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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.
81

Development of Experimental and Finite Element Models to Show Size Effects in the Forming of Thin Sheet Metals

Morris, Jeffrey D 05 August 2019 (has links)
Abstract An experimental method was developed that demonstrated the size effects in forming thin sheet metals, and a finite element model was developed to predict the effects demonstrated by the experiment. A universal testing machine (UTM) was used to form aluminum and copper of varying thicknesses (less than 1mm) into a hemispherical dome. A stereolithography additive manufacturing technology was used to fabricate the punch and die from a UV curing resin. There was agreement between the experimental and numerical models. The results showed that geometric size effects were significant for both materials, and these effects increased as the thickness of the sheets decreased. The demonstration presents an inexpensive method of testing small-scale size effects in forming processes, which can be altered easily to produce different shapes and clearances.
82

Lois de comportement des matériaux utilisés dans les contacts électriques pour application " flip chip " / Behaviour laws of materials used in electrical contacts for « flip chip » technologies

Mercier, David 25 November 2013 (has links)
Dans le cadre de l'intégration « 3D », une technologie d'assemblage par report de puces sur tranche de silicium (« flip chip ») reposant sur un procédé de microinsertion a été développée ces dernières années. Cette technologie est basée principalement sur la mise en contact par thermocompression, de réseaux de (micro)inserts en Nickel ECD, avec des plots de connexions métalliques en Al(Cu). Au cours de ce travail, un scénario de formation du contact entre un unique microinsert de Nickel rugueux et un film mince d'Aluminium lisse, prenant en compte la présence d'Alumine native à l'interface de contact, est proposé pour une gamme de pressions allant du MPa au GPa. L'analyse du contact métal-oxyde-métal se base essentiellement sur la fissuration de l'oxyde natif suivie de l'extrusion du métal au travers des fissures, et nécessite d'établir au préalable les lois de comportement des matériaux mis en jeu à partir d'essais de nanoindentation instrumentée couplés à des simulations numériques. Enfin, la mesure de l'évolution de la résistance électrique de contact en fonction de la force appliquée à l'aide de dispositifs expérimentaux originaux, permet de mettre en évidence les différents mécanismes de formation du contact métallique lors du procédé de microinsertion. / In the field of « 3D » microelectronic integration, a wafer level technology using flip chip stacking and based on a microinsertion process has been developed recently. This technology is mainly based on the contact realized by thermocompression between a network of microinserts made of Nickel ECD, with connections pads in Al(Cu). In this work, a scenario describing the contact establishment between a unique rough microinsert of Nickel and a smooth thin Aluminum film taking into account the presence of native Alumina at the contact interface, is developed for a range of pressures from MPa to GPa. The analysis of the metal-oxide-metal contact is essentially based on the fracture of the native oxide followd by the metal extrusion through cracks, and requires the knowledge of the behaviour laws of materials, obtained from instrumented nanoindentation tests coupled with numerical modeling. Finally, the measure of the electrical contact resistance evolution in function of applied load, with specific pioneering experimental setup, showcases the mechanisms driving the formation of metallic contact during the microinsertion process.
83

Posouzení vlivu orientace zkušebního tělesa na tranzitní teplotu TSP určenou pomocí protlačovacích zkoušek na miniaturních discích / Assessment of the influence of the specimen orientation on the transition temperature TSP determined using small punch test method

Tomková, Renáta January 2017 (has links)
The diploma thesis is aimed to assesment of the influence of the specimen orientation during the Small Punch Tests (SPT). Steel ČSN 41 0214, or its equivalent steel RFe80, W.-Nr. 1.104 was chosen for experiments. Resulting records from SPT were evaluated using already known correlations which are reported in literature. The correlation values were compared with values obtained by the standard tests like Charpy impact test and tensile test. The influence of axial, radial and tangential test specimens orientation is discussed in relation to Ductile-to-Brittle fracture behaviour of the steel.
84

Terminál pro docházkový systém / Attendance System Terminal

Chmelař, Jakub January 2014 (has links)
This thesis deals with electronic attendance systems which are nowadays being widely used to record employee attendance. General problem of attendance tracking is introduced in first part of the thesis along with a conceptual solution of an attendance system terminal. Author then describes a circuitry and a PCB design of a baseboard for a Cubieboard2 minicomputer, a RFID reader and a touchscreen LCD display. After successful testing of said PCB, the terminal has been completed and it was possible to focus on a software solution. Latter part of the thesis is dedicated to a specifics of the Allwinner A20 platform and its support by a GNU/Linux operating system. In following chapter author describes use of a Buildroot software for creating a Linux based binary image for an aforementioned minicomputer. Since an operating system and a peripheral support were successfully tested author could focus on a design and implementation of an attendance software that is described in the final chapter.
85

Výroba součásti z plechu s využitím technologie hlubokého tažení / Production single parts from sheet metal with usage technology deep drawing

Jurča, Jan January 2009 (has links)
JURČA Jan: The manufacturing of sheet metal part by deep draw technology. Thesis of Master´s Studies, the 5th Year of Study, the School-year 2008/2009, The Institute of Manufacturing Technology, Department of Machining, FSI VUT Brno.The thesis deals with the project of manufacturing the part of the car body – the fifth door by deep draw technology. The material is zinc-coated sheet metal HX220YD EN 10292. Mechanical properties and suitability of the material are evaluated by mechanical tests. The structure of the material is evaluated by metalography scratch pattern. The analysis of draw process and manufacturability of the part is made by calculations and AutoForm software. The production line, necessary machinery and construction solution of draw tool for the manufacturing the part are determined. Last section deals with economical evaluation of the production.
86

Výroba součásti technologií přesného stříhání / Fineblanking component and its manufacturing

Lata, Miroslav January 2010 (has links)
The diploma thesis deals with a propose of a new manufacturing technology of component called „KULISA“ drawing number 4-DP-05-10/01. The beginning of this work is prepared as a literary study about blanking. There are explained some basic concepts necessary to introduce a blanking topic. Other interest of this work is an assessment of actual state of conventional blanking technology which is being currently used for component production. With regard to the deficiencies of the existing method is proposed new technology of fine blanking. In the proposal is evaluated technological site of component construction and blanking tools are proposed with stress analysis included. Last part of the work deals with the economic evaluation, where is being compared efficiency of existing and new technology.
87

Mechanické vlastnosti nízkouhlíkových a nízkolegovaných ocelí, stanovené pomocí protlačovacích zkoušek na miniaturních discích při pokojové a snížených teplotách / Determination of mechanical properties of low carbon and low alloy steels via small punch tests at room and low temperatures

Závodský, Peter January 2016 (has links)
The presented diploma thesis deals with an innovative material test, so called Small Punch Test. There are main principles, advantages and limitations of the test stated in the thesis. There are stated also correlation procedures in order to obtain standard mechanical properties. A test fixture design has been done in order to perform test procedures at temperature range from 80 to 25 °C. Twelve experimental curves have been obtained from the test and typical quantities have been evaluated. The different accuracy of correlations with standard mechanical properties has been obtained using different correlation equations.
88

Využitelnost protlačovacích zkoušek na miniaturních discích (small punch test - SPT) pro stanovování materiálových charakteristik za vysokých teplot / Application of small punch test for determination of high temperature materials characteristics

Ječmínka, Marek January 2013 (has links)
Diploma thesis is focused on mechanical properties testing by small punch test and comparison of these properties with mechanical properties obtained by conventional tensile test. Steels P92 and AISI 316L in a shape of discs were tested. There were determined values of mechanical properties, namely yield stress, and ultimate tensile stress, obtained by the small punch test – constant deflection rate in this thesis. Values of initial stress and residual stress were evaluated from relaxation small punch test. Mechanical properties obtained by small punch test – constant deflection rate, and small punch test – relaxation, respectively, are compared with mechanical properties obtained by conventional tensile test, and relaxation tensile test, respectively. There were proposed own empirical relationships for restatement of mechanical properties obtained by small punch test to mechanical properties obtained by conventional tensile test in the thesis. Relatively small agreement of results obtained by small punch test, and conventional tensile test was demonstrated by a comparison. Application of own empirical relationships resulted in better agreement. Very good agreement of results of small punch test – relaxation, and relaxation tensile test was shown by their comparison.
89

Stanovování mechanických vlastností lehkých kovů a jejich slitin a kompozitů pomocí protlačovacích zkoušek na miniaturních discích / Determination of mechanical properties of light metals and alloys and composites via small punch test

Langer, Jiří January 2014 (has links)
The aim of diploma thesis is estimate mechanical properties (yield strength, maximum strength and elongation) of light alloys by means of SPT. For the experiments were selected aluminium alloys (Al 2024, Al 6082 T6, Al 7020 and NASA 398) magnesium alloys (MgZnMn, AZ31, AZ61) and composites (AZ91 + 20 % saffilu a Al + Al4C3). Theoretical part of this thesis is focused on analysis of conversion formulas, which were made from SPT data and conventional testing. Experimental part is dedicated to evaluation of experimental data and critical analysis validity of conversion formulas. In this part of thesis is discused the problematics of reproducibility methodology of SPT.
90

Arlecchino's Journey: Crossing Boundaries Through La Commedia Dell'arte

Sobeck, Janine Michelle 15 August 2007 (has links) (PDF)
La commedia dell'arte is a recognized, vibrant theatrical form that emerged in Italy during the Renaissance. However, while great attention has been given to the particulars of the genre (performance techniques, important troupes, leading players), there lacks a study behind the reasoning for its vast international popularity. In this thesis, I explore why this particular genre was able to cross cultural and linguistic boundaries, finding a dedicated and enthusiastic following in most European countries for over 200 years. After analyzing commedia dell'arte's original development in the Italian peninsula, examining the predominating Carnival ideology and the ability of the troupes to establish both regional and national symbols through the creation of specific stock characters, I will concentrate on the international tours and performances. By looking at the adaptive qualities of the troupes, and specifically their ability to play off of Europe's lack of national identity and Northern European's fascination with their exotic southern neighbor, I will discuss the reaction of Northern Europe with the Italian theatre, with a detailed look into the success of the troupes abroad. The popularity of the troupes will also be explored through the unique adaptation, assimilation and adoption of commedia dell'arte techniques and characters into developing national theatres of the other countries. I will conclude with a look of how commedia dell'arte has been and can continue to be effectively used in today's theatre. The examination of what drew both native and foreign audiences to the commedia dell'arte performances opens up possibilities for modern practitioners who wish to capitalize on the ability of the troupes to successfully play to a wide spectrum of people.

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