Browsing by Keyword "Composite"
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Item An Advanced Technological Lightweighted Solution for a Body in White(2016) Cischino, Elena; Di Paolo, Francesca; Mangino, Enrico; Pullini, Daniele; Elizetxea, Cristina; Maestro, Cesar; Alcalde, Estibaliz; Christiansen, Jesper deClaville; POLIMEROSFunded by the EC FP7 Program, EVolution project is using the Pininfarina Nido concept car as a baseline for its activities, with the goal to demonstrate the sustainable production of a full electric 600 kg vehicle (FEV). The project has to be finalized by the end of 2016. The existing Body in White (BiW) has been completely reviewed through a design strategy aiming to reduce the number of parts and using innovative lightweight materials and technologies. The considered Al technologies applied on high performances Al alloys provide the opportunities to obtain components with complex geometries and low thickness, merging different parts into one unique element. Besides, it is possible to process a variable thickness element with a single operation. A “green sand mold” technique allows co-casted joints among elements produced with different Al manufacturing processes. The potential cost reduction and process simplification in terms of time and assembly are promising: current state-of-the-art, based on traditional moulds, does not allow these opportunities. The BiW has been hybridized in certain areas of the underbody with a composite material of the PA family, reinforced with GF. This material has been obtained improving existing ones and developing a production process suitable for scaling to commercial requirements, throughout an advanced sheet thermoforming and 3D-injection method (CaproCAST process). Novel polypropylene nanocomposites (PNC) based on silicate and glass fiber layers demonstrate improved toughness and stiffness and have been selected for crash cross beam and side door. Polyurethane foams based on recycled polymers are explored as sustainable energy-absorbing filling in cross beam sections. Structural epoxy adhesives have been considered to join the BiW parts and welding points are reduced in number: in certain areas spot-welds have been used only to tack the parts during polymerization. In addition to the previous results, current weight of the BiW is 115 kg versus 160 kg of the baseline car. An FE-analysis on the virtual full vehicle indicates a good structural behavior, considering EU standards of crash homologation and global static and dynamic performances. The developed architecture and the integration of lightweight materials will ensure that the EU maintains its competitiveness against the Asian and United States automobile industries. This topic is focused on the results obtained on the BiW in terms of design strategies, Al and composite materials innovative technologies and joining methods.Item Effect of high content nanohydroxyapatite composite scaffolds prepared via melt extrusion additive manufacturing on the osteogenic differentiation of human mesenchymal stromal cells(2022-06) Cámara-Torres, Maria; Sinha, Ravi; Sanchez, Alberto; Habibovic, Pamela; Patelli, Alessandro; Mota, Carlos; Moroni, Lorenzo; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓNThe field of bone tissue engineering seeks to mimic the bone extracellular matrix composition, balancing the organic and inorganic components. In this regard, additive manufacturing (AM) of high content calcium phosphate (CaP)-polymer composites holds great promise towards the design of bioactive scaffolds. Yet, the biological performance of such scaffolds is still poorly characterized. In this study, melt extrusion AM (ME-AM) was used to fabricate poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT)-nanohydroxyapatite (nHA) scaffolds with up to 45 wt% nHA, which presented significantly enhanced compressive mechanical properties, to evaluate their in vitro osteogenic potential as a function of nHA content. While osteogenic gene upregulation and matrix mineralization were observed on all scaffold types when cultured in osteogenic media, human mesenchymal stromal cells did not present an explicitly clear osteogenic phenotype, within the evaluated timeframe, in basic media cultures (i.e. without osteogenic factors). Yet, due to the adsorption of calcium and inorganic phosphate ions from cell culture media and simulated body fluid, the formation of a CaP layer was observed on PEOT/PBT-nHA 45 wt% scaffolds, which is hypothesized to account for their bone forming ability in the long term in vitro, and osteoconductivity in vivo.Item The Influence of Titania Nanoparticles on the Electrodeposition of Ni-Mo-W Composites in Aqueous Electrolytes at Different Electrolyte Temperatures(2022-03-11) Izagirre‐Etxeberria, Usoa; Podlaha, Elizabeth J.; INGENIERÍA DE SUPERFICIESThe electrodeposition of Ni-Mo-W alloys and composites with TiO2 are examined with a rotating Hull cell to better understand the influence of the particle on the deposition composition and morphology. The addition of the TiO2 particle to the electrolyte and deposit, significantly affected the deposit composition when the electrolyte temperature was 650C. Both Ni and Mo composition in the deposit was enhanced, but not due to higher reaction rates. The enhancement was a result of an apparent inhibition by the hydrogen evolving side reaction. The W partial current density was most significantly inhibited. The deposit morphology changed with the addition of TiO2 with a reduction of microcracks compared to the particle-free deposit. The results suggest that the adsorption of the hydrogen intermediate from the side reaction is influenced by the particle, hindering hydrogen desorption, and indirectly affects the partial current densities of the nickel, molybdate and tungstate ion reduction and the morphology.