Digital Commons Network^™

Rendering Of Three-Dimensional Data Sets Derived From Finite-Difference And Spectral Methods, Paul A. Schubert

Theses and Dissertations

The timely visualization of three-dimensional data sets and the advantages of using a spectral method solution versus a finite-difference method solution in rendering isosurfaces is described. The Beam-Warming numerical algorithm, which uses implicit-approximate-factorization, is used to generate the steady-state solutions for a model diffusion-convection problem. The Chebyshev collocation operator is used to evaluate the right-hand side of the Beam-Warming algorithm for the spectral solution. Comparing the model problem results with the exact solution, the spectral series solution is truncated to the same degree of accuracy as the finite-difference for comparison of rendering times. The rendering algorithm employs octrees to efficiently …

Modeling Of Rapid Thermal Processing System By Finite Element Method, Helen Martynov

Theses

A finite element model for the Rapid Thermal Processing (RTP) system at NJIT was developed based on the software package MSC/NASTRAN. Based on this model, a thermal analysis of the 9" chamber, 3 zones (37 lamps) RTP system was conducted for various modes of system operation with the 6" silicon wafer temperature varying from 300°K to 1100°K. An open-loop control algorithm was developed in order to study the dependence of wafer temperature on time, position, and applied radiant heat distribution. It was shown that the non-uniformity in the radial temperature profile can be less than 3°C during wafer heating at …

Local Stress Factors Of Pipe-Nozzle Due To Radial Load, Circumferential And Longitudinal Moments, Junyu Lin

Theses

This thesis presents a series of stress factor data which provide more detailed information for the calculation of local stresses at the nozzle region, as well as the pipe region, of a pipe-nozzle intersection, subjected to an external radial load, circumferential bending moment, and longitudinal bending moment, respectively.

The pipe and nozzle thicknesses are assumed to be identical. Numerical solutions are obtained through the use of the finite element method. In obtaining the numerical solutions via ANSYS, the quadrilateral element is used to simulate the thin shell pipe-nozzle geometries. The local stresses, at eight different points on both the pipe …

Phased Array Antenna Analysis Using Hybrid Finite Element Methods, Daniel T. Mcgrath

Theses and Dissertations

This research in computational electromagnetics developed a new method for predicting the near-field mutual coupling effects in phased array antennas, using the finite element method (FEM) in combination with integral equations. Accurate feed modeling is accomplished by enforcing continuity between the FEM solution and an arbitrary number of wave guide models across a ground plane aperture. A periodic integral equation is imposed above the antenna's physical structure in order to enforce the radiation condition and to confine the analysis to an array unit cell. The electric field is expanded in terms of vector finite elements, and Galerkin's method is used …

An Investigation Of Graphite Peek Composite Under Compression With A Centrally Located Circular Discontinuity, Benjamin Wham Ii

Theses and Dissertations

The purpose of this thesis was to determine (both experimentally and analytically) the initiation and progression of failure, stress-strain response, and the failure loads of Graphite/Polyetheretherketone (Gr/PEEK) laminates, incorporating a centrally located circular discontinuity, loading in axial compression at room temperature. The laminates studied were (0°)₁₆,(90°)₁₆, (0°/90°)_4S, (± 45°)_4S, and (0°/±45°/90°)_2S. The specimens were loaded within a Boeing Open Hole Compression Fixture. The micromechanical failure modes were identified using a Scanning Electron Microscope. The analytical progression of failure was predicted using a nonlinear finite element code developed by Dr. R.S. …

A Review Of Energy Storing Prosthetic Feet And Computer Aided Structural Optimization Of A Below-Knee Prosthesis, Poonam Gope Lalwani

Theses

Because people with physical disabilities have shown an interest in participation in sports, a new class of prosthetic feet known as "energy storing prosthetic feet" has been developed. These new developments in prosthetic foot design utilize energy storage and return to improve ambulation. This thesis reviews the design, materials, advantages and disadvantages of various energy storing prosthetic feet. Research studies, comparing gait in below-knee amputees using different prosthetic designs, can be applied to the design of prosthetic feet that are lighter, stronger and more reliable. Comparisions among these feet are reviewed in the context of functional capability and patient satisfaction. …