Digital Commons Network^™

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. …

Deconvolution Techniques With Applications In Cardiovascular Systems Analysis, Lakshminarayan Rajaram

Theses

System characterization by means of Impulse and Frequency Response Functions are well known in classical linear systems analysis. Impulse Response Function is a time domain description of a linear system where as the Frequency Response Function represents the frequency domain counterpart. Linear systems are often characterized in frequency domain. In many biological research applications, it becomes necessary to examine the impulse response function in order to understand the behavior of the system under investigation. One such application is the arterial system in cardiovascular dynamics. It has been shown that although both representations are identical, some aspects of the arterial system …

Biodegradation Of Multiple Substrates In A Batch Reactor, Nilesh Naik

Theses

The biological degradation of multiple substrates was studied at room temperature in aerated 5-liter batch reactors using mixed liquor from the Passaic Valley Sewerage Commissioners wastewater treatment plant (Newark, New Jersey).

Two substrate mixtures were used (with initial concentration indicated in parenthesis): (1) phenol(100ppm) + nitrobenzene(10ppm) + 2,6-dichiorophenol(10ppm); (2) 2-chlorphenol(20ppm) + nitrobenzene(10ppm) + 2,6-dichlorphenol(10ppm). From concentration versus time data, kinetic rate constants for zero-order, first-order, and Monod models were determined. Most of the data were best fit by either the Monod or zero-order model. For all compounds tested biodegradation was the primary removal mechanism, and in many cases the rate …

The Acquisition Of Direct Sequence Spread Spectrum Communication Systems, Anthony Donald Demeri

Theses

This Paper surveys different techniques of acquiring Direct Sequence Spread Spectrum Systems.

It classifies different systems, indicates the strongpoints and weakness of each, along with some applications.

One method, The Single Dwell Serial PN Acquisition System is then focused on in detail. The detail includes analysis of standard version, derivation of the mean time to acquire, the variance, the probability of detection and the probability of a false alarm.

In the last section of the paper the analytical results of the Single Dwell Serial PN Acquisition System shall be confirmed by computer simulation.

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.

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 …

Utilization Of The Microcomputer To Improve The Productivity Of Small Manufacturing Companies, Hung-Gi Chang

Theses

The ongoing microcomputer development has led to its increasing application in manufacturing to reduce costs and improve productivity. Being more aware of this technology, most of these benefits have accrued to large firms. The intent of this thesis is to show that it is equally advantageous for small manufacturing companies to utilize them and show how they can do so.

The paper discusses the role and characteristics of microcomputers. Available software to do engineering designs, materials requirements planning, process planning, and master production scheduling is described. Using a case study a method that can be followed in selection and implementation …

Cybernetic Theory Applied In Production Control, Ding-Hsin Fang

Theses

There are many theories for the control of production. Also. there are many successful cases for each of the different theories.

Cybernetic theory is quickly evolving as a design basis for management control systems. Cybernetics is the science of self-regulation and its basic tenents are control, or the ability to direct action toward a predetermined goal, and communication, or the ability to send and receive information.

The objective of this thesis is to identify and discuss this theory applied to the management techniques of production control for a Far Eastern textile firm and to investigate the extent that the firm …

Human Resources Planning In Construction Through Operations Research, Maria Pyla-Christodoulou

Theses

The purpose of this thesis is to examine different methods in the allocation of human resources in construction, using decision making through Operations Research. The methods described are divided into methods using mathematical models, and methods using heuristics. The mathematical models yield the optimum solution, while heuristics result in a satisfactory solution which can be improved by applying the optimization procedures described herein.

The human factor in construction is also examined, and methods of improving motivation among the construction workers are discussed.

The Dielectric Slab-Wedge Antenna, B. Keith Christensen

Theses

A theoretical model and numerical investigation of the directive gain of a dielectric slab-wedge radiator is presented. The model is based on a union of the classical dielectric slab equations, local mode theory, and equivalent current distribution treatments of the truncated dielectric slab and wedge geometries.

The far field is developed from the sum of two current distributions. The slab region, up to the transition plane between slab and wedge, is replaced by equivalent electric and magnetic surface current densities. The wedge contribution is developed from a volume polarization current distribution.

Conservation of power is used to approximate the field …

Thermal Energy Storage Using Phase Change Material With Multi - Melting Temperatures, Christakis Christodoulou

Theses

Three different models are developed in this investigation, for the study of thermal energy storage, using a phase change material with multi-melting temperatures. Using Model B as the basis, the developed partial differential equations are numerically solved by a finite difference method. Two computer programs were written based on that solution, one for the charging mode and one for discharging. Finally, using the computer programs, a set of results was obtained for both charging and discharging, utilizing calcium chloride hexahydrate as the phase change material with constant and multi-melting temperatures.

Replacement Of Surface Ducted Rays Near Caustics With Guassian Beams, Carlos Javier Ruiz

Theses

Conventional approach to a solution of a wave propagation problem in an inhomogeneous medium is to utilize either rays or modes to represent the wave field. Asymptotic ray theory (ART) starts to fail in the vicinity of caustics due to rays experiencing many reflections. Even uniform representations do not properly correct this deficiency of rays when caustics start to pile up in the far range. One possible alternative is to replace these rays with modal bundles and remainders [1]. A promising technique using Gaussian Beams has been used to represent the total field due to a point or a line …

The Effects Of Platelet Activating Factor (Paf) On The Arteriolar Average Blood Velocity And Volumetric Flowrate In The Microcirculation Of The Hamster Cheek Pouch, Patricia Ann Shatynski

Theses

The effects of platelet activating factor (PAF) in vessel diameter, average red blood cell (RBC) velocity and volumetric flowrate were studied in twenty-four arterioles located in the cheek pouches of nine male syrian golden hamsters. The observed vessels were between 8-32um in diameter. These vesgs were subdivided further into two groups: 8-17um and the 21-32um group. Fluorescein isothiocyanate (FITC) labeled cells were injected into the hamster to act as velocity tracers. Immediately prior to and for a total of 60 minutes after the topical application of 10^-7M and 10^-9M PAF, selected arterioles were video taped periodically …

Isoparametric Finite Elements For Axisymmetric Solids, Ramanand R. Shetty

Theses

The finite element formulation of axisymmetric plane stress analysis is used to develop a computer program for numerical implementation. The basic relations used to derive the finite element equations for a solid continum are reviewed in the thesis. The programming organization is summarized and program list is given in Appendix.

The program portion for isoparametric elements are borrowed from Numerical Methods in Finite Element Analysis by K. J. Bathe and E. L. Wilson, and various other subroutines are used from Mr. Huang's thesis on Micropolar elasticity analysis. Mr. Huang's computer program is based on the work done by Dr. Nakamura …

An Analysis Of Carrier Facilitated Transport In Liquid Surfactant Membranes, Pei-Jen Tsai

Theses

Mathematical models describing the mass transfer through facilitated liquid membranes are proposed and solved analytically. A self-adjoint operator method is applied to solve the coupled differential equations with discontinuity in the boundary conditions. It is assumed that equilibrium of the solute at the interfaces is maintained during the separation process. The effects of film resistance are studied/ and a first order kinetic model is used to simulate the reaction which takes place at the membrane-internal phase interface.

Experimental results indicate that the model with external film resistance consideration is in good agreement with the experimental data. This shows that most …

Ray And Beam Representation Of The Glancing Phenomena, Michael Sotiriou Vogas

Theses

Asymptotic ray theory (ART) is a widely used method dealing with problems of wave propagation in an inhomogeneous medium. The main deficiency of ART is in transition regions where rays near caustics, glancing and critical incidence fail to represent the actual wave field. Ray bundles in such transition regions have been successfully replaced with modal bundles and remainders El] in well defined profiles. However , in practical problems it is difficult to implement modal representations and almost impossible to express remainders. Recently emerging Gaussian beam method (GBM) has shown promising results in representing the total field produced by a source …

Plate Stress Analysis By The Finite Element Method, Wen-Jung Chuang

Theses

The finite element formulation of plate elasticity is presented and is employed in the development of the formulation of element stiffness equations. The programming structures are also summarized.

The finite element program PLATE cited from Prof. J. N. Reddy's " An Introduction to the Finite Element Method " has been used to solve the plate bending problems with quadrilateral elements. The problems solved are:

(1) deflections and stresses in a circular plate with all edges simply supported under uniform load.

(2) deflections and stresses in a circular plate with all edges clamped under uniform load.

each case including four different …

Chebyshev Approximate Solution For Stiff Problems, Kwo-En Hoh

Theses

Chebyshev polynomial and collocation methods are adapted to solve general ordinary differential equations ( initial-value problems and boundary-value problems ). Approximate solutions of initial-value problems are obtained in step-by-step fasion. the solutions have minimax absolute error in the interval and correct values at the end points. The approximate solutions of boundary-value problem will be continuous on the whole domain and have piecewise Chebyshev approximation characteristics in each subinterval of the chosen partition.

Sensitivity Analysis Of Linear Goal Programming On Priority Level Reordering, Fu-Chia Hor

Theses

The purpose of this research is to study on the sensitivity analysis of priority level reordering of a goal programming model. Two approaches are presented in this study to handle this priority level reordering analysis. The first one is an algorithm to generate the solution of a similar problem with different priority level ordering of the original one utilizing the final solution tableau of the original problem. In doing so, calculation steps and time are saved tremendously.

The second approach is based on the fact that some goal programming problem of different priority level ordering has the same solution as …

Computational Method For Robot Manipulator Dynamics Based On The Gibbs-Appell Equations, Kwang Bok Kim

Theses

Industrial robots are open-loop multi-degree of freedom mechanisms whose dynamic characteristics are described by nonlinear differential equations. The computations of forces and torques required at each joint of robot manipulator are crucial step for real time control of robot manipulators.

Vukobratovic developed a new computational method for rigid body articulated open-loop mechanisms based on the Gibbs -Appell equations to generate differential equations of motion for spatial open - chain mechanisms. To solve these equations, he introduced the recursive kinematic transformation matrices that represent the motion of each linkage with respect to the base linkage.

Computer programs are developed in this …

Laminar Flow In A Porous Pipe With One Plugged End, Pyne-Hwa Ku

Theses

A steady laminar flow through a co-cylinder porous pipe with one plugged end was investigated theoretically to obtain velocity, pressure and shear stress distributions.

An integral momentum equation and the Darcy's law for flow through the porous wall were solved numerically by the Runge-kutta method.

As the fluid is injected from the outer wall into the porous tube, the fluid in the inner tube is accelerated from rest at the plugged end to a fully-developed velocity profile at the exit of the porous tube. It was found that the coefficient of the wall shear stress and the dimensionless pressure drop …

Computer Aided Mathematical Modeling Of A Once Through Claus Type Sulfur Recovery Process, Yuriy Osyp Kutny

Theses

The computer aided mathematical modeling of the once through Claus process for hydrogen sulfide conversion to sulfur is presented herein. This vapor phase oxidation reaction is carried out using one thermal reactor and up to three bauxite catalytic reactors with sulfur condensers in between. The method of catalytic reactor feed reheat and its ramifications upon reactor performance and total model convergence is of major importance.

The reactor feed preheat can be carried out in either of the following ways: (1) indirect heat exchange using some external heat source; (2) indirect heat exchange using other hot process streams as heat source; …

Stress Analysis Of A Pressure Vessel By The Finite Element Method, Hsin-Te Liao

Theses

The objective of this paper is to take a finite element program, called ANSYS, to analyze the surface stress distribution of a thin-wall pressure vessel with a spherical head.

The computer program ANSYS, which primarily applies the principle of virtual work in solid continuum, has been used to solve shell problems with quadrilateral element. Problems solved are: <1> hoop stress <2> meridional stress (<)3) maximum shear stress.

In this paper, the theoretical finite element formulation of axisymmetric elasticity of the ANSYS program is presented.

Finally, some numerical examples of shells with spherical heads of various radius are given. The solution obtained from ANSYS is very …

Discontinuity Stresses Analysis In Pressure Vessel, Jan-Joo Liu

Theses

In this paper, the ANSYS general purpose finite element computer aided design program was used to perform a series of stress analyses for shells with heads of various shapes.

The analysis included maximum discontinuity stresses, stress contours and displacements induced in axisymmetrical shells subjected to internal pressure loading; especially at the junction of the cylinder and heads of various shapes.

CONICAL SHELL finite elements and TWO-DIMENSIONAL ISOPARAMETRIC finite elements were used in the analysis. The results of the analyses compared very favorably with solutions derived from membrane and bending theory solutions for pressure vessels.

The effect of longitudinal and hoop …

Linearization Accuracy In Probabilistic Load Flow, Guan-Zhong Liang

Theses

This paper presents a linear load flow method which can be used for probabilistic load flow analysis. The method is based on least-square estimation. To estimate its accuracy in linear load flow calculations, the method and a previously developed linear load flow method are applied to a typical power system and the results evaluated. Comparable accuracy is noted.

Air Pollutant Emissions From Non-Vented Radiant Kerosene Heater, Anil Kumar Mishra

Theses

Gaseous emissions from non-vented kerosene heaters can generate and create significant indoor air concentrations of various gaseous pollutants. Indoor air concentrations resulting from operating a portable non-vented radiant type kerosene heater in three rooms of size 38.7, 58.1 and 137 M³ were studied. Studies in the environmental chamber having a size of 38.7 M³ under two sets of ventilation conditions showed elevated levels of CO₂, total hydrocarbons and CO. An emission rate model was used to estimate the strength of pollutant source, for total hydrocarbons, CO₂ and CO with data reported in terms of mass …

An Inventory Model For The Specialty Chemical Industry, Paul Murchison

Theses

The specialty chemical industry is a unique segment of the chemical industry. This industry produces chemical intermediate products for the pharmaceutical, agricultural, cosmetics, and other chemically related industries. Most of the products that are produced are covered by patents or involve proprietary know—how. The specialty chemical products are a minor part of a total formulation but contribute unique properties to the end product. This feature of specialty chemicals gives the manufacturer unusual pricing power compared to producers of commodity chemicals. This industry has proven to be very competitive, profitable and in the forefront of the present automation revolution over the …

On-Line Analysis Of Highly Coherent Brain Activity During Transcendental Meditation And Automated Biofeedback, Deepak Dinkerrai Rawal

Theses

Occurance of highly coherent brain activity (EEG) specific to the meditation has been reported in the literature. The present thesis is an effort to look into the mechanics of meditation using the recent technique of analysis of high coherence in the EEG. Based on previous work, reporting increased EEG coherence during practice of Transcendental Meditation, a closed loop model and hypothesis is proposed using biofeedback to close the loop. The hypothesis proposes that very high coherence in the EEG is a very significant neurophysiological parameter, reflecting instantaneous quality of meditation in the form of an average high coherence above threshold. …

Dispersion In The Laminar Flow Of Ellis Model Fluids Through Straight Tubes, Yeong-Hua Huang

Theses

Taylor-Aris dispersion theory is extended to the laminar tube flow of Carreau model fluids and Ellis model fluids and the results are compared with those of power law fluids. It is found that Carreau and Ellis models are more appropriate than power-law model, especially at low pressure gradient.

An exact solution to the unsteady convective diffusion equation in fully developed laminar flow in tube is obtained by applying the generalized dispersion theory of Gill and Sankarasubramanian for Ellis model. The results are compared with those obtained by Booras and Krantz for power-law model. The most interesting result of this work …

Nervous System Simulation, Jian Chen

Theses

This thesis deals with the nervous system simulation. The Hodgkin-Huxley model and Stein's model are used as basic tools. The author has tried to describe some practical problems by mathematical models.

First, the horse-shoe crab eye is investigated. Light intensity is reported to the brain by the firing frequency of the photoreceptoe. A Poisson process is used to simulate the stimulus to the receptor. The result of the stochastic model coincides with the theoretical one: receptor overlapping decreases the resolving power of the eye; and the lateral inhibition compensates the effect of overlapping.

Second, a nerve muscle model was set …