Bei der Stippelung handelt es sich um eine Oberflächenstruktur des Gingivaepithels, die der Gingiva ein orangenschalenartiges Aussehen verleiht. Ziel dieser Studie war es, die Stippelung der Gingiva von Kindern zu untersuchen und deren Merkmale sowie Prävalenz zu charakterisieren. Material und Methode: Für diese Querschnittsuntersuchung wurden insgesamt 274 Kinder untersucht (148 Jungen, 126 Mädchen; Durchschnittsalter 4,98 Jahre) und dabei der Zahnbefund, der Mundhygienezustand (API), der Entzündungszustand (PBI) und die ethnische Herkunft aufgenommen. Die Stippelung wurde photographisch und mit Abformung aus niedrig viskösem additionsvernetzenden Silikon dokumentiert. Die davon hergestellten Modelle wurden unter einem Stereomikroskop mit einer Kamera digitalisiert. Das Programm analySIS 3.0 diente zur Bildanalyse. Ergebnisse: Insgesamt zeigten 187 Kinder (68,2%) Stippelung (Jungen 67,2%, Mädchen 69%). Sie trat ab einem Alter von einem Jahr auf. Geschlecht, ethnische Herkunft, Karieserfahrung, API und PBI hatten keinen Einfluss auf die Häufigkeit. Sie kam signifikant häufiger im Wechselgebiss vor, ebenso im Oberkiefer und im Frontzahnbereich. Im Seitenvergleich konnte keine symmetrische Verteilung festgestellt werden. Die Tüpfelung kam bis auf eine Ausnahme ausschließlich auf der befestigten Gingiva vor und war dabei bevorzugt interradikulär, danach radikulär und zuletzt im subpapillären Bereich zu finden. Die Auswertung der Photographien und Replikas ergab eine durchschnittliche Dichte von 2,54 Stippel/mm2 bei einer Höhe von 0,10 mm bzw. einer Breite von 0,09 mm je Vertiefung. Ältere Kinder wiesen eine höhere Dichte der Tüpfelung auf. Alter und Geschlecht keinen Einfluss auf die morphometrischen Daten. Anzahl, Höhe und Breite der Stippelung waren im Oberkiefer und im Frontzahnbereich größer als im Unterkiefer bzw. im Seitenzahnbereich. Schlussfolgerung: Als alleiniges Kriterium zur Beurteilung des klinischen Entzündungszustandes der Gingiva bei Kindern ist die Stippelung nicht geeignet, da das Fehlen von Stippelung nicht immer mit dem Vorhandensein von gingivaler Entzündung übereinstimmt. Für eine korrekte Diagnose müssen vielmehr weitere Kriterien wie Farbe, Dicke, Festigkeit, Kontur der Gingiva, die Sondierungstiefe und Sondierungsblutung einbezogen werden. / Background: The aim of this study was to examine the gingival stippling in children and to characterize it. The prevalence of stippling was a special interest. Stippling is a structure of the gingival epithelium, which causes an orange peel like appearance of the gingiva. Material and methods: In this cross-sectional study 274 children (148 boys and 126 girls; average age 4.98 years) were examined. Oral status, approximal plaque index (API), papillary bleeding index (PBI) and race were noted. Photographs or replicas with a silicone impression material of low viscosity were taken if stippling was found. The replicas were used to make stone casts, which were scanned by a video camera. The obtained pictures were analysed with the software analysis 3.0. Results: 68.2% of the children showed stippling, in 67.2% of the boys and 69.0% of the girls. It was evident from an age of one year. Sex and race did not show any influence on prevalence. There was also no relation between stippling and caries, oral hygiene or gingival inflammation. Stippling was more frequent in mixed dentition than in deciduous dentition. The children showed more stippling in the upper jaw and in the anterior region. It was not spread symmetrically. Usually, it was localized to the attached gingiva with the highest frequency in the interradicular area, followed by the radicular area, and subpapillar area. Only one child showed stippling in the free gingiva, too, but this seemed to be an exception from the rule. The data obtained from photographs and replicas showed a density of 2,54 stipples per mm2, a height of 0.10 mm and a width of 0.09 mm. Older children showed a higher density. Height and width were neither influenced by sex nor by age. But stippling in upper arch and anterior region had a higher density and a larger height and width than in lower arch or posterior region. Conclusion: Gingival Stippling is not a major criterion in clinical assessment of gingival or periodontal inflammation, because missing stippling does not always coincide with presence of gingival inflammation. For a correct diagnosis more criteria, e.g. colour, contour, thickness, consistency, pocket depth and bleeding on probing, have to be considered, too.

Caracterizar propriedades de resistência à propagação de trinca em materiais dúcteis é um elemento central em métodos de avaliação de integridade estrutural de dutos destinados ao transporte de gás, petróleo e seus derivados que utilizam os aços ARBL. Sendo assim, o objetivo deste trabalho foi estudar as propriedades de fratura dúctil do aço API 5L X80, através da obtenção da curva de resistência à propagação estável de defeitos (curvas J-R) do material. O ensaio de tenacidade à fratura para obtenção da curva J-R foi conduzido utilizando a técnica do corpo-de-prova único (single specimen) empregando o método da flexibilidade no descarregamento (unloading compliance), segundo a norma de ensaios ASTM E1820-96. Os corpos-de-prova compactos C(T) apresentaram espessura B=15mm, largura W=2B e uma relação aproximada entre o tamanho de trinca (a) e a largura, a/W=0,6. O ensaio foi conduzido numa máquina universal de ensaios (MTS) servo-controlada e capacidade máxima de 250kN. Adicionalmente, foram conduzidos ensaios convencionais de tração (limite de escoamento – 550MPa, limite de resistência – 676MPa e alongamento total em 50mm – 27%), ensaios de impacto Charpy (energia absorvida de 220J à 0ºC – sentido longitudinal) e análises metalográficas (microestrutura refinada composta por ferrita, colônias de perlita e presença do constituinte MA). Tais caracterizações permitirão uma maior precisão na comparação da curva J-R do aço API 5L X80 em estudo com estudos futuros de tenacidade à fratura. / Assessments of crack growth resistance in ductile materials play a key role in structural integrity procedures for high strength, low alloy (HSLA) pipeline steels commonly employed in gas and petroleum trasmission systems. This work presents an investigation of the ductile tearing properties for an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves (J-R curves) for the material. Testing of the X80 pipeline steel employed compact tension (C(T)) fracture specimens to determine the J-R curves based upon the unloading compliance method using a single specimen technique in accordance with the ASTM E1820 standard procedure. The C(T) specimens have thickness B=15mm, width W=2B and a ratio between crack size (a) and width, a/W=0,6. The experimental tests utilized a 250 kN MTS universal machine. Conventional tensile tests were also performed to determine the tensile properties for the tested material: yield strength of 550MPa, tensile strength of 676MPa and elongation of 27% (gage length of 50 mm). The Charpy V-notch impact tests also provided and absorbed energy of 220J at 0ºC. The metallographic analysis showed colonies of perlite and MA constituent islands in a ferrite matrix. This experimental characterization provides additional toughness and mechanical data against which the general behavior of X80 class pipeline steel can be compared.

Made available in DSpace on 2017-07-21T20:42:39Z (GMT). No. of bitstreams: 1 Ederson Pauletti.pdf: 5739200 bytes, checksum: 362611be295a3342251b72d168512c61 (MD5) Previous issue date: 2013-03-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work the ductile crack growth resistance curves (J-R curves) was evaluated for the steels used in the oil and gas pipelines from the X60 and X70 API 5L grades using the unloading compliance technique. The non standardized SE (T) specimens were used due to the same has low constraint, it is feature of pipelines. The plastic area for the obtaining the J integral was performed by measuring from the crack mouth open displacement, (CMOD). The central emphasis this research was evaluated the delamination phenomenon influence from the fracture toughness and along the J-R curve. As also the microtexture in close to delamination and ductile fracture regions, by using the Electron Backscatter Diffraction (EBSD) technique. The results have shown that value average of 355kJ/m2 was similar for both the shallow and deep crack specimens. The J-R curve values average from the shallow crack specimens have displayed most steep J-R curves, namely, it obtained higher energy values along the ductile crack propagation. Specimens that showed delaminations, during fracture process, obtained higher energy values along the ductile crack propagation. The occurrence of delaminations was more common in deep crack specimens. The microtexture results have shown a random grain sizes distribution. The components with higher intensity in the delamination region were α-fiber textures: {113} <110>, {112} <110>, {223} <110> the same cause anisotropy of mechanical properties and can be influenced out-of-plane constraint during the test. Moreover, there was the occurrence of the {100} <110> recrystallization texture component, which have deleterious effect in occurrence of delamination in microalloyed steels. Whereas in the ductile fracture region occurred the {111} <231>, {111} <132> and {111} <123> γ-fiber, which it can be influenced the ductile crack propagation process. / Neste trabalho foram investigadas as curvas de resistência ao crescimento de trinca dúctil para aços utilizados em tubulações de petróleo e gás, das classes API 5L X60 e X70, utilizando-se da técnica de variação da flexibilidade elástica. Espécimes SE(T) não padronizados foram utilizados, pois o mesmo possui baixa restrição ao fluxo plástico, característica de tubulações. A área plástica para obtenção da integral J foi obtida através da medida de deslocamento de abertura de trinca (crack mouth open displacement, CMOD). A ênfase central desta pesquisa foi avaliar a influência do fenômeno da delaminação na tenacidade à fratura (JIC) e na curva J-R em geral. Como também a obtenção da microtextura em regiões próximas à delaminação e fratura dúctil, que ocorrem durante o processo de fratura no ensaio de tenacidade à fratura, pelo uso da técnica de difração de elétrons retroespalhados (EBSD). Os resultados mostraram que o valor médio de tenacidade à fratura, de 355 kJ/m2 foi equivalente para espécimes com tamanho de trinca rasa e profunda. A média dos valores de curva J-R para espécimes com tamanho de trinca rasa mostrou curvas J-R mais íngremes, ou seja, obtiveram maiores valores energia ao longo da propagação dúctil de trinca. Os espécimes que apresentaram delaminações, durante o processo de fratura, obtiveram maior valor de energia ao longo do crescimento de trinca dúctil. A ocorrência das delaminações foi mais comum em espécimes com tamanho de trinca profunda. Os resultados de microtextura mostraram uma distribuição aleatória de tamanhos de grão. As componentes com maior intensidade na região próxima à delaminação foram as texturas de fibras α: {113}<110>, {112}<110>, {223}<110> que causam anisotropia das propriedades mecânicas e podem ter influenciado no estado triaxial de tensões durante o ensaio. Além disso, houve ocorrência da componente de textura de recristalização {100}<110>, a qual tem efeito deletério na ocorrência de delaminações em aços microligados. As componentes de fibra mais intensas na região próxima à fratura dúctil foram as texturas de fibra γ: {111}<231>, {111}<132> e {111}<123>, as quais podem influenciar no processo de propagação de trinca dúctil.

The Advanced Manufacturing section at ÅF Pöyry AB is exploring the possibilities of virtual commissioning and digital twins. As part of this exploration, this thesis sets out to demonstrate a method of developing scalable, reusable and realistic digital mechatronic models – the heart of a digital twin – for the virtual environment in RobotStudio. Research has shown that one of the major obstacles to implementing virtual commissioning as a standard in industry today is the lack of scalable and reusable digital twins. This is also the experience of ÅF Pöyry AB. After reviewing existing and proposed methods for developing digital twins, this thesis explains the necessary steps for developing a SmartComponent in RobotStudio, using the programming language C#. The results show that the SmartComponent developed is scalable and thus reusable. It works with grippers with any number of fingers and allows gripping by applying pressure to the target object from both the outside and the inside. It is also realistic in the sense that the interaction between the grippers and the objects to be picked in the virtual environment behaves and looks like it does in reality. The implementation of the SmartComponent developed is much faster and less complex than the method used today at ÅF Pöyry AB. The downsides of the developed method are the added competence required of the automation engineer and the risk that the digital twin may not be future-proof. / Avdelningen Advanced Manufacturing på ÅF Pöyry AB utforskar möjligheter med ”Virtual Commissioning” och ”Digital Twins”. Som ett led i detta projekt har syftet med detta examensarbete varit att visa ett sätt att utveckla en skalbar, återanvändbar och realistisk digital mekatronisk modell för den virtuella miljön i RobotStudio. Tidigare forskning har visat, i linje med ÅF Pöyry AB:s satsning, att ett av de stora hinder för att Virtual Commissioning ska kunna implementeras som standard i industrin idag är bristen av skalbara och återanvändbara digitala tvillingar. Efter en genomgång av den befintliga och föreslagna metoden för att utveckla digitala tvillingar presenteras de nödvändiga stegen för att utveckla en SmartComponent för RobotStudio, med programmeringsspråket C#. Resultaten av utvecklingen och testen har visat att den utvecklade SmartComponent är skalbar och återanvändbar: den fungerar med gripare oavsett antal fingrar och den tillåter gripning både genom att applicera tryck på plockobjektet från utsidan och insidan. Den är också realistiskt på så vis att interaktionen mellan griparen och objekten som ska plockas i den virtuella miljön beter sig och ser ut som i verkligheten. Implementeringen av den utvecklade SmartComponent är också mycket effektivare och mindre komplex jämfört med den metod som används idag på ÅF Pöyry AB. Nackdelarna med den föreslagna metoden är de extra kompetenskraven för automationsingenjörer och risken att den digitala tvillingen inte är framtidssäker.

The goal of this project was to streamline and automate a business system. This was achieved through the implementation of four subtasks. This report describes what parts of the system that needed to be updated and why. It also describes how the development was carried out and what results the project ultimately led to.   The project's tasks were to: Create a report generator designed to generate Excel documents. Develop a symbol generator where a user, through a web-based interface, could generate symbols. The symbols could then be used in the company's mobile application. Create an interface for a web service, and to develop an add-in for the modeling software Revit Architecture 2014. / Målet med detta projekt var att effektivisera och automatisera ett företagssystem. Detta skulle uppnås genom implementationen av fyra deluppgifter. Denna rapport beskriver vilka delar av systemet som behövde utvecklas och varför. Den beskriver även hur utvecklingen genomfördes samt vilka resultat projektet slutligen ledde till.   Projektets deluppgifter var att: Skapa en rapportgenerator för generering av Excel-dokument. Utveckla en symbolgenerator där man genom ett web-baserat gränssnitt kunde generera symboler avsedda att användas i företagets mobila applikation. Skapa ett gränssnitt för en web-tjänst samt utveckla ett add-in till modelleringsprogrammet Revit Architecture 2014.

Στη παρούσα διπλωματική εργασία, πραγματοποιείται μία ποιοτική επισκόπηση του όρου Σημαντικός Ιστός και των τεχνολογιών αναπαράστασης γνώσης και συμπερασμού που υπόκεινται σε αυτόν, όπως οντολογίες, μέθοδοι και εργαλεία ανάπτυξης οντολογιών, γλώσσες αναπαράστασης οντολογιών καθώς και η επέκταση της εκφραστικότητας των οντολογιών με την προσθήκη κανόνων. Επίσης, γίνεται εκτενής αναφορά σε μία άλλη εξελικτική τάση, που κυριαρχεί στο χώρο του Web, το Web 2.0. Στα πλαίσια του Web 2.0, αναλύονται έννοιες όπως mashups και Web APIs. Ειδικά για την έννοια των Web APIs, γίνεται αναφορά και ανάλυση συγκεκριμένων APIs, όπως αυτά της Amazon και του EBay. Οι έννοιες του Σημαντικού Ιστού και του Web 2.0 παρουσιάζονται πολλές φόρες ως ανταγωνιστικές για το μέλλον του Ιστού. Εντούτοις, γίνεται σαφές όλο και περισσότερο ότι οι δύο αυτές έννοιες είναι συμπληρωματικές. Στα πλαίσια της διπλωματικής εργασίας, αναπτύχθηκε μια εφαρμογή η οποία θα συνδυάζει αυτές τις δύο κυρίαρχες τεχνολογικές τάσεις. Πιο συγκεκριμένα, η εφαρμογή αποτελεί ένα πλαίσιο αναζήτησης βιβλίων από το Amazon και το Half eBay με χαρακτήρα εξατομίκευσης. Για την εφαρμογή, κάθε χρήστης αποτελεί μία αυτόνομη οντότητα. Συνεπώς, το περιεχόμενο της εφαρμογής προσαρμόζεται ανάλογα με το προφίλ του χρήστη κάθε φορά. Η υλοποίηση της εφαρμογής στηρίζεται αποκλειστικά στην ανάπτυξη οντολογιών, στη συγγραφή κανόνων (για την εξατομίκευση), στη δημιουργία ενός mashup και στα Web APIs. Τέλος, να σημειωθεί ότι η εφαρμογή στηρίζεται σε μία κατανεμημένη αρχιτεκτονική 3-επιπέδων. / In the present diploma thesis, one qualitative review is realised for the concepts of Semantic Web and of technologies of representation of knowledge and reasoning that being in this, such as ontologies, methods and tools for ontology development, representation languages of ontologies as well as the extension of expressiveness of ontologies with the addition of rules. Also, it becomes an extensive report in an other evolutionary tendency, that dominates in the space of Web, Web 2.0. In the scope of Web 2.0, concepts such as mashups and Web APIs are analyzed. Specifically for the concept of Web APIs, we make a report and an analysis of concrete APIs, as those of Amazon and EBay. The concepts of Semantic Web and Web 2.0 are presented a lot of times as competitive for the future of Web. Nevertheless, it becomes more and more obvious that these two concepts are complemental. In the scope of these diploma thesis, was developed an application which combines these two dominant technological tendencies. In particular, the application constitutes a framework of searching books from Amazon and Half eBay with a personalised character. For the application, each user constitutes an autonomous entity. Consequently, the content of application is adapted depending on the profile of user each time. The implementation of application is supported exclusively in the ontology development, in the writing of rules (for the personalisation), in the creation of a mashup and in Web APIs. Finally, it is marked that the application is supported in a distributed 3-tier architecture.

No description available.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-25T22:19:38Z No. of bitstreams: 1 SIDERLEY FERNANDES ALBUQUERQUE – TESE (UAEMa) 2015.pdf: 14115544 bytes, checksum: 11822f51a2dc681dc362498cb6b9d1c7 (MD5) / Made available in DSpace on 2018-06-25T22:19:38Z (GMT). No. of bitstreams: 1 SIDERLEY FERNANDES ALBUQUERQUE – TESE (UAEMa) 2015.pdf: 14115544 bytes, checksum: 11822f51a2dc681dc362498cb6b9d1c7 (MD5) Previous issue date: 2015-02-27 / No Brasil, a soldagem de tubulações ainda emprega processos manuais com eletrodo revestido, porém, tem crescido as pesquisas com o objetivo de implementar processos mais produtivos, e que atendam às exigências requeridas por normas específicas. Processos de soldagem robotizados estão sendo largamente utilizados em vários países, com ganho considerável na produtividade, como também na qualidade superficial. A utilização de processos de soldagem automatizados possibilita, além da maior produtividade, um maior controle dos parâmetros de soldagem, podendo favorecer positivamente as transformações microestruturais, e consequentemente, em melhores propriedades mecânicas da junta soldada. O objetivo deste trabalho foi avaliar a tenacidade à fratura de juntas soldadas em chapas aço API 5L X80 com 19 mm de espessura, utilizados para transporte de petróleo e gás, quando submetidos à soldagem robotizada nas posições plana e vertical ascendente, utilizando processo de soldagem a arco elétrico com arame maciço para o passe de raiz (ER 120S-G), e processos de soldagem com arame tubular para os passes de enchimento e acabamento, utilizando arame do tipo flux-cored e proteção de gás externa (E101T-1), e arame do tipo autoprotegido (E91T8-G); o gás de proteção utilizado foi Ar+25%CO2. Foram realizadas análises de microdureza e microestrutural na ZTA das juntas soldadas, utilizando microscopia óptica e microscopia eletrônica de varredura; para avaliação da tenacidade na ZTA das juntas soldadas, foram usinados corpos de prova do tipo SE(B) para ensaio CTOD. A análise microestrutural na ZTA para todos os procedimentos indicam a presença de bainita e ferrita acicular, com exceção do procedimento de soldagem na posição plana utilizando arrame autoprotegido que apresentou ferrita primária. Os resultados de tenacidade a fratura obtidos indicam que os procedimentos de soldagem robotizados na posição plana apresentaram a maioria dos valores de CTOD superiores aos procedimentos de soldagem na posição vertical ascendente. Os procedimentos de soldagem robotizados na posição plana usando arame autoprotegido apresentaram o melhor resultado em termos de crescimento da pré-trinca de fadiga, com perfil na região central de forma arredondada, diferente do procedimento de soldagem na posição plana com RP- G que apresentou a forma plana. / In Brazil, the welding pipes still uses manual processes with coated electrodes, however, research has grown to implementing more productive processes, and complying with the requirements of specific rules. Robotic welding processes are in use in Sweden, USA, Canada, Russia and China, with a considerable increase in productivity, and higher quality welds surface. The use of automated welding processes increase the productivity, and promote better control of the welding parameters, and microstructural changes, and consequently, better mechanical properties of the welded joint. The objective of this study was to evaluate the fracture toughness of API 5L X80 steel welded joints with thickness for 19 mm, used for oil and gas transmission, when subjected to robotic welding in the flat and vertical upward positions using arc electric welding process with solid wire for the root pass (ER 120S-G), and tubular wire for the filler passes and finishing, using flux- cored wire (E101T-1) and Ar + 25% CO2 as shielding gas and self-protected wire (E91T8-G). For this, CTOD specimens with all notched located in HAZ were prepared and submitted to metalographic and microhardness test were also done to observe the resulting microstructure and hardness value in the region of the crack, using optical and scanning microscopy analysis. The microstructural analysis in the ZTA of the specimen for all procedures indicated the presence of Bainite and Acicular Ferrite, except those obtained in flat position using the Flux-Cored Self-Shielded welding process which also presented Primary Ferrite. The results of fracture toughness test indicated that the welding in a flat position presented the most superior CTOD values. The robotic welding procedures in the flat position using Flux-Cored SelfShielded welding process showed the best result in terms of the fatigue pre-crack growth, with profile in the central region of rounded shape, unlike flat shape in the robotic welding procedures in the flat position using Flux-Cored and Ar + 25% CO2 as shielding gas.

Submitted by ISABELA ATILIO null (isabelaatilio@hotmail.com) on 2017-10-31T16:58:11Z No. of bitstreams: 1 Dissertação Final - Isabela Atilio.pdf: 12968588 bytes, checksum: 24d1b58efcf37a8ffc0d9ed1afc4d7d4 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-11-10T19:48:34Z (GMT) No. of bitstreams: 1 atilio_i_me_guara.pdf: 12968588 bytes, checksum: 24d1b58efcf37a8ffc0d9ed1afc4d7d4 (MD5) / Made available in DSpace on 2017-11-10T19:48:34Z (GMT). No. of bitstreams: 1 atilio_i_me_guara.pdf: 12968588 bytes, checksum: 24d1b58efcf37a8ffc0d9ed1afc4d7d4 (MD5) Previous issue date: 2017-09-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O aumento da demanda por petróleo e seus derivados tem instigado o desenvolvimento de materiais para dutos com elevadas tenacidade à fratura e resistência mecânica, como os aços de alta resistência e baixa liga (ARBL) pertencentes às classes API. Aliada à utilização destes aços, a aplicação do processo de soldagem por resistência elétrica de alta frequência (HF/ERW) tem conquistado maior interesse no setor. Entretanto, defeitos nas juntas soldadas constituem uma das principais causas de falhas em dutos, principalmente quando associados às condições externas de operação, o que tem sido motivo para estudos relacionados à integridade estrutural destes tubos. O objetivo deste trabalho foi estudar a tenacidade à fratura de um tubo de aço API 5L X70 soldado pelo processo HF/ERW, a partir de dados obtidos com ensaios CTOD de espécimes de flexão por três pontos, tipo SE(B) “gull wing”. A metodologia proposta envolveu ensaios de CTOD a variadas temperaturas, incluindo a região de transição dúctil-frágil, a fim de avaliar a integridade estrutural do material em condições críticas de operação. Os ensaios foram realizados com base nas normas ASTM E1820 e BS7448, e consistiram na utilização de corpos de prova retirados diretamente da parede do tubo, com posterior planificação. De forma geral, as amostras de material base apresentaram uma boa tenacidade à fratura em todas as temperaturas de ensaio, o que não aconteceu com as amostras de material de solda, que apresentaram baixa tenacidade. Os resultados de tenacidade obtidos mostraram que a metodologia empregada para o estudo da integridade estrutural por meio de ensaios CTOD com amostras extraídas diretamente da parede do tubo, com posterior planificação, mostrou-se adequada. Embora as normas ASTM E1820 e BS7448 adotem diferentes parâmetros para a determinação do valor de CTOD, observou-se que os valores de CTOD foram bem próximos. / The increasing demand for oil and its products has driven the development of materials for ducts with high fracture toughness and high mechanical strength, such as high strength low alloy (HSLA) steels, appertaining to the API classes. In addition to the use of these steels, the application of the high frequency resistance welding process (HF/ERW) has gained greater interest in the sector. However, defects in the welded joints are one of the most causes of failures in pipelines, especially when they are associated with external operating conditions, which has been the reason for studies related to the structural integrity of these tubes. The aim of this work was to study the fracture toughness of an API 5L X70 steel tube welded by the HF/ERW process, from data obtained with CTOD tests bending specimens by three points, type SE (B) gull wing. The proposed methodology involved CTOD tests at various temperatures, including the ductile-brittle transition region, in order to assess the structural integrity of the material under critical operating conditions. The tests were performed based on the ASTM E1820 and BS7448 standards, and consisted of the use of specimens taken directly from the wall of the tube, with subsequent planning. In general, the base material samples showed good fracture toughness at all test temperatures, which did not occur with the samples of welded material, which presented low toughness. The toughness results obtained showed that the methodology used for the study of structural integrity by means of the CTOD tests with samples drawn directly from the wall of the tube, with subsequent planning, was adequate. Although the ASTM E1820 and BS7448 standards adopt different parameters for the determination of the CTOD value, it was observed that the CTOD values were very close.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-27T17:30:21Z No. of bitstreams: 1 JAILSON ALVES DA NÓBREGA - DISSERTAÇÃO PPGEM 2014..pdf: 8059019 bytes, checksum: 3342c79a6597e27674ae52970211493c (MD5) / Made available in DSpace on 2018-04-27T17:30:21Z (GMT). No. of bitstreams: 1 JAILSON ALVES DA NÓBREGA - DISSERTAÇÃO PPGEM 2014..pdf: 8059019 bytes, checksum: 3342c79a6597e27674ae52970211493c (MD5) Previous issue date: 2014-12-03 / Capes / Muitas são as variações metalúrgicas sofridas pelo material quando o mesmo é submetido a um ciclo térmico de soldagem, exercendo uma considerável influência sobre as suas propriedades mecânicas e mais especificamente sobre os níveis de tensões residuais. Na fase de projeto, uma dessas alternativas para a avaliação dos ciclos térmicos e tensões residuais de soldagem é o emprego de simulação via métodos computacionais. A partir disto, neste trabalho foi desenvolvida uma metodologia numérica para determinar o campo de temperatura e tensões residuais transversais em juntas soldadas. As simulações numéricas foram realizadas por meio de um software comercial, ABAQUS®, baseado no Método de Elementos Finitos (MEF). Foram considerados fenômenos que fazem a modelagem matemática do processo de soldagem de forma a torná-la mais robusta. Foi utilizada a fonte de calor analítica proposta por Goldak, capaz de modelar a entrada de calor. Foram avaliados os parâmetros de entrada, tais como: Corrente, voltagem, velocidade de soldagem e temperatura inicial da chapa virtual. Para validação dos resultados térmicos, foi utilizada uma chapa virtual do aço API 5L X70 soldada pelo processo FCAW. Nas demais simulações térmicas e mecânicas foram utilizadas uma chapa virtual do aço API 5L X80 soldadas pelos processos GTAW e SMAW. Foi possível observar neste estudo a influência da temperatura de pré-aquecimento e de interpasse sobre os gradientes térmicos e ciclos térmicos na junta soldada, além das mudanças nos valores das temperaturas de pico e do tempo de resfriamento entre 800 e 500 °C (∆t8/5) quando avaliados em diferentes regiões da junta soldada. Com relação às tensões residuais transversais, verificaram-se mudanças no perfil destas tensões quando aplicado mais de um passe da soldagem virtual podendo o modelo servir de base para trabalhos futuros. / Many are the metallurgical variations suffered by the material when it is subjected to a weld thermal cycle, which promote a considerable influence on mechanical properties, and specifically on the welded joint residual stresses. In the project phase, one of these alternatives is the use of computational methods via simulation. So, in this work a numerical methodology to determine the temperature field and transverse residual stresses was developed. The numerical simulations were implemented using a commercial software ABAQUS® based on finite element method (FEM). In addition, a source of heat proposed by Goldak, able to model the heat input value was used. Input parameters, such as: Current, voltage, speed and initial temperature of the virtual plate were also evaluated. To validate the thermal results and the other thermal and mechanical simulations a virtual plate of API 5L X70 and API 5L X-80 steel welded by the FCAW and GTAW and SMAW processes respectively was used. The results showed that it was possible to evaluate the influence of preheat and interpass temperature on the weld thermal gradients and thermal cycling, as well as the change in peak temperature and cooling time between 800 and 500 (∆t8/5) values in different regions of the welded joint. In relation to the transverse residual stresses, it was showed that there were changes in its profile when it was applied more than one weld pass which can serve as base model for future work in this area.