129 research outputs found
Projeto integrado como estratégia de desenho fundamentada nas exigencias de desempenho do edifício
From all the participants in the construction process, the design team is the weakest bond. When there is an anomaly inservice or even during the execution of the work, the first step is to find an error in the project. Today, design is almost arisky profession. As the project is not a single, but a summation of specifications, is always possible to find somecontradictory information between of any detail on any of them.As the project is now ultimately responsible for the performance of a building effectiveness, it is essential that thedefinition of the various elements that make up the collection of systems to be built together as an INTEGRATEDSYSTEM. If the search of the solution is sustained in by the various disciplines, it will thus be possible to substantiaterigorously every design decision. However, to manage this joint is necessary to find a common methodology, theINTEGRATED DESIGN. Each project will be part of a unique solution to build a single. Color, lighting, naturalventilation, spatial organization, can be parameterized to jointly define the CONSTRUCTION DESIG.In this article is presented an integrated strategy to articulate the information of the disciplines involved in theconstruction process
Projeto integrado como estratégia de desenho fundamentada nas exigencias de desempenho do edifício
From all the participants in the construction process, the design team is the weakest bond. When there is an anomaly inservice or even during the execution of the work, the first step is to find an error in the project. Today, design is almost arisky profession. As the project is not a single, but a summation of specifications, is always possible to find somecontradictory information between of any detail on any of them.As the project is now ultimately responsible for the performance of a building effectiveness, it is essential that thedefinition of the various elements that make up the collection of systems to be built together as an INTEGRATEDSYSTEM. If the search of the solution is sustained in by the various disciplines, it will thus be possible to substantiaterigorously every design decision. However, to manage this joint is necessary to find a common methodology, theINTEGRATED DESIGN. Each project will be part of a unique solution to build a single. Color, lighting, naturalventilation, spatial organization, can be parameterized to jointly define the CONSTRUCTION DESIG.In this article is presented an integrated strategy to articulate the information of the disciplines involved in theconstruction process
Process and parameters for laser assisted localised heat treatment in manufacturing applications
This paper presents information and results relevant for the development of a laser heat treatment process suitable to improve manufacturing in high strength steel and high strength aluminium alloys. The challenges with manufacturing of such materials include springback effect and localised fracture. The study details heat cycle and their effect in metallurgical state and mechanical properties. Such laser induced heat treatment process is intended to improve the forming behaviour of metal parts in challenging metal forming conditions, in particular for the delay or avoidance of localised fracture. Results for strength, hardness and elongation properties are presented. It was concluded that it is possible to locally modify yield strength and hardness using process duration suitable for industrial applications. Suitable process temperature ranges and target heat cycles were identified. A positive effect of material softening was observed in both hardness and strength properties. However, in some cases a reduction of ductility is apparent which must be considered for targeted industrial applications. The dimension of the heat-affected zone was also considered as design variable for the industrial process development. Preliminary results were obtained in a development forming tool.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The funding support from Projects I&DT SIT – Softening in Tool (CENTRO-02-0853-FEDER-045419) and METRICS (UID/EMS/04077/2020) is acknowledged
Estudo e ensaios experimentais destinados à caracterização do comportamento dinâmico de estruturas mecânicas de transformadores de potência quando sujeitos a curto-circuito
Dissertação de mestrado integrado em Engenharia MecânicaDevido ao crescimento da competitividade do mercado global, ao aumento da
capacidade da rede de distribuição elétrica e das normas mais restritas ao nível do ruído,
os produtores de equipamentos como um transformador de potência, têm de otimizar
constantemente os seus produtos.
A empresa Efacec Energia S.A. não é exceção. Deste modo, o trabalho apresentado,
vem precisamente efetuar uma tentativa de melhoramento estrutural do grande reforço
utilizado pela empresa referida nos seus transformadores de alta potência do tipo-Shell.
Neste trabalho, apresenta-se a seleção de um novo modelo de grande reforço, cuja
geometria e/ou material de fabricação foram alterados para permitir uma redução de
massa e um aumento da eficiência estrutural.
São também apresentados ensaios mecânicos de materiais, para a validação e
determinação dos valores reais das características mecânicas usadas na fabricação destes
componentes. Adicionalmente, os dados gerados por estes ensaios, serão usados em
simulações numéricas para otimização e determinação do comportamento desta estrutura.
Finalmente, neste texto, apresenta-se a caracterização dinâmica do grande reforço,
pela apresentação dos resultados decorrentes de análises modais experimentais e
numéricas. Estes estabelecem que o componente em questão tem frequências naturais,
em corpo livre, próximas das de excitação de um transformador.Due to the increase of competiveness in the global market, the constant increase
of the capacity of power lines and the more restrictive noise policies, the manufacturers of
equipment such as a Power Transformer, have to constantly update their products.
The company Efacec Energia S.A. is no exception. Given this statement, the
information presented in the thesis, shows an attempt to optimize the main frame, used
the referred company in their Shell-type Power Transformers.
In this dissertation, it is shown the selection of a new model of main frame, with a
different internal geometry and/or manufacturing material, in order to reduce mass and
increase structural efficiency.
There are also presented tensile tests to materials used in the manufacturing of the
referred structure, in order to determine and validate their real mechanical characteristics.
Additionally, the generated data will be used in the optimization and the determination of
the dynamic behavior of this structure, recurring it numerical simulations.
There are also presents mechanical testing to materials that are being considered
to substitute the current ones used in the manufacturing of this structure. Additionally, the
generated data will be used to perform numerical simulations, to further optimize and
determine the deformation behavior of the main frame.
Finally, it will be shown the characterization of the dynamic behavior of the main
frame, by the presentation of the information collected by the execution of experimental
and numerical modal analysis. The results of these tests determine that, in free body
conditions, the main frame has resonance frequencies in the proximity of the excitation
frequencies of the power transformer
Edifício do Terminal de Cruzeiros do Porto de Leixões: Acompanhamento dos trabalhos de Fundações e Estruturas de Suporte.
Infraestrutura com mais de um século de história, o Porto de Leixões encontra-se em fase de renovação com a criação de um emblemático Edifício de Terminal de Cruzeiros. Obra de arquitetura arrojada, o edifício é implantado em condições geológico-geotécnicas adversas e na convivência com o efeito da água do mar e das respetivas marés. O presente relatório é relativo a um Estágio realizado na obra numa fase de execução dos trabalhos de fundações e de contenções periféricas (ensecadeira). Apresentam-se as soluções sugeridas em projeto, as soluções apresentadas inicialmente pelo construtor e as alternativas a estas, propostas já durante a obra. Descrevem-se as diferentes soluções, identificando os equipamentos, recursos humanos e procedimentos envolvidos. Comparam-se os respetivos rendimentos e custos. Apresenta-se o Plano de Instrumentação e de Monitorização implementado em obra. Descreve-se em pormenor o trabalho realizado pelo estagiário, em obra, no decurso do estágio.Infrastructure with over a century of history, the Port of Leixões is undergoing renovation with the creation of an iconic Cruise Terminal. Work of bold architecture, the building is located in adverse geological and geotechnical conditions and living with the effects of seawater and the respective flows. The current report is related to a internship. in the construction above mentioned, in the implementation phase of foundations works and peripheral contentions (caisson). It presents the suggested solutions in project, the solutions presented initially by the manufacturer and alternatives to these proposals, developed during the construction. It describes the various approaches, identifying the equipment, manpower and procedures involved. It compares the respective yields and costs. It presents the Instrumentation and Monitoring Plan implemented in work. It describes in detail, the work performed by the trainee, in the construction, during the internship
Desenvolvimento socioeconômico e ICMS ecológico: uma análise da correlação entre o ICMS Ecológico e o IDHM dos municípios brasileiros
O objetivo deste texto é verificar o tipo de correlação entre os índices de desenvolvimento humano municipal e o volume financeiro do repasse per capita recebido pelos municípios dos estados brasileiros onde vigora o ICMS Ecológico (ICMS-E). Os resultados demonstraram que existe uma correlação inversa, estatisticamente significativa, entre o Índice de Desenvolvimento Humano (IDHM) e a dotação de ICMS-E per capita por município: os municípios (e estados) que receberam os maiores valores per capita do repasse ecológico também são aqueles menos desenvolvidos do ponto de vista socioeconômico. Isso significa que, além de estimular a proteção ambiental (objetivo primeiro), o ICMS Ecológico é socialmente progressivo, ou seja, também contribui positivamente para a melhoria da distribuição de renda no país
Desenvolvimento de modelos estatísticos para previsão de concentrações de Ozono
Tese de mestrado integrado. Engenharia Química. Faculdade de Engenharia. Universidade do Porto. 200
Vibration damping and acoustic behavior of PU-filled non-stochastic aluminum cellular solids
Aluminum-based cellular solids are promising lightweight structural materials considering their high specific strength and vibration damping, being potential candidates for future railway vehicles with enhanced riding comfort and low fuel consumption. The filling of these lattices with polymer-based (i.e., polyurethane) foams may further improve the overall vibration/noise-damping without significantly increasing their density. This study explores the dynamic (i.e., frequency response) and acoustic properties of unfilled and polyurethane-filled aluminum cellular solids to characterize their behavior and explore their benefits in terms of vibration and noise-damping. It is shown that polyurethane filling can increase the vibration damping and transmission loss, especially if the infiltration process uses flexible foams. Considering sound reflection, however, it is shown that polyurethane filled samples (0.27–0.30 at 300 Hz) tend to display lower values of sound absorption coefficient relatively to unfilled samples (0.75 at 600 Hz), is this attributed to a reduction in overall porosity, tortuosity and flow resistivity. Foam-filled samples (43–44 dB at 700–1200 Hz) were shown to be more suitable to reduce sound transmission rather than reflection than unfilled samples (21 dB at 700 Hz). It was shown that the morphology of these cellular solids might be optimized depending on the desired application: (i) unfilled aluminum cellular solids are appropriate to mitigate internal noises due to their high sound absorption coefficient; and (ii) PU filled cellular solids are appropriate to prevent exterior noises and vibration damping due to their high transmission loss in a wide range of frequencies and vibration damping.This work was supported by Fundação para a Ciência e a Tecnologia FCT under the
research Doctoral Grant PD/BD/114096/2015, project UIDP/04077/2020 and UIDB/04436/2020,
and Stimulus of Scientific Employment Application CEECIND/03991/2017
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