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Rotierende Balken und Schalen als Berechnungsmodelle für lang kragende Fräswerkzeuge mit Hohlschaft zur HochgeschwindigkeitsbearbeitungSchmidt, Rico 22 May 2023 (has links)
Die Verwendung von lang kragenden Schaftfräsern im Bereich der Hochgeschwindigkeitsbearbeitung birgt besondere Herausforderungen bezüglich der Prozessdynamik. In diesem Zusammenhang werden verschiedene kontinuumsmechanische Berechnungsmodelle für Werkzeuge mit Hohlschaft vorgestellt. Dabei wird eine teilweise Füllung des Schaftes mit einer fließfähigen Ausgleichsmasse zum Zweck des automatischen Wuchtens berücksichtigt. Ausgehend von der Verformungskinematik wird die systembeschreibende Variationsformulierung mit Hilfe des Hamilton'schen Prinzips hergeleitet. Dabei wird auch auf den Einfluss von stochastisch verteilten Unwuchten, geometrischen Nichtlinearitäten und Schubdeformationen eingegangen. Zur Ortsdiskretisierung werden sowohl lokale als auch globale Methoden angewendet und miteinander verglichen. Die Auswertung stellt den Einfluss von verschiedenen geometrischen sowie prozessbedingten Parametern auf die Eigenfrequenzen, stationäre Deformation, Stabilität sowie Zeitlösung dar.:1. Einleitung
1.1. Problemstellung und Motivation der Arbeit
1.2. Stand der Technik
1.2.1. Hochgeschwindigkeitsfräsen
1.2.2. Verwendung lang kragender Schaftfräser
1.3. Thema und Aufbau der Arbeit
2. Theoretische Grundlagen
2.1. Kontinuumsmechanische Grundbegriffe
2.2. Spannungen und konstitutive Gleichungen
2.3. Prinzip von Hamilton
2.4. Lösungstheorie
2.4.1. Anfangswertprobleme
2.4.2. Randwertprobleme
2.5. Stochastische Grundbegriffe
3. Balkenmodelle
3.1. Verformungskinematik des Balkens
3.2. Variationsformulierung
3.3. Modellierung der Unwucht
3.4. Globale Diskretisierung
3.4.1. Stationäre Lage und Linearisierung
3.4.2. Ortsfunktionen
3.5. Lokale Diskretisierung
3.6. Anmerkungen zur schubweichen Formulierung
3.7. Berechnungsergebnisse
3.7.1. Ruhendes Werkzeug
3.7.2. Rotierendes Werkzeug
4. Schalenmodelle
4.1. Verformungskinematik der Schale
4.2. Variationsformulierung
4.3. Globale Diskretisierung
4.3.1. Stationäre Lage und Linearisierung
4.4. Lokale Diskretisierung mittels FEM
4.4.1. Konforme flache Schalenelemente
4.5. Anmerkungen zur schubweichen Formulierung
4.6. Berechnungsergebnisse
4.6.1. Ruhender Schaft
4.6.2. Rotierender Schaft
5. Zusammenfassung und Ausblick
6. Verzeichnisse
6.1. Quellenverzeichnis
6.2. Symbolverzeichnis
6.3. Abbildungsverzeichnis
6.4. Tabellenverzeichnis
A. Feldgleichungen und Ableitungen der Ansätze für die Balkenmodelle
B. Anmerkungen zum Timoshenko-Balken
C. Feldgleichungen und Ableitungen der Ansätze für die Schalenmodelle
D. Anmerkungen zur Mindlin-Reissner-Schale / The use of long slender end mills for high-speed-cutting (HSC) holds special requirements with respect to the system dynamics. In this context, several tool models in the area of continuum mechanics are presented. Especially hollow tool shafts, with a fluid medium inside, for the purpose of automatic balancing are considered. Starting with the kinematics of deformation, Hamilton's principle is used to evaluate the variational formulation. Therefore, also the influence of a stochastic distributed unbalance, geometrical nonlinearities and shear deformations are discussed. For space discretisation local as well as global approaches are used and compared with each other. Following up on this, results are presented, which show the influence of different geometrical and process-related parameters due to the eigenfrequencies, stationary deformation, stability and time solution.:1. Einleitung
1.1. Problemstellung und Motivation der Arbeit
1.2. Stand der Technik
1.2.1. Hochgeschwindigkeitsfräsen
1.2.2. Verwendung lang kragender Schaftfräser
1.3. Thema und Aufbau der Arbeit
2. Theoretische Grundlagen
2.1. Kontinuumsmechanische Grundbegriffe
2.2. Spannungen und konstitutive Gleichungen
2.3. Prinzip von Hamilton
2.4. Lösungstheorie
2.4.1. Anfangswertprobleme
2.4.2. Randwertprobleme
2.5. Stochastische Grundbegriffe
3. Balkenmodelle
3.1. Verformungskinematik des Balkens
3.2. Variationsformulierung
3.3. Modellierung der Unwucht
3.4. Globale Diskretisierung
3.4.1. Stationäre Lage und Linearisierung
3.4.2. Ortsfunktionen
3.5. Lokale Diskretisierung
3.6. Anmerkungen zur schubweichen Formulierung
3.7. Berechnungsergebnisse
3.7.1. Ruhendes Werkzeug
3.7.2. Rotierendes Werkzeug
4. Schalenmodelle
4.1. Verformungskinematik der Schale
4.2. Variationsformulierung
4.3. Globale Diskretisierung
4.3.1. Stationäre Lage und Linearisierung
4.4. Lokale Diskretisierung mittels FEM
4.4.1. Konforme flache Schalenelemente
4.5. Anmerkungen zur schubweichen Formulierung
4.6. Berechnungsergebnisse
4.6.1. Ruhender Schaft
4.6.2. Rotierender Schaft
5. Zusammenfassung und Ausblick
6. Verzeichnisse
6.1. Quellenverzeichnis
6.2. Symbolverzeichnis
6.3. Abbildungsverzeichnis
6.4. Tabellenverzeichnis
A. Feldgleichungen und Ableitungen der Ansätze für die Balkenmodelle
B. Anmerkungen zum Timoshenko-Balken
C. Feldgleichungen und Ableitungen der Ansätze für die Schalenmodelle
D. Anmerkungen zur Mindlin-Reissner-Schale
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Bringing "Culture" to Cleveland: East Asian Art, Sympathetic Appropriation, and the Cleveland Museum of Art, 1914-1930Adams, Christa January 2015 (has links)
No description available.
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'Such Spiritual Acres': Protestantism, the land and the colonisation of Australia 1788 - 1850Lake, Meredith Elayne January 2008 (has links)
Doctor of Philosophy / This thesis examines the transmission of Protestantism to Australia by the early British colonists and its consequences for their engagement with the land between 1788 and 1850. It explores the ways in which colonists gave religious meaning to their surrounds, particularly their use of exile and exodus narratives to describe journeying to the colony and their sense of their destination as a site of banishment, a wilderness or a Promised Land. The potency of these scriptural images for colonising Europeans has been recognised in North America and elsewhere: this study establishes and details their significance in early colonial Australia. This thesis also considers the ways in which colonists’ Protestant values mediated their engagement with their surrounds and informed their behaviour towards the land and its indigenous inhabitants. It demonstrates that leading Protestants asserted and acted upon their particular values for industry, order, mission and biblicism in ways that contributed to the transformation of Aboriginal land. From the physical changes wrought by industrious agricultural labour through to the spiritual transformations achieved by rites of consecration, their specifically Protestant values enabled Britons to inhabit the land on familiar material and cultural terms. The structural basis for this study is provided by thematic biographies of five prominent colonial Protestants: Richard Johnson, Samuel Marsden, William Grant Broughton, John Wollaston and John Dunmore Lang. The private and public writings of these men are examined in light of the wider literature on religion and colonialism and environmental history. By delineating the significance of Protestantism to individual colonists’ responses to the land, this thesis confirms the trend of much recent British and Australian historiography towards a more religious understanding of the eighteenth and early nineteenth centuries. Its overarching argument is that Protestantism helped lay the foundation for colonial society by encouraging the transformation of the environment according to the colonists’ values and needs, and by providing ideological support for the British use and occupation of the territory. Prominent Protestants applied their religious ideas to Australia in ways that tended to assist, legitimate or even necessitate the colonisation of the land.
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'Such Spiritual Acres': Protestantism, the land and the colonisation of Australia 1788 - 1850Lake, Meredith Elayne January 2008 (has links)
Doctor of Philosophy / This thesis examines the transmission of Protestantism to Australia by the early British colonists and its consequences for their engagement with the land between 1788 and 1850. It explores the ways in which colonists gave religious meaning to their surrounds, particularly their use of exile and exodus narratives to describe journeying to the colony and their sense of their destination as a site of banishment, a wilderness or a Promised Land. The potency of these scriptural images for colonising Europeans has been recognised in North America and elsewhere: this study establishes and details their significance in early colonial Australia. This thesis also considers the ways in which colonists’ Protestant values mediated their engagement with their surrounds and informed their behaviour towards the land and its indigenous inhabitants. It demonstrates that leading Protestants asserted and acted upon their particular values for industry, order, mission and biblicism in ways that contributed to the transformation of Aboriginal land. From the physical changes wrought by industrious agricultural labour through to the spiritual transformations achieved by rites of consecration, their specifically Protestant values enabled Britons to inhabit the land on familiar material and cultural terms. The structural basis for this study is provided by thematic biographies of five prominent colonial Protestants: Richard Johnson, Samuel Marsden, William Grant Broughton, John Wollaston and John Dunmore Lang. The private and public writings of these men are examined in light of the wider literature on religion and colonialism and environmental history. By delineating the significance of Protestantism to individual colonists’ responses to the land, this thesis confirms the trend of much recent British and Australian historiography towards a more religious understanding of the eighteenth and early nineteenth centuries. Its overarching argument is that Protestantism helped lay the foundation for colonial society by encouraging the transformation of the environment according to the colonists’ values and needs, and by providing ideological support for the British use and occupation of the territory. Prominent Protestants applied their religious ideas to Australia in ways that tended to assist, legitimate or even necessitate the colonisation of the land.
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Det filmiska ögat : En undersökning av konstbetraktandets natur i tunnelbanan genom fotomontaget ”Den dagen, den sorgen” på Karlaplans stationLjung, Bo January 2018 (has links)
Uppsatsen undersöker konstbetraktandets natur i tunnelbanan genom en närstudie av fotomontaget ”Den dagen, den sorgen på Karlaplans tunnelbanestation i Stockholm. Uppsatsens huvudsakliga frågeställning är: Hur spelar ”Den dagen den sorgen” upp sin mening och hur tas denna emot av betraktaren i tunnelbanekontexten vid Karlaplan? Två underfrågor kompletterar frågeställningen: 1.Vilken är fotomontagets konstnärliga särart och hur är det organiserat narrativt? 2.Hur är tunnelbanans ”genius loci” och hur samverkar konstverket med platsen och rummet? Impetus för uppsatsen är konstverkets säregna och unika karaktär som konstverk. Det finns inget liknande verk i Stockholms tunnelbana. Det lockar, väcker frågor och involverar betraktaren på ett direkt sätt. Syftet med uppsatsen är därför att undersöka mekanismerna för denna betraktaraktiverande rörelse. En fråga som ofta saknas i den omfattande litteraturen om konsten i Stockholms tunnelbana är hur tunnelbanekonsten kommunicerar och tas emot av sina betraktarresenärer. Denna brist motiverar en undersökning av relationen mellan konstverk, betraktare och miljö. Uppsatsen är utförd med hjälp av en deduktiv och systematiskt tolkande arbetsmetod utifrån en receptionsteoretisk och semiotisk teoribildning. De valda frågeställningarna har riktat analysen och fotomontaget har studerats som konstnärligt och språkligt fenomen. Receptionsteorin utgår från Wolfgang Kemps begreppsanalys, vilken är strukturerad i interna och externa faktorer. Peter Gillgren kompletterar Kemp och visar hur betydelsefulla verkets interartiella referenser och den litterära meningen är för den receptionsteoretiska tolkningen. Roland Barthes semiotiska teckenanalys, där denoterande tecken omvandlas till konoterande i betraktarens medvetande, ligger också till grund för tolkningen Texten är uppbyggd av fem delar. De består av inledning, bakgrund, interna faktorer, externa faktorer samt avslutande diskussion med slutsatser och sammanfattning. Genom verkets många interartiella referenser framträder en samhällskritisk litterär mening. För att förmedla denna litterära mening har upphovsmannen medvetet sökt motverka en riskerad polysemi. Kompletterande performativa textremsor, det hyperrealistiska fotografiska bildmediet samt en återhållsamhet med fragment stramar åt och riktar bildens ”betydelse”. Bildens komposition och perspektiv samt en frekvent användning av vakanser och fokaliserande gestalter bjuder in betraktaren i bildens ”spel” och sätter dennes öga i rörelse. Verk, betraktare och miljö möts och förstår varandra i hastiga filmiska ögonblick. Sådan är konstbetraktandets natur på Karlaplans tunnelbanestation.
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Det omättliga ögatLjung, Bo January 2020 (has links)
This is a master thesis dealing with reception-theoretical aspects of the 96 meter long photomontage called That day and that grief, created by the Swedish photographer and artist Larseric Vänerlöf. The artwork is situated in the Karlaplan metro-station in Stockholm. The text is an extension of the master thesis that I wrote in 2017-2018, entitled The Cinematic eye. This new essay aims to deepen the understanding of how the photomontage reveals it´s meaning and how it is received by the viewer in the metro context at Karlaplan. Main questions: 1/ What is it in this big photomontage, that makes the viewing travellers, wanting to stay and watch it, even though they are in a hurry towards another place, in another matter? 2/ How does this artwork speak to me and how does it want me to watch it? 3/ What does the photomontage want to tell me? 4/ What does the work represents? Since my study focuses on the imagery and communication-act of the artwork, I find semiotics and reception-theory as the obvious theoretical tools. Part of the interpretation of the image relates to the semiotics of Roland Barthes and his statement that all images are polysemic and ambiguous and that they are culturally and historically conditioned. In my conclusion I discuss and to some extent challenge the mechanism and interaction between literal, denoting information and symbolic connotation in the viewer’s reception. The reception analysis is based on Wofgang Kemps conceptual apparatus formulated in The work of Art and its Beholder (1998), and Peter Gillgrens concept of interartial references. Hans Georg Gadamers view of art as a performative game complements the essays theoretical construction. I use a deductive and systematic interpretive working method. Based on the chosen semiotic and reception theoretical formation and through my questions, I have studied the phenomenology of the photomontage, i.e. as an artistic and linguistic phenomenon. Empathy in site/location, beholder and zeitgeist form the basis of the methodological work.The conclusions of the thesis are radically different from that of my former text from 2017-18. Imagery and symbolic ambiguities and focalics that refuse to reveal the "meaning" and content of the photomontage, activate the viewer in a performative way and creates a highly communicative work, which involves the viewer in the theatrical course. Through a deeper study of the “zeitgeist”, I have also concluded that the collective and political symbols from the 1970s in the work, have lost power and content at the time of the dismantling in 1982. The character that I previously perceived as "Art as weapon" has in this essay been transformed to "Art as visuality". The art of photography appears as the real subject matter for the photomontage at Karlaplan subwaystation.
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