Submitted by Rubens Chinali Canarim null (rubenscanarim@hotmail.com) on 2018-02-05T12:10:04Z No. of bitstreams: 1 TESE FINAL ENTREGA.pdf: 2914880 bytes, checksum: e1503c15204b7dbc230efbbea4f1320d (MD5) / Approved for entry into archive by Maria Marlene Zaniboni null (zaniboni@bauru.unesp.br) on 2018-02-05T15:53:59Z (GMT) No. of bitstreams: 1 canarim_rc_dr_bauru.pdf: 2914880 bytes, checksum: e1503c15204b7dbc230efbbea4f1320d (MD5) / Made available in DSpace on 2018-02-05T15:53:59Z (GMT). No. of bitstreams: 1 canarim_rc_dr_bauru.pdf: 2914880 bytes, checksum: e1503c15204b7dbc230efbbea4f1320d (MD5) Previous issue date: 2018-01-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A presente tese estudou a influência da friabilidade de dois rebolos de CBN (alta friabilidade – HF e baixa friabilidade – LF) na retificação cilíndrica externa de mergulho do aço AISI 4340, temperado e revenido, para vários avanços. Os resultados obtidos demonstraram que, comparativamente, o rebolo de baixa friabilidade (CBN LF) fornece melhor acabamento para a peça em termos de rugosidade e desvios de circularidade, com menor desgaste de rebolo, em todos os avanços. Por outro lado, o consumo de potência e seus sinais de emissão acústica foram sempre mais elevados. Para a tensão residual, a baixa friabilidade auxilia na geração de tensões compressivas na peça. Todavia, mesmo com a alta friabilidade, para condições mais agressivas de corte também é possível obter tensões compressivas elevadas. Nenhuma das condições de usinagem alterou a microestrutura das peças retificadas, com base nos resultados de microdureza Vickers. A elevada friabilidade, de um modo geral, pode promover fratura excessiva dos grãos, que acabam por aumentar o riscamento e deteriorar a qualidade superficial das peças, além de desgastar mais o rebolo, em virtude do predomínio da macrofratura sobre a microfratura. Ao mesmo tempo, contudo, reduz as forças de corte e o consumo de potência. Deve-se levar em conta todos os fatores à disposição para efetuar a melhor escolha de rebolo e sua friabilidade para determinada aplicação. / The present thesis aimed to study the influence of friability of two CBN wheels (high friability – HF and low friability – LF) on the external plunge cylindrical grinding of the AISI 4340 steel, quenched and tempered, for different feed rates. The results showed that CBN LF provided better workpiece finishing in terms of surface roughness and roundness deviations, with lower wheel wear, in all feed rates. However, power consumption and acoustic emission signals were always higher than for CBN HF. For residual stresses, low friability contributes to the generation of compressive stresses on the workpiece. For high feed conditions, even CBN HF can provide high compressive stresses. None of the grinding conditions caused alterations on the workpiece microstructure, based on the results for Vickers microhardness. High friability can promote excessive grain fracture, which can increase scratching and deteriorate the surface quality, causing higher wheel wear as well (since macrofracture predominates over microfracture). On the other side, it can reduce cutting forces and power consumption. All factors at disposal must be taken into account in order to conduct the optimal selection of grinding wheel– as well as its adequate friability – for each specific application.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós- Graduação em Educação em Ciências: Química da Vida e Saúde, Instituto de Educação, 2011. / Submitted by EDUARDO PENA (edupenaa@hotmail.com) on 2012-10-26T00:40:15Z No. of bitstreams: 1 PORTFÓLIO COLETIVO artefato do aprender a ser professor(a) em.pdf: 897728 bytes, checksum: f7d867593243c802edbc56efc46a2219 (MD5) / Approved for entry into archive by Gabriela Silva da Rosa(gabrielasilvadarosa@gmail.com) on 2013-07-02T14:31:15Z (GMT) No. of bitstreams: 1 PORTFÓLIO COLETIVO artefato do aprender a ser professor(a) em.pdf: 897728 bytes, checksum: f7d867593243c802edbc56efc46a2219 (MD5) / Made available in DSpace on 2013-07-02T14:31:15Z (GMT). No. of bitstreams: 1 PORTFÓLIO COLETIVO artefato do aprender a ser professor(a) em.pdf: 897728 bytes, checksum: f7d867593243c802edbc56efc46a2219 (MD5) Previous issue date: 2011 / A presente pesquisa apresenta os significados que emergiram das escritas em portfólios coletivos durante um processo de formação permanente. Essas escritas foram realizadas por quatro professores do ensino básico de Química e dezenove licenciandos do curso de Química Licenciatura da Universidade Federal do Rio Grande (FURG), todos participantes de um processo de formação permanente, viabilizado pelo Programa Institucional de Bolsa de Iniciação à Docência (PIBID), programa de política pública desenvolvido na FURG. Trata-se de uma pesquisa de abordagem qualitativa em uma perspectiva de grupo de pesquisa/formação. A pesquisadora participa como professora de ensino básico. No portfólio, cada professor dialogava com um determinado grupo de licenciandos através da escrita. A análise dos registros nos portfólios e do diário de campo da pesquisadora foi realizada a partir da Análise Textual Discursiva. A análise possibilitou a produção de significados a partir da organização das unidades de significado e da emergência das seguintes categorias: relações entre os diferentes personagens que constituem a escola; conversas sobre planejamento da sala de aula; conteúdo a problematizar em processos de formação permanente e descaso com a escola e a profissão professor. Os significados atribuídos a cada uma das categorias citadas, pelos professores em formação, permitiram a percepção de que estamos nos formando no coletivo e contribuindo com o argumento que defendo, relativo ao uso do portfólio coletivo como artefato do aprender a ser professor em Roda de Formação em Rede, ou seja, a formação do professor se faz no coletivo, em espaços que permitam a interação entre esses professores em formação inicial e continuada ou entre licenciandos e professores experientes da escola; o portfólio constitui documento do aprender no referido processo. / This research presents the emergent meanings of the collective written portfolios during a process of continuous formation. These writes were made by four Chemistry Teachers of basic school and nineteen university students in graduation of chemistry license in the Universidade Federal do Rio Grande (FURG), all those people are participant in a continuous formation process, make it possible by the Institutional Program of Initiation to Teacher Profession (PIBID), a politic public program developed in FURG. Is a qualitative approach research in a view of a research/formation group. The researcher participated as a basic school teacher. In the portfolio, each teacher made a dialog with a group of teachers in formation/graduation thru the write. The analysis of records in the portfolios an in the field diary of the teacher researcher was made by the Discursive Textual Analyses. The analyses made possible the production of meanings since the organization of meanings unities and the emerge of this categories: relationship between different characters that make part of the school; talking about class planning; contents/material to ponder in the continuous formation process and no care whit the school and the teacher profession. The meanings gives to each categories quoted, by teachers in formation, turn possible realized that we are in formation in the collective and cooperating whit the defended argue, related to use of collective portfolios like a tool of learn how to be a teacher in Wheels of Network Education, thus, the teacher formation is made in collective way, in spaces that make possible the interaction between this teachers in initial and continuous formation or between barely graduated teachers and experient teachers of the school; the portfolio is a document of the learn in the refer process.

Tese (doutorado)-Universidade Federal do Rio Grande, Programa de Pós-Graduação em Educação Ambiental, Instituto de Educação, 2010. / Submitted by eloisa silva (eloisa1_silva@yahoo.com.br) on 2012-11-28T17:49:21Z No. of bitstreams: 1 moacir langoni de souza.pdf: 4681725 bytes, checksum: d837dbaaded20708668f05f0d6eceb0b (MD5) / Made available in DSpace on 2012-11-28T17:49:21Z (GMT). No. of bitstreams: 1 moacir langoni de souza.pdf: 4681725 bytes, checksum: d837dbaaded20708668f05f0d6eceb0b (MD5) Previous issue date: 2010 / A Tese defendida é das Rodas de Formação em Rede como espaços privilegiados na ambientalização de professores que escrevem, lêem e contam suas histórias. Daí a aposta na narrativa e no exercício de contar histórias e partilhá-las nessas Rodas. No contexto dessas histórias encontram-se grupos de professores de Ciências de três instituições (PUCRS, Unijuí e FURG), atuando em projetos interinstitucionais de formação permanente. No foco das análises estão as narrativas de um grupo de licenciandos que, no ano de 2004, ingressou no curso de Química – Licenciatura da FURG. Doze conjuntos de quinze narrativas semanais, parte dos relatórios dos estágios realizados pelo grupo durante o segundo semestre de 2007 – Roda do Estágio V. Fragmentos destas narrativas entrecruzam-se com outros, nossos e de outros professores na rede, compondo histórias que constituem e delineiam a feitura de uma Colcha de Retalhos. E é nesse processo que toda a rede se explicita. Quadrados de colcha feitos de uma diversidade de retalhos. Histórias de muitos sujeitos, numa multiplicidade de cores e texturas, alinhavadas na busca do equilíbrio que possa, de certo modo, sustentar a Tese. Ao longo dos capítulos, termos como “ambientalização de professores” e “partilha”, fundamentais no encaminhamento dos argumentos, são discutidos nas perspectivas dos referenciais assumidos. Em alguns capítulos alternam-se retomadas de determinadas abordagens, ampliando aspectos destacados ou introduzindo outros, como o que vai contar a história do curso de licenciatura em Química e suas transformações concebidas e acalentadas nos projetos interinstitucionais no âmbito da Rede. Esta história encontra-se enredada na história da Rede, especialmente no sentido da explicitação de movimentos de grupos de professores de Ciências que, desde a década de 80, articulam parcerias no desenvolvimento de projetos interinstitucionais implicados com formação permanente de professores. As análises sustentam-se em dois referenciais: o da Análise Textual Discursiva proposta por Moraes e Galiazzi (2007), em que se busca produzir novas compreensões a respeito do que é narrado e apostando na emergência de categorias, num movimento interpretativo de caráter hermenêutico; e o da narrativa como uma técnica de pesquisa fenomenológica, tal como propõe Dutra (2002). Categorias emergentes, como “tempos da Escola” e “insegurança”, impregnam cinco histórias – quadrados da Colcha – contadas, constituídas numa diversidade de fragmentos/retalhos de narrativas. Por um lado, as memórias do acontecido, as narrativas nos Relatórios de Estágio e as anotações dos encontros efetivamente subsidiaram os textos e sustentaram diálogos; por outro, assume-se a perspectiva de fusão entre história e ficção, na perspectiva do proposto por Paul Ricoeur, uma vez que o enredo e o espaço-tempo de cada história e seus episódios foram inventados. A proposta aqui é contar um pouco destas histórias. “E estas foram histórias que se quis e que se pôde contar” é a frase que encerra a escrita da Tese. É uma manifestação que anuncia. Assume-se que sempre há possibilidades para outros arranjos dos retalhos, outros desenhos na feitura da Colcha. E como a harmonia do conjunto é, também, estabelecida em relação com o Outro, cujo olhar amplia essas possibilidades em relação à feitura, esta Tese é um convite à partilha de histórias. / This Dissertation defends Wheels of Network Education as privileged spaces in the environmentalization of teachers who write, read, and tell their stories. Therefore, I bet on narrative and on the exercise of telling stories and sharing them in these Wheels. In the context of these stories, there are Science professors who work with interinstitutional projects in in-service education at three higher education institutions (PUCRS, Unijuí, and FURG). The analyses focus on narratives written by seniors who started pursuing a teaching degree in Chemistry at FURG in 2004. The corpus comprises twelve sets of fifteen narratives and parts of the apprenticeship reports which were written during the second semester in 2007 – the Wheel of Apprenticeship V. Fragments of these narratives interweave with others which I and other professors wrote in the net, thus, composing stories that constitute and outline a Patchwork Quilt. It is in this process that all the net becomes explicit. Quilts pieces made of a diversity of patches. Many subjects’ stories, in a multiplicity of colors and textures, sewn together in search of balance to support the Dissertation. Fundamental terms such as “teachers’ environmentalization” and “sharing” are discussed in the chapters in order to defend the arguments from the perspective of the references I have selected. Some chapters address approaches which had been presented before so that certain aspects can be broadened and new ones can be introduced, e. g., the chapter about the History of the Chemistry course and the transformations that were suggested and supported in interinstitutional projects in the Net. This story is intertwined with the story of the Net, mainly regarding the movements of groups of Science teachers who have worked as partners in the development of interinstitutional projects of in-service education since the 80’s. The analyses are based on: a) Discursive Textual Analysis (proposed by Moraes and Galiazzi, 2007) which aims at producing new understanding of what is narrated and bets on the emergence of categories in an interpretative movement with hermeneutical features; and b) narrative as a technique in phenomenological research, such as the approach proposed by Dutra (2002). Emergent categories, e. g., “School time” and “lack of safety” have impregnated five stories – Quilt pieces – which were told and comprised of an array of fragments/patches of narratives. On one hand, the memories of the event, the narratives of the Apprenticeship Reports and the notes of the meetings have effectively subsidized the text and supported dialogues; on the other hand, I have taken on the perspective of the fusion between History and fiction, as proposed by Paul Ricoeur, since the plot and the space-time of each story and its episodes were made up. “My proposal is to tell a little bit of these stories, the ones that I wanted to tell and the ones that I could tell.” This is the sentence that closes my Dissertation. It is a manifestation that announces. I believe that there are always other possibilities to place the patches, other designs to use for the Quilt. Since the harmony of the whole set is also established in relation to the Other whose look broadens these possibilities, this Dissertation is an invitation to share stories.

Submitted by William Paiva (williampaiva17@hotmail.com) on 2015-04-14T17:37:17Z No. of bitstreams: 1 Fernanda Medeiros de Albuquerque.pdf: 840541 bytes, checksum: 1ebb7e0bc7532024189e54086a7d03c6 (MD5) / Approved for entry into archive by Vitor de Carvalho (vitor_carvalho_im@hotmail.com) on 2015-05-08T16:02:11Z (GMT) No. of bitstreams: 1 Fernanda Medeiros de Albuquerque.pdf: 840541 bytes, checksum: 1ebb7e0bc7532024189e54086a7d03c6 (MD5) / Made available in DSpace on 2015-05-08T16:02:11Z (GMT). No. of bitstreams: 1 Fernanda Medeiros de Albuquerque.pdf: 840541 bytes, checksum: 1ebb7e0bc7532024189e54086a7d03c6 (MD5) Previous issue date: 2012 / Este trabalho apresenta uma pesquisa sobre a formação acadêmico-profissional de licenciandos em Química da Universidade Federal do Rio Grande (FURG) que participaram do Programa de Incentivo à Docência (PIBID) nos anos de 2009 e 2010. A pesquisa foi desenvolvida com onze licenciandos formandos no curso ao final do PIBID e as informações analisadas foram histórias mensais escritas por estes participantes durante os dois anos do Programa. Alguns pressupostos orientaram a pesquisa: a formação acadêmico-profissional de sujeitos pesquisadores da sua prática em Rodas de Formação, a partir da qual, é possível o acolhimento de questionamentos, a partilha, a escuta, a construção e divulgação de novos argumentos; a escrita como modo de pensar, que por ser uma atividade interativa conta com a presença de interlocutores ativos para provocar o escrevente. Entendemos que quando os escreventes são licenciandos, tem-se na escrita a possibilidade de documentar a formação desses profissionais, conhecendo suas fragilidades e potencialidades. A análise das histórias escritas pelos participantes desta pesquisa, realizada mediante a Análise Textual Discursiva possibilitou a compreensão da contribuição das histórias na formação acadêmico-profissional de licenciandos de Química da FURG em Rodas de Formação. A tese defendida é que as histórias produzidas em Rodas de Formação contribuem para a formação acadêmico-profissional de licenciandos de Química. As histórias contêm conteúdos que podem sinalizar para a produção de currículo nos cursos de Licenciatura, expressam o medo da solidão e a ousadia no trabalho coletivo e potencializam a compreensão sobre a constituição do professor em Roda. / This study presents a research concerning the academic and professional training of Chemistry grad students at Universidade Federal do Rio Grande (FURG) who joined PIBID (a program that encourages teaching licensing courses) in 2009 and 2010. The research was developed with eleven students at their final year in PIBID program and the data analyzed were stories monthly written by these participants during their two years in the program. Some assumptions guided the study: the academic and professional training of the participants, researchers of their own practices in Wheels of Education, in which welcoming of questions, sharing, hearing and construction and spreading of new issues are possible; as well as writing as a way of thinking, considering it is an interactive activity which counts on the presence of active interlocutors in order to tease the writer. We understand that, when the writers are licensing graduates, their writing shows up a possibility of registering their professional training, getting to know their potentialities and fragilities. The analyses of the stories written by the participants of this research was taken by Textual Discursive Analysis, allowing a greater comprehension of the academic and professional training in the Wheels of Education of Chemistry graduates at FURG. The thesis raised is that stories produced in Wheels of Education have contents that can point out issues for the syllabus of licensing courses which potentiate the academic and professional training of Chemistry graduates and also remark the fear of loneliness and boldness in collective.

O uso de tintas à base de solventes tem acarretado problemas ambientais, gerando a necessidade de pesquisas para o desenvolvimento de materiais com baixo teor de compostos orgânicos voláteis (VOC) para redução do impacto ao meio ambiente. Os efeitos do VOC ao meio ambiente motivaram este estudo, que tem como objetivos desenvolver uma nova tinta de base aquosa para a aplicação na fabricação de volantes automotivos. O presente trabalho tem como objetivo estudar o desempenho por meio de medição de camada de tinta, resistência aos reagentes químicos, combustibilidade e resistência ao desgaste da pintura obtida com tintas baseadas em 1) solventes orgânicos e 2) água, aplicadas em volantes automotivos constituídos de poliuretano (PU). Os resultados demonstram que a pintura à base de água possui uma espessura de camada maior e menor velocidade de combustão em relação à pintura à base de solventes orgânicos, porém apresenta um menor desempenho no ensaio de resistência à abrasão e aos reagentes químicos em relação à tinta à base de solventes orgânicos. / The use of solvent-based paints has caused environmental problems, creating the need for research to develop materials with low volatile organic compound (VOC) to reduce the environmental impact. The effect of volatile organic compound (VOC) to the environment motivated this study, which aims to develop a new water-based paint for application in the manufacture of automotive steering wheels. The present work aim to study the performance by measuring the layer thickness, resistance to chemical reagents, combustibility and wear resistance obtained with paints based on 1) organic solvents and 2) water, applied in automotive steering wheels made of polyurethane (PU). The results has showed that water-based paint has a layer thickness greater and lower burning rate than solvent-based paint, but it has a lower performance in the test for resistance to abrasion and resistance to chemical reagents in relation to organic solvent-based paint.

M.Ing. / The aim of Spoornet is to provide a minimise predictable service. In order to provide a predictable service, it is necessary to move trains safely and effectively from the place of departure to their destination. The keywords here are safely and effectively. Although support functions such as infrastructure and train control procedures are vital in moving the train, the train or rolling stock as it is generally known, warrants some attention. Defects on the rolling stock are very costly to Spoornet. This is mainly due to the fact that a defect on the rolling stock that goes undetected can cause damage to the rolling stock and the infrastructure. This damage can eventually lead to derailments. Considering that a derailment can cost Spoornet millions of rand and cause delays to the services, it is only logical to spend time preventing derailments. It is for this reason that a workgroup was formed to investigate and solve the problem of defects causing derailments and delays by developing an early warning system. The need for an integrated train condition monitoring system became apparent when considering an early warning system. The objectives of the integrated train condition monitoring system are to provide train condition information to different users, and alarms on detection of emergency or dangerous conditions. Various train defects that may cause damage or derailments were identified. One of them being a flat wheel on a rail vehicle. A flat wheel is characterised by the flattening of the wheel on one or more positions on its circumference, so that the wheel does not have an even and completely round profile. Flat wheels are mostly caused by the wheels of a vehicle becoming locked during braking, and sliding along the rail track. The friction created by this action grinds a flat spot on the wheel. The flat wheel leads to a decline in the riding quality of the rolling stock and a rise in the levels of vibration and noise is evident. But more importantly, the flat spot causes the wheel to roll unevenly, creating impacts on the rail on some points. It is these impacts that can cause damage to the rail and the rolling stock. Depending on the length of the flat spot, the vehicle type and speed, the stresses may be sufficient to cause final failure of the rail or initiate fatigue cracks in the rail. Severe flat wheels are a safety hazard and can in some cases, cause derailments and consequent delays to trains. Smaller flat spots contribute to track deterioration and so increase maintenance costs by damaging the rails, sleepers and ballast. Flat wheels can thus be very costly to Spoornet and its public image. In addition to safety and economic considerations, wheel flats reduce the comfort levels in the passenger coaches and the noises they make is annoying. In an attempt to restrict the damage caused by flat wheels, most railway administrations place a limit on the length of the flats that may stay in service. But to effectively find a flat wheel on rolling stock is currently a very expensive exercise. Flat wheels can be detected by an audible knocking sound when standing next to the rail. This sound is impossible for the driver to hear and therefore goes undetected. Normally flat wheels are detected by random inspection of the rolling stock or when they are brought in for a routine service. The service cycle on rolling stock can be up to 24 months in Spoornet. Considering that a flat wheel has an impact roughly every 3m, a serious flat generates roughly 160 000 impacts on a single trip on the coal heavy haul export line. It is therefore clear that a flat wheel can cause a considerable amount of damage between service cycles. The severity of the problem is however not accurately defined in Spoornet, because up to a few months ago there was no detection system in use to determine the distribution of flat wheels. The research department of the Deutsche Bundesbahn however considers rail fractures due to the flat wheels to be a serious problem with a significant annual replacement cost. There are thus sound safety and economic reasons for wishing to understand the mechanisms of flat wheels and to develop an early warning system using an automatic detector.

The study is a qualitative study with interviews as a data collection method. A request from different facebook groups contributed to a targeted selection, which resulted in all interviewees having relevance in the subject. As sociology can be defined as scientific studies of society and human life, it is therefore relevant to investigate the phenomenon of downshifting more closely (Giddens & Sutton, 2013). The purpose of the study is to describe and analyze downshifting as a sociological phenomenon from the interviewees' stories.  The questions used to answer the purpose are:  What do the interviewees express that they have chosen to live a simpler life?  What do the interviewees think that a simpler life prepares for?  How can the pursuit of downshifting that the interview participants describe can be understood with the help of Fromm's concept of ownership and being?  How can the interview participants' opportunities to downshift be analyzed from a class perspective?   The results show that the interview participants chose to prioritize things like consumption, work, housing situation and digital downshifting in order to avoid the impression they do not say they need. Instead, they prepare space for social relationships, personal well-being and interests. These things come together by spending less time on one thing, freeing up time on other things. How the interviewees choose to prioritize their time varies where the interests and what the person wants to achieve with their life determines. With Fromm's (2003) theoretical concepts of life form and ownership, it emerges that the interviewees are critical of society and in terms of the importance of class Bourdieu's (1993) theory of cultural, economic, social and symbolic capital is used. / Studien är en kvalitativ studie med intervjuer som datainsamlingsmetod. En förfrågan på olika facebook-grupper bidrog till ett målinriktat urval vilket resulterade i att samtliga intervjupersoner har relevans i ämnet. Eftersom sociologi kan definieras som vetenskapliga studier av samhället samt mänskligt liv är det därför relevant att undersöka fenomenet downshifting närmare (Giddens & Sutton, 2013). Syftet med studien är att utifrån intervjudeltagarnas berättelser beskriva och analysera downshiftning som ett sociologiskt fenomen. De frågeställningar som använts för att besvara syftet är: 1.Vad uttrycker intervjudeltagarna att de valt bort i önskan att leva ett enklare liv? 2.Vad menar intervjudeltagarna att ett enklare liv bereder plats för? 3.Hur kan strävan mot downshiftning som intervjudeltagarna beskriver förstås med hjälp av Fromms begrepp ägandets och varandets livsformer? 4.Hur kan intervjudeltagarnas möjligheter att downshifta analyseras utifrån ett klassperspektiv? I resultatet framgår att intervjudeltagarna valt att prioritera ned saker som konsumtion, arbete, boendesituation samt digital downshifting för att komma undan intryck som de inte säger sig behöva. Istället bereder de plats för sociala relationer, eget välmående och intressen. Dessa saker hör ihop genom att lägga mindre tid på en sak, frigör tid att lägga på andra saker. Hur intervjudeltagarna väljer att prioritera sin tid varierar där intressen och vad personen vill åstadkomma med sitt liv avgör. Med Fromms (2003) teoretiska begrepp ägandets och varandets livsform framkommer att intervjupersonerna ställer sig kritiskt till samhället och vad gäller betydelse av klass används Bourdieus (1993) teori om kulturellt, ekonomiskt, socialt och symboliskt kapital.

L’objectif principal de cette thèse est de développer une méthodologie qui permette de définir des sollicitations simplifiées représentatives des sollicitations réelles rencontrées en exploitation, c’est-à-dire équivalentes en sévérité vis-à-vis du phénomène d’amorçage de fissure par fatigue mécanique. Cette méthodologie doit être adaptée aux problèmes multi-paramètres car les sollicitations subies par les roues ferroviaires sont multidimensionnelles (chargement vertical et latéral) et indépendantes. Enfin, la thèse vise aussi à proposer une approche fiabiliste globale du problème de fatigue des roues, qui pourra être une extension de la méthode Contrainte-Résistance aux cas des sollicitations multi-entrée. Un critère de fatigue pour l’acier des roues est identifié à partir des nouveaux essais. / The main objective of this PHD thesis is to develop a method for the definition of simplified equivalent loads representative of real loads (the severity is equivalent from fatigue phenomenon point of view). This method must be adapted to multi-input problems because loads applied on wheels are multi-dimensional (vertical and lateral loads) and independent. Finally, the thesis also aims to provide a comprehensive approach to fatigue-reliability problem of the wheels, which can be an extension of the stress-strength method for multi-input loads. A fatigue criterion for the railway will is presented and identified using a new test campaign.

In this thesis, we consider the decomposition of the complete mixed graph on v vertices denoted Mv, into every possible mixed graph on three vertices which has (like Mv) twice as many arcs as edges. Direct constructions are given in most cases. Decompositions of theλ-fold complete mixed graph λMv, are also studied.

The automotive industry faces the challenge to manufacture vehicles with reduced material usage and climate impact. To achieve this the industry has begun using other materials such as carbon fibre composite than materials such as steel and aluminium which are normally used for the manufacturing of automobile parts. Because its anisotropic structure gives the manufacturer increased opportunity to selectively use the material for the part’s stability and ability to withstand loads However Carbon fiber has drawbacks, the material is time-consuming to work with and expensive, because such automobile parts are either made by hand or with precisio nmolding equipment that requires experienced and educated personnel to produce parts with satisfactory quality. A car component whose weight reduction is crucial is the car rim. The car rims and tire’s weight determines the wheel shaft’s torque needed for steering which makes it an important component of the car. This work examines a manufacturing technology with the potential to reduce material use and the climate impact of car rims manufacturing. The manufacturing technology involves a robotic system that weaves carbon fiber threads on a winding frame that sits on a rotary table. The work’s purpose is to derive a theoretical model which describes the following characteristics: Production time, material usage, how the carrim and winding frame are to be adapted to one another to ensure the car rim can withstand loads to which it can be expected to be subjected.The objective is to generate data which describes these characteristics. To derive a theoretical model and generate data which describes the manufacturingstechnology’s characteristics, the work was split into two parts; In the first part, a theoretical formula was derived to relate material usage with the used length of a carbon fibre thread. Simulations are made to relate material usage and production time with theory for a PID-regulator.In determining the weaving pattern, material technology’s theory for anisotropy is used. The second part involves using theory from solid mechanics to derive theoretical equations which describes how the winding frame and car rim’s dimensioning are to be adapted to one another, with regards to the car rim’s critical parameters. Which in this work is the car rim’s stiffness and carbon fibre’s yield strength. To test the mechanical performance of the car rim, Finite-element-method(FEM) simulations are made and the validation of the simulation is done with the derived theoretical equations. In simplifying the work, winding frame, weaving pattern, and car rim are visualized using Computer-aided-design(CAD) tools. The conclusion from the results is that while the theoretical model showcases the manufacturing technology’s potential but further work is needed to improve it and adapt it to car rim’s industrial standards.