Browsing by Author "Marques, Eduardo do Carmo"
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- Characterization of shear strain on PDMS: numerical and experimental approachesPublication . Souza, Andrews; Marques, Eduardo do Carmo; Balsa, Carlos; Ribeiro, J.E.Polydimethylsiloxane (PDMS) is one of the most popular elastomers and has been used in di erent fields, especially in biomechanics research. Among the many interesting features of this material, its hyperelastic behavior stands out, which allows the use of PDMS in various applications, like the ones that mimic soft tissues. However, the hyperelastic behavior is not linear and needs detailed analysis, especially the characterization of shear strain. In this work, two approaches, numerical and experimental, were proposed to characterize the e ect of shear strain on PDMS. The experimental method was implemented as a simple shear testing associated with 3D digital image correlation and was made using two specimens with two thicknesses of PDMS (2 and 4 mm). A finite element software was used to implement the numerical simulations, in which four di erent simulations using the Mooney–Rivlin, Yeoh, Gent, and polynomial hyperelastic constitutive models were performed. These approaches showed that the maximum value of shear strain occurred in the central region of the PDMS, and higher values emerged for the 2 mm PDMS thickness. Qualitatively, in the central area of the specimen, the numerical and experimental results have similar behaviors and the values of shear strain are close. For higher values of displacement and thicknesses, the numerical simulation results move further away from experimental values.
- Estudo numérico do Shot-Peening no alívio de tensões residuais em soldaduras de topo MAG e TIGPublication . Marques, Eduardo do Carmo; Ribeiro, J.E.; Pereira, Alexandre LuizAo longo dos anos, os processos de manufatura industriais que envolvam ciclos térmicos têm crescido, sendo a soldadura um dos mais utilizados. Os métodos mais comuns que garantem fiabilidade em termos estruturais são as técnicas MAG para aços e TIG para ligas de alumínio. Entretanto, devido ao arrefecimento não controlado inerente ao processo, acaba por surgir tensões residuais nas zonas próxima ao cordão, que podem futuramente gerar problemas que levem a falhas mecânicas como trincas e até mesmo rutura. Nessa linha, uma das soluções comerciais, de baixo custo, para aliviar este tipo de comportamento é o tratamento superficial por jateamento de granalhas, mais conhecido por shot-peening. Neste sentido, o presente trabalho tem como objetivo determinar de forma numérica, o nível de tensões residuais antes e pós processo de granalhagem, com enfoque em peças de soldadura de topo simples. Para isto, o estudo envolve componentes analíticas e numéricas para avaliar os fenômenos térmicos e estruturais pós-soldadura. Os materiais utilizados para esta pesquisa foram o aço DIN CK20 e a liga de alumínio 6082-T6, trabalhando com as respetivas propriedades termomecânicas. Como resultado, foi verificado que o jateamento causa o alívio esperado nas tensões próximas à região do cordão, principalmente na direção σz, que se demonstrou ser o estado mais crítico. Além disso, foi utilizado um recurso na simulação térmica de soldadura para simplificar a complexidade do processo e verificou-se que os erros se encontram, em torno de 3~10% para o processo MAG e 15~18% para o TIG.
- The profile of studies on renewable energy in sustainable supply chainPublication . Marques, Eduardo do Carmo; Azevedo-Ferreira, Maxwel de; Hernández-Callejo, Luis; Boloy, Ronney Arismel Mancebo; Guimarães, Vanessa de AlmeidaOver the years, has been growing policies aiming toreducethe green-houses gases emissions–GHG, which lead for the searching ofsustainable alter-native solutions. One waymitigatesthe GHG emissionsisthe use of renewable energy sources. Nevertheless, for the use of such resources there are a series of processes inherent to the energy production and consumption, being the supply chain one of the principals. Based on this, the main objective of present article is tomapthe roleof renewable energies inside the context of sustainable supply chain, observing how the studies have been developed, looking for the main re-searchers, organizations andcollaboration networks, being at final a mapping of the 15 most cited studies in area. The research was carried out with the papers published atWeb of Science database, using VantagePoint software to quantify the information’s, including the evolution of studies over time until 2019.It was possible to perceivethat the researchhasbeen growingsince 2010, moreover, subjects related to biomass, biofuels and photovoltaic energy were the most re-currentat the most cited. However, within this framework, the theme presented itself as new and that there are still great potentials to be explored
- Thermal evaluation of MAG/TIG welding using numerical extension toolPublication . Marques, Eduardo do Carmo; Pereira, Alexandre; Ribeiro, J.E.The manufacturing processes involving thermal transitions have been more used in industries nowadays, being the welding one of the most widely used. The requirement to design and predict adverse conditions are fundamental to the development of any mechanical project. As a result, the market needs have motivated the companies to find faster and more effective solutions, being one of a recent tools an ACT (Ansys Customization Toolkit) called “Moving Heat Source”, in which is executed the Gaussian heat source to model welding and laser processes. Based on this, the present work proposes to evaluate the accuracy of that extension implementing a finite element model for the MAG/TIG welding processes in DINCK20 steel and Al6082-T6 aluminium alloy, comparing with one of the first mathematical model proposed by the literature (Rosenthal) and with a recent analytical method of high precision already validated experimentally. The results showed a smaller global error for MAG process (3~10%) when compared to TIG (15~18%) and, the temperatures measured on the surface of the plate presented errors lower than the bottom in both alloys.