Resumo O presente trabalho tem como objetivo obter uma ferramenta computacional para estimar os principais parâmetros do processo FSSW para a indústria de construção naval, utilizando uma abordagem em dois estágios, usando os Métodos de Volumes finitos e Elementos Finitos em domínios com simetria de revolução. Soldas experimentais foram realizadas em duas placas de liga de alumínio AA6082 com 3mm de espessura. Da comparação entre os resultados numéricos e experimentais, as temperaturas máximas de 423°C estiveram próximas às reportadas pela literatura. Porém, as medidas experimentais foram afetadas pela posição dos termopares embutidos no suporte de aço, medindo valores máximos inferiores, de 302°C. Os campos de velocidades circunferenciais e suas zonas de altos gradientes foram coincidentes com a zona de mistura revelada no ataque metalográfico. A técnica, não obstante, foi bem sucedida apesar das simplificações adotadas.

Abstract The main goal of the present work is to obtain a computational tool for the shipbuilding industry to estimate the main parameters of the FSSW process, by means of a two phase approach using the Finite Volume Method and the Finite Element Method on a two dimensional domain with symmetry of revolution. Experimental weldments were done on two 3mm thick overlapping plates of AA6082 Aluminum alloy. Upon comparison between numerical and experimental results, the contact conditions were well chosen and the maximum temperatures of 423°C were close to those reported in literature. Nevertheless, the experimental measurements were affected by the position of the thermocouples, into the backing steel plate, resulting in lower maxima of 302°C. Circumferential velocity fields and their high gradients zones were coincident with the mixing zone, revealed in the metallurgical attack. The technique was considered successful despite its simplifications.

Resumo Objetivo Avaliar os resultados do tratamento de 31 tumores de células gigantes da bainha do tendão da mão encontrados entre 2006 e 2015. Métodos Entre fevereiro de 2006 e novembro de 2015, um grupo de pacientes foi selecionado para avaliação retrospectiva, na qual foram estudados e avaliados 31 prontuários de pacientes submetidos a procedimento cirúrgico devido a tumor de células gigantes da bainha do tendão dos dedos da mão. O tratamento preconizado foi a excisão completa do tumor com a preservação das estruturas adjacentes. A confirmação diagnóstica foi feita pelo exame anatomopatológico. Foi avaliada a evolução do tratamento após a cirurgia, principalmente no tocante ao índice de recidivas dos tumores. Resultados Dos 31 pacientes da amostra, houve predomínio do sexo feminino e da etnia branca. O tumor acometeu principalmente indivíduos entre 30 e 50 anos. O lado mais acometido foi o esquerdo, e amaioria dos tumores estava na face flexora. Houve predominância dos dedos radiais, juntamente com sua extremidade distal. Esses pacientes têm sido acompanhados em intervalos regulares em ambulatório. Dos 27 pacientes reavaliados, foram identificados 3 casos de recidiva tumoral. Conclusão Uma técnica cirúrgica adequada é essencial para a prevenção de recidivas do TCGBT. Os resultados obtidos na pesquisa estão em concordância com a literatura atual.

Abstract Objective To evaluate the results of the treatment of 31 giant-cell tumors of the tendon sheath of the hand cared for between 2006 and 2015. Methods A group of patients for the present retrospective evaluation was defined, covering the period between February 2006 and November 2015, in which 31 records of patients who underwent surgery due to cell tumor of the tendon sheath of the fingers were studied and evaluated. The recommended treatment was complete excision of the tumor with preservation of the adjacent structures. The diagnosis was confirmed by pathological examination. The progress of the treatment after surgery was evaluated, especially regarding the rate of tumor recurrence. Results Taking all 31 patients into consideration, there was a predominance of the female gender and white ethnicity. Most of these patients were aged between 30 and 50 years. The most affected side was the left one, and most tumors were in the flexor face. There was a predominance of the radial fingers, along with their distal end. A total of 27 patients are being followed up at regular intervals at an outpatient clinic, and three cases of tumor recurrence have been identified. Conclusion An appropriate surgical technique is essential in order to prevent GCTTS recurrences. The results obtained in this research are in agreement with the literature.

ABSTRACT Friction stir spot welding (FSSW) is a novel process of metal joining. In the present work, the authors analysed the possibility of using this process to solve current problems in shipbuilding industry regarding small vessels by replacing the current arc welding techniques with the aforementioned process. Numerical simulation was carried out by the multiple purpose solver framework for Finite Element Method with a novel modelling approach. The problem was solved using a coupled mechanics system of equations in an axisymmetric continuum where material velocities were calculated in three dimensions, coupled with pressure and thermal fields. The heat source was calculated as a consequence of internal friction dissipation only. Two boundary conditions were analysed, adiabatic and with heat dissipation. Experimental welding tests were performed using a milling machine. Comparison between numerical modelling results and experimental FSSW testing results was done and analysed in detail.

O processo denominado "Friction Stir Welding" (FSW) é um método de soldagem desenvolvido pelo "The Welding Institute" (TWI) na Inglaterra em 1991. O equipamento de soldagem consiste de uma ferramenta que gira e avança ao longo da interface entre duas chapas fixas. A junção é produzida pelo calor gerado por fricção o qual causa o amolecimento de ambos os componentes atingindo uma condição visco-plástica e também pelo escoamento resultante entre as laminas a ser unidas. A modelagem numérica do processo pode fornecer uma predição real das principais variáveis do processo, reduzindo o número de testes experimentais, acelerando, portanto os processos de projeto ao mesmo tempo em que reduz custos e permite a otimização das variáveis tecnológicas envolvidas. Neste trabalho, o processo de soldagem por fricção é modelado empregando um programa de propósito geral baseado no método dos elementos finitos, procurando reproduzir a distribuição térmica e o correspondente escoamento de massa. Os resultados numéricos térmicos são comparados com distribuições termográficas experimentais e os resultados numéricos de escoamento de massa são comparados com aqueles obtidos a partir de técnicas experimentais de visualização, atingindo uma concordância aceitável.

The process of Friction Stir Welding (FSW) is a welding method developed by the "The Welding Institute" (TWI) of England in 1991. The welding equipment consists of a tool that rotates and progresses along the joint of two restrained sheets. The joint is produced by frictional heating which causes the softening of both components into a viscous-plastic condition and also by the resultant flow between the sheets to be joined. Numerical Modeling of the process can provide realistic prediction of the main variables of the process, reducing the number of experimental tests, thus accelerating the design processes while reducing costs and optimizing the involved technological variables. In this study the friction stir welding process is modeled using a general purpose finite element based program, reproducing the material thermal map and the corresponding mass flow. Numerical thermal results are compared against experimental thermographic maps and numerical material flow results are compared with material flow visualization techniques, with acceptable concordance.

Integral capacitors (IC) of one or two-layer printed wiring board (PWB) circuits were produced using comb electrodes fixtures and dielectric composites as the inter-electrode material. ICs were fabricated at laboratory scale, using copper comb electrodes and BaTiO3-epoxy composite materials deposited on a glass-Epoxy FR4 board. They were experimentally tested in order to obtain their electrical response. Furthermore, ICs behaviour was modelled through 2-dimensional models applying finite element method (FEM). Results showed that by this laboratory technique it was possible to obtained integral capacitors with low dielectric losses. Moreover, acceptable agreement was found between numerical and experimental capacitance results for all the different analysed ICs. In conclusion, 2D FEM models are a suitable tool to predict electric response of IC devices.

The present work is aimed to simulate the Friction Stir Welding process as a three-dimensional thermally coupled viscoplastic flow. A Finite Element technique is employed, within the context of a general purpose FEM framework, to provide the temperature distributions and the patterns of plastic flow for the material involved in the welded joints. The computational tool presented here may be of great relevance for technologist seeking to set the process control variables, as they are intended to obtain suitable material properties that yield the adequate on service response of the structural components.

A mathematical pultrusion model of a thermosetting matrix composite is presented. The energy balance was solved by Finite Elements techniques using a program developed for this purpose. This model is applied to describe the temperature and resin conversion profiles along the die. This study was developed considering different pulling velocity, die temperature, different composite and different sections die. The model outcomes are verified through comparison with the experimental results reported in the literature.