Mechanical Engineering Commons^™

Local Stresses On Lateral Pipe-Nozzle With 45 Degree Angle Intersection, James Jin Xu

Dissertations

This dissertation presents a comprehensive study of local stresses, due to internal pressure around a pipe-nozzle with 45 degree angle intersection_ The resulting circumferential and longitudinal stresses on the pipe around the pipe-nozzle region are normalized as local stress factors and plotted as function of beta, β, (the radius of the nozzle/the radius of the pipe) and gamma, y, (the radius of the pipe/the thickness of the pipe) through the finite element method. The range of beta, [3, is from 0.1, to 1.0, and gamma, y, from 10 to 300. Comprehensive studies were made for the boundary parameters, such as …

Implementation Of Fortran Finite Element Analysis Source Code With Application : Particle Deposition In A 90 Degree Duct Bend, Pantaleo Loiacono

Theses

Two FORTRAN 77 finite element analysis source codes, by 1.N. Reddy, were input into a PC, debugged, executed, and tested successfully. These programs are available to students interested in implementing a good finite element analysis source code on a PC or on a workstation in one or two dimensions. The programs can solve problems relating to heat transfer, stresses, beam analysis, frames, trusses, plane elasticity, plate bending, and laminar viscous incompressible fluids with various node and element combinations.

The two-dimensional program was used to obtain the velocity distributions in a 90 degree duct bend with incoming and exiting fully developed …

Experimental And Analytical Investigation Of Waterjet Cleaning Process, Ping Meng

Dissertations

This doctoral dissertation is concerned with the development of water based cleaning technology required by industry which may substitute the traditional approach based upon the use of various chemical cleansers.

The experimental study involves the waterjet removal of various coatings (rust, oil and epoxy based paints, etc.). Cleaning was carried out under a wide range of operational and geometrical conditions (standoff distance, travel speed, water pressure, diameters of sapphire nozzle and focusing tube, nozzle body type). A new designed spiral nozzle body was tested in this work. The use of surfactant was also investigated. Microscope and SEM surface were used …

Experimental And Numerical Investigation Of Abrasive Waterjet Polishing Technology, Fenggang Li

Dissertations

The objective of this investigation is the development of the abrasive waterjet (AWJ) based polishing technology. The result of the investigation will assist the implementation of AWJ polishing for manufacturing processes and procedures.

Experimental exploration of AWl polishing involving processing of difficultmachine materials such as Alumina ceramic and stainless steel. Surface improvement due to this processing is evaluated by measuring the roughness of the generated surfaces and examining the microhardness and micro-topography of the surfaces using Scanning Electronic Microscopy (SEM). The surface roughness of 0.3 micron was obtained at samples of ceramic and metal alloys at a reasonable rate using …

Global Fuzzy Control Based On Cell Mapping, Tea-Quin Kim

Dissertations

Cell mapping methods can generate global optimal controls for nonlinear dynamic systems. However, the implementation of this approach for on-line control is difficult due to its use of a table-based controller which requires a large amount of memory.

In this dissertation, a cell mapping based systematic method is developed to construct a fuzzy controller to replace the table-based controller for global optimal control of dynamic systems. The method consists of four steps: 1) An optimal control table is generated using a cell mapping algorithm. 2) The cells are linked into trajectories to characterize the optimal dynamic evolution of various cell. …

Reduction Of Inertia-Induced Forces In A General Spatial Mechanism, Sahidur Rahman

Dissertations

A computer-aided design procedure has been developed for minimizing the adverse effects of the inertia-induced forces by optimum mass redistribution amongst the links of high speed general spatial linkages. The evaluation of an optimality criterion for the mass redistribution of the mechanism will be carried out with the aid of a quadratic programming technique. This has been found to be successful in minimizing inertia induced forces and torques. The validity of the optimization procedure will be demonstrated by application to one kind of spatial linkage.

No literature has been found on the balancing of a general spatial mechanism, since its …

Granular Dynamics Study Of Sieving, Heng Yung

Theses

The objective of this thesis is to study the behaviors of granular particles under sieving. A three-dimensional dynamic simulation code was transferred and modified for this purpose, The major concern is the mass flow rate of the particles. Lots of case studies were run. The influences of the friction coefficient, the sieve aperture, and the energy of vibration are studied.

Relay Ladder Logic And Petri Nets For Discrete Event Control Design : A Comparative Study, Edward Twiss

Theses

In the 1960's and earlier discrete event systems (DES) were controlled by hardwired electromechanical relay systems. In 1969 an electronic programmable logic controller (PLC) was introduced. PLC's have been programmed utilizing relay ladder logic (RLL). RLL is a graphical programming language with software "devices" used to emulate electromechanical devices. RLL programs, however, often become large and difficult to understand because its graphical representation of physical switching devices obscures the discrete event dynamics inherent in the process to be controlled. Petri nets are a methodology for modeling discrete event systems (DES). Using a Petri net based controller, a control strategy could …

Real Time Control Of Nonlinear Dynamic Systems Using Neuro-Fuzzy Controllers, Amitava Jana

Dissertations

The problem of real time control of a nonlinear dynamic system using intelligent control techniques is considered. The current trend is to incorporate neural networks and fuzzy logic into adaptive control strategies. The focus of this work is to investigate the current neuro-fuzzy approaches from literature and adapt them for a specific application. In order to achieve this objective, an experimental nonlinear dynamic system is considered. The motivation for this comes from the desire to solve practical problems and to create a test-bed which can be used to test various control strategies. The nonlinear dynamic system considered here is an …

Investigation Of Dynamic Friction In Lubricated Surfaces, Hanuman Rachoor

Dissertations

The research reported in this dissertation is concerned with the development of friction models for lubricated contacts. A few analytical models have been developed to investigate the friction under dynamic velocity conditions. In this study, two different tribological situations such as conformal and non-conformal contacts have been chosen. Friction modeling covers boundary, mixed and full fluid film friction regions. A new theory based on the elastic properties of the surface materials, and fluid film properties of the lubricant at the contact has been developed to determine the dynamic friction in boundary, mixed and full hydrodynamic lubrication regions. In the full …

Design And Analysis Of Environmentally Safe Cooling Systems For Machine Tools, Haiping Xu

Theses

Many cooling systems of metal cutting and both their advantages and disadvantages have been reviewed. The cutting forces' relationships, stress distribution, energy consumption and heat generation of orthogonal processes are discussed. A two-dimensional finite element model has been developed to design and analyze a new proposed cooling device, which comes from the idea of "A Novel Cooling Device" proposed by Billatos et al. First, a thermal calculation is completed to compare the temperature difference between two different shapes of coiled pipe. Then, three different cutting conditions, which were considered in the experiments by Childs et al, are conducted under three …

Design For Quality Manufacturability Analysis Of Total Nonconformity Damaged Parts, Samir R. Gami

Theses

The competitive nature of modern manufacturing, demands that innovative approaches be applied in order to have a competitive edge. Shortening the product development cycle, the period from initial design to full production, is a priority for most manufacturers today. The DFQM methodology addresses the issue of quality manufacturability (QM) - the likelihood that defects will occur during manufacture of a product in a standard plant. As a consequence, DFQM helps to shorten the design cycle time. The DFQM architecture identifies a variety of design factors and variables that influence specific defects. This process of influencing defects can be described by …

Implementation Of A Three-Dimensional Non-Intrusive Particle Tracking System, Vivek Gupta

Theses

A Three-Dimensional Non-Intrusive Particle Tracking System has been developed at NJIT's Particle Technology Center to provide experimental results for validating theories being developed in the field of Particle Technology. The system utilizes the principle of magnetic induction between several high-frequency miniature transmitters mounted inside a sphere and a set of receiving loop antennae mounted outside the experimental apparatus. Basic theories and algorithms for the tracking system have already been developed. The focus of this thesis is to make the tracking system more accurate, reliable and user-friendly and to apply it to the study of vibrated beds and chute flows. Various …