. A graphical method to construct the circle-point and center-point curves and Ball point …

Close-Range, Noncontact Distance Measurement By Controlled Image Irradiance, Jaeho Kim

Dissertations

Dimensional measurement or check is a major part of the inspection and quality control in manufacturing. Most of the measurement applications are based on contact methods. While a number of non-contact methods are available, they are limited in accuracy, in flexibility, or in the range of application areas. An optical, close-range, non-contact distance measurement method has been developed for manufacturing and other applications. Based on a simple imaging principle, the method derives the distance information from the power response of a small axial image area, the irradiance of which is controlled by an active controlled illumination of the corresponding object …

Isoparametric Finite Elements For Linear Isotropic Micropolar Plate Bending, Vallanore K. Suresh

Dissertations

Finite element analysis programs for bending of linear isotropic micropolar elasticity are developed in this thesis. Isoparametric two-dimensional and three-dimensional elements are used to solve plate bending problems. Two-dimensional and three-dimensional finite element formulations are developed. Corresponding finite element programs are then developed. Patch tests are performed on the two-dimensional elements. Convergence studies are undertaken for the elements. Several plates are considered to evaluate the finite element scheme. The effects of the coupling factor N and characteristic length 1 are studied. A post processor with graphical display of displacements is developed.

Numerical results obtained for various plates are in good …

A Robot Vision System For Determining 3-D Coordinates Of Object Points, Tea-Quin Kim

Theses

A stereo disparity algorithm is implemented on an industrial robot vision system. One camera manipulated by an industrial robot is used to obtain stereo images of an object. After a pair of stereo images are processed, the points of interest are selected from each image. The similarities of three types of feature characters are used to assign initial weights of the, matching probabilities to a set of point candidates. Then a relaxation method, which is based on probabilities of local connectivity, similarity of feature characters, and smoothness of matching, is used iteratively to improve the initial probabilities of image matching. …

Design Of A Gear Driven Anti-Twister Mechanism For A Seal-Less Blood Processor, Ajit Nachiket Dastane

Theses

This thesis presents the design of a gear driven anti- twister mechanism for a blood cell separator. The anti- twister mechanism allows for continuous feed and discharge lines that are rigidly attached to the rotating centrifuge head, thus eliminating the need of rotating seals. It is anticipated that the device using a gear driven anti-twister mechanism will have smoother power transmission and closer rpm tolerances.

In addition, a procedure for the dynamic analysis of the existing device, which uses a belt-driven anti-twister mechanism, is developed. The experimental values obtained from the device are compared with the theoretical values obtained by …

Investigation Of Forces In The Course Of The Water Jet--Work Piece Interaction, Hung-Yuan Li

Theses

This study is concerned with the dynamic of the interaction between the water jet and the work-piece. The piezoelectric transducer was used to construct an experimental setup. The simultaneous use of the constructed setup and strain gage enables us to validate the experimental procedure. The forces in the impingment zone were measured at different operational conditions. Totally about 400 different combinations of these conditions were tested. It was found that the force is mainly determined by the diameter of the sapphire. The effects of the abrasive size , abrasive flow rate, the diameter of the carbide tube, and the stand-off …

An Analysis Of The Dense Packing Of Disks : A Computer Simulated Approach, Jir-Yih Tsaur

Theses

This thesis is concerned with the analysis of dense packing of hard disks. The Voronoi diagram and the geometric neighbours were first computed. The average number of geometric neighbours of a disk is six. It is thus more efficient to choose structural neighbours from among the geometric neighbours than from among all other disks.

Through the Monte Carlo simulation by Rosato et. al., disk configurations after pouring and subsequent shaking were provided for analysis. The mean number of geometric neighbours and the average coordination number were computed. The angular distribution of the structural neighbours was discussed. The packing fraction increases …

A Feasible Direction Procedure For General Multiple Objective Optimization, Wen-Tsia Liu

Dissertations

The Feasible Direction Finding Problem (DFP) of Zoutendijk is adapted to create a general Mathematical Programming (MP) algorithm for treating optimization problems with multiple objective functions. Classically such problems are reduced to standard MP form by converting them to single objective function problems by the use of weighting functions. Unfortunately not all practical problems can be so reduced. Consider the problem of maximizing the strength of a structure. Typically there are several, or even many, failure modes. All active failure modes must be included in the optimal search in such a way that resistance to one active mode can not …

Stress Analysis Of A Stepped Shaft With A Keyway, Irfan Hussain Sabir

Theses

A stress concentration case which is encountered in practice more than any other is the shoulder fillet. Shafts, axles, spindles, rotors etc., usually involve, in each case, a number of diameters connected by shoulders with fillet radii and very often it is necessary for a keyway to be near a shoulder. The objective in this study is to analyse the stresses in a shouldered shaft with a keyway subjected to an axial tensile load and to study the dependence of the keyway-end stresses on the distance between the shoulder fillet and the keyway end. This is done by performing a …

A Tracheoesophageal Puncture Voice Prosthesis, Georghios Makris

Theses

A voice prosthesis was developed that allows verbal communication of laryngectomised patients. The prosthesis requires a superiorly directed tracheoesophageal puncture in which the periscope mounted on the tracheal stoma vent is introduced. The prosthesis is operated by air injection through the periscope. Air injection is achieved by pulmonary pressure after the occlusion of the stoma vent. Stoma vent occlusion can be achieved either by the patient's finger or by the designed cover valve mounted on the prosthesis. The cover valve allows free breathing, hand-free prosthesis use, and it can release excess pressure during coughing. Periscope valve air resistance tests have …

Circular Plate Analysis Using Finite Element Method, Shyh-Rong Chiu

Theses

The ANSYS computer program is the application of finite element methods to large-scale engineering problems. In this work the ANSYS program has been employed to solve the circular plate under uniformly loaded with various boundary conditions as follows: (1) clamped along entire edge, (2) simply supported along entire edge, (3) clamped at several points along the boundary, (4) simply supported at several points along the boundary, and (5) simply supported 36 points with 4 points clamped..

The results obtained from the ANSYS program illustrated that the finite element method has no boundary conditions constraints and presents good approximations to the …

Introductory Guide To Bridgeport Series I Cnc Milling, Drilling And Boring Machine, Apurva Vinodchandra Doshi

Theses

This thesis is intended to serve as an easy introductory guide on how to work with Bridgeport Series I CNC Milling, Drilling and Boring machine. An attempt has been made to make the subject matter simpler to give the reader a good start in programming and operating this machine

The spectrum of technological implementation of CNC machine tools is extremely broad,. Companies utilizing advanced technologies such as computer graphics, DNC and Group Technology are in this field for some time. Even small shops are getting equipped with CNC machine tools. The present CNC systems, which are less costly, more reliable …

Modal Analysis Of A Cantilever Plate, Ohseop Song

Theses

This thesis discusses the vibration of a thin, flat cantilever aluminum plate. Results are based on both an analytical finite element method using the ANSYS program and an experimental analysis using a digital Fast Fourier Transform (FFT) analyzer. The FFT analyzer permits extraction of modal parameters (natural frequency, damping, mode shape) for the plate.

Substructuring Analysis For Impact Dynamics Using Ansys Finite Element Package, Chang Ho Cho

Theses

This thesis is intended to serve as an introductory guide to ANSYS finite element package for the analysis of impact dynamics. Substructuring technique has been used to reduce the degrees of freedom.

Finite element method is essentially a numerical technique to calculate elastic deformations. However, by introducing some techniques like gap element, the technique can be easily extended to rigid body dynamic analysis. To solve the equation of motion both for rigid body and elastic deformations, direct integration technique is used in this thesis, i.e., Houbolt method.

ANSYS is a large scale general purpose computer program for finite element analysis. …

Two And Three-Dimensional Isoparametric Finite Elements For Axisymmetric Micropolar Elasticity, Fuang-Yuan Huang

Dissertations

Finite element analysis program for isotropic and orthotropic axisymmetric micropolar (Cosserat) elastic solids are developed in this thesis. Isoparametric elements of 8- and 20- node are used to solve general three-dimensional problems, arid both 4- and 8-node elements are used for two-dimensional cases. Three-dimensional finite element formulation for cylindrical coordinate system is derived. Corresponding Fortran programs are then developed. Patch tests are performed for two-dimensional cases to verify the applicability of the finite element method to non-rectangular geometries. Several two-dimensional and three- dimensional problems for micropolar elastic solids are solved to verify the formulations arid computer program.

Good agreements were …

Deposition Of Suspensions In Convergent Channels Due To Electrostatic Image Forces, Kwok Wah Hui

Dissertations

The deposition of suspensions for uniform flow in convergent channels under the combined influences of inertia, viscous and electrostatic image forces was studied theorectically. The fluid phase was assumed to be two-dimensional, steady, uniform, incompressible and laminar while the particle phase was assumed to be uniform, steady, dilute and with negligible gravity effects.

Since the image force equations for convergent channels have not been derived, it becomes one of the main purposes of this study to perform the derivation of the image force equations. The lengths of the channels were chosen in a way that the exit area is only …

Deposition Of Particles In Tubes Due To Gravity And Electrostatic Charges, Win-Chung Chen

Dissertations

The deposition of particles in a parallel-plate channel and a circular tube under the influence of inertia, fluid viscosity, gravity and electrostatic image forces was studied by analytical and numerical methods. A laminar flow with uniform and parabolic velocity profiles was investigated with a particle initial velocity of zero as well as that of the local fluid velocity.

The governing equations were solved by the Lagrangian approach to obtain the particle trajectories from which the fraction of deposition was calculated. Closed form solutions for particle trajectory and a complete deposition of particles in a finite length of the flow passage …

Computer Aided Stress Analysis Of Long Bones Utilizing Computed Tomography, Shlomo Asher Marom

Dissertations

A computer aided analysis method, utilizing computed tomography (CT) has been developed, which together with a finite element program determines the stress-displacement pattern in a long bone section. The CT data file provides the geometry, the density and the material properties for the generated finite element model.

A three-dimensional finite element model of a tibial shaft is automatically generated from the CT file by a pre-processing procedure for a finite element program. The developed pre-processor includes an edge detection algorithm which determines the boundaries of the reconstructed cross-sectional images of the scanned bone. A mesh generation procedure then automatically generates …

An Analysis Of The Heating And Densification Process During Rotational Molding Of A Thermoplastic Powder In A Uniaxially Rotating Cylindrical Cavity, Floyd Steven Ribe

Dissertations

This dissertation presents the results of an experimental and theoretical investigation of the heating and densification portion of the rotational molding process in a uniaxial, cylindrical mold.

A thorough literature survey is included which reviewed past analysis of the rotational molding process and other areas that assisted in understanding of the process.

The results presented in this dissertation included an analysis of the densification process by use of Scanning Electronic Microscope (SEM) photography producing intermediate correlations between the physical properties of the densifying material and neck radius of adjacent coalescing spheres. In addition, a hybrid experimental procedure coupled with a …

Finite Element Modeling Of A Femoral Stem In A Total Hip Prosthesis, Robert C. Cohen

Theses

A three-dimensional model was produced to study of effects of stress on a femoral stem in a total hip prosthesis. Using the ANSYS General Purpose Finite Element Computer Program, a reproduction of the system was constructed for the loads acting on the hip joint at intervals of a walking cycle. With isotropic properties for cortical bone, cancellous bone, cement, and selected alloys, the model was generated using three-dimensional, isoparametric, eight-node, solid elements (STIF45). The model consists of over 700 nodes and 442 elements. This model can be used to produce computer calculated stress data, if disc storage space allows.

On Analysis Of Small Bore Piping Vibrations, Nitinkumar Shroff

Theses

This thesis investigates the natural frequency and vibration induced stress of small bore power plant piping. Straight piping and piping with concentrated load, such as a valve, located anywhere along the span are studied. Four different boundary conditions of fixed-free, simple-fixed, fixed-fixed and simple-simple are investigated, as any single span piping may be approximated by one of these boundary conditions.

The results otained [sic] for frequency and stress coefficients in the case of straight piping are plotted. Plots of frequency factor and stress ratio for the piping with concentrated load are also presented.

The results obtained for the natural frequencies …

Finite Element Analysis Of The Femoral Head, Ghandikota Ramamurthy

Theses

Femoral component loosening and Prosthetic stem fractures have renewed interest in conservative alternatives to conventional total hip replacements. One such alternative is the concept of surface replacement. The objective in this study is a finite element analysis of a femoral surface replacement cup with Particular attention given to the interfacial stresses. An axisymmetric model with a grid of two-dimensional isoparametric elements is generated. This study utilizes an adaptive model so as to include the effect of bone remodeling in response to stress. The stiffness is considered to be linearly proportional to the stress in the femoral head and neck. Isotropic …

Computer Simulation Of Cavity Filling During Injection Molding Process, Sumit Banerjee

Theses

A numerical technique is proposed for the simulation of cavity filling process during injection molding of glass-bead filled polypropylene. The mold cavity is of cylindrical shape. Marker And Cell (MAC) method is utilized for solving the transient flow phenomena, after a mathematical simulation of the flow model is carried out by using the relevant continuity and-momentum equations governing the system. The complexity of the equations involved, results in the simplifying assumption of incompressible and isothermal flow process. A computer program is written on the basis of finite-difference equations developed during the application of MAC method under the prevailing conditions.

The …

One-Dimensional Compressible Flow Analysis : Isentropic And Normal Shock, Su-Bo Wong

Theses

A computer program to compute and analyse one-dimensional isentropic compressible flow through variable cross-sectional area with or without a normal shock is developed. The program is written in the "FORTRAN LANGUAGE".

In this work, the area change is the predominant cause of change of flow condition. One of the advantage of this program is set on general uses for isentropic flow. In common practice, the values of the isentropic flow property ratios were tabulated or graphically presented as function of the Mach number with a specified specific heat ratio, K (normally K=1.40 was presented). With todays technology, the most versatile …

Crimp-Type Electrical Connectors, Ted Lai-Che Kuo

Dissertations

Three types of surface conditions (plain surface, plain surface with oxidation inhibitor, and toothed surface) and four types of environmental gases (air, nitrogen, hydrogen, and oxygen) were used to study the performance of electrical connectors installed on aluminum conductors. All of the connectors were placed insealed vessels which allowed the desired type of gas to flow at a steady rate. The connectors were then current cycled.

For the connections prepared with plain surfaces, the connectors deteriorated equally fast in air, nitrogen and hydrogen. Only the connectorsexposed to oxygen showed a higher deterioration rate than the others.

Connections prepared withhaving plain …

Deposition Of Particles In Vertical Conduits Due To Electrostatic Charge, Diffusion, And Gravity, Melvin Wilbur Gelber

Dissertations

This investigation was made to determine the effect on the deposition of fine particles in a vertical channel and in a vertical tube due to the influences of electrostatic charge, diffusion, and gravity acting in the direction of flow. The flow considered was laminar, incompressible and steady.

The governing equations for the fluid phase were derived from the Navier-Stokes equation and the continuity equation while the equations for the particle phase were derived from Poisson's potential equation and the continuity equation. Since the governing equations are non-linear partial differential equations the solutions were developed using numerical methods.

The flow patterns …

Impingement Of An Axi-Symmetric Jet On A Flat Surface, Amir J. Daibes

Theses

An incompressible, inviscid irrotational flow model was used to represent the normal impingement of a circular axisymmetric jet upon a flat plate. An analytical investigation was conducted to determine the free surface of the jet and the solution of the potential flow problem was obtained using finite difference techniques for jet height-to-nozzle radius ratio of 2.4.

The velocity and pressure distributions at the plate surface and along the jet centerline were obtained.

The results from the finite difference solution are in close agreement with other most recent results from available experimental, and approximate solutions to the potential flow problem.

Inplane And Out Of Plane Buckling Of Thick Rings Subjected To Hydrostatic Pressure, Thomas Michael Juliano

Dissertations

The problem of inplane and out of plane buckling of a thick circular ring subjected to a hydrostatic pressure is analyzed from first principals. The equations of equilibrium from nonlinear elasticity theory are used to describe two adjacent equilibrium positions, i.e., an initial and final state. The initial position problem is assumed to be governed by linear theory. The resulting incremental value equations obtained by subtracting the two equilibrium states, are also linear in nature. These problems are reduced to a one dimensional ring theory problem by the method of power series expansion of the displacements in the radial and …

A Three-Dimensional Kinematic Model Of The Human Knee, Wayne Ke-Wung Li

Theses

This thesis describes two kinematic models of human knee which may be used to study the motion of the knee and the forces in the ligaments of the knee. In one model, the ligaments are simulated by rigid links connected to links representing the articulating bones at the centroids of the areas of insertion of the ligaments. The condylar higher pair connections are simulated by equivalent linkages connected by resolutes. In an advanced model, the rigid ligament links are replaced by springs.

The IMP procedure, a powerful kinematic linkage analysis method, is employed to study the motion and forces in …