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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Analysis of bow crushing in ship collision

Kim, Ji Young, 1968- January 2000 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2000. / Includes bibliographical references (leaves 108-110). / Collision of ships with oil tankers poses, next to grounding, one of the most serious environmental threats at sea. In many previous analyses of the collision problem, the bow of the impacting ship was considered rigid. The objective of the present research is to include the finite strength of the bow in the overall collision simulation. The emphasis will be placed on typical raked shapes because some work already has been reported in the past on bulbous bows. The main structural members will include side shell and the deck. Transverse and longitudinal stiffeners will be taken into account by means of a smearing technique. A structural model is developed by identifying localized zones of plastic deformations from photographs of damaged ships. Then, the contributions of the membrane and bending resistance is assessed and a simple computational model is developed. The solution includes determination of the force-indentation relationship, a number of folds and a total amount of damage for a given speed of a ship. Five scale model tests were run and the force-deflection characteristics were recorded. A good correlation was obtained between the analytical solution and experimental results. / by Ji Young Kim. / S.M.
192

Low-frequency bottom backscattering data analysis using multiple constraints beamforming

Li, Dan, 1969- January 1995 (has links)
Thesis (Ocean. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1995. / Includes bibliographical references (leaves 83-87). / by Dan Li. / Ocean.E.
193

Development and analysis of panel methods for propellers in unsteady flow

Hsin, Ching-Yeh January 1990 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1990. / Includes bibliographical references (leaves 137-144). / by Ching-Yeh Hsin. / Ph.D.
194

Premature cleavage of ship plating under reversed bending

Muragishi, Osamu, 1961- January 2001 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, February 2001. / Includes bibliographical references (p. 71-75). / The objective of the thesis is to develop and apply testing methodology for fracture initiation of actual components of a ship's hull and to provide engineering design data to be used by the industry in predicting the effects of extreme loads such as accidents at sea or earthquakes. Since cleavage is more dangerous than ductile fracture, attention was focused on conditions controlling cleavage fracture. A careful inspection of damaged components of ships and structures damaged in the 1995 Kobe earthquake showed that fracture often initiates in the zones of large bending strains. It was found from the literature that tensile strains resulting from bending alone are not sufficient to cause fracture. A certain amount of reversed strain is needed. Also, temperature is an important parameter of the process. A comprehensive experimental program was undertaken to study the effects of pre-strain, reversed strain, and temperature. A total of 39 bending specimens cut from actual ship plating were tested and on that basis a 3-D failure surface was constructed for the AH36 steel, suitable for practical applications. The failure surface was formed in terms of compressive pre-strain, temperature, and reverse tensile strain. As-rolled plates pre-strained by -0.43 at room temperature with a Charpy 20 J work transition of 6⁰ C, cleaved with very small reversed strain of 0.011 at low service temperatures of-40⁰ C. Machining the surface, as done with conventional test specimens, raised the reversed strain to cleavage to 0.33. / (cont.) Thus, a serious risk is hidden in the use of machined specimens in bending. Effects of other parameters such as aging were also studied on separate types of specimens. In addition, several mechanisms that could be responsible for the initiation of cleavage were identified and discussed in some depth. Because of the complex interaction between these various mechanisms and effects, it is not possible to make fracture prediction based on first principles. This difficulty necessitates conducting experiments on full-scale test specimens on ship plating which was one of the main objectives of the present thesis. In practical terms, the thesis gives a relatively simple method to chose a steel that could withstand anticipated accidental conditions. / by Osamu Muragishi. / Ph.D.
195

An image processing based system for three dimensional sail shape analysis

Freides, Drew Scott January 1991 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1991. / Title as it appears in the June, 1991 M.I.T. Graduate List: An image processing based approach to 3-dimensional sail shape analysis. / Includes bibliographical references (leaf 63). / by Drew Scott Freides. / M.S.
196

Second-order steady forces on floating bodies with forward speed

Ferreira, Marcos Donato Auler da Silva January 1997 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997. / Includes bibliographical references (leaves 145-148). / by Marcos Donato Auler da Silva Ferreira. / Ph.D.
197

Algorithms for rational spline surface intersections

Kriezis, George Anthony January 1990 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1990. / Includes bibliographical references (leaves 255-263). / by George Anthony Kriezis. / Ph.D.
198

The importance of scale structure in scattering from random, rough surfaces

Lupien, Vincent (Vincent-Hugues), 1970- January 1998 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1998. / Includes bibliographical references (leaves 237-244). / by Vincent Lupien. / Ph.D.
199

Wave scattering from cylindrical fluid inclusions in an elastic medium and determination of effective medium properties

Laible, Henry A January 1995 (has links)
Thesis (Ocean. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1995. / Includes bibliographical references (leaves 76-68). / by Henry A. Laible. / Ocean.E.
200

Structures, statistics and mechanisms of low Froude number free-surface turbulence : a simulation-based study / Structures, statistics and mechanisms of low Froude number FST

Shen, Lian, 1970- January 2001 (has links)
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, February 2001. / Includes bibliographical references (p. 248-256). / by Lian Shen. / Sc.D.

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