15 documents found, page 1 of 2
A comparative thermoacoustic insulation study of silica aerogels reinforced wit...
Linhares, Teresa Conceição Amaral; Carneiro, Vítor Hugo Pimenta; Amorim, M. T. Pessoa de; Durães, LuisaSilica aerogels are highly porous materials with exceptional thermal insulation performance. They become even more attractive if combined thermal and acoustic insulation is achieved. Silica aerogel composites reinforced with fibres are an ingenious way to surpass the fragility stemmed from the aerogel’s intrinsic porosity, and textile fibres are good sound absorption materials. Reclaimed fibres are a relatively...
A new methodology to manufacture biodegradable magnesium stents
Lopes, Vítor Emanuel Rebelo; Puga, Hélder; Carneiro, Vítor Hugo PimentaStent manufacturing is usually performed by laser cutting, being both expensive and complex due to the required fine geometric and dimensional details. This is especially relevant in bioabsorbable magnesium alloys due to their high reactivity. This study details the development of a novel methodology to manufacture thin-walled biodegradable magnesium stents. This technique uses additive manufacturing, Yttria-ba...
Optimizing high-volume ultrasonic melt degassing using synchronized kinematic t...
Puga, Hélder; Barbosa, J.; Carneiro, Vítor Hugo Pimenta; Barbosa, Flávia Vieira; Teixeira, J. CarlosUltrasonic vibration is a physical processing technique that has been gathering support as an environmentally friendly approach to degas light alloy melts. Since metallic sonotrodes promote melt inclusions due to erosion, ceramic sonotrodes have also been shown as a viable solution for ultrasonic melt degassing in industrial scales. This study shows that resonant ceramic sonotrodes are characterized by a comple...
Macro-, meso- and microstructural characterization of metallic lattice structur...
Carneiro, Vítor Hugo Pimenta; Rawson, S. D.; Puga, Hélder; Withers, P. J.Cellular materials are recognized for their high specific mechanical properties, making them desirable in ultra-lightweight applications. Periodic lattices have tunable properties and may be manufactured by metallic additive manufacturing (AM) techniques. However, AM can lead to issues with un-melted powder, macro/micro porosity, dimensional control and heterogeneous microstructures. This study overcomes these ...
Vibration damping and acoustic behavior of PU-filled non-stochastic aluminum ce...
Carneiro, Vítor Hugo Pimenta; Puga, Hélder; Meireles, José F.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 increasi...
Manufacturing methodology on casting-based aluminium matrix composites: systema...
Grilo, José Luís Coelho Ferreira; Carneiro, Vítor Hugo Pimenta; Teixeira, J. Carlos; Puga, HélderOngoing industrial demand for lightweight materials has spiked the research interest in aluminium-based metal matrix composites for its specific properties. The amount of scientific publication available on the matter has led to the vast production of knowledge, which highlights the need for a systematic assessment if further progress is expected. In this paper, a systematic review of the published literature i...
Additive manufacturing assisted investment casting: a low-cost method to fabric...
Carneiro, Vítor Hugo Pimenta; Rawson, S. D.; Puga, Hélder; Meireles, José; Withers, P.J.Metallic cellular solids are a class of materials known for their high specific mechanical properties, being desirable in applications where a combination of high strength or stiffness and low density are important. These lightweight materials are often stochastic and manufactured by foaming or casting. If regular (periodic) lattice structures are desired, they may be manufactured by metallic additive manufactu...
The role of acoustic pressure during solidification of AlSi7Mg alloy in sand mo...
Puga, Hélder; Barbosa, J.; Carneiro, Vítor Hugo PimentaNew alloy processes have been developed and casting techniques are continuously evolving. Such constant development implies a consequent development and optimization of melt processing and treatment. The present work proposes a method for studying the influence of acoustic pressure in the overall refinement of sand cast aluminum alloys, using and correlating experimental and numerical approaches. It is shown th...
Positive, zero and negative Poisson’s ratio non-stochastic metallic cellular so...
Carneiro, Vítor Hugo Pimenta; Puga, Hélder; Meireles, José F.Cellular solids are attractive materials due to their high specific static and dynamic mechanical properties. Even though these mechanical domains are interdependent, they are generally studied separately. This study uses a combination of additive manufacturing and vacuum assisted investment casting to manufacture low specific density (0.042 to 0.098) non-stochastic metallic cellular solids. An in-situ unitary ...
Ultrasonic assisted turning of Al alloys: influence of material processing to i...
Puga, Hélder; Grilo, José; Carneiro, Vítor Hugo PimentaUltrasonic machining has been used over a decade to enhance the surface finishing and overall processing characteristics of conventional technologies. The benefits that are usually associated to this approach generate an increasing interest in both academic and industrial fields, especially in the turning operation due to its simple application. In this study, ultrasonic assisted turning is used to study the ef...