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Full-Text Articles in Mechanical Engineering

Analytical Solutions Of Openings Formed By Intersection Of A Cylindrical Shell And An Oblique Nozzle Under Internal Pressure, Hengming Cai Dec 1996

Analytical Solutions Of Openings Formed By Intersection Of A Cylindrical Shell And An Oblique Nozzle Under Internal Pressure, Hengming Cai

Dissertations

Since several decades ago, many authors have published their research results about local stress distributions of shells and shell-nozzles both analytically and numerically. However, there has not been a published paper, which deals with analytical solutions of cylindrical shell and oblique nozzle, even though in the case of openings formed by intersection of a cylindrical shell and an oblique nozzle.

A comprehensive analytical study of local stress factors at the area of openings formed by intersection of a cylindrical shell and an oblique nozzle under internal pressure is presented in this dissertation.

By means of traditional approach in theory of ...


Shaped Charges Having A Porous Tungsten Liner-An Experimental And Theoretical Study Of Metal Compression, Jet Formation And Penetration Mechanics, Brian Edward Fuchs Dec 1996

Shaped Charges Having A Porous Tungsten Liner-An Experimental And Theoretical Study Of Metal Compression, Jet Formation And Penetration Mechanics, Brian Edward Fuchs

Dissertations

The use of porous tungsten as a liner for shaped charges to improve their penetration was proposed by Ki-Hwan Oh in his invention disclosure "Shock Extrusion of Ingots from Powders or Solids", at the New Mexico Institute of Mining and Technology, Socorro NM on June 7, 1988. The intention was to increase the ductility of the normally brittle metal by heating the liner to a high temperature by shock compaction during its acceleration just before jet formation.

The feasibility of increasing the ductility of tungsten in this way is the subject of the present study. The theory and prior experimental ...


Local Stresses On Lateral Pipe-Nozzle With 45 Degree Angle Intersection, James Jin Xu Oct 1996

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 ...


Experimental And Analytical Investigation Of Waterjet Cleaning Process, Ping Meng May 1996

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 ...


Global Fuzzy Control Based On Cell Mapping, Tea-Quin Kim May 1996

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 ...


Experimental And Numerical Investigation Of Abrasive Waterjet Polishing Technology, Fenggang Li May 1996

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 ...


Reduction Of Inertia-Induced Forces In A General Spatial Mechanism, Sahidur Rahman May 1996

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 ...