Application and analysis of stiffened side shell panel failure for naval patrol craft

Thesis (S.M. in Mechanical Engineering and Naval Architecture and Marine Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (p. 173-176).Over their lifetime, naval patrol craft are subjected to many different types of loading scenarios, most of which are perfectly safe. In rare instances, through a variety of different reasons, these craft are loaded beyond their means, resulting in structural failure. This thesis focuses on how side shell stiffened panel failure occurs from a global and local perspective, bridging the gap between a real life problem and mechanics theory in an effort to reduce uncertainty in the ship structural design and construction process. It incorporates aspects of basic ship structural design theory, detailing static and dynamic shipboard loads, progressive collapse behavior, and global causes of hull strength reduction. Locally, it examines stiffened panel failure modes due to axial loading through a comparison analysis with consideration for sources of panel strength loss. Finally, this thesis discusses methods for avoidance and mitigation of failure in the future at the design, construction, and operational levels. On the global level, this thesis draws from two incidents in the last decade where U.S. Navy and U.S. Coast Guard patrol craft have had class-wide incidents of structural failure. These failures have ranged from buckling, to yield, to fracture. Each ship's background is discussed, and primary stress calculations are presented with design margins based on classification societies, along with an engineering analysis of the failures that occurred on each vessel. Internal and external factors for overall hull strength reduction are examined and applied to each case, including considerations for slamming and saltwater corrosion.(cont.) Using one of the failure incidents that took place on the U.S. Coast Guard 123', local failure modes are examined across several analysis methods for axially loaded panels. Buckling and ultimate load values are calculated through a parametric design space, while boundary conditions and geometric properties are varied. Finite element analysis and proven analytical methods are used, including those developed by Von Karman. A comparison analysis is completed using experimental data, where local causes for strength reduction in panels are considered, including construction imperfections, shearing, residual stresses, cracking, and initial deflection.by Matthew K. A. Mothander.S.M.in Mechanical Engineering and Naval Architecture and Marine Engineerin

A New Set of Normalized Geometric Moments Based on Schlick's Approximation

Schlick’s approximation of the term x p is used primarily to reduce the complexity of specular lighting calculations in graphics applications. Since moment functions have a kernel defined using a monomial x p y p , the same approximation could be effectively used in the computation of normalized geometric moments and invariants. This paper outlines a framework for computing moments of various orders of an image using a simplified kernel, and shows the advantages provided by the approximating function through a series of experimental results

Foundations of realistic rendering : a mathematical approach

Die vorliegende Dissertation ist keine gewöhnliche Abhandlung, sondern sie ist als Lehrbuch zum realistischen Rendering für Studenten im zweiten Studienabschnitt, sowie Forscher und am Thema Interessierte konzipiert. Aus mathematischer Sicht versteht man unter realistischem Rendering das Lösen der stationären Lichttransportgleichung, einer komplizierten Fredholm Integralgleichung der 2tenArt, deren exakte Lösung, wenn überhaupt berechenbar, nur in einem unendlich- dimensionalen Funktionenraum existiert. Während in den existierenden Büchern, die sich mit globaler Beleuchtungstheorie beschäftigen, vorwiegend die praktische Implementierung von Lösungsansätzen im Vordergrund steht, sind wir eher daran interessiert, den Leser mit den mathematischen Hilfsmitteln vertraut zu machen, mit welchen das globale Beleuchtungsproblem streng mathematisch formuliert und letzendlich auch gelöst werden kann. Neue, effzientere und elegantere Algorithmen zur Berechnung zumindest approxima- tiver Lösungen der Lichttransportgleichung und ihrer unterschiedlichen Varianten können nur im Kontext mit einem vertieften Verständnis der Lichttransportgleichung entwickelt werden. Da die Probleme des realistischen Renderings tief in verschiedenen mathematis- chen Disziplinen verwurzelt sind, setzt das vollständige Verständnis des globalen Beleuch- tungsproblems Kenntnisse aus verschiedenen Bereichen der Mathematik voraus. Als zen- trale Konzepte kristallisieren sich dabei Prinzipien der Funktionalanalysis, der Theorie der Integralgleichungen, der Maß- und Integrationstheorie sowie der Wahrscheinlichkeitstheo- rie heraus. Wir haben uns zum Ziel gesetzt, dieses Knäuel an mathematischen Konzepten zu entflechten, sie für Studenten verständlich darzustellen und ihnen bei Bedarf und je nach speziellem Interesse erschöpfend Auskunft zu geben.The available doctoral thesis is not a usual paper but it is conceived as a text book for realistic rendering, made for students in upper courses, as well as for researchers and interested people. From mathematical point of view, realistic rendering means solving the stationary light transport equation, a complicated Fredholm Integral equation of 2nd kind. Its exact solution exists|if possible at all|in an infinite dimensional functional space. Whereas practical implementation of approaches for solving problems are in the center of attentionin the existing textbooks that treat global illumination theory, we are more interested in familiarizing our reader with the mathematical tools which permit them to formulate the global illumination problem in accordance with strong mathematical principles and last but not least to solve it. New, more eficient and more elegant algorithms to calculate approximate solutions for the light transport equation and their different variants must be developed in the context of deep and complete understanding of the light transport equation. As the problems of realistic rendering are deeply rooted in different mathematical disciplines, there must precede the complete comprehension of all those areas. There are evolving principles of functional analysis, theory of integral equations, measure and integration theory as well as probability theory. We have set ourselves the target to remerge this bundle of fluff of mathematical concepts and principles, to represent them to the students in an understandable manner, and to give them, if required, exhaustive information

Different ways of seeing: the language games of mothering

My thesis is original in placing together Wittgenstein's ideas of how language works, and arguments for the philosophical significance of the embodied and relational figure of the mother. I both use and resist a Wittgensteinian therapy to overcome the problem of the forgetting of the mother in philosophy. I begin with the problem of essentialism, important to Wittgenstein and to feminist philosophy. My reading of Wittgenstein finds an ignored lacuna between language and (female) experience. I add in to the debate the type specimen approach from botany. Adopting this approach enables me to avoid a classification which requires a true inner essence to mothering, and provides a way for me to denote the significant place of the language games of mothering in language games about women. I argue for a different symbol of the mother. I agree with Wittgenstein's account of language, but add to it. I show the importance of Wittgenstein's insight that although meaning is not fixed independently of use, use does not fix meaning in that I create new meanings for the figure of the mother. I argue, through an exploration of Wittgenstein's concept of `übersichtlichen Darstellung ; that Wittgenstein can help us to see the phenomena of our life differently, in a way that makes space for understanding female difference. His concept of a form of life provides such openings. As the Wittgensteinian agent seems distinctly un-female, I bring in the philosophy of Kierkegaard in my argument for a different relational self as mother. I argue for a Kierkegaardian flexible maternal self with mobile edges. I insert the language games of the mother into Kierkegaard's writing on women. My aim is a more adequate representation of a (true) reality. I use the work of John Wisdom to make a bridge between Wittgenstein and the narrative form, which I use throughout. Wisdom's strategy is to engage in unconventional reflection in looking for new ways of telling philosophical stories, and in finding new patterns of meaning in the familiar. I claim that the narrative form enables me to express the shifting essence of the mother and the diversity of mothers; and to acknowledge the silences which are part of the mother's story. My aim in this thesis is creative. I use Wittgenstein to create a new kind of relation to philosophy. I do not offer a correct reading of Wittgenstein or Kierkegaard. Instead, aided by the insights provided by feminist philosophy, I write in the language games of the mother to their ideas. Thus, I bring into existence through utterance a different, feminist philosophical symbol of the mother

Different ways of seeing : the language games of mothering

My thesis is original in placing together Wittgenstein's ideas of how language works, and arguments for the philosophical significance of the embodied and relational figure of the mother. I both use and resist a Wittgensteinian therapy to overcome the problem of the forgetting of the mother in philosophy. I begin with the problem of essentialism, important to Wittgenstein and to feminist philosophy. My reading of Wittgenstein finds an ignored lacuna between language and (female) experience. I add in to the debate the type specimen approach from botany. Adopting this approach enables me to avoid a classification which requires a true inner essence to mothering, and provides a way for me to denote the significant place of the language games of mothering in language games about women. I argue for a different symbol of the mother. I agree with Wittgenstein's account of language, but add to it. I show the importance of Wittgenstein's insight that although meaning is not fixed independently of use, use does not fix meaning in that I create new meanings for the figure of the mother. I argue, through an exploration of Wittgenstein's concept of `übersichtlichen Darstellung ; that Wittgenstein can help us to see the phenomena of our life differently, in a way that makes space for understanding female difference. His concept of a form of life provides such openings. As the Wittgensteinian agent seems distinctly un-female, I bring in the philosophy of Kierkegaard in my argument for a different relational self as mother. I argue for a Kierkegaardian flexible maternal self with mobile edges. I insert the language games of the mother into Kierkegaard's writing on women. My aim is a more adequate representation of a (true) reality. I use the work of John Wisdom to make a bridge between Wittgenstein and the narrative form, which I use throughout. Wisdom's strategy is to engage in unconventional reflection in looking for new ways of telling philosophical stories, and in finding new patterns of meaning in the familiar. I claim that the narrative form enables me to express the shifting essence of the mother and the diversity of mothers; and to acknowledge the silences which are part of the mother's story. My aim in this thesis is creative. I use Wittgenstein to create a new kind of relation to philosophy. I do not offer a correct reading of Wittgenstein or Kierkegaard. Instead, aided by the insights provided by feminist philosophy, I write in the language games of the mother to their ideas. Thus, I bring into existence through utterance a different, feminist philosophical symbol of the mother.EThOS - Electronic Theses Online ServiceGBUnited Kingdo