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The Global ETD Search service is a free service for researchers
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Progressive Failure Analysis of Laminated Composite StructuresKhan, Arafat Islam 15 December 2015 (has links)
Laminated composite structures have started to play a very significant role in today's aircraft industry. The application of composite materials has now gone beyond the borders of aircraft design and has entered into such fields as automotive, athletics and recreational equipment, etc. The light weight and high specific strength of composite material helps design vehicles with higher fuel efficiency and longevity. In order to understand the influence of design parameters related to the use of composite materials in these applications, a proper study of the laminated composite structures requires a complete failure analysis, which includes both initiation and propagation of damage. In this work a progressive failure methodology is developed and implemented in the commercial Finite Element software package, Abaqus. Out of the numerous failure criteria available in the literature to study damage initiation and propagation in unidirectional fiber reinforced composites, Puck and Schurmann's failure criteria have been chosen due to their ability to predict results close to those observed experimentally. Key features of the Puck and Schurmann's failure criteria for three-dimensional deformations of unidirectional fiber reinforced composites have been summarized. Failure modes in the matrix and the fiber are considered separately. The failure criteria are simplified for plane stress deformations. Whereas the failure plane can be analytically identified for plane stress deformations, a numerical search algorithm is needed for three-dimensional problems. Subsequent to the initiation of matrix failure, elastic moduli are degraded and values of these degradation parameters and fracture plane angles are found by using a Continuum Damage Mechanics (CDM) approach. It is found that the assumption that the material response remains transversely isotropic even after the matrix failure has initiated requires the degradation of the transverse Poisson's ratio. The Puck and Schurmann's failure criteria and the material degradation process have been implemented as a User Defined Field (USDFLD) subroutine in Abaqus. The implementation has been verified by analytically computing results for simple loadings and comparing them with predictions from using the USDFLD in Abaqus. Subsequently, both two- and three-dimensional problems of more realistic geometries and loadings have been analyzed and computed results compared with either experimental findings or results available in the literature. Major contributions of the work include identifying the degradation parameter for the transverse Poisson's ratio in terms of the matrix degradation parameter for the matrix failure in compression, development of the USDFLD based on Puck and Schurmann's failure criteria, implementing the USDFLD in the commercial finite element software, Abaqus, and verifying that results computing using the USDFLD for various laminates and loadings agree with those from either the analytical solution of the problem or those available in the literature. / Ph. D.
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Ontologi efter dekonstruktionen av arké : En fråga om övergången och relationen mellan princip och anarki hos Reiner Schürmann och Giorgio Agamben / Ontology after the Deconstruction of Arché : A Question of Transition and Relation between Principle and Anarchy in the Work of Reiner Schürmann and Giorgio AgambenEriksson, Magnus January 2024 (has links)
This work considers what ontology might be after the deconstruction of arché in Reiner Schürmann's and Giorgio Agamben's thinking. It addresses the question by reading Schürmanns historical deduction of the categories of presencing in his book Heidegger On being Acting: From Principles to Anarchy. This deduction is at the heart of his thought in that it tries to manifest what it means to live the transition from arché to an-arché, from a life under principles and why's, to a life without why, and the principle of anarchy. This transitional thought rests on what he calls the hypothesis of closure of the metaphysical field. The deduction is therefore a question of a relation between the first beginnings end as an other beginning. He shows this by establishing categories that are both conceptual- and sensible form. This reaches its full articulation in what he calls the categories of transition; categories in which the distinction between category and intuition seems to collapse – that are its own gaze or eye, that sees both the past and the future at the same time. This is a question regarding relationality: the transition from a causal relationality to an anarchic relationality, from a substance ontology to relational ontology. What is the relational status of the transition itself and its categories? This question lead to the main one: is the transition between arché and an-arché a relation between the two? The overall purpose is to explore this question in order to open, in the end, a path between him and Agamben. The later has pointed out that the key problem to live truly anarchic is a critique of the ontological relation because language presuppositional structure manifests in it, which takes its “full” form in his work The Use of Bodies. Here, perhaps – which we only can point to – Schürmann's thought can meet Agamben's in the caesura between arché and an-arché. Can anarchy ever be in a position of principle? In the end we will have to point to the notion of oikonomia as an area of further research to understand the question of anarchy between Agamben and Schürmann.
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Heidegger et la question du mal / Heidegger and the question of evilDonnet, Benoît 07 April 2018 (has links)
« C’est seulement lorsque nous nous ouvrons à ce qui est plein de secret et plein de grâce comme à cela qui nous donne proprement à penser, qu’il nous est aussi donné de penser ce que nous tenons pour la malignité du mal », notait Heidegger au moment de méditer la vérité de l’être dans l’exploration de la dimension inouïe au sein de laquelle elle se déploie, à l'heure de mettre fin à la philosophie pour commencer seulement à penser.Comment comprendre que l’expérience du mal ait pu accompagner le chemin de la pensée ? N’est-ce pas cette singulière concomittance qui en éclaire, à l’époque du nihilisme, l’implacable urgence, ainsi que l’indifférence apparente aux questions éthiques ? Car si le mal est accessible à la pensée par delà la différence ontologique, c'est qu'il n’est pas qu’une valeur et excède la législature de la morale. Que signifie-t-il alors et que peut vouloir dire en lever le règne ?Répondre à cette question n'ira pas sans impliquer un retour sur la signification philosophique et théologique du mal, au moment d'en attester, à l'instant de penser, l'incomplétude. Le champ dans lequel Heidegger a pu de manière ou d'autre faire sienne cette tâche n’implique-t-il pas alors de soustraire au silence sa singulière relation au christianisme, dont la morale à laquelle il s'agit de retrancher la vérité du mal porte aussi la trace ?Et si la pensée de l’Ereignis s’accomplit comme surmontement de tout mal, si c’est la paix des choses et des mortels qu’il s’agit d’y construire, la résonance du silence qui structure la langue pour en faire le plus haut de ses modes et dont nous recevons en y répondant ce que nous avons de plus propre, le dire, de quelle paix la pensée en chemin peut-elle porter l'annonce ? Quel sens revêt à cet égard la responsabilité dont l’essence de la langue nous rend face à l’être, titulaires ? / As he takes to addressing the question of being, Heidegger writes: « Only when we open ourselves to what is full of secrets and full of grace as we do to something that makes us think, are we also enabled to think what we consider as the malignancy of evil. »How is one to understand that the experience of evil goes along with the path of thinking ? Is it not this concurrence alone that can explain why evil seemingly ignores ethical questions ? For one can think of evil beyond mere metaphysics as it is not only a value and overrides the laws of morality. What is, then, the meaning of evil, and what could it possibly mean to undo its domination ? Answering this question necessarily implies to reassess the philosophical, and biblical, meaning of evil, with its incompleteness being asserted as the thinking process begins. Aiming at uprooting the truth of evil out of the Christian morality, marked as it is by silence, one wonders whether the field in which Heidegger sets out to make this task his own in one way or another, indeed involves to remove silence off its special relationship to Christianity ?
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Three Eras of Citizen-Rights in Canada: An Interpretation of the Relationship Between Citizen-Rights and Executive PowerTsuji, Kathleen Elizabeth 21 August 2013 (has links)
In Canada’s recent history, the cases of Kanao Inouye, Omar Khadr, and Maher Arar shed light on the relationship between citizen-rights and sovereign power, a problem which this thesis studies through its three-pronged strategy of analysis. First, it takes a postmetaphysical approach to the problem of exceptionality as it has been explored in the works of Jacques Derrida, Gianni Vattimo, and Reiner Schürmann. Their responses to the problem of exceptionality provide a framework that enables this thesis to capture the relationship between citizen-rights and sovereign power in relative detail. Second, it applies Schürmann’s epochal theory in order to offer a historical periodization of citizen-rights in Canada that highlights the effect of sovereign power on citizen-rights. Lastly, in light of its philosophical and theoretical framework, it interprets the Inouye, Khadr, Arar cases in order to account for the effect of Charter rights on sovereign power. / Graduate / 0626 / tsujikt@gmail.com
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Johann Friedrich von Uffenbach. Sammler – Stifter – Wissenschaftler / Johann Friedrich von Uffenbach. Collector - Donor - ScientistMeyerhöfer, Dietrich 28 January 2020 (has links)
No description available.
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