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- Optimisation of process and material for cork 3D printingPublication . Vasu, Gowtham Ram; Matias, João ManuelThis report focuses on improving the quality and optimisation of cork material that was produced for applications on additive manufacturing. A brief discussion about different cork composite materials and additive manufacturing methods are stated in this thesis report. Extensive experimental work was performed to explore the characteristics that the cork composite material has to be used as raw material for specific applications. Cork composite material are being tested by varying different variables like mass fraction, volume fraction of core material (Cork) and binder (Polymer resin) added to it. The key variables that influence the properties of material such as print speed of print head (x, y axis) direction, focal distance later thickness and particle size are addressed. Two methods of experiment conducted in this thesis are Manual infill method and 3D additive infill method. Manual method is done by filling up the cork composite inside the mould manually to obtain the final specimen. Where in the 3D additive infill method is done by creating the preform of the composite material using the selective heat sintering method in additive manufacturing process. This preform is created according to the required specimen geometry using design software’s and printed in the 3D printer. Then the printed preform is placed inside the mould to obtain the specimen. Then the specimens obtained from the two different methods are implemented into different mechanical test to obtain the data for calculations. Based on different results from testing and calculations. The best suitable results are derived to enhance the productivity and quality of product
- Assessment of Seismic Behavior of an RC Precast BuildingPublication . Vitorino, Hugo; Batalha, Nadia; Sousa, Romain; Fernandes, Paulo; Varum, Humberto; Rodrigues, HugoPast earthquakes brought attention to the poor performance of precast reinforced concrete structures. One of the problems observed in those structures is related to the beam-to-column connections. The evaluation of different methodologies for the analysis of beam-to-column connections in industrial buildings is an important aspect that should be studied. The numerical analyses developed allowed the study of the effect that different connection properties have on the frequencies of vibration, members drifts, and seismic coefficients. The connection properties were modeled through a macro-element that considers the friction (between concrete–concrete and concrete–neoprene) and the steel dowels. The results showed that the friction between concrete elements and the consideration of the neoprene in the connection has a small impact on the drifts demands in the columns and seismic coefficient of the analyzed structure; on the other hand, the effect of the steel dowel on the drift demand and seismic coefficient is significant. The comparison of the models with different properties and connections allowed a better understanding of the factors with a higher impact on the results.