No abstract

Railways passenger transportation seeks weight reductions as a means to reinforce its sustainability. The use of aluminium alloys for the vehicle car bodies is a possible alternative, but difficulties are foreseen concerning the fatigue behaviour of the connection of heavy equipment to the underside of the structural floor panels. This study was conducted within the LighTRAIN project, involving two universities, two industrial companies and one research centre, that aims to improve the life cycle of the underframe of a passenger railway car, with a novel light-weighted solution. The main objective of present work was to study the fatigue behaviour of 2.0 mm thick aluminium AA6082-T6 welded joints based on two different welding processes: Friction Stir Welding (FSW) manufactured at Instituto Superior Tecnico (IST) and Laser Beam Welding (LBW) manufactured at QUANTAL. The paper presents the experimental results obtained in tensile and fatigue tests of welded lap joints. The specimen types include the loading condition applied to the specimen in a transverse or longitudinal direction to the weld bead. The fatigue tests were carried out under a constant amplitude loading with a stress ratio R=0.1 for a wide range of applied stress. The mechanical behaviour, including microstructural, microhardness, tensile and fatigue tests results of AA6082 2.0 mm thick FSW welded joints are compared with LBW welded joints in the framework of the aforementioned QREN project. Moreover, details of fracture surfaces obtained with optical microscopy are also presented.

Purpose – Friction stir welding lap joints of aluminum alloy AA6082-T6 were joined using two distinct configurations. The purpose of this paper is to study the effect of the welding line direction on the fatigue life of the specimens. For that purpose, specimens with the welding line parallel to the loading direction and with the welding line perpendicular to the loading direction were designed and manufactured. Fatigue tests were performed under constant amplitude load and stress ratio of R=0.1. As shown in previous studies, the hook defect plays a decisive role in the mechanical behavior of the joint, in particular when submitted to fatigue. The specimen geometry with the welding line parallel to the loading direction showed a superior fatigue behavior: for a given number of cycles to rupture, the level of stress is approximately twice as high as for the perpendicular configuration. Design/methodology/approach – Two finite element models were created in order to study the behavior of the welded zone and, in particular, to compare influence of the hook defect in both configurations. Findings – The specimen geometry with the welding line parallel to the loading direction showed a superior fatigue behavior: for a given number of cycles to rupture, the level of stress is approximately twice as high as for the perpendicular configuration. Originality/value – The main objective of this work is to study the effect of the welding line direction on the fatigue life of the specimens. For that purpose, specimens with the welding line parallel to the loading direction and with the welding line perpendicular to the loading direction were designed and manufactured. Fatigue tests were performed under constant amplitude load and stress ratio of R=0.1. As shown in previous studies, the hook defect plays a decisive role in the mechanical behavior of the joint, in particular when submitted to fatigue.

O presente artigo discute a municipalização da política de habitação social no estado do Rio Grande do Norte (RN), analisando as condições administrativas apresentadas pelos municípios do estado que compõem a região do Semiárido para implementar e gerir as estratégias direcionadas ao setor habitacional. Serão consideradas a estrutura administrativa municipal montada para o setor habitacional, as formas alternativas de provisão habitacional, bem como a capacidade financeira dos municípios analisados. A pesquisa envolveu um levantamento de dados e informações a partir das seguintes fontes: MUNIC, o SICONFI e a Plataforma Meu Município. Este artigo possibilitou ampliar uma abordagem crítica sobre a política habitacional no RN, ancorada no levantamento sistemático da política habitacional norte-rio-grandense numa escala analítica pouco explorada: o semiárido brasileiro, considerando-se suas particularidades e fragilidades, fundamentais para o desenho e execução da política habitacional. A análise da política habitacional no semiárido potiguar demonstrou que há um esforço considerável das gestões locais para responder à institucionalização da política. No entanto, a ausência de capacidade financeira e o insuficiente acúmulo de experiência coloca em xeque ações estratégicas de participação, planejamento e de implementação das ações habitacionais. Abstract. This article discusses the municipalization of social housing policy in the state of Rio Grande do Norte (RN), more specifically analyzing the administrative conditions presented by the municipalities of the state that make up the Semiárido region to manage and implement strategies aimed at the housing sector. It considers the municipal administrative structure set up for the housing sector, the alternative forms of housing provision, as well as the financial capacity of the municipalities analyzed. The research involved a survey of data and information in the MUNIC database, SICONFI and in the Meu Município platform. This article made it possible to expand a critical approach to housing policy in RN, anchored in the systematic survey of housing policy in Rio Grande do Norte on an analytical scale that has not been explored: the Brazilian semi-arid region, considering its particularities and weaknesses, which are fundamental for the design and implementation of the policy housing. The analysis of the housing policy in the Potiguar semi-arid region showed that there is a considerable effort by local authorities to respond to the institutionalization of the policy, however, the lack of financial capacity and the lack of accumulated experience makes it difficult to create strategic actions of participation, planning and implementation of housing actions.